[PATCH v20 00/23] LSM: Module stacking for AppArmor

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Revision v20 of 61 in this series.

63 messages, 7 authors, 2020-09-10 · open the first message on its own page

[PATCH v20 00/23] LSM: Module stacking for AppArmor

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:01:30 

This patchset provides the changes required for
the AppArmor security module to stack safely with any other.

v20: Rebase to 5.9-rc1
     Change the BPF security module to use the lsmblob data. (patch 0002)
     Repair length logic in subject label processing (patch 0015)
     Handle -EINVAL from the empty BPF setprocattr hook (patch 0020)
     Correct length processing in append_ctx() (patch 0022)
v19: Rebase to 5.8-rc6
     Incorporate feedback from v18
     - Revert UDS SO_PEERSEC implementation to use lsmblobs
       directly, rather than allocating as needed. The correct
       treatment of out-of-memory conditions in the later case
       is difficult to define. (patch 0005)
     - Use a size_t in append_ctx() (patch 0021)
     - Fix a memory leak when creating compound contexts. (patch 0021)
     Fix build error when CONFIG_SECURITY isn't set (patch 0013)
     Fix build error when CONFIG_SECURITY isn't set (patch 0020)
     Fix build error when CONFIG_SECURITY isn't set (patch 0021)

v18: Rebase to 5.8-rc3
     Incorporate feedback from v17
     - Null pointer checking in UDS (patch 0005)
     Match changes in IMA code (patch 0012)
     Fix the behavior of LSM context supplimental audit
     records so that there's always exactly one when it's
     appropriate for there to be one. This is a substantial
     change that requires extention of the audit_context beyond
     syscall events. (patch 0020)

v17: Rebase to 5.7-rc4

v16: Rebase to 5.6
     Incorporate feedback from v15 - Thanks Stephen, Mimi and Paul
     - Generally improve commit messages WRT scaffolding
     - Comment ima_lsm_isset() (patch 0002)
     - Some question may remain on IMA warning (patch 0002)
     - Mark lsm_slot as __lsm_ro_after_init not __init_data (patch 0002)
     - Change name of lsmblob variable in ima_match_rules() (patch 0003)
     - Instead of putting a struct lsmblob into the unix_skb_parms
       structure put a pointer to an allocated instance. There is
       currently only space for 5 u32's in unix_skb_parms and it is
       likely to get even tighter. Fortunately, the lifecycle
       management of the allocated lsmblob is simple. (patch 0005)
     - Dropped Acks due to the above change (patch 0005)
     - Improved commentary on secmark labeling scaffolding. (patch 0006)
     - Reduced secmark related labeling scaffolding. (patch 0006)
     - Replace use of the zeroth entry of an lsmblob in scaffolding
       with a function lsmblob_value() to hopefully make it less
       obscure. (patch 0006)
     - Convert security_secmark_relabel_packet to use lsmblob as
       this reduces much of the most contentious scaffolding. (patch 0006)
     - Dropped Acks due to the above change (patch 0006)
     - Added BUILD_BUG_ON() for CIPSO tag 6. (patch 0018)
     - Reworked audit subject information. Instead of adding fields in
       the middle of existing records add a new record to the event. When
       a separate record is required use subj="?". (patch 0020)
     - Dropped Acks due to the above change (patch 0020)
     - Reworked audit object information. Instead of adding fields in
       the middle of existing records add a new record to the event. When
       a separate record is required use obj="?". (patch 0021)
     - Dropped Acks due to the above change (patch 0021)
     - Enhanced documentation (patch 0022)
     - Removed unnecessary error code check in security_getprocattr()
       (patch 0021)

v15: Rebase to 5.6-rc1
     - Revise IMA data use (patch 0002)
     Incorporate feedback from v14
     - Fix lockdown module registration naming (patch 0002)
     - Revise how /proc/self/attr/context is gathered. (patch 0022)
     - Revise access modes on /proc/self/attr/context. (patch 0022)
     - Revise documentation on LSM external interfaces. (patch 0022)

v14: Rebase to 5.5-rc5
     Incorporate feedback from v13
     - Use an array of audit rules (patch 0002)
     - Significant change, removed Acks (patch 0002)
     - Remove unneeded include (patch 0013)
     - Use context.len correctly (patch 0015)
     - Reorder code to be more sensible (patch 0016)
     - Drop SO_PEERCONTEXT as it's not needed yet (patch 0023)

v13: Rebase to 5.5-rc2
     Incorporate feedback from v12
     - Print lsmblob size with %z (Patch 0002)
     - Convert lockdown LSM initialization. (Patch 0002)
     - Restore error check in nft_secmark_compute_secid (Patch 0006)
     - Correct blob scaffolding in ima_must_appraise() (Patch 0009)
     - Make security_setprocattr() clearer (Patch 0013)
     - Use lsm_task_display more widely (Patch 0013)
     - Use passed size in lsmcontext_init() (Patch 0014)
     - Don't add a smack_release_secctx() hook (Patch 0014)
     - Don't print warning in security_release_secctx() (Patch 0014)
     - Don't duplicate the label in nfs4_label_init_security() (Patch 0016)
     - Remove reviewed-by as code has significant change (Patch 0016)
     - Send the entire lsmblob for Tag 6 (Patch 0019)
     - Fix description of socket_getpeersec_stream parameters (Patch 0023)
     - Retain LSMBLOB_FIRST. What was I thinking? (Patch 0023)
     - Add compound context to LSM documentation (Patch 0023)

v12: Rebase to 5.5-rc1
     Fixed a couple of incorrect contractions in the text.

v11: Rebase to 5.4-rc6
     Incorporate feedback from v10
     - Disambiguate reading /proc/.../attr/display by restricting
       all use of the interface to the current process.
     - Fix a merge error in AppArmor's display attribute check

v10: Ask the security modules if the display can be changed.

v9: There is no version 9

v8: Incorporate feedback from v7
    - Minor clean-up in display value management
    - refactor "compound" context creation to use a common
      append_ctx() function.

v7: Incorporate feedback from v6
    - Make setting the display a privileged operation. The
      availability of compound contexts reduces the need for
      setting the display.

v6: Incorporate feedback from v5
    - Add subj_<lsm>= and obj_<lsm>= fields to audit records
    - Add /proc/.../attr/context to get the full context in
      lsmname\0value\0... format as suggested by Simon McVittie
    - Add SO_PEERCONTEXT for getsockopt() to get the full context
      in the same format, also suggested by Simon McVittie.
    - Add /sys/kernel/security/lsm_display_default to provide
      the display default value.

v5: Incorporate feedback from v4
    - Initialize the lsmcontext in security_secid_to_secctx()
    - Clear the lsmcontext in all security_release_secctx() cases
    - Don't use the "display" on strictly internal context
      interfaces.
    - The SELinux binder hooks check for cases where the context
      "display" isn't compatible with SELinux.

v4: Incorporate feedback from v3
    - Mark new lsm_<blob>_alloc functions static
    - Replace the lsm and slot fields of the security_hook_list
      with a pointer to a LSM allocated lsm_id structure. The
      LSM identifies if it needs a slot explicitly. Use the
      lsm_id rather than make security_add_hooks return the
      slot value.
    - Validate slot values used in security.c
    - Reworked the "display" process attribute handling so that
      it works right and doesn't use goofy list processing.
    - fix display value check in dentry_init_security
    - Replace audit_log of secids with '?' instead of deleting
      the audit log

v3: Incorporate feedback from v2
    - Make lsmblob parameter and variable names more
      meaningful, changing "le" and "l" to "blob".
    - Improve consistency of constant naming.
    - Do more sanity checking during LSM initialization.
    - Be a bit clearer about what is temporary scaffolding.
    - Rather than clutter security_getpeersec_dgram with
      otherwise unnecessary checks remove the apparmor
      stub, which does nothing useful.

Patch 0001 moves management of the sock security blob
from the individual modules to the infrastructure.

Patches 0002-0012 replace system use of a "secid" with
a structure "lsmblob" containing information from the
security modules to be held and reused later. At this
point lsmblob contains an array of u32 secids, one "slot"
for each of the security modules compiled into the
kernel that used secids. A "slot" is allocated when
a security module requests one.
The infrastructure is changed to use the slot number
to pass the correct secid to or from the security module
hooks.

It is important that the lsmblob be a fixed size entity
that does not have to be allocated. Several of the places
where it is used would have performance and/or locking
issues with dynamic allocation.

Patch 0013 provides a mechanism for a process to
identify which security module's hooks should be used
when displaying or converting a security context string.
A new interface /proc/self/attr/display contains the name
of the security module to show. Reading from this file
will present the name of the module, while writing to
it will set the value. Only names of active security
modules are accepted. Internally, the name is translated
to the appropriate "slot" number for the module which
is then stored in the task security blob. Setting the
display requires that all modules using the /proc interfaces
allow the transition. The "display" of other processess
can be neither read nor written. All suggested cases
for reading the display of a different process have race
conditions.

Patch 0014 Starts the process of changing how a security
context is represented. Since it is possible for a
security context to have been generated by more than one
security module it is now necessary to note which module
created a security context so that the correct "release"
hook can be called. There are several places where the
module that created a security context cannot be inferred.

This is achieved by introducing a "lsmcontext" structure
which contains the context string, its length and the
"slot" number of the security module that created it.
The security_release_secctx() interface is changed,
replacing the (string,len) pointer pair with a lsmcontext
pointer.

Patches 0015-0017 convert the security interfaces from
(string,len) pointer pairs to a lsmcontext pointer.
The slot number identifying the creating module is
added by the infrastructure. Where the security context
is stored for extended periods the data type is changed.

The Netlabel code is converted to save lsmblob structures
instead of secids in Patch 0018.

Patch 0019 adds checks to the binder hooks which verify
that if both ends of a transaction use the same "display".

Patches 0020-0021 add addition audit records for subject
and object LSM data when there are multiple security modules
with such data. The AUDIT_MAC_TASK_CONTEXTS record is
used in conjuction with a "subj=?" field to identify the
subject data. The AUDIT_MAC_OBJ_CONTEXTS record is used in
conjuction with a "obj=?" field to identify the object data.
The AUDIT_MAC_TASK_CONTEXTS record identifies the security
module with the data: "subj_selinux=xyz_t subj_apparmor=abc".
The AUDIT_MAC_OBJ_CONTEXTS record identifies the security
module with the data: "obj_selinux=xyz_t obj_apparmor=abc".
While AUDIT_MAC_TASK_CONTEXTS records will always contain
an entry for each possible security modules, AUDIT_MAC_OBJ_CONTEXTS
records will only contain entries for security modules for
which the object in question has data.

Patch 0022 adds a new interfaces for getting the
compound security contexts. /proc/self/attr/context

Finally, with all interference on the AppArmor hooks
removed, Patch 0023 removes the exclusive bit from
AppArmor. An unnecessary stub hook was also removed.

The Ubuntu project is using an earlier version of
this patchset in their distribution to enable stacking
for containers.

Performance measurements to date have the change
within the "noise". The sockperf and dbench results
are on the order of 0.2% to 0.8% difference, with
better performance being as common as worse. The
benchmarks were run with AppArmor and Smack on Ubuntu.

https://github.com/cschaufler/lsm-stacking.git#stack-5.8-rc6-a-v19

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---

[PATCH v20 01/23] LSM: Infrastructure management of the sock security

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:02:38 

Move management of the sock->sk_security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/lsm_hooks.h         |  1 +
 security/apparmor/include/net.h   |  6 ++-
 security/apparmor/lsm.c           | 38 ++++-----------
 security/security.c               | 36 +++++++++++++-
 security/selinux/hooks.c          | 78 +++++++++++++++----------------
 security/selinux/include/objsec.h |  5 ++
 security/selinux/netlabel.c       | 23 ++++-----
 security/smack/smack.h            |  5 ++
 security/smack/smack_lsm.c        | 64 ++++++++++++-------------
 security/smack/smack_netfilter.c  |  8 ++--
 10 files changed, 144 insertions(+), 120 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 9e2e3e63719d..cce6e0585dc5 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1550,6 +1550,7 @@ struct lsm_blob_sizes {
 	int	lbs_cred;
 	int	lbs_file;
 	int	lbs_inode;
+	int	lbs_sock;
 	int	lbs_ipc;
 	int	lbs_msg_msg;
 	int	lbs_task;
diff --git a/security/apparmor/include/net.h b/security/apparmor/include/net.h
index 2431c011800d..5b6f52c62058 100644
--- a/security/apparmor/include/net.h
+++ b/security/apparmor/include/net.h
@@ -51,7 +51,11 @@ struct aa_sk_ctx {
 	struct aa_label *peer;
 };
 
-#define SK_CTX(X) ((X)->sk_security)
+static inline struct aa_sk_ctx *aa_sock(const struct sock *sk)
+{
+	return sk->sk_security + apparmor_blob_sizes.lbs_sock;
+}
+
 #define SOCK_ctx(X) SOCK_INODE(X)->i_security
 #define DEFINE_AUDIT_NET(NAME, OP, SK, F, T, P)				  \
 	struct lsm_network_audit NAME ## _net = { .sk = (SK),		  \
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index ffeaee5ed968..f1c365905d5e 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -766,33 +766,15 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo
 	return error;
 }
 
-/**
- * apparmor_sk_alloc_security - allocate and attach the sk_security field
- */
-static int apparmor_sk_alloc_security(struct sock *sk, int family, gfp_t flags)
-{
-	struct aa_sk_ctx *ctx;
-
-	ctx = kzalloc(sizeof(*ctx), flags);
-	if (!ctx)
-		return -ENOMEM;
-
-	SK_CTX(sk) = ctx;
-
-	return 0;
-}
-
 /**
  * apparmor_sk_free_security - free the sk_security field
  */
 static void apparmor_sk_free_security(struct sock *sk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
-	SK_CTX(sk) = NULL;
 	aa_put_label(ctx->label);
 	aa_put_label(ctx->peer);
-	kfree(ctx);
 }
 
 /**
@@ -801,8 +783,8 @@ static void apparmor_sk_free_security(struct sock *sk)
 static void apparmor_sk_clone_security(const struct sock *sk,
 				       struct sock *newsk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
-	struct aa_sk_ctx *new = SK_CTX(newsk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
+	struct aa_sk_ctx *new = aa_sock(newsk);
 
 	if (new->label)
 		aa_put_label(new->label);
@@ -858,7 +840,7 @@ static int apparmor_socket_post_create(struct socket *sock, int family,
 		label = aa_get_current_label();
 
 	if (sock->sk) {
-		struct aa_sk_ctx *ctx = SK_CTX(sock->sk);
+		struct aa_sk_ctx *ctx = aa_sock(sock->sk);
 
 		aa_put_label(ctx->label);
 		ctx->label = aa_get_label(label);
@@ -1043,7 +1025,7 @@ static int apparmor_socket_shutdown(struct socket *sock, int how)
  */
 static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!skb->secmark)
 		return 0;
@@ -1056,7 +1038,7 @@ static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 static struct aa_label *sk_peer_label(struct sock *sk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (ctx->peer)
 		return ctx->peer;
@@ -1140,7 +1122,7 @@ static int apparmor_socket_getpeersec_dgram(struct socket *sock,
  */
 static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!ctx->label)
 		ctx->label = aa_get_current_label();
@@ -1150,7 +1132,7 @@ static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
 static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 				      struct request_sock *req)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!skb->secmark)
 		return 0;
@@ -1167,6 +1149,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
 	.lbs_cred = sizeof(struct aa_task_ctx *),
 	.lbs_file = sizeof(struct aa_file_ctx),
 	.lbs_task = sizeof(struct aa_task_ctx),
+	.lbs_sock = sizeof(struct aa_sk_ctx),
 };
 
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
@@ -1203,7 +1186,6 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 	LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 
-	LSM_HOOK_INIT(sk_alloc_security, apparmor_sk_alloc_security),
 	LSM_HOOK_INIT(sk_free_security, apparmor_sk_free_security),
 	LSM_HOOK_INIT(sk_clone_security, apparmor_sk_clone_security),
 
@@ -1754,7 +1736,7 @@ static unsigned int apparmor_ip_postroute(void *priv,
 	if (sk == NULL)
 		return NF_ACCEPT;
 
-	ctx = SK_CTX(sk);
+	ctx = aa_sock(sk);
 	if (!apparmor_secmark_check(ctx->label, OP_SENDMSG, AA_MAY_SEND,
 				    skb->secmark, sk))
 		return NF_ACCEPT;
diff --git a/security/security.c b/security/security.c
index 70a7ad357bc6..d2366c694cd8 100644
--- a/security/security.c
+++ b/security/security.c
@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/msg.h>
 #include <net/flow.h>
+#include <net/sock.h>
 
 #define MAX_LSM_EVM_XATTR	2
 
@@ -201,6 +202,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
 	lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
 	lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
 	lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
+	lsm_set_blob_size(&needed->lbs_sock, &blob_sizes.lbs_sock);
 	lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
 }
 
@@ -336,6 +338,7 @@ static void __init ordered_lsm_init(void)
 	init_debug("inode blob size    = %d\n", blob_sizes.lbs_inode);
 	init_debug("ipc blob size      = %d\n", blob_sizes.lbs_ipc);
 	init_debug("msg_msg blob size  = %d\n", blob_sizes.lbs_msg_msg);
+	init_debug("sock blob size     = %d\n", blob_sizes.lbs_sock);
 	init_debug("task blob size     = %d\n", blob_sizes.lbs_task);
 
 	/*
@@ -654,6 +657,28 @@ static int lsm_msg_msg_alloc(struct msg_msg *mp)
 	return 0;
 }
 
+/**
+ * lsm_sock_alloc - allocate a composite sock blob
+ * @sock: the sock that needs a blob
+ * @priority: allocation mode
+ *
+ * Allocate the sock blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_sock_alloc(struct sock *sock, gfp_t priority)
+{
+	if (blob_sizes.lbs_sock == 0) {
+		sock->sk_security = NULL;
+		return 0;
+	}
+
+	sock->sk_security = kzalloc(blob_sizes.lbs_sock, priority);
+	if (sock->sk_security == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
 /**
  * lsm_early_task - during initialization allocate a composite task blob
  * @task: the task that needs a blob
@@ -2177,12 +2202,21 @@ EXPORT_SYMBOL(security_socket_getpeersec_dgram);
 
 int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
 {
-	return call_int_hook(sk_alloc_security, 0, sk, family, priority);
+	int rc = lsm_sock_alloc(sk, priority);
+
+	if (unlikely(rc))
+		return rc;
+	rc = call_int_hook(sk_alloc_security, 0, sk, family, priority);
+	if (unlikely(rc))
+		security_sk_free(sk);
+	return rc;
 }
 
 void security_sk_free(struct sock *sk)
 {
 	call_void_hook(sk_free_security, sk);
+	kfree(sk->sk_security);
+	sk->sk_security = NULL;
 }
 
 void security_sk_clone(const struct sock *sk, struct sock *newsk)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ca901025802a..3c7620862c3e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4477,7 +4477,7 @@ static int socket_sockcreate_sid(const struct task_security_struct *tsec,
 
 static int sock_has_perm(struct sock *sk, u32 perms)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 
@@ -4534,7 +4534,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 	isec->initialized = LABEL_INITIALIZED;
 
 	if (sock->sk) {
-		sksec = sock->sk->sk_security;
+		sksec = selinux_sock(sock->sk);
 		sksec->sclass = sclass;
 		sksec->sid = sid;
 		/* Allows detection of the first association on this socket */
@@ -4550,8 +4550,8 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 static int selinux_socket_socketpair(struct socket *socka,
 				     struct socket *sockb)
 {
-	struct sk_security_struct *sksec_a = socka->sk->sk_security;
-	struct sk_security_struct *sksec_b = sockb->sk->sk_security;
+	struct sk_security_struct *sksec_a = selinux_sock(socka->sk);
+	struct sk_security_struct *sksec_b = selinux_sock(sockb->sk);
 
 	sksec_a->peer_sid = sksec_b->sid;
 	sksec_b->peer_sid = sksec_a->sid;
@@ -4566,7 +4566,7 @@ static int selinux_socket_socketpair(struct socket *socka,
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family;
 	int err;
 
@@ -4701,7 +4701,7 @@ static int selinux_socket_connect_helper(struct socket *sock,
 					 struct sockaddr *address, int addrlen)
 {
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 
 	err = sock_has_perm(sk, SOCKET__CONNECT);
@@ -4880,9 +4880,9 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 					      struct sock *other,
 					      struct sock *newsk)
 {
-	struct sk_security_struct *sksec_sock = sock->sk_security;
-	struct sk_security_struct *sksec_other = other->sk_security;
-	struct sk_security_struct *sksec_new = newsk->sk_security;
+	struct sk_security_struct *sksec_sock = selinux_sock(sock);
+	struct sk_security_struct *sksec_other = selinux_sock(other);
+	struct sk_security_struct *sksec_new = selinux_sock(newsk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	int err;
@@ -4914,8 +4914,8 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 static int selinux_socket_unix_may_send(struct socket *sock,
 					struct socket *other)
 {
-	struct sk_security_struct *ssec = sock->sk->sk_security;
-	struct sk_security_struct *osec = other->sk->sk_security;
+	struct sk_security_struct *ssec = selinux_sock(sock->sk);
+	struct sk_security_struct *osec = selinux_sock(other->sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 
@@ -4957,7 +4957,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 				       u16 family)
 {
 	int err = 0;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
@@ -4990,7 +4990,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	int err;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family = sk->sk_family;
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
@@ -5058,13 +5058,15 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	return err;
 }
 
-static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *optval,
-					    int __user *optlen, unsigned len)
+static int selinux_socket_getpeersec_stream(struct socket *sock,
+					    char __user *optval,
+					    int __user *optlen,
+					    unsigned int len)
 {
 	int err = 0;
 	char *scontext;
 	u32 scontext_len;
-	struct sk_security_struct *sksec = sock->sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sock->sk);
 	u32 peer_sid = SECSID_NULL;
 
 	if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
@@ -5124,34 +5126,27 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *
 
 static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
 {
-	struct sk_security_struct *sksec;
-
-	sksec = kzalloc(sizeof(*sksec), priority);
-	if (!sksec)
-		return -ENOMEM;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	sksec->peer_sid = SECINITSID_UNLABELED;
 	sksec->sid = SECINITSID_UNLABELED;
 	sksec->sclass = SECCLASS_SOCKET;
 	selinux_netlbl_sk_security_reset(sksec);
-	sk->sk_security = sksec;
 
 	return 0;
 }
 
 static void selinux_sk_free_security(struct sock *sk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
-	sk->sk_security = NULL;
 	selinux_netlbl_sk_security_free(sksec);
-	kfree(sksec);
 }
 
 static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = sksec->sid;
 	newsksec->peer_sid = sksec->peer_sid;
@@ -5165,7 +5160,7 @@ static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
 	if (!sk)
 		*secid = SECINITSID_ANY_SOCKET;
 	else {
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 
 		*secid = sksec->sid;
 	}
@@ -5175,7 +5170,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 {
 	struct inode_security_struct *isec =
 		inode_security_novalidate(SOCK_INODE(parent));
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||
 	    sk->sk_family == PF_UNIX)
@@ -5190,7 +5185,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 				      struct sk_buff *skb)
 {
-	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(ep->base.sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	u8 peerlbl_active;
@@ -5341,8 +5336,8 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,
 static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
 				  struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	/* If policy does not support SECCLASS_SCTP_SOCKET then call
 	 * the non-sctp clone version.
@@ -5359,7 +5354,7 @@ static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
 static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 				     struct request_sock *req)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 	u16 family = req->rsk_ops->family;
 	u32 connsid;
@@ -5380,7 +5375,7 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 static void selinux_inet_csk_clone(struct sock *newsk,
 				   const struct request_sock *req)
 {
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = req->secid;
 	newsksec->peer_sid = req->peer_secid;
@@ -5397,7 +5392,7 @@ static void selinux_inet_csk_clone(struct sock *newsk,
 static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
 {
 	u16 family = sk->sk_family;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* handle mapped IPv4 packets arriving via IPv6 sockets */
 	if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
@@ -5481,7 +5476,7 @@ static int selinux_tun_dev_attach_queue(void *security)
 static int selinux_tun_dev_attach(struct sock *sk, void *security)
 {
 	struct tun_security_struct *tunsec = security;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* we don't currently perform any NetLabel based labeling here and it
 	 * isn't clear that we would want to do so anyway; while we could apply
@@ -5625,7 +5620,7 @@ static unsigned int selinux_ip_output(struct sk_buff *skb,
 			return NF_ACCEPT;
 
 		/* standard practice, label using the parent socket */
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		sid = sksec->sid;
 	} else
 		sid = SECINITSID_KERNEL;
@@ -5664,7 +5659,7 @@ static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
 
 	if (sk == NULL)
 		return NF_ACCEPT;
-	sksec = sk->sk_security;
+	sksec = selinux_sock(sk);
 
 	ad.type = LSM_AUDIT_DATA_NET;
 	ad.u.net = &net;
@@ -5756,7 +5751,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
 		u32 skb_sid;
 		struct sk_security_struct *sksec;
 
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
 			return NF_DROP;
 		/* At this point, if the returned skb peerlbl is SECSID_NULL
@@ -5785,7 +5780,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
 	} else {
 		/* Locally generated packet, fetch the security label from the
 		 * associated socket. */
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 		peer_sid = sksec->sid;
 		secmark_perm = PACKET__SEND;
 	}
@@ -5850,7 +5845,7 @@ static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 	unsigned int data_len = skb->len;
 	unsigned char *data = skb->data;
 	struct nlmsghdr *nlh;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 sclass = sksec->sclass;
 	u32 perm;
 
@@ -6875,6 +6870,7 @@ struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
 	.lbs_inode = sizeof(struct inode_security_struct),
 	.lbs_ipc = sizeof(struct ipc_security_struct),
 	.lbs_msg_msg = sizeof(struct msg_security_struct),
+	.lbs_sock = sizeof(struct sk_security_struct),
 };
 
 #ifdef CONFIG_PERF_EVENTS
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index 330b7b6d44e0..9ca41988281f 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -189,4 +189,9 @@ static inline u32 current_sid(void)
 	return tsec->sid;
 }
 
+static inline struct sk_security_struct *selinux_sock(const struct sock *sock)
+{
+	return sock->sk_security + selinux_blob_sizes.lbs_sock;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index abaab7683840..6a94b31b5472 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -17,6 +17,7 @@
 #include <linux/gfp.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/lsm_hooks.h>
 #include <net/sock.h>
 #include <net/netlabel.h>
 #include <net/ip.h>
@@ -67,7 +68,7 @@ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
 static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (sksec->nlbl_secattr != NULL)
@@ -100,7 +101,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
 							const struct sock *sk,
 							u32 sid)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr;
 
 	if (secattr == NULL)
@@ -235,7 +236,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 	 * being labeled by it's parent socket, if it is just exit */
 	sk = skb_to_full_sk(skb);
 	if (sk != NULL) {
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 
 		if (sksec->nlbl_state != NLBL_REQSKB)
 			return 0;
@@ -273,7 +274,7 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
 {
 	int rc;
 	struct netlbl_lsm_secattr secattr;
-	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(ep->base.sk);
 	struct sockaddr_in addr4;
 	struct sockaddr_in6 addr6;
 
@@ -352,7 +353,7 @@ int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family)
  */
 void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (family == PF_INET)
 		sksec->nlbl_state = NLBL_LABELED;
@@ -370,8 +371,8 @@ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
  */
 void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->nlbl_state = sksec->nlbl_state;
 }
@@ -389,7 +390,7 @@ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (family != PF_INET && family != PF_INET6)
@@ -504,7 +505,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock,
 {
 	int rc = 0;
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr secattr;
 
 	if (selinux_netlbl_option(level, optname) &&
@@ -542,7 +543,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 						struct sockaddr *addr)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	/* connected sockets are allowed to disconnect when the address family
@@ -581,7 +582,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 int selinux_netlbl_socket_connect_locked(struct sock *sk,
 					 struct sockaddr *addr)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sksec->nlbl_state != NLBL_REQSKB &&
 	    sksec->nlbl_state != NLBL_CONNLABELED)
diff --git a/security/smack/smack.h b/security/smack/smack.h
index e9e817d09785..7481fa71de19 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -364,6 +364,11 @@ static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
 	return ipc->security + smack_blob_sizes.lbs_ipc;
 }
 
+static inline struct socket_smack *smack_sock(const struct sock *sock)
+{
+	return sock->sk_security + smack_blob_sizes.lbs_sock;
+}
+
 /*
  * Is the directory transmuting?
  */
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 8ffbf951b7ed..4f9023f7f219 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1444,7 +1444,7 @@ static int smack_inode_getsecurity(struct inode *inode,
 		if (sock == NULL || sock->sk == NULL)
 			return -EOPNOTSUPP;
 
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 
 		if (strcmp(name, XATTR_SMACK_IPIN) == 0)
 			isp = ssp->smk_in;
@@ -1826,7 +1826,7 @@ static int smack_file_receive(struct file *file)
 
 	if (inode->i_sb->s_magic == SOCKFS_MAGIC) {
 		sock = SOCKET_I(inode);
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		tsp = smack_cred(current_cred());
 		/*
 		 * If the receiving process can't write to the
@@ -2233,11 +2233,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 {
 	struct smack_known *skp = smk_of_current();
-	struct socket_smack *ssp;
-
-	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
-	if (ssp == NULL)
-		return -ENOMEM;
+	struct socket_smack *ssp = smack_sock(sk);
 
 	/*
 	 * Sockets created by kernel threads receive web label.
@@ -2251,11 +2247,10 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 	}
 	ssp->smk_packet = NULL;
 
-	sk->sk_security = ssp;
-
 	return 0;
 }
 
+#ifdef SMACK_IPV6_PORT_LABELING
 /**
  * smack_sk_free_security - Free a socket blob
  * @sk: the socket
@@ -2264,7 +2259,6 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
  */
 static void smack_sk_free_security(struct sock *sk)
 {
-#ifdef SMACK_IPV6_PORT_LABELING
 	struct smk_port_label *spp;
 
 	if (sk->sk_family == PF_INET6) {
@@ -2277,9 +2271,8 @@ static void smack_sk_free_security(struct sock *sk)
 		}
 		rcu_read_unlock();
 	}
-#endif
-	kfree(sk->sk_security);
 }
+#endif
 
 /**
 * smack_ipv4host_label - check host based restrictions
@@ -2395,7 +2388,7 @@ static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip)
 static int smack_netlabel(struct sock *sk, int labeled)
 {
 	struct smack_known *skp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	int rc = 0;
 
 	/*
@@ -2440,7 +2433,7 @@ static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 	int rc;
 	int sk_lbl;
 	struct smack_known *hkp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smk_audit_info ad;
 
 	rcu_read_lock();
@@ -2514,7 +2507,7 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
 {
 	struct sock *sk = sock->sk;
 	struct sockaddr_in6 *addr6;
-	struct socket_smack *ssp = sock->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
 	struct smk_port_label *spp;
 	unsigned short port = 0;
 
@@ -2603,7 +2596,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 				int act)
 {
 	struct smk_port_label *spp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp = NULL;
 	unsigned short port;
 	struct smack_known *object;
@@ -2696,7 +2689,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	if (sock == NULL || sock->sk == NULL)
 		return -EOPNOTSUPP;
 
-	ssp = sock->sk->sk_security;
+	ssp = smack_sock(sock->sk);
 
 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
 		ssp->smk_in = skp;
@@ -2744,7 +2737,7 @@ static int smack_socket_post_create(struct socket *sock, int family,
 	 * Sockets created by kernel threads receive web label.
 	 */
 	if (unlikely(current->flags & PF_KTHREAD)) {
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		ssp->smk_in = &smack_known_web;
 		ssp->smk_out = &smack_known_web;
 	}
@@ -2769,8 +2762,8 @@ static int smack_socket_post_create(struct socket *sock, int family,
 static int smack_socket_socketpair(struct socket *socka,
 		                   struct socket *sockb)
 {
-	struct socket_smack *asp = socka->sk->sk_security;
-	struct socket_smack *bsp = sockb->sk->sk_security;
+	struct socket_smack *asp = smack_sock(socka->sk);
+	struct socket_smack *bsp = smack_sock(sockb->sk);
 
 	asp->smk_packet = bsp->smk_out;
 	bsp->smk_packet = asp->smk_out;
@@ -2833,7 +2826,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
 		if (__is_defined(SMACK_IPV6_SECMARK_LABELING))
 			rsp = smack_ipv6host_label(sip);
 		if (rsp != NULL) {
-			struct socket_smack *ssp = sock->sk->sk_security;
+			struct socket_smack *ssp = smack_sock(sock->sk);
 
 			rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
 					    SMK_CONNECTING);
@@ -3561,9 +3554,9 @@ static int smack_unix_stream_connect(struct sock *sock,
 {
 	struct smack_known *skp;
 	struct smack_known *okp;
-	struct socket_smack *ssp = sock->sk_security;
-	struct socket_smack *osp = other->sk_security;
-	struct socket_smack *nsp = newsk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock);
+	struct socket_smack *osp = smack_sock(other);
+	struct socket_smack *nsp = smack_sock(newsk);
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
@@ -3609,8 +3602,8 @@ static int smack_unix_stream_connect(struct sock *sock,
  */
 static int smack_unix_may_send(struct socket *sock, struct socket *other)
 {
-	struct socket_smack *ssp = sock->sk->sk_security;
-	struct socket_smack *osp = other->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
+	struct socket_smack *osp = smack_sock(other->sk);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -3647,7 +3640,7 @@ static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
 	struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
 #endif
 #ifdef SMACK_IPV6_SECMARK_LABELING
-	struct socket_smack *ssp = sock->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
 	struct smack_known *rsp;
 #endif
 	int rc = 0;
@@ -3820,7 +3813,7 @@ static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
 static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	struct netlbl_lsm_secattr secattr;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp = NULL;
 	int rc = 0;
 	struct smk_audit_info ad;
@@ -3941,7 +3934,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock,
 	int slen = 1;
 	int rc = 0;
 
-	ssp = sock->sk->sk_security;
+	ssp = smack_sock(sock->sk);
 	if (ssp->smk_packet != NULL) {
 		rcp = ssp->smk_packet->smk_known;
 		slen = strlen(rcp) + 1;
@@ -3991,7 +3984,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
 
 	switch (family) {
 	case PF_UNIX:
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		s = ssp->smk_out->smk_secid;
 		break;
 	case PF_INET:
@@ -4004,7 +3997,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
 		 * Translate what netlabel gave us.
 		 */
 		if (sock != NULL && sock->sk != NULL)
-			ssp = sock->sk->sk_security;
+			ssp = smack_sock(sock->sk);
 		netlbl_secattr_init(&secattr);
 		rc = netlbl_skbuff_getattr(skb, family, &secattr);
 		if (rc == 0) {
@@ -4042,7 +4035,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
 	    (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
 		return;
 
-	ssp = sk->sk_security;
+	ssp = smack_sock(sk);
 	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	/* cssp->smk_packet is already set in smack_inet_csk_clone() */
@@ -4062,7 +4055,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 {
 	u16 family = sk->sk_family;
 	struct smack_known *skp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct netlbl_lsm_secattr secattr;
 	struct sockaddr_in addr;
 	struct iphdr *hdr;
@@ -4161,7 +4154,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 static void smack_inet_csk_clone(struct sock *sk,
 				 const struct request_sock *req)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp;
 
 	if (req->peer_secid != 0) {
@@ -4653,6 +4646,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_inode = sizeof(struct inode_smack),
 	.lbs_ipc = sizeof(struct smack_known *),
 	.lbs_msg_msg = sizeof(struct smack_known *),
+	.lbs_sock = sizeof(struct socket_smack),
 };
 
 static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
@@ -4762,7 +4756,9 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream),
 	LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram),
 	LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security),
+#ifdef SMACK_IPV6_PORT_LABELING
 	LSM_HOOK_INIT(sk_free_security, smack_sk_free_security),
+#endif
 	LSM_HOOK_INIT(sock_graft, smack_sock_graft),
 	LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request),
 	LSM_HOOK_INIT(inet_csk_clone, smack_inet_csk_clone),
diff --git a/security/smack/smack_netfilter.c b/security/smack/smack_netfilter.c
index fc7399b45373..635e2339579e 100644
--- a/security/smack/smack_netfilter.c
+++ b/security/smack/smack_netfilter.c
@@ -28,8 +28,8 @@ static unsigned int smack_ipv6_output(void *priv,
 	struct socket_smack *ssp;
 	struct smack_known *skp;
 
-	if (sk && sk->sk_security) {
-		ssp = sk->sk_security;
+	if (sk && smack_sock(sk)) {
+		ssp = smack_sock(sk);
 		skp = ssp->smk_out;
 		skb->secmark = skp->smk_secid;
 	}
@@ -46,8 +46,8 @@ static unsigned int smack_ipv4_output(void *priv,
 	struct socket_smack *ssp;
 	struct smack_known *skp;
 
-	if (sk && sk->sk_security) {
-		ssp = sk->sk_security;
+	if (sk && smack_sock(sk)) {
+		ssp = smack_sock(sk);
 		skp = ssp->smk_out;
 		skb->secmark = skp->smk_secid;
 	}
-- 
2.24.1

[PATCH v20 02/23] LSM: Create and manage the lsmblob data structure.

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:03:44 

When more than one security module is exporting data to
audit and networking sub-systems a single 32 bit integer
is no longer sufficient to represent the data. Add a
structure to be used instead.

The lsmblob structure is currently an array of
u32 "secids". There is an entry for each of the
security modules built into the system that would
use secids if active. The system assigns the module
a "slot" when it registers hooks. If modules are
compiled in but not registered there will be unused
slots.

A new lsm_id structure, which contains the name
of the LSM and its slot number, is created. There
is an instance for each LSM, which assigns the name
and passes it to the infrastructure to set the slot.

The audit rules data is expanded to use an array of
security module data rather than a single instance.
Because IMA uses the audit rule functions it is
affected as well.

Acked-by: Stephen Smalley <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/audit.h               |  4 +-
 include/linux/lsm_hooks.h           | 12 ++++-
 include/linux/security.h            | 67 +++++++++++++++++++++++++--
 kernel/auditfilter.c                | 24 +++++-----
 kernel/auditsc.c                    | 12 ++---
 security/apparmor/lsm.c             |  7 ++-
 security/bpf/hooks.c                | 12 ++++-
 security/commoncap.c                |  7 ++-
 security/integrity/ima/ima_policy.c | 40 +++++++++++-----
 security/loadpin/loadpin.c          |  8 +++-
 security/lockdown/lockdown.c        |  7 ++-
 security/safesetid/lsm.c            |  8 +++-
 security/security.c                 | 72 ++++++++++++++++++++++++-----
 security/selinux/hooks.c            |  8 +++-
 security/smack/smack_lsm.c          |  7 ++-
 security/tomoyo/tomoyo.c            |  8 +++-
 security/yama/yama_lsm.c            |  7 ++-
 17 files changed, 254 insertions(+), 56 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index b3d859831a31..ba1cd38d601b 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -11,6 +11,7 @@
 
 #include <linux/sched.h>
 #include <linux/ptrace.h>
+#include <linux/security.h>
 #include <uapi/linux/audit.h>
 #include <uapi/linux/netfilter/nf_tables.h>
 
@@ -65,8 +66,9 @@ struct audit_field {
 		kuid_t			uid;
 		kgid_t			gid;
 		struct {
+			bool		lsm_isset;
 			char		*lsm_str;
-			void		*lsm_rule;
+			void		*lsm_rules[LSMBLOB_ENTRIES];
 		};
 	};
 	u32				op;
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index cce6e0585dc5..983008c6fede 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1532,6 +1532,14 @@ struct security_hook_heads {
 	#undef LSM_HOOK
 } __randomize_layout;
 
+/*
+ * Information that identifies a security module.
+ */
+struct lsm_id {
+	const char	*lsm;	/* Name of the LSM */
+	int		slot;	/* Slot in lsmblob if one is allocated */
+};
+
 /*
  * Security module hook list structure.
  * For use with generic list macros for common operations.
@@ -1540,7 +1548,7 @@ struct security_hook_list {
 	struct hlist_node		list;
 	struct hlist_head		*head;
 	union security_list_options	hook;
-	char				*lsm;
+	struct lsm_id			*lsmid;
 } __randomize_layout;
 
 /*
@@ -1575,7 +1583,7 @@ extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm);
+			       struct lsm_id *lsmid);
 
 #define LSM_FLAG_LEGACY_MAJOR	BIT(0)
 #define LSM_FLAG_EXCLUSIVE	BIT(1)
diff --git a/include/linux/security.h b/include/linux/security.h
index 0a0a03b36a3b..c91389d7aebc 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -131,6 +131,65 @@ enum lockdown_reason {
 
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
 
+/*
+ * Data exported by the security modules
+ *
+ * Any LSM that provides secid or secctx based hooks must be included.
+ */
+#define LSMBLOB_ENTRIES ( \
+	(IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0))
+
+struct lsmblob {
+	u32     secid[LSMBLOB_ENTRIES];
+};
+
+#define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
+#define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
+#define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+
+/**
+ * lsmblob_init - initialize an lsmblob structure.
+ * @blob: Pointer to the data to initialize
+ * @secid: The initial secid value
+ *
+ * Set all secid for all modules to the specified value.
+ */
+static inline void lsmblob_init(struct lsmblob *blob, u32 secid)
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		blob->secid[i] = secid;
+}
+
+/**
+ * lsmblob_is_set - report if there is an value in the lsmblob
+ * @blob: Pointer to the exported LSM data
+ *
+ * Returns true if there is a secid set, false otherwise
+ */
+static inline bool lsmblob_is_set(struct lsmblob *blob)
+{
+	struct lsmblob empty = {};
+
+	return !!memcmp(blob, &empty, sizeof(*blob));
+}
+
+/**
+ * lsmblob_equal - report if the two lsmblob's are equal
+ * @bloba: Pointer to one LSM data
+ * @blobb: Pointer to the other LSM data
+ *
+ * Returns true if all entries in the two are equal, false otherwise
+ */
+static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
+{
+	return !memcmp(bloba, blobb, sizeof(*bloba));
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -1820,8 +1879,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
 #ifdef CONFIG_SECURITY
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
-void security_audit_rule_free(void *lsmrule);
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule);
+void security_audit_rule_free(void **lsmrule);
 
 #else
 
@@ -1837,12 +1896,12 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
 }
 
 static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
-					    void *lsmrule)
+					    void **lsmrule)
 {
 	return 0;
 }
 
-static inline void security_audit_rule_free(void *lsmrule)
+static inline void security_audit_rule_free(void **lsmrule)
 { }
 
 #endif /* CONFIG_SECURITY */
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index a10e2997aa6c..f9a632ae7be1 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -74,7 +74,7 @@ static void audit_free_lsm_field(struct audit_field *f)
 	case AUDIT_OBJ_LEV_LOW:
 	case AUDIT_OBJ_LEV_HIGH:
 		kfree(f->lsm_str);
-		security_audit_rule_free(f->lsm_rule);
+		security_audit_rule_free(f->lsm_rules);
 	}
 }
 
@@ -519,9 +519,10 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 				goto exit_free;
 			}
 			entry->rule.buflen += f_val;
+			f->lsm_isset = true;
 			f->lsm_str = str;
 			err = security_audit_rule_init(f->type, f->op, str,
-						       (void **)&f->lsm_rule);
+						       f->lsm_rules);
 			/* Keep currently invalid fields around in case they
 			 * become valid after a policy reload. */
 			if (err == -EINVAL) {
@@ -774,7 +775,7 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 	return 0;
 }
 
-/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
+/* Duplicate LSM field information.  The lsm_rules is opaque, so must be
  * re-initialized. */
 static inline int audit_dupe_lsm_field(struct audit_field *df,
 					   struct audit_field *sf)
@@ -788,9 +789,9 @@ static inline int audit_dupe_lsm_field(struct audit_field *df,
 		return -ENOMEM;
 	df->lsm_str = lsm_str;
 
-	/* our own (refreshed) copy of lsm_rule */
+	/* our own (refreshed) copy of lsm_rules */
 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
-				       (void **)&df->lsm_rule);
+				       df->lsm_rules);
 	/* Keep currently invalid fields around in case they
 	 * become valid after a policy reload. */
 	if (ret == -EINVAL) {
@@ -842,7 +843,7 @@ struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 	new->tree = old->tree;
 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 
-	/* deep copy this information, updating the lsm_rule fields, because
+	/* deep copy this information, updating the lsm_rules fields, because
 	 * the originals will all be freed when the old rule is freed. */
 	for (i = 0; i < fcount; i++) {
 		switch (new->fields[i].type) {
@@ -1358,10 +1359,11 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_TYPE:
 			case AUDIT_SUBJ_SEN:
 			case AUDIT_SUBJ_CLR:
-				if (f->lsm_rule) {
+				if (f->lsm_isset) {
 					security_task_getsecid(current, &sid);
 					result = security_audit_rule_match(sid,
-						   f->type, f->op, f->lsm_rule);
+						   f->type, f->op,
+						   f->lsm_rules);
 				}
 				break;
 			case AUDIT_EXE:
@@ -1388,7 +1390,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 	return ret;
 }
 
-static int update_lsm_rule(struct audit_krule *r)
+static int update_lsm_rules(struct audit_krule *r)
 {
 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
 	struct audit_entry *nentry;
@@ -1420,7 +1422,7 @@ static int update_lsm_rule(struct audit_krule *r)
 	return err;
 }
 
-/* This function will re-initialize the lsm_rule field of all applicable rules.
+/* This function will re-initialize the lsm_rules field of all applicable rules.
  * It will traverse the filter lists serarching for rules that contain LSM
  * specific filter fields.  When such a rule is found, it is copied, the
  * LSM field is re-initialized, and the old rule is replaced with the
@@ -1435,7 +1437,7 @@ int audit_update_lsm_rules(void)
 
 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
-			int res = update_lsm_rule(r);
+			int res = update_lsm_rules(r);
 			if (!err)
 				err = res;
 		}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8dba8f0983b5..16e3430f7d07 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -667,14 +667,14 @@ static int audit_filter_rules(struct task_struct *tsk,
 			   match for now to avoid losing information that
 			   may be wanted.   An error message will also be
 			   logged upon error */
-			if (f->lsm_rule) {
+			if (f->lsm_isset) {
 				if (need_sid) {
 					security_task_getsecid(tsk, &sid);
 					need_sid = 0;
 				}
 				result = security_audit_rule_match(sid, f->type,
 								   f->op,
-								   f->lsm_rule);
+								   f->lsm_rules);
 			}
 			break;
 		case AUDIT_OBJ_USER:
@@ -684,21 +684,21 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_OBJ_LEV_HIGH:
 			/* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
 			   also applies here */
-			if (f->lsm_rule) {
+			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
 					result = security_audit_rule_match(
 								name->osid,
 								f->type,
 								f->op,
-								f->lsm_rule);
+								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
 						if (security_audit_rule_match(
 								n->osid,
 								f->type,
 								f->op,
-								f->lsm_rule)) {
+								f->lsm_rules)) {
 							++result;
 							break;
 						}
@@ -709,7 +709,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 					break;
 				if (security_audit_rule_match(ctx->ipc.osid,
 							      f->type, f->op,
-							      f->lsm_rule))
+							      f->lsm_rules))
 					++result;
 			}
 			break;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index f1c365905d5e..432915c1d427 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1152,6 +1152,11 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
 	.lbs_sock = sizeof(struct aa_sk_ctx),
 };
 
+static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
+	.lsm  = "apparmor",
+	.slot = LSMBLOB_NEEDED
+};
+
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -1852,7 +1857,7 @@ static int __init apparmor_init(void)
 		goto buffers_out;
 	}
 	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
-				"apparmor");
+				&apparmor_lsmid);
 
 	/* Report that AppArmor successfully initialized */
 	apparmor_initialized = 1;
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index 32d32d485451..62f4bc6bbe19 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -13,9 +13,19 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
 	#undef LSM_HOOK
 };
 
+/*
+ * slot has to be LSMBLOB_NEEDED because some of the hooks
+ * supplied by this module require a slot.
+ */
+struct lsm_id bpf_lsmid __lsm_ro_after_init = {
+	.lsm = "bpf",
+	.slot = LSMBLOB_NEEDED
+};
+
 static int __init bpf_lsm_init(void)
 {
-	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf");
+	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks),
+			   &bpf_lsmid);
 	pr_info("LSM support for eBPF active\n");
 	return 0;
 }
diff --git a/security/commoncap.c b/security/commoncap.c
index 59bf3c1674c8..959a9f96b7f1 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -1341,6 +1341,11 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
 
 #ifdef CONFIG_SECURITY
 
+static struct lsm_id capability_lsmid __lsm_ro_after_init = {
+	.lsm  = "capability",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(capable, cap_capable),
 	LSM_HOOK_INIT(settime, cap_settime),
@@ -1365,7 +1370,7 @@ static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 static int __init capability_init(void)
 {
 	security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
-				"capability");
+			   &capability_lsmid);
 	return 0;
 }
 
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 07f033634b27..5a647eba96dd 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -73,7 +73,7 @@ struct ima_rule_entry {
 	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
 	int pcr;
 	struct {
-		void *rule;	/* LSM file metadata specific */
+		void *rules[LSMBLOB_ENTRIES]; /* LSM file metadata specific */
 		char *args_p;	/* audit value */
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
@@ -82,6 +82,22 @@ struct ima_rule_entry {
 	struct ima_template_desc *template;
 };
 
+/**
+ * ima_lsm_isset - Is a rule set for any of the active security modules
+ * @rules: The set of IMA rules to check.
+ *
+ * If a rule is set for any LSM return true, otherwise return false.
+ */
+static inline bool ima_lsm_isset(void *rules[])
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		if (rules[i])
+			return true;
+	return false;
+}
+
 /*
  * Without LSM specific knowledge, the default policy can only be
  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
@@ -256,9 +272,11 @@ __setup("ima_appraise_tcb", default_appraise_policy_setup);
 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 {
 	int i;
+	int r;
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		ima_filter_rule_free(entry->lsm[i].rule);
+		for (r = 0; r < LSMBLOB_ENTRIES; r++)
+			ima_filter_rule_free(entry->lsm[i].rules[r]);
 		kfree(entry->lsm[i].args_p);
 	}
 }
@@ -310,8 +328,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 
 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 				     nentry->lsm[i].args_p,
-				     &nentry->lsm[i].rule);
-		if (!nentry->lsm[i].rule)
+				     &nentry->lsm[i].rules[0]);
+		if (!ima_lsm_isset(nentry->lsm[i].rules))
 			pr_warn("rule for LSM \'%s\' is undefined\n",
 				nentry->lsm[i].args_p);
 	}
@@ -483,7 +501,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 		int rc = 0;
 		u32 osid;
 
-		if (!rule->lsm[i].rule) {
+		if (!ima_lsm_isset(rule->lsm[i].rules)) {
 			if (!rule->lsm[i].args_p)
 				continue;
 			else
@@ -496,14 +514,14 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 			security_inode_getsecid(inode, &osid);
 			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rule);
+						   rule->lsm[i].rules);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
 			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rule);
+						   rule->lsm[i].rules);
 		default:
 			break;
 		}
@@ -890,7 +908,7 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 {
 	int result;
 
-	if (entry->lsm[lsm_rule].rule)
+	if (ima_lsm_isset(entry->lsm[lsm_rule].rules))
 		return -EINVAL;
 
 	entry->lsm[lsm_rule].args_p = match_strdup(args);
@@ -900,8 +918,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 	entry->lsm[lsm_rule].type = audit_type;
 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
 				      entry->lsm[lsm_rule].args_p,
-				      &entry->lsm[lsm_rule].rule);
-	if (!entry->lsm[lsm_rule].rule) {
+				      &entry->lsm[lsm_rule].rules[0]);
+	if (!ima_lsm_isset(entry->lsm[lsm_rule].rules)) {
 		pr_warn("rule for LSM \'%s\' is undefined\n",
 			entry->lsm[lsm_rule].args_p);
 
@@ -1681,7 +1699,7 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		if (entry->lsm[i].rule) {
+		if (ima_lsm_isset(entry->lsm[i].rules)) {
 			switch (i) {
 			case LSM_OBJ_USER:
 				seq_printf(m, pt(Opt_obj_user),
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 670a1aebb8a1..494934282d0c 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -181,6 +181,11 @@ static int loadpin_load_data(enum kernel_load_data_id id)
 	return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
 }
 
+static struct lsm_id loadpin_lsmid __lsm_ro_after_init = {
+	.lsm  = "loadpin",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
 	LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
@@ -228,7 +233,8 @@ static int __init loadpin_init(void)
 	pr_info("ready to pin (currently %senforcing)\n",
 		enforce ? "" : "not ");
 	parse_exclude();
-	security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), "loadpin");
+	security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks),
+			   &loadpin_lsmid);
 	return 0;
 }
 
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 87cbdc64d272..4e24ea3f7b7e 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -75,6 +75,11 @@ static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),
 };
 
+static struct lsm_id lockdown_lsmid __lsm_ro_after_init = {
+	.lsm = "lockdown",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static int __init lockdown_lsm_init(void)
 {
 #if defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY)
@@ -83,7 +88,7 @@ static int __init lockdown_lsm_init(void)
 	lock_kernel_down("Kernel configuration", LOCKDOWN_CONFIDENTIALITY_MAX);
 #endif
 	security_add_hooks(lockdown_hooks, ARRAY_SIZE(lockdown_hooks),
-			   "lockdown");
+			   &lockdown_lsmid);
 	return 0;
 }
 
diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
index 7760019ad35d..950dfb7f931e 100644
--- a/security/safesetid/lsm.c
+++ b/security/safesetid/lsm.c
@@ -149,6 +149,11 @@ static int safesetid_task_fix_setuid(struct cred *new,
 	return -EACCES;
 }
 
+static struct lsm_id safesetid_lsmid __lsm_ro_after_init = {
+	.lsm  = "safesetid",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list safesetid_security_hooks[] = {
 	LSM_HOOK_INIT(task_fix_setuid, safesetid_task_fix_setuid),
 	LSM_HOOK_INIT(capable, safesetid_security_capable)
@@ -157,7 +162,8 @@ static struct security_hook_list safesetid_security_hooks[] = {
 static int __init safesetid_security_init(void)
 {
 	security_add_hooks(safesetid_security_hooks,
-			   ARRAY_SIZE(safesetid_security_hooks), "safesetid");
+			   ARRAY_SIZE(safesetid_security_hooks),
+			   &safesetid_lsmid);
 
 	/* Report that SafeSetID successfully initialized */
 	safesetid_initialized = 1;
diff --git a/security/security.c b/security/security.c
index d2366c694cd8..17d701cd7f69 100644
--- a/security/security.c
+++ b/security/security.c
@@ -340,6 +340,7 @@ static void __init ordered_lsm_init(void)
 	init_debug("msg_msg blob size  = %d\n", blob_sizes.lbs_msg_msg);
 	init_debug("sock blob size     = %d\n", blob_sizes.lbs_sock);
 	init_debug("task blob size     = %d\n", blob_sizes.lbs_task);
+	init_debug("lsmblob size       = %zu\n", sizeof(struct lsmblob));
 
 	/*
 	 * Create any kmem_caches needed for blobs
@@ -467,21 +468,36 @@ static int lsm_append(const char *new, char **result)
 	return 0;
 }
 
+/*
+ * Current index to use while initializing the lsmblob secid list.
+ */
+static int lsm_slot __lsm_ro_after_init;
+
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
  * @hooks: the hooks to add
  * @count: the number of hooks to add
- * @lsm: the name of the security module
+ * @lsmid: the the identification information for the security module
  *
  * Each LSM has to register its hooks with the infrastructure.
+ * If the LSM is using hooks that export secids allocate a slot
+ * for it in the lsmblob.
  */
 void __init security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm)
+			       struct lsm_id *lsmid)
 {
 	int i;
 
+	if (lsmid->slot == LSMBLOB_NEEDED) {
+		if (lsm_slot >= LSMBLOB_ENTRIES)
+			panic("%s Too many LSMs registered.\n", __func__);
+		lsmid->slot = lsm_slot++;
+		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
+			   lsmid->slot);
+	}
+
 	for (i = 0; i < count; i++) {
-		hooks[i].lsm = lsm;
+		hooks[i].lsmid = lsmid;
 		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
 	}
 
@@ -490,7 +506,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	 * and fix this up afterwards.
 	 */
 	if (slab_is_available()) {
-		if (lsm_append(lsm, &lsm_names) < 0)
+		if (lsm_append(lsmid->lsm, &lsm_names) < 0)
 			panic("%s - Cannot get early memory.\n", __func__);
 	}
 }
@@ -1989,7 +2005,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 	struct security_hook_list *hp;
 
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
-		if (lsm != NULL && strcmp(lsm, hp->lsm))
+		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
 		return hp->hook.getprocattr(p, name, value);
 	}
@@ -2002,7 +2018,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 	struct security_hook_list *hp;
 
 	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
-		if (lsm != NULL && strcmp(lsm, hp->lsm))
+		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
 		return hp->hook.setprocattr(name, value, size);
 	}
@@ -2494,7 +2510,24 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
-	return call_int_hook(audit_rule_init, 0, field, op, rulestr, lsmrule);
+	struct security_hook_list *hp;
+	bool one_is_good = false;
+	int rc = 0;
+	int trc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		trc = hp->hook.audit_rule_init(field, op, rulestr,
+					       &lsmrule[hp->lsmid->slot]);
+		if (trc == 0)
+			one_is_good = true;
+		else
+			rc = trc;
+	}
+	if (one_is_good)
+		return 0;
+	return rc;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2502,14 +2535,31 @@ int security_audit_rule_known(struct audit_krule *krule)
 	return call_int_hook(audit_rule_known, 0, krule);
 }
 
-void security_audit_rule_free(void *lsmrule)
+void security_audit_rule_free(void **lsmrule)
 {
-	call_void_hook(audit_rule_free, lsmrule);
+	struct security_hook_list *hp;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_free, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.audit_rule_free(lsmrule[hp->lsmid->slot]);
+	}
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
 {
-	return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
+	struct security_hook_list *hp;
+	int rc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.audit_rule_match(secid, field, op,
+					       &lsmrule[hp->lsmid->slot]);
+		if (rc)
+			return rc;
+	}
+	return 0;
 }
 #endif /* CONFIG_AUDIT */
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3c7620862c3e..1172b3f30f99 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6934,6 +6934,11 @@ static int selinux_perf_event_write(struct perf_event *event)
 }
 #endif
 
+static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
+	.lsm  = "selinux",
+	.slot = LSMBLOB_NEEDED
+};
+
 /*
  * IMPORTANT NOTE: When adding new hooks, please be careful to keep this order:
  * 1. any hooks that don't belong to (2.) or (3.) below,
@@ -7245,7 +7250,8 @@ static __init int selinux_init(void)
 
 	hashtab_cache_init();
 
-	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux");
+	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks),
+			   &selinux_lsmid);
 
 	if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
 		panic("SELinux: Unable to register AVC netcache callback\n");
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4f9023f7f219..d4655dec2d70 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4649,6 +4649,11 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_sock = sizeof(struct socket_smack),
 };
 
+static struct lsm_id smack_lsmid __lsm_ro_after_init = {
+	.lsm  = "smack",
+	.slot = LSMBLOB_NEEDED
+};
+
 static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
@@ -4848,7 +4853,7 @@ static __init int smack_init(void)
 	/*
 	 * Register with LSM
 	 */
-	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
+	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), &smack_lsmid);
 	smack_enabled = 1;
 
 	pr_info("Smack:  Initializing.\n");
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 1f3cd432d830..22f62c67f2ec 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -523,6 +523,11 @@ static void tomoyo_task_free(struct task_struct *task)
 	}
 }
 
+static struct lsm_id tomoyo_lsmid __lsm_ro_after_init = {
+	.lsm  = "tomoyo",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 /*
  * tomoyo_security_ops is a "struct security_operations" which is used for
  * registering TOMOYO.
@@ -575,7 +580,8 @@ static int __init tomoyo_init(void)
 	struct tomoyo_task *s = tomoyo_task(current);
 
 	/* register ourselves with the security framework */
-	security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo");
+	security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks),
+			   &tomoyo_lsmid);
 	pr_info("TOMOYO Linux initialized\n");
 	s->domain_info = &tomoyo_kernel_domain;
 	atomic_inc(&tomoyo_kernel_domain.users);
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 536c99646f6a..c582757669f6 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -421,6 +421,11 @@ static int yama_ptrace_traceme(struct task_struct *parent)
 	return rc;
 }
 
+static struct lsm_id yama_lsmid __lsm_ro_after_init = {
+	.lsm  = "yama",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list yama_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, yama_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, yama_ptrace_traceme),
@@ -477,7 +482,7 @@ static inline void yama_init_sysctl(void) { }
 static int __init yama_init(void)
 {
 	pr_info("Yama: becoming mindful.\n");
-	security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), "yama");
+	security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), &yama_lsmid);
 	yama_init_sysctl();
 	return 0;
 }
-- 
2.24.1

[PATCH v20 03/23] LSM: Use lsmblob in security_audit_rule_match

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:04:54 

Change the secid parameter of security_audit_rule_match
to a lsmblob structure pointer. Pass the entry from the
lsmblob structure for the approprite slot to the LSM hook.

Change the users of security_audit_rule_match to use the
lsmblob instead of a u32. The scaffolding function lsmblob_init()
fills the blob with the value of the old secid, ensuring that
it is available to the appropriate module hook. The sources of
the secid, security_task_getsecid() and security_inode_getsecid(),
will be converted to use the blob structure later in the series.
At the point the use of lsmblob_init() is dropped.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h            |  7 ++++---
 kernel/auditfilter.c                |  6 ++++--
 kernel/auditsc.c                    | 14 ++++++++++----
 security/integrity/ima/ima.h        |  4 ++--
 security/integrity/ima/ima_policy.c |  7 +++++--
 security/security.c                 | 10 ++++++++--
 6 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index c91389d7aebc..cbf1eea42e72 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1879,7 +1879,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
 #ifdef CONFIG_SECURITY
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule);
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
+			      void **lsmrule);
 void security_audit_rule_free(void **lsmrule);
 
 #else
@@ -1895,8 +1896,8 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
 	return 0;
 }
 
-static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
-					    void **lsmrule)
+static inline int security_audit_rule_match(struct lsmblob *blob, u32 field,
+					    u32 op, void **lsmrule)
 {
 	return 0;
 }
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index f9a632ae7be1..15a7fb80d6a7 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1331,6 +1331,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 			struct audit_field *f = &e->rule.fields[i];
 			pid_t pid;
 			u32 sid;
+			struct lsmblob blob;
 
 			switch (f->type) {
 			case AUDIT_PID:
@@ -1361,8 +1362,9 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_CLR:
 				if (f->lsm_isset) {
 					security_task_getsecid(current, &sid);
-					result = security_audit_rule_match(sid,
-						   f->type, f->op,
+					lsmblob_init(&blob, sid);
+					result = security_audit_rule_match(
+						   &blob, f->type, f->op,
 						   f->lsm_rules);
 				}
 				break;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 16e3430f7d07..7dd6b815a9eb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -474,6 +474,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 	const struct cred *cred;
 	int i, need_sid = 1;
 	u32 sid;
+	struct lsmblob blob;
 	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
@@ -672,7 +673,9 @@ static int audit_filter_rules(struct task_struct *tsk,
 					security_task_getsecid(tsk, &sid);
 					need_sid = 0;
 				}
-				result = security_audit_rule_match(sid, f->type,
+				lsmblob_init(&blob, sid);
+				result = security_audit_rule_match(&blob,
+								   f->type,
 								   f->op,
 								   f->lsm_rules);
 			}
@@ -687,15 +690,17 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
+					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
-								name->osid,
+								&blob,
 								f->type,
 								f->op,
 								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
+						lsmblob_init(&blob, name->osid);
 						if (security_audit_rule_match(
-								n->osid,
+								&blob,
 								f->type,
 								f->op,
 								f->lsm_rules)) {
@@ -707,7 +712,8 @@ static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				if (security_audit_rule_match(ctx->ipc.osid,
+				lsmblob_init(&blob, ctx->ipc.osid);
+				if (security_audit_rule_match(&blob,
 							      f->type, f->op,
 							      f->lsm_rules))
 					++result;
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 38043074ce5e..d7fe1d5ee8c9 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -429,8 +429,8 @@ static inline void ima_filter_rule_free(void *lsmrule)
 {
 }
 
-static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
-					void *lsmrule)
+static inline int ima_filter_rule_match(struct lsmblob *blob, u32 field,
+					u32 op, void *lsmrule)
 {
 	return -EINVAL;
 }
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5a647eba96dd..3b30105113df 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -500,6 +500,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
 		u32 osid;
+		struct lsmblob lsmdata;
 
 		if (!ima_lsm_isset(rule->lsm[i].rules)) {
 			if (!rule->lsm[i].args_p)
@@ -512,14 +513,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 		case LSM_OBJ_ROLE:
 		case LSM_OBJ_TYPE:
 			security_inode_getsecid(inode, &osid);
-			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
+			lsmblob_init(&lsmdata, osid);
+			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rules);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
-			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
+			lsmblob_init(&lsmdata, secid);
+			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rules);
 		default:
diff --git a/security/security.c b/security/security.c
index 17d701cd7f69..f9a249a93215 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2542,11 +2542,14 @@ void security_audit_rule_free(void **lsmrule)
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_free, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		hp->hook.audit_rule_free(lsmrule[hp->lsmid->slot]);
 	}
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
+			      void **lsmrule)
 {
 	struct security_hook_list *hp;
 	int rc;
@@ -2554,7 +2557,10 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.audit_rule_match(secid, field, op,
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
+		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
+					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
 		if (rc)
 			return rc;
-- 
2.24.1

[PATCH v20 04/23] LSM: Use lsmblob in security_kernel_act_as

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:06:00 

Change the security_kernel_act_as interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its only caller, set_security_override,
to do the same. Change that one's only caller,
set_security_override_from_ctx, to call it with the new
parameter type.

The security module hook is unchanged, still taking a secid.
The infrastructure passes the correct entry from the lsmblob.
lsmblob_init() is used to fill the lsmblob structure, however
this will be removed later in the series when security_secctx_to_secid()
is undated to provide a lsmblob instead of a secid.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/cred.h     |  3 ++-
 include/linux/security.h |  5 +++--
 kernel/cred.c            | 10 ++++++----
 security/security.c      | 14 ++++++++++++--
 4 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/include/linux/cred.h b/include/linux/cred.h
index 18639c069263..03ae0182cba6 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -18,6 +18,7 @@
 
 struct cred;
 struct inode;
+struct lsmblob;
 
 /*
  * COW Supplementary groups list
@@ -165,7 +166,7 @@ extern const struct cred *override_creds(const struct cred *);
 extern void revert_creds(const struct cred *);
 extern struct cred *prepare_kernel_cred(struct task_struct *);
 extern int change_create_files_as(struct cred *, struct inode *);
-extern int set_security_override(struct cred *, u32);
+extern int set_security_override(struct cred *, struct lsmblob *);
 extern int set_security_override_from_ctx(struct cred *, const char *);
 extern int set_create_files_as(struct cred *, struct inode *);
 extern int cred_fscmp(const struct cred *, const struct cred *);
diff --git a/include/linux/security.h b/include/linux/security.h
index cbf1eea42e72..e2ef982b3dd7 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -442,7 +442,7 @@ void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
 void security_cred_getsecid(const struct cred *c, u32 *secid);
-int security_kernel_act_as(struct cred *new, u32 secid);
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
 int security_kernel_load_data(enum kernel_load_data_id id);
@@ -1056,7 +1056,8 @@ static inline void security_transfer_creds(struct cred *new,
 {
 }
 
-static inline int security_kernel_act_as(struct cred *cred, u32 secid)
+static inline int security_kernel_act_as(struct cred *cred,
+					 struct lsmblob *blob)
 {
 	return 0;
 }
diff --git a/kernel/cred.c b/kernel/cred.c
index 421b1149c651..22e0e7cbefde 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -733,14 +733,14 @@ EXPORT_SYMBOL(prepare_kernel_cred);
 /**
  * set_security_override - Set the security ID in a set of credentials
  * @new: The credentials to alter
- * @secid: The LSM security ID to set
+ * @blob: The LSM security information to set
  *
  * Set the LSM security ID in a set of credentials so that the subjective
  * security is overridden when an alternative set of credentials is used.
  */
-int set_security_override(struct cred *new, u32 secid)
+int set_security_override(struct cred *new, struct lsmblob *blob)
 {
-	return security_kernel_act_as(new, secid);
+	return security_kernel_act_as(new, blob);
 }
 EXPORT_SYMBOL(set_security_override);
 
@@ -756,6 +756,7 @@ EXPORT_SYMBOL(set_security_override);
  */
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
+	struct lsmblob blob;
 	u32 secid;
 	int ret;
 
@@ -763,7 +764,8 @@ int set_security_override_from_ctx(struct cred *new, const char *secctx)
 	if (ret < 0)
 		return ret;
 
-	return set_security_override(new, secid);
+	lsmblob_init(&blob, secid);
+	return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
 
diff --git a/security/security.c b/security/security.c
index f9a249a93215..d6d882b1f7d5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1692,9 +1692,19 @@ void security_cred_getsecid(const struct cred *c, u32 *secid)
 }
 EXPORT_SYMBOL(security_cred_getsecid);
 
-int security_kernel_act_as(struct cred *new, u32 secid)
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob)
 {
-	return call_int_hook(kernel_act_as, 0, new, secid);
+	struct security_hook_list *hp;
+	int rc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.kernel_act_as, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.kernel_act_as(new, blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			return rc;
+	}
+	return 0;
 }
 
 int security_kernel_create_files_as(struct cred *new, struct inode *inode)
-- 
2.24.1

[PATCH v20 05/23] net: Prepare UDS for security module stacking

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:07:10 

Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index e2ef982b3dd7..ae623b89cdf4 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1398,7 +1398,8 @@ int security_socket_shutdown(struct socket *sock, int how);
 int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb);
 int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				      int __user *optlen, unsigned len);
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid);
+int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+				     struct lsmblob *blob);
 int security_sk_alloc(struct sock *sk, int family, gfp_t priority);
 void security_sk_free(struct sock *sk);
 void security_sk_clone(const struct sock *sk, struct sock *newsk);
@@ -1536,7 +1537,9 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
 	return -ENOPROTOOPT;
 }
 
-static inline int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
+static inline int security_socket_getpeersec_dgram(struct socket *sock,
+						   struct sk_buff *skb,
+						   struct lsmblob *blob)
 {
 	return -ENOPROTOOPT;
 }
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
 	kgid_t			gid;
 	struct scm_fp_list	*fp;		/* Passed files		*/
 #ifdef CONFIG_SECURITY_NETWORK
-	u32			secid;		/* Security ID		*/
+	struct lsmblob		lsmblob;	/* Security LSM data	*/
 #endif
 	u32			consumed;
 } __randomize_layout;
diff --git a/include/net/scm.h b/include/net/scm.h
index 1ce365f4c256..e2e71c4bf9d0 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -33,7 +33,7 @@ struct scm_cookie {
 	struct scm_fp_list	*fp;		/* Passed files		*/
 	struct scm_creds	creds;		/* Skb credentials	*/
 #ifdef CONFIG_SECURITY_NETWORK
-	u32			secid;		/* Passed security ID 	*/
+	struct lsmblob		lsmblob;	/* Passed LSM data	*/
 #endif
 };
 
@@ -46,7 +46,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
 #ifdef CONFIG_SECURITY_NETWORK
 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
 {
-	security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
+	security_socket_getpeersec_dgram(sock, NULL, &scm->lsmblob);
 }
 #else
 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
@@ -97,7 +97,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
+		/* Scaffolding - it has to be element 0 for now */
+		err = security_secid_to_secctx(scm->lsmblob.secid[0],
+					       &secdata, &seclen);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index d2c223554ff7..551dfbc717e9 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -130,15 +130,17 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
+	struct lsmblob lb;
 	char *secdata;
-	u32 seclen, secid;
+	u32 seclen;
 	int err;
 
-	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
+	err = security_socket_getpeersec_dgram(NULL, skb, &lb);
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(secid, &secdata, &seclen);
+	/* Scaffolding - it has to be element 0 */
+	err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
 	if (err)
 		return;
 
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 181ea6fb56a6..c15668b80d1d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -138,17 +138,17 @@ static struct hlist_head *unix_sockets_unbound(void *addr)
 #ifdef CONFIG_SECURITY_NETWORK
 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	UNIXCB(skb).secid = scm->secid;
+	UNIXCB(skb).lsmblob = scm->lsmblob;
 }
 
 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	scm->secid = UNIXCB(skb).secid;
+	scm->lsmblob = UNIXCB(skb).lsmblob;
 }
 
 static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	return (scm->secid == UNIXCB(skb).secid);
+	return lsmblob_equal(&scm->lsmblob, &(UNIXCB(skb).lsmblob));
 }
 #else
 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
diff --git a/security/security.c b/security/security.c
index d6d882b1f7d5..c42873876954 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2219,10 +2219,22 @@ int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				optval, optlen, len);
 }
 
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
+int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+				     struct lsmblob *blob)
 {
-	return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock,
-			     skb, secid);
+	struct security_hook_list *hp;
+	int rc = -ENOPROTOOPT;
+
+	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_dgram,
+			     list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.socket_getpeersec_dgram(sock, skb,
+						&blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			break;
+	}
+	return rc;
 }
 EXPORT_SYMBOL(security_socket_getpeersec_dgram);
 
-- 
2.24.1

[PATCH v20 06/23] LSM: Use lsmblob in security_secctx_to_secid

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:08:16 

Change security_secctx_to_secid() to fill in a lsmblob instead
of a u32 secid. Multiple LSMs may be able to interpret the
string, and this allows for setting whichever secid is
appropriate. Change security_secmark_relabel_packet() to use a
lsmblob instead of a u32 secid. In some other cases there is
scaffolding where interfaces have yet to be converted.

Reviewed-by: Kees Cook <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 include/linux/security.h          | 30 +++++++++++++++++++++++----
 include/net/scm.h                 |  7 +++++--
 kernel/cred.c                     |  4 +---
 net/ipv4/ip_sockglue.c            |  6 ++++--
 net/netfilter/nft_meta.c          | 18 +++++++++-------
 net/netfilter/xt_SECMARK.c        |  9 ++++++--
 net/netlabel/netlabel_unlabeled.c | 23 +++++++++++++--------
 security/security.c               | 34 ++++++++++++++++++++++++++-----
 8 files changed, 98 insertions(+), 33 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index ae623b89cdf4..f8770c228356 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -190,6 +190,27 @@ static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
 	return !memcmp(bloba, blobb, sizeof(*bloba));
 }
 
+/**
+ * lsmblob_value - find the first non-zero value in an lsmblob structure.
+ * @blob: Pointer to the data
+ *
+ * This needs to be used with extreme caution, as the cases where
+ * it is appropriate are rare.
+ *
+ * Return the first secid value set in the lsmblob.
+ * There should only be one.
+ */
+static inline u32 lsmblob_value(const struct lsmblob *blob)
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		if (blob->secid[i])
+			return blob->secid[i];
+
+	return 0;
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -503,7 +524,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+			     struct lsmblob *blob);
 void security_release_secctx(char *secdata, u32 seclen);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1322,7 +1344,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle
 
 static inline int security_secctx_to_secid(const char *secdata,
 					   u32 seclen,
-					   u32 *secid)
+					   struct lsmblob *blob)
 {
 	return -EOPNOTSUPP;
 }
@@ -1412,7 +1434,7 @@ void security_inet_csk_clone(struct sock *newsk,
 			const struct request_sock *req);
 void security_inet_conn_established(struct sock *sk,
 			struct sk_buff *skb);
-int security_secmark_relabel_packet(u32 secid);
+int security_secmark_relabel_packet(struct lsmblob *blob);
 void security_secmark_refcount_inc(void);
 void security_secmark_refcount_dec(void);
 int security_tun_dev_alloc_security(void **security);
@@ -1585,7 +1607,7 @@ static inline void security_inet_conn_established(struct sock *sk,
 {
 }
 
-static inline int security_secmark_relabel_packet(u32 secid)
+static inline int security_secmark_relabel_packet(struct lsmblob *blob)
 {
 	return 0;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index e2e71c4bf9d0..c09f2dfeec88 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -97,8 +97,11 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		/* Scaffolding - it has to be element 0 for now */
-		err = security_secid_to_secctx(scm->lsmblob.secid[0],
+		/* There can currently be only one value in the lsmblob,
+		 * so getting it from lsmblob_value is appropriate until
+		 * security_secid_to_secctx() is converted to taking a
+		 * lsmblob directly. */
+		err = security_secid_to_secctx(lsmblob_value(&scm->lsmblob),
 					       &secdata, &seclen);
 
 		if (!err) {
diff --git a/kernel/cred.c b/kernel/cred.c
index 22e0e7cbefde..848306c7d823 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -757,14 +757,12 @@ EXPORT_SYMBOL(set_security_override);
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
 	struct lsmblob blob;
-	u32 secid;
 	int ret;
 
-	ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
+	ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
 	if (ret < 0)
 		return ret;
 
-	lsmblob_init(&blob, secid);
 	return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 551dfbc717e9..c568574abfae 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -139,8 +139,10 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	/* Scaffolding - it has to be element 0 */
-	err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
+	/* There can only be one secid in the lsmblob at this point,
+	 * so getting it using lsmblob_value() is sufficient until
+	 * security_secid_to_secctx() is changed to use a lsmblob */
+	err = security_secid_to_secctx(lsmblob_value(&lb), &secdata, &seclen);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 7bc6537f3ccb..7db487d93618 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -801,7 +801,7 @@ struct nft_expr_type nft_meta_type __read_mostly = {
 
 #ifdef CONFIG_NETWORK_SECMARK
 struct nft_secmark {
-	u32 secid;
+	struct lsmblob lsmdata;
 	char *ctx;
 };
 
@@ -811,21 +811,21 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
 
 static int nft_secmark_compute_secid(struct nft_secmark *priv)
 {
-	u32 tmp_secid = 0;
+	struct lsmblob blob;
 	int err;
 
-	err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
+	err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
 	if (err)
 		return err;
 
-	if (!tmp_secid)
+	if (!lsmblob_is_set(&blob))
 		return -ENOENT;
 
-	err = security_secmark_relabel_packet(tmp_secid);
+	err = security_secmark_relabel_packet(&blob);
 	if (err)
 		return err;
 
-	priv->secid = tmp_secid;
+	priv->lsmdata = blob;
 	return 0;
 }
 
@@ -835,7 +835,11 @@ static void nft_secmark_obj_eval(struct nft_object *obj, struct nft_regs *regs,
 	const struct nft_secmark *priv = nft_obj_data(obj);
 	struct sk_buff *skb = pkt->skb;
 
-	skb->secmark = priv->secid;
+	/* It is not possible for more than one secid to be set in
+	 * the lsmblob structure because it is set using
+	 * security_secctx_to_secid(). Any secid that is set must therefore
+	 * be the one that should go in the secmark. */
+	skb->secmark = lsmblob_value(&priv->lsmdata);
 }
 
 static int nft_secmark_obj_init(const struct nft_ctx *ctx,
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index 75625d13e976..5a268707eeda 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -43,13 +43,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
 
 static int checkentry_lsm(struct xt_secmark_target_info *info)
 {
+	struct lsmblob blob;
 	int err;
 
 	info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
 	info->secid = 0;
 
 	err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
-				       &info->secid);
+				       &blob);
 	if (err) {
 		if (err == -EINVAL)
 			pr_info_ratelimited("invalid security context \'%s\'\n",
@@ -57,13 +58,17 @@ static int checkentry_lsm(struct xt_secmark_target_info *info)
 		return err;
 	}
 
+	/* xt_secmark_target_info can't be changed to use lsmblobs because
+	 * it is exposed as an API. Use lsmblob_value() to get the one
+	 * value that got set by security_secctx_to_secid(). */
+	info->secid = lsmblob_value(&blob);
 	if (!info->secid) {
 		pr_info_ratelimited("unable to map security context \'%s\'\n",
 				    info->secctx);
 		return -ENOENT;
 	}
 
-	err = security_secmark_relabel_packet(info->secid);
+	err = security_secmark_relabel_packet(&blob);
 	if (err) {
 		pr_info_ratelimited("unable to obtain relabeling permission\n");
 		return err;
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 77bb1bb22c3b..8948557eaebb 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -882,7 +882,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	void *addr;
 	void *mask;
 	u32 addr_len;
-	u32 secid;
+	struct lsmblob blob;
 	struct netlbl_audit audit_info;
 
 	/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -906,13 +906,18 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	ret_val = security_secctx_to_secid(
 		                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
 				  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-				  &secid);
+				  &blob);
 	if (ret_val != 0)
 		return ret_val;
 
+	/* netlbl_unlhsh_add will be changed to pass a struct lsmblob *
+	 * instead of a u32 later in this patch set. security_secctx_to_secid()
+	 * will only be setting one entry in the lsmblob struct, so it is
+	 * safe to use lsmblob_value() to get that one value. */
+
 	return netlbl_unlhsh_add(&init_net,
-				 dev_name, addr, mask, addr_len, secid,
-				 &audit_info);
+				 dev_name, addr, mask, addr_len,
+				 lsmblob_value(&blob), &audit_info);
 }
 
 /**
@@ -933,7 +938,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	void *addr;
 	void *mask;
 	u32 addr_len;
-	u32 secid;
+	struct lsmblob blob;
 	struct netlbl_audit audit_info;
 
 	/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -955,13 +960,15 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	ret_val = security_secctx_to_secid(
 		                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
 				  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-				  &secid);
+				  &blob);
 	if (ret_val != 0)
 		return ret_val;
 
+	/* security_secctx_to_secid() will only put one secid into the lsmblob
+	 * so it's safe to use lsmblob_value() to get the secid. */
 	return netlbl_unlhsh_add(&init_net,
-				 NULL, addr, mask, addr_len, secid,
-				 &audit_info);
+				 NULL, addr, mask, addr_len,
+				 lsmblob_value(&blob), &audit_info);
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index c42873876954..5c2ed1db0658 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2065,10 +2065,22 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 }
 EXPORT_SYMBOL(security_secid_to_secctx);
 
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+			     struct lsmblob *blob)
 {
-	*secid = 0;
-	return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
+	struct security_hook_list *hp;
+	int rc;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.secctx_to_secid(secdata, seclen,
+					      &blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			return rc;
+	}
+	return 0;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2301,9 +2313,21 @@ void security_inet_conn_established(struct sock *sk,
 }
 EXPORT_SYMBOL(security_inet_conn_established);
 
-int security_secmark_relabel_packet(u32 secid)
+int security_secmark_relabel_packet(struct lsmblob *blob)
 {
-	return call_int_hook(secmark_relabel_packet, 0, secid);
+	struct security_hook_list *hp;
+	int rc = 0;
+
+	hlist_for_each_entry(hp, &security_hook_heads.secmark_relabel_packet,
+			     list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.secmark_relabel_packet(
+						blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			break;
+	}
+	return rc;
 }
 EXPORT_SYMBOL(security_secmark_relabel_packet);
 
-- 
2.24.1

[PATCH v20 07/23] LSM: Use lsmblob in security_secid_to_secctx

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:09:20 

Change security_secid_to_secctx() to take a lsmblob as input
instead of a u32 secid. It will then call the LSM hooks
using the lsmblob element allocated for that module. The
callers have been updated as well. This allows for the
possibility that more than one module may be called upon
to translate a secid to a string, as can occur in the
audit code.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 drivers/android/binder.c                | 12 +++++++++-
 include/linux/security.h                |  5 +++--
 include/net/scm.h                       |  8 ++-----
 kernel/audit.c                          | 20 +++++++++++++++--
 kernel/auditsc.c                        | 28 +++++++++++++++++++----
 net/ipv4/ip_sockglue.c                  |  5 +----
 net/netfilter/nf_conntrack_netlink.c    | 14 ++++++++++--
 net/netfilter/nf_conntrack_standalone.c |  4 +++-
 net/netfilter/nfnetlink_queue.c         | 11 +++++++--
 net/netlabel/netlabel_unlabeled.c       | 30 +++++++++++++++++++++----
 net/netlabel/netlabel_user.c            |  6 ++---
 security/security.c                     | 11 +++++----
 12 files changed, 117 insertions(+), 37 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f936530a19b0..40e5e2f5b516 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3111,10 +3111,20 @@ static void binder_transaction(struct binder_proc *proc,
 
 	if (target_node && target_node->txn_security_ctx) {
 		u32 secid;
+		struct lsmblob blob;
 		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &secid);
-		ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
+		/*
+		 * Later in this patch set security_task_getsecid() will
+		 * provide a lsmblob instead of a secid. lsmblob_init
+		 * is used to ensure that all the secids in the lsmblob
+		 * get the value returned from security_task_getsecid(),
+		 * which means that the one expected by
+		 * security_secid_to_secctx() will be set.
+		 */
+		lsmblob_init(&blob, secid);
+		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/security.h b/include/linux/security.h
index f8770c228356..5c66348d9ab0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -523,7 +523,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
+int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(char *secdata, u32 seclen);
@@ -1337,7 +1337,8 @@ static inline int security_ismaclabel(const char *name)
 	return 0;
 }
 
-static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+static inline int security_secid_to_secctx(struct lsmblob *blob,
+					   char **secdata, u32 *seclen)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index c09f2dfeec88..31ae605fcc0a 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -97,12 +97,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		/* There can currently be only one value in the lsmblob,
-		 * so getting it from lsmblob_value is appropriate until
-		 * security_secid_to_secctx() is converted to taking a
-		 * lsmblob directly. */
-		err = security_secid_to_secctx(lsmblob_value(&scm->lsmblob),
-					       &secdata, &seclen);
+		err = security_secid_to_secctx(&scm->lsmblob, &secdata,
+					       &seclen);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
diff --git a/kernel/audit.c b/kernel/audit.c
index 7efaece534a9..605f5125c844 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1443,7 +1443,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	case AUDIT_SIGNAL_INFO:
 		len = 0;
 		if (audit_sig_sid) {
-			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
+			struct lsmblob blob;
+
+			/*
+			 * lsmblob_init sets all values in the lsmblob
+			 * to audit_sig_sid. This is temporary until
+			 * audit_sig_sid is converted to a lsmblob, which
+			 * happens later in this patch set.
+			 */
+			lsmblob_init(&blob, audit_sig_sid);
+			err = security_secid_to_secctx(&blob, &ctx, &len);
 			if (err)
 				return err;
 		}
@@ -2129,12 +2138,19 @@ int audit_log_task_context(struct audit_buffer *ab)
 	unsigned len;
 	int error;
 	u32 sid;
+	struct lsmblob blob;
 
 	security_task_getsecid(current, &sid);
 	if (!sid)
 		return 0;
 
-	error = security_secid_to_secctx(sid, &ctx, &len);
+	/*
+	 * lsmblob_init sets all values in the lsmblob to sid.
+	 * This is temporary until security_task_getsecid is converted
+	 * to use a lsmblob, which happens later in this patch set.
+	 */
+	lsmblob_init(&blob, sid);
+	error = security_secid_to_secctx(&blob, &ctx, &len);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 7dd6b815a9eb..5f9bdd62f78d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -673,6 +673,13 @@ static int audit_filter_rules(struct task_struct *tsk,
 					security_task_getsecid(tsk, &sid);
 					need_sid = 0;
 				}
+				/*
+				 * lsmblob_init sets all values in the lsmblob
+				 * to sid. This is temporary until
+				 * security_task_getsecid() is converted to
+				 * provide a lsmblob, which happens later in
+				 * this patch set.
+				 */
 				lsmblob_init(&blob, sid);
 				result = security_audit_rule_match(&blob,
 								   f->type,
@@ -690,6 +697,13 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
+					/*
+					 * lsmblob_init sets all values in the
+					 * lsmblob to sid. This is temporary
+					 * until name->osid is converted to a
+					 * lsmblob, which happens later in
+					 * this patch set.
+					 */
 					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
 								&blob,
@@ -995,6 +1009,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
+	struct lsmblob blob;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
 	if (!ab)
@@ -1004,7 +1019,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (sid) {
-		if (security_secid_to_secctx(sid, &ctx, &len)) {
+		lsmblob_init(&blob, sid);
+		if (security_secid_to_secctx(&blob, &ctx, &len)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1247,7 +1263,10 @@ static void show_special(struct audit_context *context, int *call_panic)
 		if (osid) {
 			char *ctx = NULL;
 			u32 len;
-			if (security_secid_to_secctx(osid, &ctx, &len)) {
+			struct lsmblob blob;
+
+			lsmblob_init(&blob, osid);
+			if (security_secid_to_secctx(&blob, &ctx, &len)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1397,9 +1416,10 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 	if (n->osid != 0) {
 		char *ctx = NULL;
 		u32 len;
+		struct lsmblob blob;
 
-		if (security_secid_to_secctx(
-			n->osid, &ctx, &len)) {
+		lsmblob_init(&blob, n->osid);
+		if (security_secid_to_secctx(&blob, &ctx, &len)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index c568574abfae..c235c57d7469 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -139,10 +139,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	/* There can only be one secid in the lsmblob at this point,
-	 * so getting it using lsmblob_value() is sufficient until
-	 * security_secid_to_secctx() is changed to use a lsmblob */
-	err = security_secid_to_secctx(lsmblob_value(&lb), &secdata, &seclen);
+	err = security_secid_to_secctx(&lb, &secdata, &seclen);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 832eabecfbdd..380b660d0d39 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -333,8 +333,13 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	struct nlattr *nest_secctx;
 	int len, ret;
 	char *secctx;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
+	 * security_secid_to_secctx() will know which security module
+	 * to use to create the secctx.  */
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, &secctx, &len);
 	if (ret)
 		return 0;
 
@@ -647,8 +652,13 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 {
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 	int len, ret;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, NULL, &len);
+	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
+	 * security_secid_to_secctx() will know which security module
+	 * to use to create the secctx.  */
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, NULL, &len);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index a604f43e3e6b..18376e68fea6 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -175,8 +175,10 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	int ret;
 	u32 len;
 	char *secctx;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, &secctx, &len);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index dadfc06245a3..7b00dc833a31 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -305,13 +305,20 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 {
 	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
+	struct lsmblob blob;
+
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
 
 	read_lock_bh(&skb->sk->sk_callback_lock);
 
-	if (skb->secmark)
-		security_secid_to_secctx(skb->secmark, secdata, &seclen);
+	if (skb->secmark) {
+		/* lsmblob_init() puts ct->secmark into all of the secids in
+		 * blob. security_secid_to_secctx() will know which security
+		 * module to use to create the secctx.  */
+		lsmblob_init(&blob, skb->secmark);
+		security_secid_to_secctx(&blob, secdata, &seclen);
+	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
 #endif
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 8948557eaebb..2ebe29ddf05e 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -376,6 +376,7 @@ int netlbl_unlhsh_add(struct net *net,
 	struct audit_buffer *audit_buf = NULL;
 	char *secctx = NULL;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
 	    addr_len != sizeof(struct in6_addr))
@@ -438,7 +439,11 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(secid,
+		/* lsmblob_init() puts secid into all of the secids in blob.
+		 * security_secid_to_secctx() will know which security module
+		 * to use to create the secctx.  */
+		lsmblob_init(&blob, secid);
+		if (security_secid_to_secctx(&blob,
 					     &secctx,
 					     &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
@@ -475,6 +480,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct net_device *dev;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
@@ -494,8 +500,13 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		if (dev != NULL)
 			dev_put(dev);
+		/* lsmblob_init() puts entry->secid into all of the secids
+		 * in blob. security_secid_to_secctx() will know which
+		 * security module to use to create the secctx.  */
+		if (entry != NULL)
+			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
+		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
@@ -537,6 +548,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct net_device *dev;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
@@ -555,8 +567,13 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		if (dev != NULL)
 			dev_put(dev);
+		/* lsmblob_init() puts entry->secid into all of the secids
+		 * in blob. security_secid_to_secctx() will know which
+		 * security module to use to create the secctx.  */
+		if (entry != NULL)
+			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
+		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
@@ -1082,6 +1099,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	u32 secid;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
 			   cb_arg->seq, &netlbl_unlabel_gnl_family,
@@ -1136,7 +1154,11 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		secid = addr6->secid;
 	}
 
-	ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len);
+        /* lsmblob_init() secid into all of the secids in blob.
+         * security_secid_to_secctx() will know which security module
+         * to use to create the secctx.  */
+	lsmblob_init(&blob, secid);
+	ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 3ed4fea2a2de..893301ae0131 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -86,6 +86,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 	struct audit_buffer *audit_buf;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
@@ -98,10 +99,9 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
+	lsmblob_init(&blob, audit_info->secid);
 	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(audit_info->secid,
-				     &secctx,
-				     &secctx_len) == 0) {
+	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
 		audit_log_format(audit_buf, " subj=%s", secctx);
 		security_release_secctx(secctx, secctx_len);
 	}
diff --git a/security/security.c b/security/security.c
index 5c2ed1db0658..ce0934395c53 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2046,17 +2046,16 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
 {
 	struct security_hook_list *hp;
 	int rc;
 
-	/*
-	 * Currently, only one LSM can implement secid_to_secctx (i.e this
-	 * LSM hook is not "stackable").
-	 */
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
-		rc = hp->hook.secid_to_secctx(secid, secdata, seclen);
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
+					      secdata, seclen);
 		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
 			return rc;
 	}
-- 
2.24.1

[PATCH v20 08/23] LSM: Use lsmblob in security_ipc_getsecid

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:10:24 

There may be more than one LSM that provides IPC data
for auditing. Change security_ipc_getsecid() to fill in
a lsmblob structure instead of the u32 secid. The
audit data structure containing the secid will be updated
later, so there is a bit of scaffolding here.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 ++++---
 kernel/auditsc.c         |  7 ++++++-
 security/security.c      | 12 +++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 5c66348d9ab0..5f38bde9162f 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -494,7 +494,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			unsigned long arg4, unsigned long arg5);
 void security_task_to_inode(struct task_struct *p, struct inode *inode);
 int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag);
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid);
+void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob);
 int security_msg_msg_alloc(struct msg_msg *msg);
 void security_msg_msg_free(struct msg_msg *msg);
 int security_msg_queue_alloc(struct kern_ipc_perm *msq);
@@ -1215,9 +1215,10 @@ static inline int security_ipc_permission(struct kern_ipc_perm *ipcp,
 	return 0;
 }
 
-static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp,
+					 struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_msg_msg_alloc(struct msg_msg *msg)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 5f9bdd62f78d..35d6bd0526a2 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2341,11 +2341,16 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
 	struct audit_context *context = audit_context();
+	struct lsmblob blob;
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	security_ipc_getsecid(ipcp, &context->ipc.osid);
+	security_ipc_getsecid(ipcp, &blob);
+	/* context->ipc.osid will be changed to a lsmblob later in
+	 * the patch series. This will allow auditing of all the object
+	 * labels associated with the ipc object. */
+	context->ipc.osid = lsmblob_value(&blob);
 	context->type = AUDIT_IPC;
 }
 
diff --git a/security/security.c b/security/security.c
index ce0934395c53..c74c7722e5f4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1866,10 +1866,16 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
 	return call_int_hook(ipc_permission, 0, ipcp, flag);
 }
 
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(ipc_getsecid, ipcp, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.ipc_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.ipc_getsecid(ipcp, &blob->secid[hp->lsmid->slot]);
+	}
 }
 
 int security_msg_msg_alloc(struct msg_msg *msg)
-- 
2.24.1

[PATCH v20 09/23] LSM: Use lsmblob in security_task_getsecid

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:11:38 

Change the security_task_getsecid() interface to fill in
a lsmblob structure instead of a u32 secid in support of
LSM stacking. Audit interfaces will need to collect all
possible secids for possible reporting.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
 drivers/android/binder.c              | 12 +------
 include/linux/security.h              |  7 ++--
 kernel/audit.c                        | 16 ++++-----
 kernel/auditfilter.c                  |  4 +--
 kernel/auditsc.c                      | 25 +++++++-------
 net/netlabel/netlabel_unlabeled.c     |  5 ++-
 net/netlabel/netlabel_user.h          |  6 +++-
 security/integrity/ima/ima_appraise.c | 10 +++---
 security/integrity/ima/ima_main.c     | 49 +++++++++++++++------------
 security/security.c                   | 12 +++++--
 10 files changed, 76 insertions(+), 70 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 40e5e2f5b516..1d9b0e385cd0 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3110,20 +3110,10 @@ static void binder_transaction(struct binder_proc *proc,
 	t->priority = task_nice(current);
 
 	if (target_node && target_node->txn_security_ctx) {
-		u32 secid;
 		struct lsmblob blob;
 		size_t added_size;
 
-		security_task_getsecid(proc->tsk, &secid);
-		/*
-		 * Later in this patch set security_task_getsecid() will
-		 * provide a lsmblob instead of a secid. lsmblob_init
-		 * is used to ensure that all the secids in the lsmblob
-		 * get the value returned from security_task_getsecid(),
-		 * which means that the one expected by
-		 * security_secid_to_secctx() will be set.
-		 */
-		lsmblob_init(&blob, secid);
+		security_task_getsecid(proc->tsk, &blob);
 		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
diff --git a/include/linux/security.h b/include/linux/security.h
index 5f38bde9162f..56702d17c0c0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -477,7 +477,7 @@ int security_task_fix_setgid(struct cred *new, const struct cred *old,
 int security_task_setpgid(struct task_struct *p, pid_t pgid);
 int security_task_getpgid(struct task_struct *p);
 int security_task_getsid(struct task_struct *p);
-void security_task_getsecid(struct task_struct *p, u32 *secid);
+void security_task_getsecid(struct task_struct *p, struct lsmblob *blob);
 int security_task_setnice(struct task_struct *p, int nice);
 int security_task_setioprio(struct task_struct *p, int ioprio);
 int security_task_getioprio(struct task_struct *p);
@@ -1142,9 +1142,10 @@ static inline int security_task_getsid(struct task_struct *p)
 	return 0;
 }
 
-static inline void security_task_getsecid(struct task_struct *p, u32 *secid)
+static inline void security_task_getsecid(struct task_struct *p,
+					  struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_task_setnice(struct task_struct *p, int nice)
diff --git a/kernel/audit.c b/kernel/audit.c
index 605f5125c844..0f7cadd5221a 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2137,19 +2137,12 @@ int audit_log_task_context(struct audit_buffer *ab)
 	char *ctx = NULL;
 	unsigned len;
 	int error;
-	u32 sid;
 	struct lsmblob blob;
 
-	security_task_getsecid(current, &sid);
-	if (!sid)
+	security_task_getsecid(current, &blob);
+	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	/*
-	 * lsmblob_init sets all values in the lsmblob to sid.
-	 * This is temporary until security_task_getsecid is converted
-	 * to use a lsmblob, which happens later in this patch set.
-	 */
-	lsmblob_init(&blob, sid);
 	error = security_secid_to_secctx(&blob, &ctx, &len);
 	if (error) {
 		if (error != -EINVAL)
@@ -2357,6 +2350,7 @@ int audit_set_loginuid(kuid_t loginuid)
 int audit_signal_info(int sig, struct task_struct *t)
 {
 	kuid_t uid = current_uid(), auid;
+	struct lsmblob blob;
 
 	if (auditd_test_task(t) &&
 	    (sig == SIGTERM || sig == SIGHUP ||
@@ -2367,7 +2361,9 @@ int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid(current, &audit_sig_sid);
+		security_task_getsecid(current, &blob);
+		/* scaffolding until audit_sig_sid is converted */
+		audit_sig_sid = blob.secid[0];
 	}
 
 	return audit_signal_info_syscall(t);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 15a7fb80d6a7..31732023b689 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1330,7 +1330,6 @@ int audit_filter(int msgtype, unsigned int listtype)
 		for (i = 0; i < e->rule.field_count; i++) {
 			struct audit_field *f = &e->rule.fields[i];
 			pid_t pid;
-			u32 sid;
 			struct lsmblob blob;
 
 			switch (f->type) {
@@ -1361,8 +1360,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_SEN:
 			case AUDIT_SUBJ_CLR:
 				if (f->lsm_isset) {
-					security_task_getsecid(current, &sid);
-					lsmblob_init(&blob, sid);
+					security_task_getsecid(current, &blob);
 					result = security_audit_rule_match(
 						   &blob, f->type, f->op,
 						   f->lsm_rules);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 35d6bd0526a2..8916a13406c3 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -473,7 +473,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 {
 	const struct cred *cred;
 	int i, need_sid = 1;
-	u32 sid;
 	struct lsmblob blob;
 	unsigned int sessionid;
 
@@ -670,17 +669,9 @@ static int audit_filter_rules(struct task_struct *tsk,
 			   logged upon error */
 			if (f->lsm_isset) {
 				if (need_sid) {
-					security_task_getsecid(tsk, &sid);
+					security_task_getsecid(tsk, &blob);
 					need_sid = 0;
 				}
-				/*
-				 * lsmblob_init sets all values in the lsmblob
-				 * to sid. This is temporary until
-				 * security_task_getsecid() is converted to
-				 * provide a lsmblob, which happens later in
-				 * this patch set.
-				 */
-				lsmblob_init(&blob, sid);
 				result = security_audit_rule_match(&blob,
 								   f->type,
 								   f->op,
@@ -2440,12 +2431,15 @@ int __audit_sockaddr(int len, void *a)
 void __audit_ptrace(struct task_struct *t)
 {
 	struct audit_context *context = audit_context();
+	struct lsmblob blob;
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = task_uid(t);
 	context->target_sessionid = audit_get_sessionid(t);
-	security_task_getsecid(t, &context->target_sid);
+	security_task_getsecid(t, &blob);
+	/* scaffolding - until target_sid is converted */
+	context->target_sid = blob.secid[0];
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2461,6 +2455,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 	struct audit_aux_data_pids *axp;
 	struct audit_context *ctx = audit_context();
 	kuid_t t_uid = task_uid(t);
+	struct lsmblob blob;
 
 	if (!audit_signals || audit_dummy_context())
 		return 0;
@@ -2472,7 +2467,9 @@ int audit_signal_info_syscall(struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t_uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		security_task_getsecid(t, &ctx->target_sid);
+		security_task_getsecid(t, &blob);
+		/* scaffolding until target_sid is converted */
+		ctx->target_sid = blob.secid[0];
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2493,7 +2490,9 @@ int audit_signal_info_syscall(struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t_uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
+	security_task_getsecid(t, &blob);
+	/* scaffolding until target_sid is converted */
+	axp->target_sid[axp->pid_count] = blob.secid[0];
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 2ebe29ddf05e..f4a6204f4205 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1557,11 +1557,14 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
+	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid(current, &audit_info.secid);
+	security_task_getsecid(current, &blob);
+	/* scaffolding until audit_info.secid is converted */
+	audit_info.secid = blob.secid[0];
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 3c67afce64f1..438b5db6c714 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,7 +34,11 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	security_task_getsecid(current, &audit_info->secid);
+	struct lsmblob blob;
+
+	security_task_getsecid(current, &blob);
+	/* scaffolding until secid is converted */
+	audit_info->secid = blob.secid[0];
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 372d16382960..8a198fc98ffb 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -54,14 +54,16 @@ bool is_ima_appraise_enabled(void)
  */
 int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
 {
-	u32 secid;
+	struct lsmblob blob;
 
 	if (!ima_appraise)
 		return 0;
 
-	security_task_getsecid(current, &secid);
-	return ima_match_policy(inode, current_cred(), secid, func, mask,
-				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
+	security_task_getsecid(current, &blob);
+	/* scaffolding the .secid[0] */
+	return ima_match_policy(inode, current_cred(), blob.secid[0], func,
+				mask, IMA_APPRAISE | IMA_HASH, NULL, NULL,
+				NULL);
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 8a91711ca79b..9ad475f6fca5 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -382,12 +382,13 @@ static int process_measurement(struct file *file, const struct cred *cred,
  */
 int ima_file_mmap(struct file *file, unsigned long prot)
 {
-	u32 secid;
+	struct lsmblob blob;
 
 	if (file && (prot & PROT_EXEC)) {
-		security_task_getsecid(current, &secid);
-		return process_measurement(file, current_cred(), secid, NULL,
-					   0, MAY_EXEC, MMAP_CHECK);
+		security_task_getsecid(current, &blob);
+		/* scaffolding - until process_measurement changes */
+		return process_measurement(file, current_cred(), blob.secid[0],
+					   NULL, 0, MAY_EXEC, MMAP_CHECK);
 	}
 
 	return 0;
@@ -413,9 +414,9 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	char *pathbuf = NULL;
 	const char *pathname = NULL;
 	struct inode *inode;
+	struct lsmblob blob;
 	int result = 0;
 	int action;
-	u32 secid;
 	int pcr;
 
 	/* Is mprotect making an mmap'ed file executable? */
@@ -423,9 +424,10 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
-	security_task_getsecid(current, &secid);
+	security_task_getsecid(current, &blob);
 	inode = file_inode(vma->vm_file);
-	action = ima_get_action(inode, current_cred(), secid, MAY_EXEC,
+	/* scaffolding */
+	action = ima_get_action(NULL, current_cred(), blob.secid[0], 0,
 				MMAP_CHECK, &pcr, &template, 0);
 
 	/* Is the mmap'ed file in policy? */
@@ -462,10 +464,12 @@ int ima_bprm_check(struct linux_binprm *bprm)
 {
 	int ret;
 	u32 secid;
+	struct lsmblob blob;
 
-	security_task_getsecid(current, &secid);
-	ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
-				  MAY_EXEC, BPRM_CHECK);
+	security_task_getsecid(current, &blob);
+	/* scaffolding until process_measurement changes */
+	ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
+				  NULL, 0, MAY_EXEC, BPRM_CHECK);
 	if (ret)
 		return ret;
 
@@ -486,10 +490,11 @@ int ima_bprm_check(struct linux_binprm *bprm)
  */
 int ima_file_check(struct file *file, int mask)
 {
-	u32 secid;
+	struct lsmblob blob;
 
-	security_task_getsecid(current, &secid);
-	return process_measurement(file, current_cred(), secid, NULL, 0,
+	security_task_getsecid(current, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
 					   MAY_APPEND), FILE_CHECK);
 }
@@ -647,7 +652,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 		       enum kernel_read_file_id read_id)
 {
 	enum ima_hooks func;
-	u32 secid;
+	struct lsmblob blob;
 
 	if (!file && read_id == READING_FIRMWARE) {
 		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
@@ -669,9 +674,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 	}
 
 	func = read_idmap[read_id] ?: FILE_CHECK;
-	security_task_getsecid(current, &secid);
-	return process_measurement(file, current_cred(), secid, buf, size,
-				   MAY_READ, func);
+	security_task_getsecid(current, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(file, current_cred(), blob.secid[0], buf,
+				   size, MAY_READ, func);
 }
 
 /**
@@ -755,7 +761,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
 	} hash = {};
 	int violation = 0;
 	int action = 0;
-	u32 secid;
+	struct lsmblob blob;
 
 	if (!ima_policy_flag)
 		return;
@@ -768,9 +774,10 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
 	 * buffer measurements.
 	 */
 	if (func) {
-		security_task_getsecid(current, &secid);
-		action = ima_get_action(inode, current_cred(), secid, 0, func,
-					&pcr, &template, keyring);
+		security_task_getsecid(current, &blob);
+		/* scaffolding */
+		action = ima_get_action(inode, current_cred(), blob.secid[0],
+					0, func, &pcr, &template, keyring);
 		if (!(action & IMA_MEASURE))
 			return;
 	}
diff --git a/security/security.c b/security/security.c
index c74c7722e5f4..01c1561901fa 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1783,10 +1783,16 @@ int security_task_getsid(struct task_struct *p)
 	return call_int_hook(task_getsid, 0, p);
 }
 
-void security_task_getsecid(struct task_struct *p, u32 *secid)
+void security_task_getsecid(struct task_struct *p, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(task_getsecid, p, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.task_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.task_getsecid(p, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_task_getsecid);
 
-- 
2.24.1

[PATCH v20 10/23] LSM: Use lsmblob in security_inode_getsecid

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:12:34 

Change the security_inode_getsecid() interface to fill in a
lsmblob structure instead of a u32 secid. This allows for its
callers to gather data from all registered LSMs. Data is provided
for IMA and audit.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Stephen Smalley <redacted>
cc: linux-integrity@vger.kernel.org
---
 include/linux/security.h            |  7 ++++---
 kernel/auditsc.c                    |  6 +++++-
 security/integrity/ima/ima_policy.c |  4 +---
 security/security.c                 | 11 +++++++++--
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 56702d17c0c0..63d0c9a6cb42 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -435,7 +435,7 @@ int security_inode_killpriv(struct dentry *dentry);
 int security_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
 int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
-void security_inode_getsecid(struct inode *inode, u32 *secid);
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
 int security_inode_copy_up_xattr(const char *name);
 int security_kernfs_init_security(struct kernfs_node *kn_dir,
@@ -958,9 +958,10 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer,
 	return 0;
 }
 
-static inline void security_inode_getsecid(struct inode *inode, u32 *secid)
+static inline void security_inode_getsecid(struct inode *inode,
+					   struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8916a13406c3..b58b0048702a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1980,13 +1980,17 @@ static void audit_copy_inode(struct audit_names *name,
 			     const struct dentry *dentry,
 			     struct inode *inode, unsigned int flags)
 {
+	struct lsmblob blob;
+
 	name->ino   = inode->i_ino;
 	name->dev   = inode->i_sb->s_dev;
 	name->mode  = inode->i_mode;
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &name->osid);
+	security_inode_getsecid(inode, &blob);
+	/* scaffolding until osid is updated */
+	name->osid = blob.secid[0];
 	if (flags & AUDIT_INODE_NOEVAL) {
 		name->fcap_ver = -1;
 		return;
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3b30105113df..a86b35dad4fa 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -499,7 +499,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 		return false;
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
-		u32 osid;
 		struct lsmblob lsmdata;
 
 		if (!ima_lsm_isset(rule->lsm[i].rules)) {
@@ -512,8 +511,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 		case LSM_OBJ_USER:
 		case LSM_OBJ_ROLE:
 		case LSM_OBJ_TYPE:
-			security_inode_getsecid(inode, &osid);
-			lsmblob_init(&lsmdata, osid);
+			security_inode_getsecid(inode, &lsmdata);
 			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rules);
diff --git a/security/security.c b/security/security.c
index 01c1561901fa..d641c6dc5933 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1442,9 +1442,16 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
 }
 EXPORT_SYMBOL(security_inode_listsecurity);
 
-void security_inode_getsecid(struct inode *inode, u32 *secid)
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob)
 {
-	call_void_hook(inode_getsecid, inode, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.inode_getsecid(inode, &blob->secid[hp->lsmid->slot]);
+	}
 }
 
 int security_inode_copy_up(struct dentry *src, struct cred **new)
-- 
2.24.1

[PATCH v20 11/23] LSM: Use lsmblob in security_cred_getsecid

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:13:48 

Change the security_cred_getsecid() interface to fill in a
lsmblob instead of a u32 secid. The associated data elements
in the audit sub-system are changed from a secid to a lsmblob
to accommodate multiple possible LSM audit users.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
 include/linux/security.h          |  2 +-
 kernel/audit.c                    | 25 +++++++----------------
 kernel/audit.h                    |  5 +++--
 kernel/auditsc.c                  | 33 +++++++++++--------------------
 security/integrity/ima/ima_main.c |  8 ++++----
 security/security.c               | 12 ++++++++---
 6 files changed, 36 insertions(+), 49 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 63d0c9a6cb42..7de2b4e62f55 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -462,7 +462,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
 void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
-void security_cred_getsecid(const struct cred *c, u32 *secid);
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob);
 int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
diff --git a/kernel/audit.c b/kernel/audit.c
index 0f7cadd5221a..88b55b42756e 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -125,7 +125,7 @@ static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
 /* The identity of the user shutting down the audit system. */
 kuid_t		audit_sig_uid = INVALID_UID;
 pid_t		audit_sig_pid = -1;
-u32		audit_sig_sid = 0;
+struct lsmblob	audit_sig_lsm;
 
 /* Records can be lost in several ways:
    0) [suppressed in audit_alloc]
@@ -1442,29 +1442,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	}
 	case AUDIT_SIGNAL_INFO:
 		len = 0;
-		if (audit_sig_sid) {
-			struct lsmblob blob;
-
-			/*
-			 * lsmblob_init sets all values in the lsmblob
-			 * to audit_sig_sid. This is temporary until
-			 * audit_sig_sid is converted to a lsmblob, which
-			 * happens later in this patch set.
-			 */
-			lsmblob_init(&blob, audit_sig_sid);
-			err = security_secid_to_secctx(&blob, &ctx, &len);
+		if (lsmblob_is_set(&audit_sig_lsm)) {
+			err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
+						       &len);
 			if (err)
 				return err;
 		}
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			if (audit_sig_sid)
+			if (lsmblob_is_set(&audit_sig_lsm))
 				security_release_secctx(ctx, len);
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
-		if (audit_sig_sid) {
+		if (lsmblob_is_set(&audit_sig_lsm)) {
 			memcpy(sig_data->ctx, ctx, len);
 			security_release_secctx(ctx, len);
 		}
@@ -2350,7 +2342,6 @@ int audit_set_loginuid(kuid_t loginuid)
 int audit_signal_info(int sig, struct task_struct *t)
 {
 	kuid_t uid = current_uid(), auid;
-	struct lsmblob blob;
 
 	if (auditd_test_task(t) &&
 	    (sig == SIGTERM || sig == SIGHUP ||
@@ -2361,9 +2352,7 @@ int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid(current, &blob);
-		/* scaffolding until audit_sig_sid is converted */
-		audit_sig_sid = blob.secid[0];
+		security_task_getsecid(current, &audit_sig_lsm);
 	}
 
 	return audit_signal_info_syscall(t);
diff --git a/kernel/audit.h b/kernel/audit.h
index ddc22878433d..ec0cfa7364cc 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -9,6 +9,7 @@
 #include <linux/fs.h>
 #include <linux/audit.h>
 #include <linux/skbuff.h>
+#include <linux/security.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
 
@@ -134,7 +135,7 @@ struct audit_context {
 	kuid_t		    target_auid;
 	kuid_t		    target_uid;
 	unsigned int	    target_sessionid;
-	u32		    target_sid;
+	struct lsmblob	    target_lsm;
 	char		    target_comm[TASK_COMM_LEN];
 
 	struct audit_tree_refs *trees, *first_trees;
@@ -329,7 +330,7 @@ extern char *audit_unpack_string(void **bufp, size_t *remain, size_t len);
 
 extern pid_t audit_sig_pid;
 extern kuid_t audit_sig_uid;
-extern u32 audit_sig_sid;
+extern struct lsmblob audit_sig_lsm;
 
 extern int audit_filter(int msgtype, unsigned int listtype);
 
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b58b0048702a..b15222181700 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -113,7 +113,7 @@ struct audit_aux_data_pids {
 	kuid_t			target_auid[AUDIT_AUX_PIDS];
 	kuid_t			target_uid[AUDIT_AUX_PIDS];
 	unsigned int		target_sessionid[AUDIT_AUX_PIDS];
-	u32			target_sid[AUDIT_AUX_PIDS];
+	struct lsmblob		target_lsm[AUDIT_AUX_PIDS];
 	char 			target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
 	int			pid_count;
 };
@@ -993,14 +993,14 @@ static inline void audit_free_context(struct audit_context *context)
 }
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
-				 kuid_t auid, kuid_t uid, unsigned int sessionid,
-				 u32 sid, char *comm)
+				 kuid_t auid, kuid_t uid,
+				 unsigned int sessionid,
+				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
-	struct lsmblob blob;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
 	if (!ab)
@@ -1009,9 +1009,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
-	if (sid) {
-		lsmblob_init(&blob, sid);
-		if (security_secid_to_secctx(&blob, &ctx, &len)) {
+	if (lsmblob_is_set(blob)) {
+		if (security_secid_to_secctx(blob, &ctx, &len)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1582,7 +1581,7 @@ static void audit_log_exit(void)
 						  axs->target_auid[i],
 						  axs->target_uid[i],
 						  axs->target_sessionid[i],
-						  axs->target_sid[i],
+						  &axs->target_lsm[i],
 						  axs->target_comm[i]))
 				call_panic = 1;
 	}
@@ -1591,7 +1590,7 @@ static void audit_log_exit(void)
 	    audit_log_pid_context(context, context->target_pid,
 				  context->target_auid, context->target_uid,
 				  context->target_sessionid,
-				  context->target_sid, context->target_comm))
+				  &context->target_lsm, context->target_comm))
 			call_panic = 1;
 
 	if (context->pwd.dentry && context->pwd.mnt) {
@@ -1769,7 +1768,7 @@ void __audit_syscall_exit(int success, long return_code)
 	context->aux = NULL;
 	context->aux_pids = NULL;
 	context->target_pid = 0;
-	context->target_sid = 0;
+	lsmblob_init(&context->target_lsm, 0);
 	context->sockaddr_len = 0;
 	context->type = 0;
 	context->fds[0] = -1;
@@ -2435,15 +2434,12 @@ int __audit_sockaddr(int len, void *a)
 void __audit_ptrace(struct task_struct *t)
 {
 	struct audit_context *context = audit_context();
-	struct lsmblob blob;
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = task_uid(t);
 	context->target_sessionid = audit_get_sessionid(t);
-	security_task_getsecid(t, &blob);
-	/* scaffolding - until target_sid is converted */
-	context->target_sid = blob.secid[0];
+	security_task_getsecid(t, &context->target_lsm);
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2459,7 +2455,6 @@ int audit_signal_info_syscall(struct task_struct *t)
 	struct audit_aux_data_pids *axp;
 	struct audit_context *ctx = audit_context();
 	kuid_t t_uid = task_uid(t);
-	struct lsmblob blob;
 
 	if (!audit_signals || audit_dummy_context())
 		return 0;
@@ -2471,9 +2466,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t_uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		security_task_getsecid(t, &blob);
-		/* scaffolding until target_sid is converted */
-		ctx->target_sid = blob.secid[0];
+		security_task_getsecid(t, &ctx->target_lsm);
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2494,9 +2487,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t_uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	security_task_getsecid(t, &blob);
-	/* scaffolding until target_sid is converted */
-	axp->target_sid[axp->pid_count] = blob.secid[0];
+	security_task_getsecid(t, &axp->target_lsm[axp->pid_count]);
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9ad475f6fca5..97b26c425ac5 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -463,7 +463,6 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 int ima_bprm_check(struct linux_binprm *bprm)
 {
 	int ret;
-	u32 secid;
 	struct lsmblob blob;
 
 	security_task_getsecid(current, &blob);
@@ -473,9 +472,10 @@ int ima_bprm_check(struct linux_binprm *bprm)
 	if (ret)
 		return ret;
 
-	security_cred_getsecid(bprm->cred, &secid);
-	return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
-				   MAY_EXEC, CREDS_CHECK);
+	security_cred_getsecid(bprm->cred, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(bprm->file, bprm->cred, blob.secid[0],
+				   NULL, 0, MAY_EXEC, CREDS_CHECK);
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index d641c6dc5933..c3bac45bbb79 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1692,10 +1692,16 @@ void security_transfer_creds(struct cred *new, const struct cred *old)
 	call_void_hook(cred_transfer, new, old);
 }
 
-void security_cred_getsecid(const struct cred *c, u32 *secid)
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(cred_getsecid, c, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.cred_getsecid(c, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_cred_getsecid);
 
-- 
2.24.1

[PATCH v20 12/23] IMA: Change internal interfaces to use lsmblobs

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:14:48 

The IMA interfaces ima_get_action() and ima_match_policy()
call LSM functions that use lsmblobs. Change the IMA functions
to pass the lsmblob to be compatible with the LSM functions.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
 security/integrity/ima/ima.h          | 11 +++++----
 security/integrity/ima/ima_api.c      | 10 ++++----
 security/integrity/ima/ima_appraise.c |  6 ++---
 security/integrity/ima/ima_main.c     | 35 +++++++++++----------------
 security/integrity/ima/ima_policy.c   | 14 +++++------
 5 files changed, 34 insertions(+), 42 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index d7fe1d5ee8c9..81b00d07490f 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -252,9 +252,9 @@ static inline void ima_process_queued_keys(void) {}
 #endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */
 
 /* LIM API function definitions */
-int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
-		   int mask, enum ima_hooks func, int *pcr,
-		   struct ima_template_desc **template_desc,
+int ima_get_action(struct inode *inode, const struct cred *cred,
+		   struct lsmblob *blob, int mask, enum ima_hooks func,
+		   int *pcr, struct ima_template_desc **template_desc,
 		   const char *keyring);
 int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
 int ima_collect_measurement(struct integrity_iint_cache *iint,
@@ -280,8 +280,9 @@ void ima_free_template_entry(struct ima_template_entry *entry);
 const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
 
 /* IMA policy related functions */
-int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
-		     enum ima_hooks func, int mask, int flags, int *pcr,
+int ima_match_policy(struct inode *inode, const struct cred *cred,
+		     struct lsmblob *blob, enum ima_hooks func, int mask,
+		     int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
 		     const char *keyring);
 void ima_init_policy(void);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 4f39fb93f278..e83fa1c32843 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -164,7 +164,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
  * ima_get_action - appraise & measure decision based on policy.
  * @inode: pointer to the inode associated with the object being validated
  * @cred: pointer to credentials structure to validate
- * @secid: secid of the task being validated
+ * @blob: LSM data of the task being validated
  * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC,
  *        MAY_APPEND)
  * @func: caller identifier
@@ -183,16 +183,16 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
  * Returns IMA_MEASURE, IMA_APPRAISE mask.
  *
  */
-int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
-		   int mask, enum ima_hooks func, int *pcr,
-		   struct ima_template_desc **template_desc,
+int ima_get_action(struct inode *inode, const struct cred *cred,
+		   struct lsmblob *blob, int mask, enum ima_hooks func,
+		   int *pcr, struct ima_template_desc **template_desc,
 		   const char *keyring)
 {
 	int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;
 
 	flags &= ima_policy_flag;
 
-	return ima_match_policy(inode, cred, secid, func, mask, flags, pcr,
+	return ima_match_policy(inode, cred, blob, func, mask, flags, pcr,
 				template_desc, keyring);
 }
 
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 8a198fc98ffb..9c22d5410b81 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -60,10 +60,8 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
 		return 0;
 
 	security_task_getsecid(current, &blob);
-	/* scaffolding the .secid[0] */
-	return ima_match_policy(inode, current_cred(), blob.secid[0], func,
-				mask, IMA_APPRAISE | IMA_HASH, NULL, NULL,
-				NULL);
+	return ima_match_policy(inode, current_cred(), &blob, func, mask,
+				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 97b26c425ac5..4031590b91a6 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -188,8 +188,8 @@ void ima_file_free(struct file *file)
 }
 
 static int process_measurement(struct file *file, const struct cred *cred,
-			       u32 secid, char *buf, loff_t size, int mask,
-			       enum ima_hooks func)
+			       struct lsmblob *blob, char *buf, loff_t size,
+			       int mask, enum ima_hooks func)
 {
 	struct inode *inode = file_inode(file);
 	struct integrity_iint_cache *iint = NULL;
@@ -212,7 +212,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	 * bitmask based on the appraise/audit/measurement policy.
 	 * Included is the appraise submask.
 	 */
-	action = ima_get_action(inode, cred, secid, mask, func, &pcr,
+	action = ima_get_action(inode, cred, blob, mask, func, &pcr,
 				&template_desc, NULL);
 	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
 			   (ima_policy_flag & IMA_MEASURE));
@@ -386,8 +386,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
 
 	if (file && (prot & PROT_EXEC)) {
 		security_task_getsecid(current, &blob);
-		/* scaffolding - until process_measurement changes */
-		return process_measurement(file, current_cred(), blob.secid[0],
+		return process_measurement(file, current_cred(), &blob,
 					   NULL, 0, MAY_EXEC, MMAP_CHECK);
 	}
 
@@ -426,8 +425,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 
 	security_task_getsecid(current, &blob);
 	inode = file_inode(vma->vm_file);
-	/* scaffolding */
-	action = ima_get_action(NULL, current_cred(), blob.secid[0], 0,
+	action = ima_get_action(NULL, current_cred(), &blob, 0,
 				MMAP_CHECK, &pcr, &template, 0);
 
 	/* Is the mmap'ed file in policy? */
@@ -466,16 +464,14 @@ int ima_bprm_check(struct linux_binprm *bprm)
 	struct lsmblob blob;
 
 	security_task_getsecid(current, &blob);
-	/* scaffolding until process_measurement changes */
-	ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
-				  NULL, 0, MAY_EXEC, BPRM_CHECK);
+	ret = process_measurement(bprm->file, current_cred(), &blob, NULL, 0,
+				  MAY_EXEC, BPRM_CHECK);
 	if (ret)
 		return ret;
 
 	security_cred_getsecid(bprm->cred, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(bprm->file, bprm->cred, blob.secid[0],
-				   NULL, 0, MAY_EXEC, CREDS_CHECK);
+	return process_measurement(bprm->file, bprm->cred, &blob, NULL, 0,
+				   MAY_EXEC, CREDS_CHECK);
 }
 
 /**
@@ -493,8 +489,7 @@ int ima_file_check(struct file *file, int mask)
 	struct lsmblob blob;
 
 	security_task_getsecid(current, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
+	return process_measurement(file, current_cred(), &blob, NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
 					   MAY_APPEND), FILE_CHECK);
 }
@@ -675,9 +670,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 
 	func = read_idmap[read_id] ?: FILE_CHECK;
 	security_task_getsecid(current, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(file, current_cred(), blob.secid[0], buf,
-				   size, MAY_READ, func);
+	return process_measurement(file, current_cred(), &blob, buf, size,
+				   MAY_READ, func);
 }
 
 /**
@@ -775,9 +769,8 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
 	 */
 	if (func) {
 		security_task_getsecid(current, &blob);
-		/* scaffolding */
-		action = ima_get_action(inode, current_cred(), blob.secid[0],
-					0, func, &pcr, &template, keyring);
+		action = ima_get_action(inode, current_cred(), &blob, 0, func,
+					&pcr, &template, keyring);
 		if (!(action & IMA_MEASURE))
 			return;
 	}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index a86b35dad4fa..b057c758b430 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -446,7 +446,7 @@ static bool ima_match_keyring(struct ima_rule_entry *rule,
  * @rule: a pointer to a rule
  * @inode: a pointer to an inode
  * @cred: a pointer to a credentials structure for user validation
- * @secid: the secid of the task to be validated
+ * @blob: the lsm data of the task to be validated
  * @func: LIM hook identifier
  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
  * @keyring: keyring name to check in policy for KEY_CHECK func
@@ -454,7 +454,7 @@ static bool ima_match_keyring(struct ima_rule_entry *rule,
  * Returns true on rule match, false on failure.
  */
 static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
-			    const struct cred *cred, u32 secid,
+			    const struct cred *cred, struct lsmblob *blob,
 			    enum ima_hooks func, int mask,
 			    const char *keyring)
 {
@@ -519,7 +519,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
-			lsmblob_init(&lsmdata, secid);
 			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rules);
@@ -562,7 +561,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * @inode: pointer to an inode for which the policy decision is being made
  * @cred: pointer to a credentials structure for which the policy decision is
  *        being made
- * @secid: LSM secid of the task to be validated
+ * @blob: LSM data of the task to be validated
  * @func: IMA hook identifier
  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
  * @pcr: set the pcr to extend
@@ -577,8 +576,9 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * list when walking it.  Reads are many orders of magnitude more numerous
  * than writes so ima_match_policy() is classical RCU candidate.
  */
-int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
-		     enum ima_hooks func, int mask, int flags, int *pcr,
+int ima_match_policy(struct inode *inode, const struct cred *cred,
+		     struct lsmblob *blob, enum ima_hooks func, int mask,
+		     int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
 		     const char *keyring)
 {
@@ -594,7 +594,7 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
 		if (!(entry->action & actmask))
 			continue;
 
-		if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+		if (!ima_match_rules(entry, inode, cred, blob, func, mask,
 				     keyring))
 			continue;
 
-- 
2.24.1

[PATCH v20 13/23] LSM: Specify which LSM to display

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:17:04 

Create a new entry "display" in the procfs attr directory for
controlling which LSM security information is displayed for a
process. A process can only read or write its own display value.

The name of an active LSM that supplies hooks for
human readable data may be written to "display" to set the
value. The name of the LSM currently in use can be read from
"display". At this point there can only be one LSM capable
of display active. A helper function lsm_task_display() is
provided to get the display slot for a task_struct.

Setting the "display" requires that all security modules using
setprocattr hooks allow the action. Each security module is
responsible for defining its policy.

AppArmor hook provided by John Johansen [off-list ref]
SELinux hook provided by Stephen Smalley [off-list ref]

Reviewed-by: Kees Cook <redacted>
Acked-by: Stephen Smalley <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 fs/proc/base.c                       |   1 +
 include/linux/lsm_hooks.h            |  17 +++
 security/apparmor/include/apparmor.h |   3 +-
 security/apparmor/lsm.c              |  32 +++++
 security/security.c                  | 167 ++++++++++++++++++++++++---
 security/selinux/hooks.c             |  11 ++
 security/selinux/include/classmap.h  |   2 +-
 security/smack/smack_lsm.c           |   7 ++
 8 files changed, 221 insertions(+), 19 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 617db4e0faa0..2edb51d4c725 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2803,6 +2803,7 @@ static const struct pid_entry attr_dir_stuff[] = {
 	ATTR(NULL, "fscreate",		0666),
 	ATTR(NULL, "keycreate",		0666),
 	ATTR(NULL, "sockcreate",	0666),
+	ATTR(NULL, "display",		0666),
 #ifdef CONFIG_SECURITY_SMACK
 	DIR("smack",			0555,
 	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 983008c6fede..e559df1df169 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1647,4 +1647,21 @@ static inline void security_delete_hooks(struct security_hook_list *hooks,
 
 extern int lsm_inode_alloc(struct inode *inode);
 
+/**
+ * lsm_task_display - the "display" LSM for this task
+ * @task: The task to report on
+ *
+ * Returns the task's display LSM slot.
+ */
+static inline int lsm_task_display(struct task_struct *task)
+{
+#ifdef CONFIG_SECURITY
+	int *display = task->security;
+
+	if (display)
+		return *display;
+#endif
+	return LSMBLOB_INVALID;
+}
+
 #endif /* ! __LINUX_LSM_HOOKS_H */
diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
index 1fbabdb565a8..b1622fcb4394 100644
--- a/security/apparmor/include/apparmor.h
+++ b/security/apparmor/include/apparmor.h
@@ -28,8 +28,9 @@
 #define AA_CLASS_SIGNAL		10
 #define AA_CLASS_NET		14
 #define AA_CLASS_LABEL		16
+#define AA_CLASS_DISPLAY_LSM	17
 
-#define AA_CLASS_LAST		AA_CLASS_LABEL
+#define AA_CLASS_LAST		AA_CLASS_DISPLAY_LSM
 
 /* Control parameters settable through module/boot flags */
 extern enum audit_mode aa_g_audit;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 432915c1d427..31a6f11890f1 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -612,6 +612,25 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 	return error;
 }
 
+
+static int profile_display_lsm(struct aa_profile *profile,
+			       struct common_audit_data *sa)
+{
+	struct aa_perms perms = { };
+	unsigned int state;
+
+	state = PROFILE_MEDIATES(profile, AA_CLASS_DISPLAY_LSM);
+	if (state) {
+		aa_compute_perms(profile->policy.dfa, state, &perms);
+		aa_apply_modes_to_perms(profile, &perms);
+		aad(sa)->label = &profile->label;
+
+		return aa_check_perms(profile, &perms, AA_MAY_WRITE, sa, NULL);
+	}
+
+	return 0;
+}
+
 static int apparmor_setprocattr(const char *name, void *value,
 				size_t size)
 {
@@ -623,6 +642,19 @@ static int apparmor_setprocattr(const char *name, void *value,
 	if (size == 0)
 		return -EINVAL;
 
+	/* LSM infrastructure does actual setting of display if allowed */
+	if (!strcmp(name, "display")) {
+		struct aa_profile *profile;
+		struct aa_label *label;
+
+		aad(&sa)->info = "set display lsm";
+		label = begin_current_label_crit_section();
+		error = fn_for_each_confined(label, profile,
+					     profile_display_lsm(profile, &sa));
+		end_current_label_crit_section(label);
+		return error;
+	}
+
 	/* AppArmor requires that the buffer must be null terminated atm */
 	if (args[size - 1] != '\0') {
 		/* null terminate */
diff --git a/security/security.c b/security/security.c
index c3bac45bbb79..e1c9f87db64b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -75,7 +75,14 @@ static struct kmem_cache *lsm_file_cache;
 static struct kmem_cache *lsm_inode_cache;
 
 char *lsm_names;
-static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
+
+/*
+ * The task blob includes the "display" slot used for
+ * chosing which module presents contexts.
+ */
+static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
+	.lbs_task = sizeof(int),
+};
 
 /* Boot-time LSM user choice */
 static __initdata const char *chosen_lsm_order;
@@ -470,8 +477,10 @@ static int lsm_append(const char *new, char **result)
 
 /*
  * Current index to use while initializing the lsmblob secid list.
+ * Pointers to the LSM id structures for local use.
  */
 static int lsm_slot __lsm_ro_after_init;
+static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES];
 
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
@@ -491,6 +500,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	if (lsmid->slot == LSMBLOB_NEEDED) {
 		if (lsm_slot >= LSMBLOB_ENTRIES)
 			panic("%s Too many LSMs registered.\n", __func__);
+		lsm_slotlist[lsm_slot] = lsmid;
 		lsmid->slot = lsm_slot++;
 		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
 			   lsmid->slot);
@@ -620,6 +630,8 @@ int lsm_inode_alloc(struct inode *inode)
  */
 static int lsm_task_alloc(struct task_struct *task)
 {
+	int *display;
+
 	if (blob_sizes.lbs_task == 0) {
 		task->security = NULL;
 		return 0;
@@ -628,6 +640,15 @@ static int lsm_task_alloc(struct task_struct *task)
 	task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
 	if (task->security == NULL)
 		return -ENOMEM;
+
+	/*
+	 * The start of the task blob contains the "display" LSM slot number.
+	 * Start with it set to the invalid slot number, indicating that the
+	 * default first registered LSM be displayed.
+	 */
+	display = task->security;
+	*display = LSMBLOB_INVALID;
+
 	return 0;
 }
 
@@ -1628,14 +1649,26 @@ int security_file_open(struct file *file)
 
 int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
 {
+	int *odisplay = current->security;
+	int *ndisplay;
 	int rc = lsm_task_alloc(task);
 
-	if (rc)
+	if (unlikely(rc))
 		return rc;
+
 	rc = call_int_hook(task_alloc, 0, task, clone_flags);
-	if (unlikely(rc))
+	if (unlikely(rc)) {
 		security_task_free(task);
-	return rc;
+		return rc;
+	}
+
+	if (odisplay) {
+		ndisplay = task->security;
+		if (ndisplay)
+			*ndisplay = *odisplay;
+	}
+
+	return 0;
 }
 
 void security_task_free(struct task_struct *task)
@@ -2038,23 +2071,110 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 				char **value)
 {
 	struct security_hook_list *hp;
+	int display = lsm_task_display(current);
+	int slot = 0;
+
+	if (!strcmp(name, "display")) {
+		/*
+		 * lsm_slot will be 0 if there are no displaying modules.
+		 */
+		if (lsm_slot == 0)
+			return -EINVAL;
+
+		/*
+		 * Only allow getting the current process' display.
+		 * There are too few reasons to get another process'
+		 * display and too many LSM policy issues.
+		 */
+		if (current != p)
+			return -EINVAL;
+
+		display = lsm_task_display(p);
+		if (display != LSMBLOB_INVALID)
+			slot = display;
+		*value = kstrdup(lsm_slotlist[slot]->lsm, GFP_KERNEL);
+		if (*value)
+			return strlen(*value);
+		return -ENOMEM;
+	}
 
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
+		if (lsm == NULL && display != LSMBLOB_INVALID &&
+		    display != hp->lsmid->slot)
+			continue;
 		return hp->hook.getprocattr(p, name, value);
 	}
 	return LSM_RET_DEFAULT(getprocattr);
 }
 
+/**
+ * security_setprocattr - Set process attributes via /proc
+ * @lsm: name of module involved, or NULL
+ * @name: name of the attribute
+ * @value: value to set the attribute to
+ * @size: size of the value
+ *
+ * Set the process attribute for the specified security module
+ * to the specified value. Note that this can only be used to set
+ * the process attributes for the current, or "self" process.
+ * The /proc code has already done this check.
+ *
+ * Returns 0 on success, an appropriate code otherwise.
+ */
 int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size)
 {
 	struct security_hook_list *hp;
+	char *termed;
+	char *copy;
+	int *display = current->security;
+	int rc = -EINVAL;
+	int slot = 0;
+
+	if (!strcmp(name, "display")) {
+		/*
+		 * Change the "display" value only if all the security
+		 * modules that support setting a procattr allow it.
+		 * It is assumed that all such security modules will be
+		 * cooperative.
+		 */
+		if (size == 0)
+			return -EINVAL;
+
+		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
+				     list) {
+			rc = hp->hook.setprocattr(name, value, size);
+			if (rc < 0)
+				return rc;
+		}
+
+		rc = -EINVAL;
+
+		copy = kmemdup_nul(value, size, GFP_KERNEL);
+		if (copy == NULL)
+			return -ENOMEM;
+
+		termed = strsep(&copy, " \n");
+
+		for (slot = 0; slot < lsm_slot; slot++)
+			if (!strcmp(termed, lsm_slotlist[slot]->lsm)) {
+				*display = lsm_slotlist[slot]->slot;
+				rc = size;
+				break;
+			}
+
+		kfree(termed);
+		return rc;
+	}
 
 	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
+		if (lsm == NULL && *display != LSMBLOB_INVALID &&
+		    *display != hp->lsmid->slot)
+			continue;
 		return hp->hook.setprocattr(name, value, size);
 	}
 	return LSM_RET_DEFAULT(setprocattr);
@@ -2074,15 +2194,15 @@ EXPORT_SYMBOL(security_ismaclabel);
 int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
 {
 	struct security_hook_list *hp;
-	int rc;
+	int display = lsm_task_display(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
-					      secdata, seclen);
-		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
-			return rc;
+		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot)
+			return hp->hook.secid_to_secctx(
+					blob->secid[hp->lsmid->slot],
+					secdata, seclen);
 	}
 
 	return LSM_RET_DEFAULT(secid_to_secctx);
@@ -2093,16 +2213,15 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob)
 {
 	struct security_hook_list *hp;
-	int rc;
+	int display = lsm_task_display(current);
 
 	lsmblob_init(blob, 0);
 	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.secctx_to_secid(secdata, seclen,
-					      &blob->secid[hp->lsmid->slot]);
-		if (rc != 0)
-			return rc;
+		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot)
+			return hp->hook.secctx_to_secid(secdata, seclen,
+						&blob->secid[hp->lsmid->slot]);
 	}
 	return 0;
 }
@@ -2110,7 +2229,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
 
 void security_release_secctx(char *secdata, u32 seclen)
 {
-	call_void_hook(release_secctx, secdata, seclen);
+	struct security_hook_list *hp;
+	int display = lsm_task_display(current);
+
+	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
+		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot) {
+			hp->hook.release_secctx(secdata, seclen);
+			return;
+		}
 }
 EXPORT_SYMBOL(security_release_secctx);
 
@@ -2251,8 +2377,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
 int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				      int __user *optlen, unsigned len)
 {
-	return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
-				optval, optlen, len);
+	int display = lsm_task_display(current);
+	struct security_hook_list *hp;
+
+	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
+			     list)
+		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot)
+			return hp->hook.socket_getpeersec_stream(sock, optval,
+								 optlen, len);
+	return -ENOPROTOOPT;
 }
 
 int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1172b3f30f99..f73dec68ee32 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6335,6 +6335,17 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
 	/*
 	 * Basic control over ability to set these attributes at all.
 	 */
+
+	/*
+	 * For setting display, we only perform a permission check;
+	 * the actual update to the display value is handled by the
+	 * LSM framework.
+	 */
+	if (!strcmp(name, "display"))
+		return avc_has_perm(&selinux_state,
+				    mysid, mysid, SECCLASS_PROCESS2,
+				    PROCESS2__SETDISPLAY, NULL);
+
 	if (!strcmp(name, "exec"))
 		error = avc_has_perm(&selinux_state,
 				     mysid, mysid, SECCLASS_PROCESS,
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 40cebde62856..1858aa47b32a 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -53,7 +53,7 @@ struct security_class_mapping secclass_map[] = {
 	    "execmem", "execstack", "execheap", "setkeycreate",
 	    "setsockcreate", "getrlimit", NULL } },
 	{ "process2",
-	  { "nnp_transition", "nosuid_transition", NULL } },
+	  { "nnp_transition", "nosuid_transition", "setdisplay", NULL } },
 	{ "system",
 	  { "ipc_info", "syslog_read", "syslog_mod",
 	    "syslog_console", "module_request", "module_load", NULL } },
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d4655dec2d70..8b708cca921a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3494,6 +3494,13 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
 	struct smack_known_list_elem *sklep;
 	int rc;
 
+	/*
+	 * Allow the /proc/.../attr/current and SO_PEERSEC "display"
+	 * to be reset at will.
+	 */
+	if (strcmp(name, "display") == 0)
+		return 0;
+
 	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
 		return -EPERM;
 
-- 
2.24.1

[PATCH v20 14/23] LSM: Ensure the correct LSM context releaser

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:17:27 

Add a new lsmcontext data structure to hold all the information
about a "security context", including the string, its size and
which LSM allocated the string. The allocation information is
necessary because LSMs have different policies regarding the
lifecycle of these strings. SELinux allocates and destroys
them on each use, whereas Smack provides a pointer to an entry
in a list that never goes away.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 drivers/android/binder.c                | 10 ++++---
 fs/ceph/xattr.c                         |  6 ++++-
 fs/nfs/nfs4proc.c                       |  8 ++++--
 fs/nfsd/nfs4xdr.c                       |  7 +++--
 include/linux/security.h                | 35 +++++++++++++++++++++++--
 include/net/scm.h                       |  5 +++-
 kernel/audit.c                          | 14 +++++++---
 kernel/auditsc.c                        | 12 ++++++---
 net/ipv4/ip_sockglue.c                  |  4 ++-
 net/netfilter/nf_conntrack_netlink.c    |  4 ++-
 net/netfilter/nf_conntrack_standalone.c |  4 ++-
 net/netfilter/nfnetlink_queue.c         | 13 ++++++---
 net/netlabel/netlabel_unlabeled.c       | 19 +++++++++++---
 net/netlabel/netlabel_user.c            |  4 ++-
 security/security.c                     | 11 ++++----
 15 files changed, 121 insertions(+), 35 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 1d9b0e385cd0..b0d9e9fad07a 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2861,6 +2861,7 @@ static void binder_transaction(struct binder_proc *proc,
 	int t_debug_id = atomic_inc_return(&binder_last_id);
 	char *secctx = NULL;
 	u32 secctx_sz = 0;
+	struct lsmcontext scaff; /* scaffolding */
 
 	e = binder_transaction_log_add(&binder_transaction_log);
 	e->debug_id = t_debug_id;
@@ -3163,7 +3164,8 @@ static void binder_transaction(struct binder_proc *proc,
 			t->security_ctx = 0;
 			WARN_ON(1);
 		}
-		security_release_secctx(secctx, secctx_sz);
+		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
+		security_release_secctx(&scaff);
 		secctx = NULL;
 	}
 	t->buffer->debug_id = t->debug_id;
@@ -3496,8 +3498,10 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_alloc_free_buf(&target_proc->alloc, t->buffer);
 err_binder_alloc_buf_failed:
 err_bad_extra_size:
-	if (secctx)
-		security_release_secctx(secctx, secctx_sz);
+	if (secctx) {
+		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
+		security_release_secctx(&scaff);
+	}
 err_get_secctx_failed:
 	kfree(tcomplete);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 3a733ac33d9b..27932f6b4cd6 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1272,12 +1272,16 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 
 void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
 {
+#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
+	struct lsmcontext scaff; /* scaffolding */
+#endif
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	posix_acl_release(as_ctx->acl);
 	posix_acl_release(as_ctx->default_acl);
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	security_release_secctx(as_ctx->sec_ctx, as_ctx->sec_ctxlen);
+	lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
+	security_release_secctx(&scaff);
 #endif
 	if (as_ctx->pagelist)
 		ceph_pagelist_release(as_ctx->pagelist);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index dbd01548335b..079634557ad4 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -131,8 +131,12 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 static inline void
 nfs4_label_release_security(struct nfs4_label *label)
 {
-	if (label)
-		security_release_secctx(label->label, label->len);
+	struct lsmcontext scaff; /* scaffolding */
+
+	if (label) {
+		lsmcontext_init(&scaff, label->label, label->len, 0);
+		security_release_secctx(&scaff);
+	}
 }
 static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
 {
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 259d5ad0e3f4..0fc505392728 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2717,6 +2717,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+	struct lsmcontext scaff; /* scaffolding */
 	void *context = NULL;
 	int contextlen;
 #endif
@@ -3228,8 +3229,10 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context)
-		security_release_secctx(context, contextlen);
+	if (context) {
+		lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
+		security_release_secctx(&scaff);
+	}
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index 7de2b4e62f55..54d5f74d3565 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -131,6 +131,37 @@ enum lockdown_reason {
 
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
 
+/*
+ * A "security context" is the text representation of
+ * the information used by LSMs.
+ * This structure contains the string, its length, and which LSM
+ * it is useful for.
+ */
+struct lsmcontext {
+	char	*context;	/* Provided by the module */
+	u32	len;
+	int	slot;		/* Identifies the module */
+};
+
+/**
+ * lsmcontext_init - initialize an lsmcontext structure.
+ * @cp: Pointer to the context to initialize
+ * @context: Initial context, or NULL
+ * @size: Size of context, or 0
+ * @slot: Which LSM provided the context
+ *
+ * Fill in the lsmcontext from the provided information.
+ * This is a scaffolding function that will be removed when
+ * lsmcontext integration is complete.
+ */
+static inline void lsmcontext_init(struct lsmcontext *cp, char *context,
+				   u32 size, int slot)
+{
+	cp->slot = slot;
+	cp->context = context;
+	cp->len = size;
+}
+
 /*
  * Data exported by the security modules
  *
@@ -526,7 +557,7 @@ int security_ismaclabel(const char *name);
 int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
-void security_release_secctx(char *secdata, u32 seclen);
+void security_release_secctx(struct lsmcontext *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
@@ -1353,7 +1384,7 @@ static inline int security_secctx_to_secid(const char *secdata,
 	return -EOPNOTSUPP;
 }
 
-static inline void security_release_secctx(char *secdata, u32 seclen)
+static inline void security_release_secctx(struct lsmcontext *cp)
 {
 }
 
diff --git a/include/net/scm.h b/include/net/scm.h
index 31ae605fcc0a..30ba801c91bd 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -92,6 +92,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
 #ifdef CONFIG_SECURITY_NETWORK
 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 {
+	struct lsmcontext context;
 	char *secdata;
 	u32 seclen;
 	int err;
@@ -102,7 +103,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
-			security_release_secctx(secdata, seclen);
+			/*scaffolding*/
+			lsmcontext_init(&context, secdata, seclen, 0);
+			security_release_secctx(&context);
 		}
 	}
 }
diff --git a/kernel/audit.c b/kernel/audit.c
index 88b55b42756e..32be5b4cc068 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1193,6 +1193,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	struct audit_sig_info   *sig_data;
 	char			*ctx = NULL;
 	u32			len;
+	struct lsmcontext	scaff; /* scaffolding */
 
 	err = audit_netlink_ok(skb, msg_type);
 	if (err)
@@ -1450,15 +1451,18 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		}
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			if (lsmblob_is_set(&audit_sig_lsm))
-				security_release_secctx(ctx, len);
+			if (lsmblob_is_set(&audit_sig_lsm)) {
+				lsmcontext_init(&scaff, ctx, len, 0);
+				security_release_secctx(&scaff);
+			}
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			memcpy(sig_data->ctx, ctx, len);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&scaff, ctx, len, 0);
+			security_release_secctx(&scaff);
 		}
 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
 				 sig_data, sizeof(*sig_data) + len);
@@ -2130,6 +2134,7 @@ int audit_log_task_context(struct audit_buffer *ab)
 	unsigned len;
 	int error;
 	struct lsmblob blob;
+	struct lsmcontext scaff; /* scaffolding */
 
 	security_task_getsecid(current, &blob);
 	if (!lsmblob_is_set(&blob))
@@ -2143,7 +2148,8 @@ int audit_log_task_context(struct audit_buffer *ab)
 	}
 
 	audit_log_format(ab, " subj=%s", ctx);
-	security_release_secctx(ctx, len);
+	lsmcontext_init(&scaff, ctx, len, 0);
+	security_release_secctx(&scaff);
 	return 0;
 
 error_path:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b15222181700..2b06171bedeb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -998,6 +998,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
+	struct lsmcontext lsmcxt;
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
@@ -1015,7 +1016,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			rc = 1;
 		} else {
 			audit_log_format(ab, " obj=%s", ctx);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
+			security_release_secctx(&lsmcxt);
 		}
 	}
 	audit_log_format(ab, " ocomm=");
@@ -1228,6 +1230,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
 
 static void show_special(struct audit_context *context, int *call_panic)
 {
+	struct lsmcontext lsmcxt;
 	struct audit_buffer *ab;
 	int i;
 
@@ -1261,7 +1264,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 				*call_panic = 1;
 			} else {
 				audit_log_format(ab, " obj=%s", ctx);
-				security_release_secctx(ctx, len);
+				lsmcontext_init(&lsmcxt, ctx, len, 0);
+				security_release_secctx(&lsmcxt);
 			}
 		}
 		if (context->ipc.has_perm) {
@@ -1407,6 +1411,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		char *ctx = NULL;
 		u32 len;
 		struct lsmblob blob;
+		struct lsmcontext lsmcxt;
 
 		lsmblob_init(&blob, n->osid);
 		if (security_secid_to_secctx(&blob, &ctx, &len)) {
@@ -1415,7 +1420,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				*call_panic = 2;
 		} else {
 			audit_log_format(ab, " obj=%s", ctx);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
+			security_release_secctx(&lsmcxt);
 		}
 	}
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index c235c57d7469..f2ee29d55ad6 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -130,6 +130,7 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
+	struct lsmcontext context;
 	struct lsmblob lb;
 	char *secdata;
 	u32 seclen;
@@ -144,7 +145,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 		return;
 
 	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
-	security_release_secctx(secdata, seclen);
+	lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
+	security_release_secctx(&context);
 }
 
 static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 380b660d0d39..1c45ca8c3c21 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -334,6 +334,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	int len, ret;
 	char *secctx;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
 	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
 	 * security_secid_to_secctx() will know which security module
@@ -354,7 +355,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 
 	ret = 0;
 nla_put_failure:
-	security_release_secctx(secctx, len);
+	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
+	security_release_secctx(&context);
 	return ret;
 }
 #else
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 18376e68fea6..87a70159ecc9 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -176,6 +176,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	u32 len;
 	char *secctx;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
 	ret = security_secid_to_secctx(&blob, &secctx, &len);
@@ -184,7 +185,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 
 	seq_printf(s, "secctx=%s ", secctx);
 
-	security_release_secctx(secctx, len);
+	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
+	security_release_secctx(&context);
 }
 #else
 static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 7b00dc833a31..d175477d68cc 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -398,6 +398,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	enum ip_conntrack_info ctinfo;
 	struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
+	struct lsmcontext scaff; /* scaffolding */
 	char *secdata = NULL;
 	u32 seclen = 0;
 
@@ -628,8 +629,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	nlh->nlmsg_len = skb->len;
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen) {
+		lsmcontext_init(&scaff, secdata, seclen, 0);
+		security_release_secctx(&scaff);
+	}
 	return skb;
 
 nla_put_failure:
@@ -637,8 +640,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 nlmsg_failure:
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen) {
+		lsmcontext_init(&scaff, secdata, seclen, 0);
+		security_release_secctx(&scaff);
+	}
 	return NULL;
 }
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index f4a6204f4205..5785e6dcf54b 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -374,6 +374,7 @@ int netlbl_unlhsh_add(struct net *net,
 	struct net_device *dev;
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
+	struct lsmcontext context;
 	char *secctx = NULL;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -447,7 +448,9 @@ int netlbl_unlhsh_add(struct net *net,
 					     &secctx,
 					     &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			/* scaffolding */
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -478,6 +481,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct netlbl_unlhsh_addr4 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -509,7 +513,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			/* scaffolding */
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -546,6 +552,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct netlbl_unlhsh_addr6 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -576,7 +583,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -1095,6 +1103,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	int ret_val = -ENOMEM;
 	struct netlbl_unlhsh_walk_arg *cb_arg = arg;
 	struct net_device *dev;
+	struct lsmcontext context;
 	void *data;
 	u32 secid;
 	char *secctx;
@@ -1165,7 +1174,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 			  NLBL_UNLABEL_A_SECCTX,
 			  secctx_len,
 			  secctx);
-	security_release_secctx(secctx, secctx_len);
+	/* scaffolding */
+	lsmcontext_init(&context, secctx, secctx_len, 0);
+	security_release_secctx(&context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 893301ae0131..ef139d8ae7cd 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,6 +84,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -103,7 +104,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 	if (audit_info->secid != 0 &&
 	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
 		audit_log_format(audit_buf, " subj=%s", secctx);
-		security_release_secctx(secctx, secctx_len);
+		lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
+		security_release_secctx(&context);
 	}
 
 	return audit_buf;
diff --git a/security/security.c b/security/security.c
index e1c9f87db64b..a6d0b6851a66 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2227,16 +2227,17 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
-void security_release_secctx(char *secdata, u32 seclen)
+void security_release_secctx(struct lsmcontext *cp)
 {
 	struct security_hook_list *hp;
-	int display = lsm_task_display(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
-		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot) {
-			hp->hook.release_secctx(secdata, seclen);
-			return;
+		if (cp->slot == hp->lsmid->slot) {
+			hp->hook.release_secctx(cp->context, cp->len);
+			break;
 		}
+
+	memset(cp, 0, sizeof(*cp));
 }
 EXPORT_SYMBOL(security_release_secctx);
 
-- 
2.24.1

[PATCH v20 15/23] LSM: Use lsmcontext in security_secid_to_secctx

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:18:13 

Replace the (secctx,seclen) pointer pair with a single
lsmcontext pointer to allow return of the LSM identifier
along with the context and context length. This allows
security_release_secctx() to know how to release the
context. Callers have been modified to use or save the
returned data from the new structure.

Reviewed-by: Kees Cook <redacted>
Acked-by: Stephen Smalley <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 drivers/android/binder.c                | 26 +++++++---------
 include/linux/security.h                |  4 +--
 include/net/scm.h                       | 10 ++-----
 kernel/audit.c                          | 39 +++++++++++-------------
 kernel/auditsc.c                        | 31 +++++++------------
 net/ipv4/ip_sockglue.c                  |  7 ++---
 net/netfilter/nf_conntrack_netlink.c    | 18 +++++------
 net/netfilter/nf_conntrack_standalone.c |  7 ++---
 net/netfilter/nfnetlink_queue.c         |  5 +++-
 net/netlabel/netlabel_unlabeled.c       | 40 ++++++++-----------------
 net/netlabel/netlabel_user.c            |  7 ++---
 security/security.c                     | 10 +++++--
 12 files changed, 80 insertions(+), 124 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index b0d9e9fad07a..0bde1b96680e 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2859,9 +2859,7 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_size_t last_fixup_min_off = 0;
 	struct binder_context *context = proc->context;
 	int t_debug_id = atomic_inc_return(&binder_last_id);
-	char *secctx = NULL;
-	u32 secctx_sz = 0;
-	struct lsmcontext scaff; /* scaffolding */
+	struct lsmcontext lsmctx = { };
 
 	e = binder_transaction_log_add(&binder_transaction_log);
 	e->debug_id = t_debug_id;
@@ -3115,14 +3113,14 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
+		ret = security_secid_to_secctx(&blob, &lsmctx);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
 			return_error_line = __LINE__;
 			goto err_get_secctx_failed;
 		}
-		added_size = ALIGN(secctx_sz, sizeof(u64));
+		added_size = ALIGN(lsmctx.len, sizeof(u64));
 		extra_buffers_size += added_size;
 		if (extra_buffers_size < added_size) {
 			/* integer overflow of extra_buffers_size */
@@ -3149,24 +3147,22 @@ static void binder_transaction(struct binder_proc *proc,
 		t->buffer = NULL;
 		goto err_binder_alloc_buf_failed;
 	}
-	if (secctx) {
+	if (lsmctx.context) {
 		int err;
 		size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
 				    ALIGN(tr->offsets_size, sizeof(void *)) +
 				    ALIGN(extra_buffers_size, sizeof(void *)) -
-				    ALIGN(secctx_sz, sizeof(u64));
+				    ALIGN(lsmctx.len, sizeof(u64));
 
 		t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
 		err = binder_alloc_copy_to_buffer(&target_proc->alloc,
 						  t->buffer, buf_offset,
-						  secctx, secctx_sz);
+						  lsmctx.context, lsmctx.len);
 		if (err) {
 			t->security_ctx = 0;
 			WARN_ON(1);
 		}
-		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
-		security_release_secctx(&scaff);
-		secctx = NULL;
+		security_release_secctx(&lsmctx);
 	}
 	t->buffer->debug_id = t->debug_id;
 	t->buffer->transaction = t;
@@ -3222,7 +3218,7 @@ static void binder_transaction(struct binder_proc *proc,
 	off_end_offset = off_start_offset + tr->offsets_size;
 	sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
 	sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
-		ALIGN(secctx_sz, sizeof(u64));
+		ALIGN(lsmctx.len, sizeof(u64));
 	off_min = 0;
 	for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
 	     buffer_offset += sizeof(binder_size_t)) {
@@ -3498,10 +3494,8 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_alloc_free_buf(&target_proc->alloc, t->buffer);
 err_binder_alloc_buf_failed:
 err_bad_extra_size:
-	if (secctx) {
-		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
-		security_release_secctx(&scaff);
-	}
+	if (lsmctx.context)
+		security_release_secctx(&lsmctx);
 err_get_secctx_failed:
 	kfree(tcomplete);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
diff --git a/include/linux/security.h b/include/linux/security.h
index 54d5f74d3565..de6b44751dee 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -554,7 +554,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1372,7 +1372,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   char **secdata, u32 *seclen)
+					   struct lsmcontext *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index 30ba801c91bd..4a6ad8caf423 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -93,18 +93,14 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 {
 	struct lsmcontext context;
-	char *secdata;
-	u32 seclen;
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(&scm->lsmblob, &secdata,
-					       &seclen);
+		err = security_secid_to_secctx(&scm->lsmblob, &context);
 
 		if (!err) {
-			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
-			/*scaffolding*/
-			lsmcontext_init(&context, secdata, seclen, 0);
+			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY,
+				 context.len, context.context);
 			security_release_secctx(&context);
 		}
 	}
diff --git a/kernel/audit.c b/kernel/audit.c
index 32be5b4cc068..594b42fc88ff 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1191,9 +1191,6 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	struct audit_buffer	*ab;
 	u16			msg_type = nlh->nlmsg_type;
 	struct audit_sig_info   *sig_data;
-	char			*ctx = NULL;
-	u32			len;
-	struct lsmcontext	scaff; /* scaffolding */
 
 	err = audit_netlink_ok(skb, msg_type);
 	if (err)
@@ -1441,33 +1438,34 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		kfree(new);
 		break;
 	}
-	case AUDIT_SIGNAL_INFO:
-		len = 0;
+	case AUDIT_SIGNAL_INFO: {
+		struct lsmcontext context = { };
+		int len = 0;
+
 		if (lsmblob_is_set(&audit_sig_lsm)) {
-			err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
-						       &len);
+			err = security_secid_to_secctx(&audit_sig_lsm,
+						       &context);
 			if (err)
 				return err;
 		}
-		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
+		sig_data = kmalloc(sizeof(*sig_data) + context.len, GFP_KERNEL);
 		if (!sig_data) {
-			if (lsmblob_is_set(&audit_sig_lsm)) {
-				lsmcontext_init(&scaff, ctx, len, 0);
-				security_release_secctx(&scaff);
-			}
+			if (lsmblob_is_set(&audit_sig_lsm))
+				security_release_secctx(&context);
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
 		if (lsmblob_is_set(&audit_sig_lsm)) {
-			memcpy(sig_data->ctx, ctx, len);
-			lsmcontext_init(&scaff, ctx, len, 0);
-			security_release_secctx(&scaff);
+			len = context.len;
+			memcpy(sig_data->ctx, context.context, len);
+			security_release_secctx(&context);
 		}
 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
 				 sig_data, sizeof(*sig_data) + len);
 		kfree(sig_data);
 		break;
+	}
 	case AUDIT_TTY_GET: {
 		struct audit_tty_status s;
 		unsigned int t;
@@ -2130,26 +2128,23 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 
 int audit_log_task_context(struct audit_buffer *ab)
 {
-	char *ctx = NULL;
-	unsigned len;
 	int error;
 	struct lsmblob blob;
-	struct lsmcontext scaff; /* scaffolding */
+	struct lsmcontext context;
 
 	security_task_getsecid(current, &blob);
 	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	error = security_secid_to_secctx(&blob, &ctx, &len);
+	error = security_secid_to_secctx(&blob, &context);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
 		return 0;
 	}
 
-	audit_log_format(ab, " subj=%s", ctx);
-	lsmcontext_init(&scaff, ctx, len, 0);
-	security_release_secctx(&scaff);
+	audit_log_format(ab, " subj=%s", context.context);
+	security_release_secctx(&context);
 	return 0;
 
 error_path:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 2b06171bedeb..4af5861bcb9a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -998,9 +998,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
-	struct lsmcontext lsmcxt;
-	char *ctx = NULL;
-	u32 len;
+	struct lsmcontext lsmctx;
 	int rc = 0;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1011,13 +1009,12 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &ctx, &len)) {
+		if (security_secid_to_secctx(blob, &lsmctx)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
-			audit_log_format(ab, " obj=%s", ctx);
-			lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
-			security_release_secctx(&lsmcxt);
+			audit_log_format(ab, " obj=%s", lsmctx.context);
+			security_release_secctx(&lsmctx);
 		}
 	}
 	audit_log_format(ab, " ocomm=");
@@ -1230,7 +1227,6 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
 
 static void show_special(struct audit_context *context, int *call_panic)
 {
-	struct lsmcontext lsmcxt;
 	struct audit_buffer *ab;
 	int i;
 
@@ -1254,17 +1250,15 @@ static void show_special(struct audit_context *context, int *call_panic)
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
 		if (osid) {
-			char *ctx = NULL;
-			u32 len;
+			struct lsmcontext lsmcxt;
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &ctx, &len)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
-				audit_log_format(ab, " obj=%s", ctx);
-				lsmcontext_init(&lsmcxt, ctx, len, 0);
+				audit_log_format(ab, " obj=%s", lsmcxt.context);
 				security_release_secctx(&lsmcxt);
 			}
 		}
@@ -1408,20 +1402,17 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				 MAJOR(n->rdev),
 				 MINOR(n->rdev));
 	if (n->osid != 0) {
-		char *ctx = NULL;
-		u32 len;
 		struct lsmblob blob;
-		struct lsmcontext lsmcxt;
+		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &ctx, &len)) {
+		if (security_secid_to_secctx(&blob, &lsmctx)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
 		} else {
-			audit_log_format(ab, " obj=%s", ctx);
-			lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
-			security_release_secctx(&lsmcxt);
+			audit_log_format(ab, " obj=%s", lsmctx.context);
+			security_release_secctx(&lsmctx);
 		}
 	}
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index f2ee29d55ad6..58bf1f3532ae 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -132,20 +132,17 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
 	struct lsmcontext context;
 	struct lsmblob lb;
-	char *secdata;
-	u32 seclen;
 	int err;
 
 	err = security_socket_getpeersec_dgram(NULL, skb, &lb);
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(&lb, &secdata, &seclen);
+	err = security_secid_to_secctx(&lb, &context);
 	if (err)
 		return;
 
-	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
-	lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
+	put_cmsg(msg, SOL_IP, SCM_SECURITY, context.len, context.context);
 	security_release_secctx(&context);
 }
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 1c45ca8c3c21..e38b5182e301 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -331,8 +331,7 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
 static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 {
 	struct nlattr *nest_secctx;
-	int len, ret;
-	char *secctx;
+	int ret;
 	struct lsmblob blob;
 	struct lsmcontext context;
 
@@ -340,7 +339,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &secctx, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return 0;
 
@@ -349,13 +348,12 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	if (!nest_secctx)
 		goto nla_put_failure;
 
-	if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
+	if (nla_put_string(skb, CTA_SECCTX_NAME, context.context))
 		goto nla_put_failure;
 	nla_nest_end(skb, nest_secctx);
 
 	ret = 0;
 nla_put_failure:
-	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
 	security_release_secctx(&context);
 	return ret;
 }
@@ -655,15 +653,15 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 	int len, ret;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
-	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
-	 * security_secid_to_secctx() will know which security module
-	 * to use to create the secctx.  */
-	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, NULL, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return 0;
 
+	len = context.len;
+	security_release_secctx(&context);
+
 	return nla_total_size(0) /* CTA_SECCTX */
 	       + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
 #else
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 87a70159ecc9..71bec249d23b 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -173,19 +173,16 @@ static void ct_seq_stop(struct seq_file *s, void *v)
 static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 {
 	int ret;
-	u32 len;
-	char *secctx;
 	struct lsmblob blob;
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &secctx, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return;
 
-	seq_printf(s, "secctx=%s ", secctx);
+	seq_printf(s, "secctx=%s ", context.context);
 
-	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
 	security_release_secctx(&context);
 }
 #else
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index d175477d68cc..d3f8e808c5d3 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -306,6 +306,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
 	struct lsmblob blob;
+	struct lsmcontext context = { };
 
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
@@ -317,10 +318,12 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, secdata, &seclen);
+		security_secid_to_secctx(&blob, &context);
+		*secdata = context.context;
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
+	seclen = context.len;
 #endif
 	return seclen;
 }
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 5785e6dcf54b..cf4c56beb3ec 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -375,8 +375,6 @@ int netlbl_unlhsh_add(struct net *net,
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
 	struct lsmcontext context;
-	char *secctx = NULL;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
@@ -444,12 +442,9 @@ int netlbl_unlhsh_add(struct net *net,
 		 * security_secid_to_secctx() will know which security module
 		 * to use to create the secctx.  */
 		lsmblob_init(&blob, secid);
-		if (security_secid_to_secctx(&blob,
-					     &secctx,
-					     &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			/* scaffolding */
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		if (security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
@@ -482,8 +477,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
@@ -510,11 +503,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (entry != NULL)
 			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			/* scaffolding */
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		    security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -553,8 +544,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
@@ -580,10 +569,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (entry != NULL)
 			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		    security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -1106,8 +1094,6 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	struct lsmcontext context;
 	void *data;
 	u32 secid;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
@@ -1167,15 +1153,13 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
          * security_secid_to_secctx() will know which security module
          * to use to create the secctx.  */
 	lsmblob_init(&blob, secid);
-	ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
+	ret_val = security_secid_to_secctx(&blob, &context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
 			  NLBL_UNLABEL_A_SECCTX,
-			  secctx_len,
-			  secctx);
-	/* scaffolding */
-	lsmcontext_init(&context, secctx, secctx_len, 0);
+			  context.len,
+			  context.context);
 	security_release_secctx(&context);
 	if (ret_val != 0)
 		goto list_cb_failure;
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index ef139d8ae7cd..951ba0639d20 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -85,8 +85,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 {
 	struct audit_buffer *audit_buf;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
@@ -102,9 +100,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 
 	lsmblob_init(&blob, audit_info->secid);
 	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
-		audit_log_format(audit_buf, " subj=%s", secctx);
-		lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
+	    security_secid_to_secctx(&blob, &context) == 0) {
+		audit_log_format(audit_buf, " subj=%s", context.context);
 		security_release_secctx(&context);
 	}
 
diff --git a/security/security.c b/security/security.c
index a6d0b6851a66..862f0bc2f114 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2191,18 +2191,22 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
 {
 	struct security_hook_list *hp;
 	int display = lsm_task_display(current);
 
+	memset(cp, 0, sizeof(*cp));
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot)
+		if (display == LSMBLOB_INVALID || display == hp->lsmid->slot) {
+			cp->slot = hp->lsmid->slot;
 			return hp->hook.secid_to_secctx(
 					blob->secid[hp->lsmid->slot],
-					secdata, seclen);
+					&cp->context, &cp->len);
+		}
 	}
 
 	return LSM_RET_DEFAULT(secid_to_secctx);
-- 
2.24.1

[PATCH v20 16/23] LSM: Use lsmcontext in security_inode_getsecctx

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:19:13 

Change the security_inode_getsecctx() interface to fill
a lsmcontext structure instead of data and length pointers.
This provides the information about which LSM created the
context so that security_release_secctx() can use the
correct hook.

Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 fs/nfsd/nfs4xdr.c        | 23 +++++++++--------------
 include/linux/security.h |  5 +++--
 security/security.c      | 13 +++++++++++--
 3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 0fc505392728..9352c05f3086 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2600,11 +2600,11 @@ nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 {
 	__be32 *p;
 
-	p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
+	p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
 	if (!p)
 		return nfserr_resource;
 
@@ -2614,13 +2614,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 	 */
 	*p++ = cpu_to_be32(0); /* lfs */
 	*p++ = cpu_to_be32(0); /* pi */
-	p = xdr_encode_opaque(p, context, len);
+	p = xdr_encode_opaque(p, context->context, context->len);
 	return 0;
 }
 #else
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 { return 0; }
 #endif
 
@@ -2717,9 +2717,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	struct lsmcontext scaff; /* scaffolding */
-	void *context = NULL;
-	int contextlen;
+	struct lsmcontext context = { };
 #endif
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
@@ -2777,7 +2775,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
 			err = security_inode_getsecctx(d_inode(dentry),
-						&context, &contextlen);
+						       &context);
 		else
 			err = -EOPNOTSUPP;
 		contextsupport = (err == 0);
@@ -3207,8 +3205,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
-		status = nfsd4_encode_security_label(xdr, rqstp, context,
-								contextlen);
+		status = nfsd4_encode_security_label(xdr, rqstp, &context);
 		if (status)
 			goto out;
 	}
@@ -3229,10 +3226,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context) {
-		lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
-		security_release_secctx(&scaff);
-	}
+	if (context.context)
+		security_release_secctx(&context);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index de6b44751dee..40260bfc3a0d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -561,7 +561,7 @@ void security_release_secctx(struct lsmcontext *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp);
 int security_locked_down(enum lockdown_reason what);
 #else /* CONFIG_SECURITY */
 
@@ -1400,7 +1400,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
 {
 	return -EOPNOTSUPP;
 }
-static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static inline int security_inode_getsecctx(struct inode *inode,
+					   struct lsmcontext *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index 862f0bc2f114..ddbaf2073b02 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2263,9 +2263,18 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 }
 EXPORT_SYMBOL(security_inode_setsecctx);
 
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp)
 {
-	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen);
+	struct security_hook_list *hp;
+
+	memset(cp, 0, sizeof(*cp));
+
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) {
+		cp->slot = hp->lsmid->slot;
+		return hp->hook.inode_getsecctx(inode, (void **)&cp->context,
+						&cp->len);
+	}
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
-- 
2.24.1

[PATCH v20 17/23] LSM: security_secid_to_secctx in netlink netfilter

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:20:31 

Change netlink netfilter interfaces to use lsmcontext
pointers, and remove scaffolding.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: netdev@vger.kernel.org
---
 net/netfilter/nfnetlink_queue.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index d3f8e808c5d3..c830401f7792 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -301,12 +301,10 @@ static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk)
 	return -1;
 }
 
-static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
+static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 {
-	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
 	struct lsmblob blob;
-	struct lsmcontext context = { };
 
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
@@ -318,14 +316,14 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, &context);
-		*secdata = context.context;
+		security_secid_to_secctx(&blob, context);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
-	seclen = context.len;
+	return context->len;
+#else
+	return 0;
 #endif
-	return seclen;
 }
 
 static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry)
@@ -401,8 +399,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	enum ip_conntrack_info ctinfo;
 	struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
-	struct lsmcontext scaff; /* scaffolding */
-	char *secdata = NULL;
+	struct lsmcontext context = { };
 	u32 seclen = 0;
 
 	size = nlmsg_total_size(sizeof(struct nfgenmsg))
@@ -469,7 +466,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) {
-		seclen = nfqnl_get_sk_secctx(entskb, &secdata);
+		seclen = nfqnl_get_sk_secctx(entskb, &context);
 		if (seclen)
 			size += nla_total_size(seclen);
 	}
@@ -604,7 +601,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	    nfqnl_put_sk_uidgid(skb, entskb->sk) < 0)
 		goto nla_put_failure;
 
-	if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata))
+	if (seclen && nla_put(skb, NFQA_SECCTX, context.len, context.context))
 		goto nla_put_failure;
 
 	if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
@@ -632,10 +629,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	nlh->nlmsg_len = skb->len;
-	if (seclen) {
-		lsmcontext_init(&scaff, secdata, seclen, 0);
-		security_release_secctx(&scaff);
-	}
+	if (seclen)
+		security_release_secctx(&context);
 	return skb;
 
 nla_put_failure:
@@ -643,10 +638,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 nlmsg_failure:
-	if (seclen) {
-		lsmcontext_init(&scaff, secdata, seclen, 0);
-		security_release_secctx(&scaff);
-	}
+	if (seclen)
+		security_release_secctx(&context);
 	return NULL;
 }
 
-- 
2.24.1

[PATCH v20 18/23] NET: Store LSM netlabel data in a lsmblob

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:21:30 

Netlabel uses LSM interfaces requiring an lsmblob and
the internal storage is used to pass information between
these interfaces, so change the internal data from a secid
to a lsmblob. Update the netlabel interfaces and their
callers to accommodate the change. This requires that the
modules using netlabel use the lsm_id.slot to access the
correct secid when using netlabel.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 include/net/netlabel.h              |  8 +--
 net/ipv4/cipso_ipv4.c               | 27 ++++++----
 net/netlabel/netlabel_kapi.c        |  6 +--
 net/netlabel/netlabel_unlabeled.c   | 79 +++++++++--------------------
 net/netlabel/netlabel_unlabeled.h   |  2 +-
 security/selinux/hooks.c            |  2 +-
 security/selinux/include/security.h |  1 +
 security/selinux/netlabel.c         |  2 +-
 security/selinux/ss/services.c      |  4 +-
 security/smack/smack.h              |  1 +
 security/smack/smack_lsm.c          |  5 +-
 security/smack/smackfs.c            | 10 ++--
 12 files changed, 65 insertions(+), 82 deletions(-)

diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 43ae50337685..73fc25b4042b 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -166,7 +166,7 @@ struct netlbl_lsm_catmap {
  * @attr.mls: MLS sensitivity label
  * @attr.mls.cat: MLS category bitmap
  * @attr.mls.lvl: MLS sensitivity level
- * @attr.secid: LSM specific secid token
+ * @attr.lsmblob: LSM specific data
  *
  * Description:
  * This structure is used to pass security attributes between NetLabel and the
@@ -201,7 +201,7 @@ struct netlbl_lsm_secattr {
 			struct netlbl_lsm_catmap *cat;
 			u32 lvl;
 		} mls;
-		u32 secid;
+		struct lsmblob lsmblob;
 	} attr;
 };
 
@@ -415,7 +415,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 				const void *addr,
 				const void *mask,
 				u16 family,
-				u32 secid,
+				struct lsmblob *lsmblob,
 				struct netlbl_audit *audit_info);
 int netlbl_cfg_unlbl_static_del(struct net *net,
 				const char *dev_name,
@@ -523,7 +523,7 @@ static inline int netlbl_cfg_unlbl_static_add(struct net *net,
 					      const void *addr,
 					      const void *mask,
 					      u16 family,
-					      u32 secid,
+					      struct lsmblob *lsmblob,
 					      struct netlbl_audit *audit_info)
 {
 	return -ENOSYS;
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 2eb71579f4d2..8182b923e802 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -106,15 +106,17 @@ int cipso_v4_rbm_strictvalid = 1;
 /* Base length of the local tag (non-standard tag).
  *  Tag definition (may change between kernel versions)
  *
- * 0          8          16         24         32
- * +----------+----------+----------+----------+
- * | 10000000 | 00000110 | 32-bit secid value  |
- * +----------+----------+----------+----------+
- * | in (host byte order)|
- * +----------+----------+
- *
+ * 0          8          16                    16 + sizeof(struct lsmblob)
+ * +----------+----------+---------------------+
+ * | 10000000 | 00000110 | LSM blob data       |
+ * +----------+----------+---------------------+
+ *
+ * All secid and flag fields are in host byte order.
+ * The lsmblob structure size varies depending on which
+ * Linux security modules are built in the kernel.
+ * The data is opaque.
  */
-#define CIPSO_V4_TAG_LOC_BLEN         6
+#define CIPSO_V4_TAG_LOC_BLEN         (2 + sizeof(struct lsmblob))
 
 /*
  * Helper Functions
@@ -1469,7 +1471,12 @@ static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
 
 	buffer[0] = CIPSO_V4_TAG_LOCAL;
 	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
-	*(u32 *)&buffer[2] = secattr->attr.secid;
+	/* Ensure that there is sufficient space in the CIPSO header
+	 * for the LSM data. This should never become an issue.
+	 * The check is made from an abundance of caution. */
+	BUILD_BUG_ON(CIPSO_V4_TAG_LOC_BLEN > CIPSO_V4_OPT_LEN_MAX);
+	memcpy(&buffer[2], &secattr->attr.lsmblob,
+	       sizeof(secattr->attr.lsmblob));
 
 	return CIPSO_V4_TAG_LOC_BLEN;
 }
@@ -1489,7 +1496,7 @@ static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
 				 const unsigned char *tag,
 				 struct netlbl_lsm_secattr *secattr)
 {
-	secattr->attr.secid = *(u32 *)&tag[2];
+	memcpy(&secattr->attr.lsmblob, &tag[2], sizeof(secattr->attr.lsmblob));
 	secattr->flags |= NETLBL_SECATTR_SECID;
 
 	return 0;
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index 5e1239cef000..bbfaff539416 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -196,7 +196,7 @@ int netlbl_cfg_unlbl_map_add(const char *domain,
  * @addr: IP address in network byte order (struct in[6]_addr)
  * @mask: address mask in network byte order (struct in[6]_addr)
  * @family: address family
- * @secid: LSM secid value for the entry
+ * @lsmblob: LSM data value for the entry
  * @audit_info: NetLabel audit information
  *
  * Description:
@@ -210,7 +210,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 				const void *addr,
 				const void *mask,
 				u16 family,
-				u32 secid,
+				struct lsmblob *lsmblob,
 				struct netlbl_audit *audit_info)
 {
 	u32 addr_len;
@@ -230,7 +230,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 
 	return netlbl_unlhsh_add(net,
 				 dev_name, addr, mask, addr_len,
-				 secid, audit_info);
+				 lsmblob, audit_info);
 }
 
 /**
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index cf4c56beb3ec..c14a485ff045 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -66,7 +66,7 @@ struct netlbl_unlhsh_tbl {
 #define netlbl_unlhsh_addr4_entry(iter) \
 	container_of(iter, struct netlbl_unlhsh_addr4, list)
 struct netlbl_unlhsh_addr4 {
-	u32 secid;
+	struct lsmblob lsmblob;
 
 	struct netlbl_af4list list;
 	struct rcu_head rcu;
@@ -74,7 +74,7 @@ struct netlbl_unlhsh_addr4 {
 #define netlbl_unlhsh_addr6_entry(iter) \
 	container_of(iter, struct netlbl_unlhsh_addr6, list)
 struct netlbl_unlhsh_addr6 {
-	u32 secid;
+	struct lsmblob lsmblob;
 
 	struct netlbl_af6list list;
 	struct rcu_head rcu;
@@ -220,7 +220,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
  * @iface: the associated interface entry
  * @addr: IPv4 address in network byte order
  * @mask: IPv4 address mask in network byte order
- * @secid: LSM secid value for entry
+ * @lsmblob: LSM data value for entry
  *
  * Description:
  * Add a new address entry into the unlabeled connection hash table using the
@@ -231,7 +231,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
 static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 				   const struct in_addr *addr,
 				   const struct in_addr *mask,
-				   u32 secid)
+				   struct lsmblob *lsmblob)
 {
 	int ret_val;
 	struct netlbl_unlhsh_addr4 *entry;
@@ -243,7 +243,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 	entry->list.addr = addr->s_addr & mask->s_addr;
 	entry->list.mask = mask->s_addr;
 	entry->list.valid = 1;
-	entry->secid = secid;
+	entry->lsmblob = *lsmblob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	ret_val = netlbl_af4list_add(&entry->list, &iface->addr4_list);
@@ -260,7 +260,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
  * @iface: the associated interface entry
  * @addr: IPv6 address in network byte order
  * @mask: IPv6 address mask in network byte order
- * @secid: LSM secid value for entry
+ * @lsmblob: LSM data value for entry
  *
  * Description:
  * Add a new address entry into the unlabeled connection hash table using the
@@ -271,7 +271,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
 				   const struct in6_addr *addr,
 				   const struct in6_addr *mask,
-				   u32 secid)
+				   struct lsmblob *lsmblob)
 {
 	int ret_val;
 	struct netlbl_unlhsh_addr6 *entry;
@@ -287,7 +287,7 @@ static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
 	entry->list.addr.s6_addr32[3] &= mask->s6_addr32[3];
 	entry->list.mask = *mask;
 	entry->list.valid = 1;
-	entry->secid = secid;
+	entry->lsmblob = *lsmblob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	ret_val = netlbl_af6list_add(&entry->list, &iface->addr6_list);
@@ -366,7 +366,7 @@ int netlbl_unlhsh_add(struct net *net,
 		      const void *addr,
 		      const void *mask,
 		      u32 addr_len,
-		      u32 secid,
+		      struct lsmblob *lsmblob,
 		      struct netlbl_audit *audit_info)
 {
 	int ret_val;
@@ -375,7 +375,6 @@ int netlbl_unlhsh_add(struct net *net,
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
 	    addr_len != sizeof(struct in6_addr))
@@ -408,7 +407,7 @@ int netlbl_unlhsh_add(struct net *net,
 		const struct in_addr *addr4 = addr;
 		const struct in_addr *mask4 = mask;
 
-		ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, secid);
+		ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, lsmblob);
 		if (audit_buf != NULL)
 			netlbl_af4list_audit_addr(audit_buf, 1,
 						  dev_name,
@@ -421,7 +420,7 @@ int netlbl_unlhsh_add(struct net *net,
 		const struct in6_addr *addr6 = addr;
 		const struct in6_addr *mask6 = mask;
 
-		ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, secid);
+		ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, lsmblob);
 		if (audit_buf != NULL)
 			netlbl_af6list_audit_addr(audit_buf, 1,
 						  dev_name,
@@ -438,11 +437,7 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		/* lsmblob_init() puts secid into all of the secids in blob.
-		 * security_secid_to_secctx() will know which security module
-		 * to use to create the secctx.  */
-		lsmblob_init(&blob, secid);
-		if (security_secid_to_secctx(&blob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -477,7 +472,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
@@ -497,13 +491,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		if (dev != NULL)
 			dev_put(dev);
-		/* lsmblob_init() puts entry->secid into all of the secids
-		 * in blob. security_secid_to_secctx() will know which
-		 * security module to use to create the secctx.  */
-		if (entry != NULL)
-			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -544,7 +533,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
@@ -563,13 +551,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		if (dev != NULL)
 			dev_put(dev);
-		/* lsmblob_init() puts entry->secid into all of the secids
-		 * in blob. security_secid_to_secctx() will know which
-		 * security module to use to create the secctx.  */
-		if (entry != NULL)
-			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -923,14 +906,8 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	if (ret_val != 0)
 		return ret_val;
 
-	/* netlbl_unlhsh_add will be changed to pass a struct lsmblob *
-	 * instead of a u32 later in this patch set. security_secctx_to_secid()
-	 * will only be setting one entry in the lsmblob struct, so it is
-	 * safe to use lsmblob_value() to get that one value. */
-
-	return netlbl_unlhsh_add(&init_net,
-				 dev_name, addr, mask, addr_len,
-				 lsmblob_value(&blob), &audit_info);
+	return netlbl_unlhsh_add(&init_net, dev_name, addr, mask, addr_len,
+				 &blob, &audit_info);
 }
 
 /**
@@ -977,11 +954,8 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	if (ret_val != 0)
 		return ret_val;
 
-	/* security_secctx_to_secid() will only put one secid into the lsmblob
-	 * so it's safe to use lsmblob_value() to get the secid. */
-	return netlbl_unlhsh_add(&init_net,
-				 NULL, addr, mask, addr_len,
-				 lsmblob_value(&blob), &audit_info);
+	return netlbl_unlhsh_add(&init_net, NULL, addr, mask, addr_len, &blob,
+				 &audit_info);
 }
 
 /**
@@ -1093,8 +1067,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	struct net_device *dev;
 	struct lsmcontext context;
 	void *data;
-	u32 secid;
-	struct lsmblob blob;
+	struct lsmblob *lsmb;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
 			   cb_arg->seq, &netlbl_unlabel_gnl_family,
@@ -1132,7 +1105,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		if (ret_val != 0)
 			goto list_cb_failure;
 
-		secid = addr4->secid;
+		lsmb = (struct lsmblob *)&addr4->lsmblob;
 	} else {
 		ret_val = nla_put_in6_addr(cb_arg->skb,
 					   NLBL_UNLABEL_A_IPV6ADDR,
@@ -1146,14 +1119,10 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		if (ret_val != 0)
 			goto list_cb_failure;
 
-		secid = addr6->secid;
+		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-        /* lsmblob_init() secid into all of the secids in blob.
-         * security_secid_to_secctx() will know which security module
-         * to use to create the secctx.  */
-	lsmblob_init(&blob, secid);
-	ret_val = security_secid_to_secctx(&blob, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1505,7 +1474,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
 					      &iface->addr4_list);
 		if (addr4 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = netlbl_unlhsh_addr4_entry(addr4)->secid;
+		secattr->attr.lsmblob = netlbl_unlhsh_addr4_entry(addr4)->lsmblob;
 		break;
 	}
 #if IS_ENABLED(CONFIG_IPV6)
@@ -1518,7 +1487,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
 					      &iface->addr6_list);
 		if (addr6 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = netlbl_unlhsh_addr6_entry(addr6)->secid;
+		secattr->attr.lsmblob = netlbl_unlhsh_addr6_entry(addr6)->lsmblob;
 		break;
 	}
 #endif /* IPv6 */
diff --git a/net/netlabel/netlabel_unlabeled.h b/net/netlabel/netlabel_unlabeled.h
index 058e3a285d56..168920780994 100644
--- a/net/netlabel/netlabel_unlabeled.h
+++ b/net/netlabel/netlabel_unlabeled.h
@@ -211,7 +211,7 @@ int netlbl_unlhsh_add(struct net *net,
 		      const void *addr,
 		      const void *mask,
 		      u32 addr_len,
-		      u32 secid,
+		      struct lsmblob *lsmblob,
 		      struct netlbl_audit *audit_info);
 int netlbl_unlhsh_remove(struct net *net,
 			 const char *dev_name,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f73dec68ee32..89c22769506b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6945,7 +6945,7 @@ static int selinux_perf_event_write(struct perf_event *event)
 }
 #endif
 
-static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
+struct lsm_id selinux_lsmid __lsm_ro_after_init = {
 	.lsm  = "selinux",
 	.slot = LSMBLOB_NEEDED
 };
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index b0e02cfe3ce1..cee2987647dd 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -71,6 +71,7 @@
 struct netlbl_lsm_secattr;
 
 extern int selinux_enabled_boot;
+extern struct lsm_id selinux_lsmid;
 
 /* Policy capabilities */
 enum {
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 6a94b31b5472..d8d7603ab14e 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -108,7 +108,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
 		return NULL;
 
 	if ((secattr->flags & NETLBL_SECATTR_SECID) &&
-	    (secattr->attr.secid == sid))
+	    (secattr->attr.lsmblob.secid[selinux_lsmid.slot] == sid))
 		return secattr;
 
 	return NULL;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 1caf4e603309..ffad57e41168 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -3637,7 +3637,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
 	if (secattr->flags & NETLBL_SECATTR_CACHE)
 		*sid = *(u32 *)secattr->cache->data;
 	else if (secattr->flags & NETLBL_SECATTR_SECID)
-		*sid = secattr->attr.secid;
+		*sid = secattr->attr.lsmblob.secid[selinux_lsmid.slot];
 	else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
 		rc = -EIDRM;
 		ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
@@ -3710,7 +3710,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
 	if (secattr->domain == NULL)
 		goto out;
 
-	secattr->attr.secid = sid;
+	secattr->attr.lsmblob.secid[selinux_lsmid.slot] = sid;
 	secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
 	mls_export_netlbl_lvl(policydb, ctx, secattr);
 	rc = mls_export_netlbl_cat(policydb, ctx, secattr);
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 7481fa71de19..c284b104e1cc 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -310,6 +310,7 @@ void smk_destroy_label_list(struct list_head *list);
  * Shared data.
  */
 extern int smack_enabled;
+extern struct lsm_id smack_lsmid;
 extern int smack_cipso_direct;
 extern int smack_cipso_mapped;
 extern struct smack_known *smack_net_ambient;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 8b708cca921a..6f0cdb40addc 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3751,7 +3751,8 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 		/*
 		 * Looks like a fallback, which gives us a secid.
 		 */
-		return smack_from_secid(sap->attr.secid);
+		return smack_from_secid(
+				sap->attr.lsmblob.secid[smack_lsmid.slot]);
 	/*
 	 * Without guidance regarding the smack value
 	 * for the packet fall back on the network
@@ -4656,7 +4657,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_sock = sizeof(struct socket_smack),
 };
 
-static struct lsm_id smack_lsmid __lsm_ro_after_init = {
+struct lsm_id smack_lsmid __lsm_ro_after_init = {
 	.lsm  = "smack",
 	.slot = LSMBLOB_NEEDED
 };
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 9c4308077574..dcabf6bd8faa 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -1136,6 +1136,7 @@ static void smk_net4addr_insert(struct smk_net4addr *new)
 static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
+	struct lsmblob lsmblob;
 	struct smk_net4addr *snp;
 	struct sockaddr_in newname;
 	char *smack;
@@ -1267,10 +1268,13 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 	 * this host so that incoming packets get labeled.
 	 * but only if we didn't get the special CIPSO option
 	 */
-	if (rc == 0 && skp != NULL)
+	if (rc == 0 && skp != NULL) {
+		lsmblob_init(&lsmblob, 0);
+		lsmblob.secid[smack_lsmid.slot] = snp->smk_label->smk_secid;
 		rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
-			&snp->smk_host, &snp->smk_mask, PF_INET,
-			snp->smk_label->smk_secid, &audit_info);
+			&snp->smk_host, &snp->smk_mask, PF_INET, &lsmblob,
+			&audit_info);
+	}
 
 	if (rc == 0)
 		rc = count;
-- 
2.24.1

[PATCH v20 19/23] LSM: Verify LSM display sanity in binder

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:22:38 

Verify that the tasks on the ends of a binder transaction
use the same "display" security module. This prevents confusion
of security "contexts".

Reviewed-by: Kees Cook <redacted>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/security.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/security/security.c b/security/security.c
index ddbaf2073b02..95b48721fb17 100644
--- a/security/security.c
+++ b/security/security.c
@@ -788,9 +788,38 @@ int security_binder_set_context_mgr(struct task_struct *mgr)
 	return call_int_hook(binder_set_context_mgr, 0, mgr);
 }
 
+/**
+ * security_binder_transaction - Binder driver transaction check
+ * @from: source of the transaction
+ * @to: destination of the transaction
+ *
+ * Verify that the tasks have the same LSM "display", then
+ * call the security module hooks.
+ *
+ * Returns -EINVAL if the displays don't match, or the
+ * result of the security module checks.
+ */
 int security_binder_transaction(struct task_struct *from,
 				struct task_struct *to)
 {
+	int from_display = lsm_task_display(from);
+	int to_display = lsm_task_display(to);
+
+	/*
+	 * If the display is LSMBLOB_INVALID the first module that has
+	 * an entry is used. This will be in the 0 slot.
+	 *
+	 * This is currently only required if the server has requested
+	 * peer contexts, but it would be unwieldly to have too much of
+	 * the binder driver detail here.
+	 */
+	if (from_display == LSMBLOB_INVALID)
+		from_display = 0;
+	if (to_display == LSMBLOB_INVALID)
+		to_display = 0;
+	if (from_display != to_display)
+		return -EINVAL;
+
 	return call_int_hook(binder_transaction, 0, from, to);
 }
 
-- 
2.24.1

[PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:23:38 

Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
---
 drivers/android/binder.c                |  2 +-
 include/linux/audit.h                   | 13 +++-
 include/linux/security.h                | 18 ++++-
 include/net/netlabel.h                  |  2 +-
 include/net/scm.h                       |  3 +-
 include/net/xfrm.h                      |  4 +-
 include/uapi/linux/audit.h              |  1 +
 kernel/audit.c                          | 89 ++++++++++++++++++-------
 kernel/auditfilter.c                    |  2 +-
 kernel/auditsc.c                        | 87 ++++++++++++++++++++++--
 net/ipv4/ip_sockglue.c                  |  2 +-
 net/netfilter/nf_conntrack_netlink.c    |  4 +-
 net/netfilter/nf_conntrack_standalone.c |  2 +-
 net/netfilter/nfnetlink_queue.c         |  2 +-
 net/netlabel/netlabel_unlabeled.c       | 16 ++---
 net/netlabel/netlabel_user.c            | 12 ++--
 net/netlabel/netlabel_user.h            |  6 +-
 security/integrity/integrity_audit.c    |  2 +-
 security/security.c                     | 73 +++++++++++++++-----
 security/smack/smackfs.c                |  3 +-
 20 files changed, 259 insertions(+), 84 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 0bde1b96680e..93781dad0c28 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3113,7 +3113,7 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &lsmctx);
+		ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index ba1cd38d601b..fe027df0d9a8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,7 +186,9 @@ extern void		    audit_log_path_denied(int type,
 						  const char *operation);
 extern void		    audit_log_lost(const char *message);
 
-extern int audit_log_task_context(struct audit_buffer *ab);
+extern void audit_log_lsm(struct lsmblob *blob, bool exiting);
+extern int audit_log_task_context(struct audit_buffer *ab,
+				  struct lsmblob *blob);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
 extern int		    audit_update_lsm_rules(void);
@@ -246,7 +248,10 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
 { }
 static inline void audit_log_path_denied(int type, const char *operation)
 { }
-static inline int audit_log_task_context(struct audit_buffer *ab)
+static inline void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{ }
+static inline int audit_log_task_context(struct audit_buffer *ab,
+					 struct lsmblob *blob);
 {
 	return 0;
 }
@@ -305,6 +310,7 @@ extern void audit_seccomp(unsigned long syscall, long signr, int code);
 extern void audit_seccomp_actions_logged(const char *names,
 					 const char *old_names, int res);
 extern void __audit_ptrace(struct task_struct *t);
+extern void audit_stamp_context(struct audit_context *ctx);
 
 static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
 {
@@ -682,6 +688,9 @@ static inline void audit_ntp_log(const struct audit_ntp_data *ad)
 static inline void audit_ptrace(struct task_struct *t)
 { }
 
+static inline void audit_stamp_context(struct audit_context *ctx)
+{ }
+
 static inline void audit_log_nfcfg(const char *name, u8 af,
 				   unsigned int nentries,
 				   enum audit_nfcfgop op, gfp_t gfp)
diff --git a/include/linux/security.h b/include/linux/security.h
index 40260bfc3a0d..3cbe24be1563 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -180,6 +180,8 @@ struct lsmblob {
 #define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
 #define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
 #define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+#define LSMBLOB_DISPLAY		-4	/* Use the "display" slot */
+#define LSMBLOB_FIRST		-5	/* Use the default "display" slot */
 
 /**
  * lsmblob_init - initialize an lsmblob structure.
@@ -242,6 +244,17 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
 	return 0;
 }
 
+const char *security_lsm_slot_name(int slot);
+
+static inline bool lsm_multiple_contexts(void)
+{
+#ifdef CONFIG_SECURITY
+	return security_lsm_slot_name(1) != NULL;
+#else
+	return false;
+#endif
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -554,7 +567,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1372,7 +1386,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   struct lsmcontext *cp)
+					   struct lsmcontext *cp, int display)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 73fc25b4042b..216cb1ffc8f0 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -97,7 +97,7 @@ struct calipso_doi;
 
 /* NetLabel audit information */
 struct netlbl_audit {
-	u32 secid;
+	struct lsmblob lsmdata;
 	kuid_t loginuid;
 	unsigned int sessionid;
 };
diff --git a/include/net/scm.h b/include/net/scm.h
index 4a6ad8caf423..8b5a4737e1b8 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -96,7 +96,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(&scm->lsmblob, &context);
+		err = security_secid_to_secctx(&scm->lsmblob, &context,
+					       LSMBLOB_DISPLAY);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY,
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 2737d24ec244..9e8cac6228b4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -675,11 +675,13 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
+	audit_stamp_context(audit_context());
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
 				    AUDIT_MAC_IPSEC_EVENT);
 	if (audit_buf == NULL)
 		return NULL;
 	audit_log_format(audit_buf, "op=%s", op);
+	audit_log_lsm(NULL, false);
 	return audit_buf;
 }
 
@@ -693,7 +695,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
 		AUDIT_SID_UNSET;
 
 	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
-	audit_log_task_context(audit_buf);
+	audit_log_task_context(audit_buf, NULL);
 }
 
 void xfrm_audit_policy_add(struct xfrm_policy *xp, int result, bool task_valid);
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index cd2d8279a5e4..2a63720e56f6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -139,6 +139,7 @@
 #define AUDIT_MAC_UNLBL_STCDEL	1417	/* NetLabel: del a static label */
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 594b42fc88ff..0e7831c9f321 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -394,10 +394,11 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
 		return rc;
 	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
 	audit_log_session_info(ab);
-	rc = audit_log_task_context(ab);
+	rc = audit_log_task_context(ab, NULL);
 	if (rc)
 		allow_changes = 0; /* Something weird, deny request */
 	audit_log_format(ab, " res=%d", allow_changes);
+	audit_log_lsm(NULL, false);
 	audit_log_end(ab);
 	return rc;
 }
@@ -1070,13 +1071,31 @@ static void audit_log_common_recv_msg(struct audit_context *context,
 		return;
 	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
 	audit_log_session_info(*ab);
-	audit_log_task_context(*ab);
+	audit_log_task_context(*ab, NULL);
 }
 
 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
 					   u16 msg_type)
 {
-	audit_log_common_recv_msg(NULL, ab, msg_type);
+	struct audit_context *context;
+
+	if (!lsm_multiple_contexts()) {
+		audit_log_common_recv_msg(NULL, ab, msg_type);
+		return;
+	}
+
+	context = audit_context();
+	if (context) {
+		if (!context->in_syscall)
+			audit_stamp_context(context);
+		audit_log_common_recv_msg(context, ab, msg_type);
+		return;
+	}
+
+	audit_alloc(current);
+	context = audit_context();
+
+	audit_log_common_recv_msg(context, ab, msg_type);
 }
 
 int is_audit_feature_set(int i)
@@ -1372,6 +1391,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				audit_log_n_untrustedstring(ab, str, data_len);
 			}
 			audit_log_end(ab);
+			audit_log_lsm(NULL, false);
 		}
 		break;
 	case AUDIT_ADD_RULE:
@@ -1444,7 +1464,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			err = security_secid_to_secctx(&audit_sig_lsm,
-						       &context);
+						       &context, LSMBLOB_FIRST);
 			if (err)
 				return err;
 		}
@@ -1572,7 +1592,7 @@ static void audit_log_multicast(int group, const char *op, int err)
 			 tty ? tty_name(tty) : "(none)",
 			 audit_get_sessionid(current));
 	audit_put_tty(tty);
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm); /* exe= */
@@ -1869,6 +1889,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	}
 
 	audit_get_stamp(ab->ctx, &t, &serial);
+	if (type == AUDIT_MAC_TASK_CONTEXTS && ab->ctx->serial == 0) {
+		audit_stamp_context(ab->ctx);
+		audit_get_stamp(ab->ctx, &t, &serial);
+	}
 	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
 			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
 
@@ -2126,30 +2150,47 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 		audit_log_format(ab, "(null)");
 }
 
-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob)
 {
+	int i;
 	int error;
-	struct lsmblob blob;
-	struct lsmcontext context;
+	struct lsmblob localblob;
+	struct lsmcontext lsmdata;
 
-	security_task_getsecid(current, &blob);
-	if (!lsmblob_is_set(&blob))
+	/*
+	 * If there is more than one security module that has a
+	 * subject "context" it's necessary to put the subject data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		audit_log_format(ab, " subj=?");
 		return 0;
+	}
 
-	error = security_secid_to_secctx(&blob, &context);
-	if (error) {
-		if (error != -EINVAL)
-			goto error_path;
-		return 0;
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob)) {
+			audit_log_format(ab, " subj=?");
+			return 0;
+		}
+		blob = &localblob;
 	}
 
-	audit_log_format(ab, " subj=%s", context.context);
-	security_release_secctx(&context);
-	return 0;
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_task_context");
+			return error;
+		}
 
-error_path:
-	audit_panic("error in audit_log_task_context");
-	return error;
+		audit_log_format(ab, " subj=%s", lsmdata.context);
+		security_release_secctx(&lsmdata);
+		break;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
@@ -2221,7 +2262,7 @@ void audit_log_task_info(struct audit_buffer *ab)
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 }
 EXPORT_SYMBOL(audit_log_task_info);
 
@@ -2279,6 +2320,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	if (!audit_enabled)
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
 	if (!ab)
 		return;
@@ -2289,11 +2331,12 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	tty = audit_get_tty();
 
 	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
 			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
 			 oldsessionid, sessionid, !rc);
 	audit_put_tty(tty);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 31732023b689..6c03e463668e 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1107,7 +1107,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 	if (!ab)
 		return;
 	audit_log_session_info(ab);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s", action);
 	audit_log_key(ab, rule->filterkey);
 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4af5861bcb9a..cf5dbd0e3a3d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -473,7 +473,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 {
 	const struct cred *cred;
 	int i, need_sid = 1;
-	struct lsmblob blob;
+	struct lsmblob blob = { };
 	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
@@ -962,10 +962,12 @@ int audit_alloc(struct task_struct *tsk)
 		return 0; /* Return if not auditing. */
 
 	state = audit_filter_task(tsk, &key);
-	if (state == AUDIT_DISABLED) {
+	if (!lsm_multiple_contexts() && state == AUDIT_DISABLED) {
 		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 		return 0;
 	}
+	if (state == AUDIT_DISABLED)
+		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 
 	if (!(context = audit_alloc_context(state))) {
 		kfree(key);
@@ -1009,7 +1011,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx)) {
+		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1254,7 +1256,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt,
+						     LSMBLOB_FIRST)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1406,7 +1409,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx)) {
+		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
@@ -1483,6 +1486,52 @@ static void audit_log_proctitle(void)
 	audit_log_end(ab);
 }
 
+void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{
+	struct audit_context *context = audit_context();
+	struct lsmcontext lsmdata;
+	struct audit_buffer *ab;
+	struct lsmblob localblob;
+	bool sep = false;
+	int error;
+	int i;
+
+	if (!lsm_multiple_contexts())
+		return;
+
+	if (context && context->in_syscall && !exiting)
+		return;
+
+	ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
+	if (!ab)
+		return;	/* audit_panic or being filtered */
+
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob))
+			return;
+		blob = &localblob;
+	}
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_lsm");
+			return;
+		}
+
+		audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
+				 security_lsm_slot_name(i), lsmdata.context);
+		sep = true;
+
+		security_release_secctx(&lsmdata);
+	}
+
+	audit_log_end(ab);
+}
+
 static void audit_log_exit(void)
 {
 	int i, call_panic = 0;
@@ -1606,6 +1655,7 @@ static void audit_log_exit(void)
 	}
 
 	audit_log_proctitle();
+	audit_log_lsm(NULL, true);
 
 	/* Send end of event record to help user space know we are finished */
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
@@ -2217,6 +2267,21 @@ void __audit_inode_child(struct inode *parent,
 }
 EXPORT_SYMBOL_GPL(__audit_inode_child);
 
+/**
+ * audit_stamp_context - set the timestamp+serial in an audit context
+ * @ctx: audit_context to set
+ */
+void audit_stamp_context(struct audit_context *ctx)
+{
+	/* ctx will be NULL unless lsm_multiple_contexts() is true */
+	if (!ctx)
+		return;
+
+	ktime_get_coarse_real_ts64(&ctx->ctime);
+	ctx->serial = audit_serial();
+	ctx->current_state = AUDIT_BUILD_CONTEXT;
+}
+ 
 /**
  * auditsc_get_stamp - get local copies of audit_context values
  * @ctx: audit_context for the task
@@ -2228,6 +2293,12 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 int auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec64 *t, unsigned int *serial)
 {
+	if (ctx->serial && !ctx->in_syscall) {
+		t->tv_sec  = ctx->ctime.tv_sec;
+		t->tv_nsec = ctx->ctime.tv_nsec;
+		*serial    = ctx->serial;
+		return 1;
+	}
 	if (!ctx->in_syscall)
 		return 0;
 	if (!ctx->serial)
@@ -2622,7 +2693,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 			 name, af, nentries, audit_nfcfgs[op].s);
 
 	audit_log_format(ab, " pid=%u", task_pid_nr(current));
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_end(ab);
@@ -2645,7 +2716,7 @@ static void audit_log_task(struct audit_buffer *ab)
 			 from_kuid(&init_user_ns, uid),
 			 from_kgid(&init_user_ns, gid),
 			 sessionid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
@@ -2668,11 +2739,13 @@ void audit_core_dumps(long signr)
 	if (signr == SIGQUIT)	/* don't care for those */
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
 	if (unlikely(!ab))
 		return;
 	audit_log_task(ab);
 	audit_log_format(ab, " sig=%ld res=1", signr);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 58bf1f3532ae..16fa8f1fb4e0 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -138,7 +138,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(&lb, &context);
+	err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index e38b5182e301..3c90b9a488d5 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -339,7 +339,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
@@ -655,7 +655,7 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 	struct lsmblob blob;
 	struct lsmcontext context;
 
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 71bec249d23b..ca01bf2b73c2 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -177,7 +177,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index c830401f7792..9c557f9091ab 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -316,7 +316,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, context);
+		security_secid_to_secctx(&blob, context, LSMBLOB_DISPLAY);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index c14a485ff045..99579fa49293 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -437,7 +437,8 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(lsmblob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -492,7 +493,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -552,7 +554,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -1122,7 +1125,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-	ret_val = security_secid_to_secctx(lsmb, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context, LSMBLOB_FIRST);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1521,14 +1524,11 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
-	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid(current, &blob);
-	/* scaffolding until audit_info.secid is converted */
-	audit_info.secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info.lsmdata);
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..4e9064754b5f 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,12 +84,12 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
-	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
 
+	audit_stamp_context(audit_context());
+
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
 	if (audit_buf == NULL)
 		return NULL;
@@ -98,12 +98,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
-	lsmblob_init(&blob, audit_info->secid);
-	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &context) == 0) {
-		audit_log_format(audit_buf, " subj=%s", context.context);
-		security_release_secctx(&context);
-	}
+	audit_log_task_context(audit_buf, &audit_info->lsmdata);
+	audit_log_lsm(&audit_info->lsmdata, false);
 
 	return audit_buf;
 }
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 438b5db6c714..bd4335443b87 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,11 +34,7 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	struct lsmblob blob;
-
-	security_task_getsecid(current, &blob);
-	/* scaffolding until secid is converted */
-	audit_info->secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info->lsmdata);
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index f25e7df099c8..418f7e45753d 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -50,7 +50,7 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
 			 from_kuid(&init_user_ns, current_cred()->uid),
 			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
 			 audit_get_sessionid(current));
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s cause=%s comm=", op, cause);
 	audit_log_untrustedstring(ab, get_task_comm(name, current));
 	if (fname) {
diff --git a/security/security.c b/security/security.c
index 95b48721fb17..4752291376bf 100644
--- a/security/security.c
+++ b/security/security.c
@@ -480,7 +480,31 @@ static int lsm_append(const char *new, char **result)
  * Pointers to the LSM id structures for local use.
  */
 static int lsm_slot __lsm_ro_after_init;
-static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES];
+static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES] __lsm_ro_after_init;
+
+/**
+ * security_lsm_slot_name - Get the name of the security module in a slot
+ * @slot: index into the "display" slot list.
+ *
+ * Provide the name of the security module associated with
+ * a display slot.
+ *
+ * If @slot is LSMBLOB_INVALID return the value
+ * for slot 0 if it has been set, otherwise NULL.
+ *
+ * Returns a pointer to the name string or NULL.
+ */
+const char *security_lsm_slot_name(int slot)
+{
+	if (slot == LSMBLOB_INVALID)
+		slot = 0;
+	else if (slot >= LSMBLOB_ENTRIES || slot < 0)
+		return NULL;
+
+	if (lsm_slotlist[slot] == NULL)
+		return NULL;
+	return lsm_slotlist[slot]->lsm;
+}
 
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
@@ -2175,7 +2199,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
 				     list) {
 			rc = hp->hook.setprocattr(name, value, size);
-			if (rc < 0)
+			if (rc < 0 && rc != -EINVAL)
 				return rc;
 		}
 
@@ -2220,13 +2244,32 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display)
 {
 	struct security_hook_list *hp;
-	int display = lsm_task_display(current);
 
 	memset(cp, 0, sizeof(*cp));
 
+	/*
+	 * display either is the slot number use for formatting
+	 * or an instruction on which relative slot to use.
+	 */
+	if (display == LSMBLOB_DISPLAY)
+		display = lsm_task_display(current);
+	else if (display == LSMBLOB_FIRST)
+		display = LSMBLOB_INVALID;
+	else if (display < 0) {
+		WARN_ONCE(true,
+			"LSM: %s unknown display\n", __func__);
+		display = LSMBLOB_INVALID;
+	} else if (display >= lsm_slot) {
+		WARN_ONCE(true,
+			"LSM: %s invalid display\n", __func__);
+		display = LSMBLOB_INVALID;
+	}
+
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
@@ -2256,7 +2299,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			return hp->hook.secctx_to_secid(secdata, seclen,
 						&blob->secid[hp->lsmid->slot]);
 	}
-	return 0;
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2757,23 +2800,17 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
 	struct security_hook_list *hp;
-	bool one_is_good = false;
-	int rc = 0;
-	int trc;
+	int display = lsm_task_display(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		trc = hp->hook.audit_rule_init(field, op, rulestr,
-					       &lsmrule[hp->lsmid->slot]);
-		if (trc == 0)
-			one_is_good = true;
-		else
-			rc = trc;
+		if (display != LSMBLOB_INVALID && display != hp->lsmid->slot)
+			continue;
+		return hp->hook.audit_rule_init(field, op, rulestr,
+						&lsmrule[hp->lsmid->slot]);
 	}
-	if (one_is_good)
-		return 0;
-	return rc;
+	return 0;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2805,6 +2842,8 @@ int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			continue;
 		if (lsmrule[hp->lsmid->slot] == NULL)
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
 					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index dcabf6bd8faa..15fa4b7eb2e6 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -185,7 +185,8 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap)
 
 	nap->loginuid = audit_get_loginuid(current);
 	nap->sessionid = audit_get_sessionid(current);
-	nap->secid = skp->smk_secid;
+	lsmblob_init(&nap->lsmdata, 0);
+	nap->lsmdata.secid[smack_lsmid.slot] = skp->smk_secid;
 }
 
 /*
-- 
2.24.1

[PATCH v20 21/23] Audit: Add a new record for multiple object LSM attributes

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:24:42 

Create a new audit record type to contain the object information
when there are multiple security modules that require such data.
This record is emitted before the other records for the event, but
is linked with the same timestamp and serial number.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
---
 include/linux/audit.h      |  2 ++
 include/uapi/linux/audit.h |  1 +
 kernel/audit.c             | 53 +++++++++++++++++++++++++++++
 kernel/audit.h             |  4 +--
 kernel/auditsc.c           | 70 +++++---------------------------------
 5 files changed, 67 insertions(+), 63 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index fe027df0d9a8..55cc03c1bed8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -189,6 +189,8 @@ extern void		    audit_log_lost(const char *message);
 extern void audit_log_lsm(struct lsmblob *blob, bool exiting);
 extern int audit_log_task_context(struct audit_buffer *ab,
 				  struct lsmblob *blob);
+extern int audit_log_object_context(struct audit_buffer *ab,
+				    struct lsmblob *blob);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
 extern int		    audit_update_lsm_rules(void);
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 2a63720e56f6..dbb1dce16962 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -140,6 +140,7 @@
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
 #define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
+#define AUDIT_MAC_OBJ_CONTEXTS	1421	/* Multiple LSM object contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 0e7831c9f321..8991a0c0ba0b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2194,6 +2194,59 @@ int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob)
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
+int audit_log_object_context(struct audit_buffer *ab,
+				    struct lsmblob *blob)
+{
+	int i;
+	int error;
+	bool sep = false;
+	struct lsmcontext lsmdata;
+	struct audit_buffer *lsmab = NULL;
+	struct audit_context *context = NULL;
+
+	/*
+	 * If there is more than one security module that has a
+	 * object "context" it's necessary to put the object data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		audit_log_format(ab, " obj=?");
+		context = ab->ctx;
+		if (context)
+			lsmab = audit_log_start(context, GFP_KERNEL,
+						AUDIT_MAC_OBJ_CONTEXTS);
+	}
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_object_context");
+			return error;
+		}
+
+		if (context) {
+			audit_log_format(lsmab, "%sobj_%s=%s",
+					 sep ? " " : "",
+					 security_lsm_slot_name(i),
+					 lsmdata.context);
+			sep = true;
+		} else
+			audit_log_format(ab, " obj=%s", lsmdata.context);
+
+		security_release_secctx(&lsmdata);
+		if (!context)
+			break;
+	}
+
+	if (context)
+		audit_log_end(lsmab);
+
+	return 0;
+}
+EXPORT_SYMBOL(audit_log_object_context);
+
 void audit_log_d_path_exe(struct audit_buffer *ab,
 			  struct mm_struct *mm)
 {
diff --git a/kernel/audit.h b/kernel/audit.h
index ec0cfa7364cc..ab9d4a466198 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -78,7 +78,7 @@ struct audit_names {
 	kuid_t			uid;
 	kgid_t			gid;
 	dev_t			rdev;
-	u32			osid;
+	struct lsmblob		oblob;
 	struct audit_cap_data	fcap;
 	unsigned int		fcap_ver;
 	unsigned char		type;		/* record type */
@@ -152,7 +152,7 @@ struct audit_context {
 			kuid_t			uid;
 			kgid_t			gid;
 			umode_t			mode;
-			u32			osid;
+			struct lsmblob		oblob;
 			int			has_perm;
 			uid_t			perm_uid;
 			gid_t			perm_gid;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index cf5dbd0e3a3d..7269deb4a348 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -688,14 +688,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
-					/*
-					 * lsmblob_init sets all values in the
-					 * lsmblob to sid. This is temporary
-					 * until name->osid is converted to a
-					 * lsmblob, which happens later in
-					 * this patch set.
-					 */
-					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
 								&blob,
 								f->type,
@@ -703,7 +695,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
-						lsmblob_init(&blob, name->osid);
 						if (security_audit_rule_match(
 								&blob,
 								f->type,
@@ -717,8 +708,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				lsmblob_init(&blob, ctx->ipc.osid);
-				if (security_audit_rule_match(&blob,
+				if (security_audit_rule_match(&ctx->ipc.oblob,
 							      f->type, f->op,
 							      f->lsm_rules))
 					++result;
@@ -1000,7 +990,6 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
-	struct lsmcontext lsmctx;
 	int rc = 0;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1010,15 +999,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
-	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
-			audit_log_format(ab, " obj=(none)");
-			rc = 1;
-		} else {
-			audit_log_format(ab, " obj=%s", lsmctx.context);
-			security_release_secctx(&lsmctx);
-		}
-	}
+	rc = audit_log_object_context(ab, blob);
 	audit_log_format(ab, " ocomm=");
 	audit_log_untrustedstring(ab, comm);
 	audit_log_end(ab);
@@ -1245,26 +1226,14 @@ static void show_special(struct audit_context *context, int *call_panic)
 				context->socketcall.args[i]);
 		break; }
 	case AUDIT_IPC: {
-		u32 osid = context->ipc.osid;
+		struct lsmblob *oblob = &context->ipc.oblob;
 
 		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
 				 from_kuid(&init_user_ns, context->ipc.uid),
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
-		if (osid) {
-			struct lsmcontext lsmcxt;
-			struct lsmblob blob;
-
-			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt,
-						     LSMBLOB_FIRST)) {
-				audit_log_format(ab, " osid=%u", osid);
-				*call_panic = 1;
-			} else {
-				audit_log_format(ab, " obj=%s", lsmcxt.context);
-				security_release_secctx(&lsmcxt);
-			}
-		}
+		if (audit_log_object_context(ab, oblob))
+			*call_panic = 1;
 		if (context->ipc.has_perm) {
 			audit_log_end(ab);
 			ab = audit_log_start(context, GFP_KERNEL,
@@ -1404,20 +1373,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				 from_kgid(&init_user_ns, n->gid),
 				 MAJOR(n->rdev),
 				 MINOR(n->rdev));
-	if (n->osid != 0) {
-		struct lsmblob blob;
-		struct lsmcontext lsmctx;
-
-		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
-			audit_log_format(ab, " osid=%u", n->osid);
-			if (call_panic)
-				*call_panic = 2;
-		} else {
-			audit_log_format(ab, " obj=%s", lsmctx.context);
-			security_release_secctx(&lsmctx);
-		}
-	}
+	if (audit_log_object_context(ab, &n->oblob) && call_panic)
+		*call_panic = 2;
 
 	/* log the audit_names record type */
 	switch (n->type) {
@@ -2026,17 +1983,13 @@ static void audit_copy_inode(struct audit_names *name,
 			     const struct dentry *dentry,
 			     struct inode *inode, unsigned int flags)
 {
-	struct lsmblob blob;
-
 	name->ino   = inode->i_ino;
 	name->dev   = inode->i_sb->s_dev;
 	name->mode  = inode->i_mode;
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &blob);
-	/* scaffolding until osid is updated */
-	name->osid = blob.secid[0];
+	security_inode_getsecid(inode, &name->oblob);
 	if (flags & AUDIT_INODE_NOEVAL) {
 		name->fcap_ver = -1;
 		return;
@@ -2403,16 +2356,11 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
 	struct audit_context *context = audit_context();
-	struct lsmblob blob;
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	security_ipc_getsecid(ipcp, &blob);
-	/* context->ipc.osid will be changed to a lsmblob later in
-	 * the patch series. This will allow auditing of all the object
-	 * labels associated with the ipc object. */
-	context->ipc.osid = lsmblob_value(&blob);
+	security_ipc_getsecid(ipcp, &context->ipc.oblob);
 	context->type = AUDIT_IPC;
 }
 
-- 
2.24.1

[PATCH v20 22/23] LSM: Add /proc attr entry for full LSM context

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:25:46 

Add an entry /proc/.../attr/context which displays the full
process security "context" in compound format:
        lsm1\0value\0lsm2\0value\0...
This entry is not writable.

A security module may decide that its policy does not allow
this information to be displayed. In this case none of the
information will be displayed.

Reviewed-by: Kees Cook <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-api@vger.kernel.org
---
 Documentation/security/lsm.rst       | 28 ++++++++++
 fs/proc/base.c                       |  1 +
 include/linux/lsm_hooks.h            |  6 +++
 security/apparmor/include/procattr.h |  2 +-
 security/apparmor/lsm.c              |  8 ++-
 security/apparmor/procattr.c         | 22 ++++----
 security/security.c                  | 79 ++++++++++++++++++++++++++++
 security/selinux/hooks.c             |  2 +-
 security/smack/smack_lsm.c           |  2 +-
 9 files changed, 135 insertions(+), 15 deletions(-)

diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
index 6a2a2e973080..fd4c87358d54 100644
--- a/Documentation/security/lsm.rst
+++ b/Documentation/security/lsm.rst
@@ -129,3 +129,31 @@ to identify it as the first security module to be registered.
 The capabilities security module does not use the general security
 blobs, unlike other modules. The reasons are historical and are
 based on overhead, complexity and performance concerns.
+
+LSM External Interfaces
+=======================
+
+The LSM infrastructure does not generally provide external interfaces.
+The individual security modules provide what external interfaces they
+require.
+
+The file ``/sys/kernel/security/lsm`` provides a comma
+separated list of the active security modules.
+
+The file ``/proc/pid/attr/display`` contains the name of the security
+module for which the ``/proc/pid/attr/current`` interface will
+apply. This interface can be written to.
+
+The infrastructure does provide an interface for the special
+case where multiple security modules provide a process context.
+This is provided in compound context format.
+
+-  `lsm\0value\0lsm\0value\0`
+
+The `lsm` and `value` fields are nul terminated bytestrings.
+Each field may contain whitespace or non-printable characters.
+The nul bytes are included in the size of a compound context.
+The context ``Bell\0Secret\0Biba\0Loose\0`` has a size of 23.
+
+The file ``/proc/pid/attr/context`` provides the security
+context of the identified process.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 2edb51d4c725..a6802573c238 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2804,6 +2804,7 @@ static const struct pid_entry attr_dir_stuff[] = {
 	ATTR(NULL, "keycreate",		0666),
 	ATTR(NULL, "sockcreate",	0666),
 	ATTR(NULL, "display",		0666),
+	ATTR(NULL, "context",		0444),
 #ifdef CONFIG_SECURITY_SMACK
 	DIR("smack",			0555,
 	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index e559df1df169..b99d51c6771c 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1359,6 +1359,12 @@
  *	@pages contains the number of pages.
  *	Return 0 if permission is granted.
  *
+ * @getprocattr:
+ *	Provide the named process attribute for display in special files in
+ *	the /proc/.../attr directory.  Attribute naming and the data displayed
+ *	is at the discretion of the security modules.  The exception is the
+ *	"context" attribute, which will contain the security context of the
+ *	task as a nul terminated text string without trailing whitespace.
  * @ismaclabel:
  *	Check if the extended attribute specified by @name
  *	represents a MAC label. Returns 1 if name is a MAC
diff --git a/security/apparmor/include/procattr.h b/security/apparmor/include/procattr.h
index 31689437e0e1..03dbfdb2f2c0 100644
--- a/security/apparmor/include/procattr.h
+++ b/security/apparmor/include/procattr.h
@@ -11,7 +11,7 @@
 #ifndef __AA_PROCATTR_H
 #define __AA_PROCATTR_H
 
-int aa_getprocattr(struct aa_label *label, char **string);
+int aa_getprocattr(struct aa_label *label, char **string, bool newline);
 int aa_setprocattr_changehat(char *args, size_t size, int flags);
 
 #endif /* __AA_PROCATTR_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 31a6f11890f1..7ce570b0f491 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -593,6 +593,7 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 	const struct cred *cred = get_task_cred(task);
 	struct aa_task_ctx *ctx = task_ctx(current);
 	struct aa_label *label = NULL;
+	bool newline = true;
 
 	if (strcmp(name, "current") == 0)
 		label = aa_get_newest_label(cred_label(cred));
@@ -600,11 +601,14 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 		label = aa_get_newest_label(ctx->previous);
 	else if (strcmp(name, "exec") == 0 && ctx->onexec)
 		label = aa_get_newest_label(ctx->onexec);
-	else
+	else if (strcmp(name, "context") == 0) {
+		label = aa_get_newest_label(cred_label(cred));
+		newline = false;
+	} else
 		error = -EINVAL;
 
 	if (label)
-		error = aa_getprocattr(label, value);
+		error = aa_getprocattr(label, value, newline);
 
 	aa_put_label(label);
 	put_cred(cred);
diff --git a/security/apparmor/procattr.c b/security/apparmor/procattr.c
index c929bf4a3df1..be3b083d9b74 100644
--- a/security/apparmor/procattr.c
+++ b/security/apparmor/procattr.c
@@ -20,6 +20,7 @@
  * aa_getprocattr - Return the profile information for @profile
  * @profile: the profile to print profile info about  (NOT NULL)
  * @string: Returns - string containing the profile info (NOT NULL)
+ * @newline: Should a newline be added to @string.
  *
  * Returns: length of @string on success else error on failure
  *
@@ -30,20 +31,21 @@
  *
  * Returns: size of string placed in @string else error code on failure
  */
-int aa_getprocattr(struct aa_label *label, char **string)
+int aa_getprocattr(struct aa_label *label, char **string, bool newline)
 {
 	struct aa_ns *ns = labels_ns(label);
 	struct aa_ns *current_ns = aa_get_current_ns();
+	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED;
 	int len;
 
 	if (!aa_ns_visible(current_ns, ns, true)) {
 		aa_put_ns(current_ns);
 		return -EACCES;
 	}
+	if (newline)
+		flags |= FLAG_SHOW_MODE;
 
-	len = aa_label_snxprint(NULL, 0, current_ns, label,
-				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
-				FLAG_HIDDEN_UNCONFINED);
+	len = aa_label_snxprint(NULL, 0, current_ns, label, flags);
 	AA_BUG(len < 0);
 
 	*string = kmalloc(len + 2, GFP_KERNEL);
@@ -52,19 +54,19 @@ int aa_getprocattr(struct aa_label *label, char **string)
 		return -ENOMEM;
 	}
 
-	len = aa_label_snxprint(*string, len + 2, current_ns, label,
-				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
-				FLAG_HIDDEN_UNCONFINED);
+	len = aa_label_snxprint(*string, len + 2, current_ns, label, flags);
 	if (len < 0) {
 		aa_put_ns(current_ns);
 		return len;
 	}
 
-	(*string)[len] = '\n';
-	(*string)[len + 1] = 0;
+	if (newline) {
+		(*string)[len] = '\n';
+		(*string)[++len] = 0;
+	}
 
 	aa_put_ns(current_ns);
-	return len + 1;
+	return len;
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index 4752291376bf..537df0839404 100644
--- a/security/security.c
+++ b/security/security.c
@@ -754,6 +754,57 @@ static void __init lsm_early_task(struct task_struct *task)
 		panic("%s: Early task alloc failed.\n", __func__);
 }
 
+/**
+ * append_ctx - append a lsm/context pair to a compound context
+ * @ctx: the existing compound context
+ * @ctxlen: size of the old context, including terminating nul byte
+ * @lsm: new lsm name, nul terminated
+ * @new: new context, possibly nul terminated
+ * @newlen: maximum size of @new
+ *
+ * replace @ctx with a new compound context, appending @newlsm and @new
+ * to @ctx. On exit the new data replaces the old, which is freed.
+ * @ctxlen is set to the new size, which includes a trailing nul byte.
+ *
+ * Returns 0 on success, -ENOMEM if no memory is available.
+ */
+static int append_ctx(char **ctx, int *ctxlen, const char *lsm, char *new,
+		      int newlen)
+{
+	char *final;
+	size_t llen;
+	size_t nlen;
+	size_t flen;
+
+	llen = strlen(lsm) + 1;
+	/*
+	 * A security module may or may not provide a trailing nul on
+	 * when returning a security context. There is no definition
+	 * of which it should be, and there are modules that do it
+	 * each way.
+	 */
+	nlen = strnlen(new, newlen);
+
+	flen = *ctxlen + llen + nlen + 1;
+	final = kzalloc(flen, GFP_KERNEL);
+
+	if (final == NULL)
+		return -ENOMEM;
+
+	if (*ctxlen)
+		memcpy(final, *ctx, *ctxlen);
+
+	memcpy(final + *ctxlen, lsm, llen);
+	memcpy(final + *ctxlen + llen, new, nlen);
+
+	kfree(*ctx);
+
+	*ctx = final;
+	*ctxlen = flen;
+
+	return 0;
+}
+
 /*
  * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
  * can be accessed with:
@@ -2124,6 +2175,10 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 				char **value)
 {
 	struct security_hook_list *hp;
+	char *final = NULL;
+	char *cp;
+	int rc = 0;
+	int finallen = 0;
 	int display = lsm_task_display(current);
 	int slot = 0;
 
@@ -2151,6 +2206,30 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 		return -ENOMEM;
 	}
 
+	if (!strcmp(name, "context")) {
+		hlist_for_each_entry(hp, &security_hook_heads.getprocattr,
+				     list) {
+			rc = hp->hook.getprocattr(p, "context", &cp);
+			if (rc == -EINVAL)
+				continue;
+			if (rc < 0) {
+				kfree(final);
+				return rc;
+			}
+			rc = append_ctx(&final, &finallen, hp->lsmid->lsm,
+					cp, rc);
+			kfree(cp);
+			if (rc < 0) {
+				kfree(final);
+				return rc;
+			}
+		}
+		if (final == NULL)
+			return -EINVAL;
+		*value = final;
+		return finallen;
+	}
+
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 89c22769506b..09379ea04fc4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6293,7 +6293,7 @@ static int selinux_getprocattr(struct task_struct *p,
 			goto bad;
 	}
 
-	if (!strcmp(name, "current"))
+	if (!strcmp(name, "current") || !strcmp(name, "context"))
 		sid = __tsec->sid;
 	else if (!strcmp(name, "prev"))
 		sid = __tsec->osid;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6f0cdb40addc..d7bb6442f192 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3463,7 +3463,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 	char *cp;
 	int slen;
 
-	if (strcmp(name, "current") != 0)
+	if (strcmp(name, "current") != 0 && strcmp(name, "context") != 0)
 		return -EINVAL;
 
 	cp = kstrdup(skp->smk_known, GFP_KERNEL);
-- 
2.24.1

[PATCH v20 23/23] AppArmor: Remove the exclusive flag

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:26:53 

With the inclusion of the "display" process attribute
mechanism AppArmor no longer needs to be treated as an
"exclusive" security module. Remove the flag that indicates
it is exclusive. Remove the stub getpeersec_dgram AppArmor
hook as it has no effect in the single LSM case and
interferes in the multiple LSM case.

Acked-by: Stephen Smalley <redacted>
Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/apparmor/lsm.c | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 7ce570b0f491..4b7cbe9bb1be 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1129,22 +1129,6 @@ static int apparmor_socket_getpeersec_stream(struct socket *sock,
 	return error;
 }
 
-/**
- * apparmor_socket_getpeersec_dgram - get security label of packet
- * @sock: the peer socket
- * @skb: packet data
- * @secid: pointer to where to put the secid of the packet
- *
- * Sets the netlabel socket state on sk from parent
- */
-static int apparmor_socket_getpeersec_dgram(struct socket *sock,
-					    struct sk_buff *skb, u32 *secid)
-
-{
-	/* TODO: requires secid support */
-	return -ENOPROTOOPT;
-}
-
 /**
  * apparmor_sock_graft - Initialize newly created socket
  * @sk: child sock
@@ -1248,8 +1232,6 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 #endif
 	LSM_HOOK_INIT(socket_getpeersec_stream,
 		      apparmor_socket_getpeersec_stream),
-	LSM_HOOK_INIT(socket_getpeersec_dgram,
-		      apparmor_socket_getpeersec_dgram),
 	LSM_HOOK_INIT(sock_graft, apparmor_sock_graft),
 #ifdef CONFIG_NETWORK_SECMARK
 	LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request),
@@ -1918,7 +1900,7 @@ static int __init apparmor_init(void)
 
 DEFINE_LSM(apparmor) = {
 	.name = "apparmor",
-	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
+	.flags = LSM_FLAG_LEGACY_MAJOR,
 	.enabled = &apparmor_enabled,
 	.blobs = &apparmor_blob_sizes,
 	.init = apparmor_init,
-- 
2.24.1

Re: [PATCH v20 00/23] LSM: Module stacking for AppArmor

From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2020-08-26 15:27:09 

On 8/26/2020 7:52 AM, Casey Schaufler wrote:
This patchset provides the changes required for
the AppArmor security module to stack safely with any other.

v20: Rebase to 5.9-rc1
     Change the BPF security module to use the lsmblob data. (patch 0002)
     Repair length logic in subject label processing (patch 0015)
     Handle -EINVAL from the empty BPF setprocattr hook (patch 0020)
     Correct length processing in append_ctx() (patch 0022)
...

https://github.com/cschaufler/lsm-stacking.git#stack-5.8-rc6-a-v19
https://github.com/cschaufler/lsm-stacking.git#stack-5.9-rc1-v20

Sorry about the old URL.

Re: [PATCH v20 22/23] LSM: Add /proc attr entry for full LSM context

From: Randy Dunlap <hidden>
Date: 2020-08-26 18:03:08 

Hi,

On 8/26/20 7:52 AM, Casey Schaufler wrote:
quoted hunk
diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
index 6a2a2e973080..fd4c87358d54 100644
--- a/Documentation/security/lsm.rst
+++ b/Documentation/security/lsm.rst
@@ -129,3 +129,31 @@ to identify it as the first security module to be registered.
 The capabilities security module does not use the general security
 blobs, unlike other modules. The reasons are historical and are
 based on overhead, complexity and performance concerns.
+
+LSM External Interfaces
+=======================
+
+The LSM infrastructure does not generally provide external interfaces.
+The individual security modules provide what external interfaces they
+require.
+
+The file ``/sys/kernel/security/lsm`` provides a comma
+separated list of the active security modules.
+
+The file ``/proc/pid/attr/display`` contains the name of the security
+module for which the ``/proc/pid/attr/current`` interface will
+apply. This interface can be written to.
+
+The infrastructure does provide an interface for the special
+case where multiple security modules provide a process context.
+This is provided in compound context format.
+
+-  `lsm\0value\0lsm\0value\0`
+
+The `lsm` and `value` fields are nul terminated bytestrings.
Preferably                          NUL-terminated

+Each field may contain whitespace or non-printable characters.
+The nul bytes are included in the size of a compound context.
       NUL

+The context ``Bell\0Secret\0Biba\0Loose\0`` has a size of 23.
+
+The file ``/proc/pid/attr/context`` provides the security
+context of the identified process.

thanks.
-- 
~Randy
Reported-by: Randy Dunlap <redacted>

Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

From: James Morris <jmorris@namei.org>
Date: 2020-09-03 16:28:56 

On Wed, 26 Aug 2020, Casey Schaufler wrote:

Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
This needs some review by networking folk, and/or LSM maintainers. You 
should probably cc netdev on anything touching the networking code.
quoted hunk
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index e2ef982b3dd7..ae623b89cdf4 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1398,7 +1398,8 @@ int security_socket_shutdown(struct socket *sock, int how);
 int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb);
 int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				      int __user *optlen, unsigned len);
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid);
+int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+				     struct lsmblob *blob);
 int security_sk_alloc(struct sock *sk, int family, gfp_t priority);
 void security_sk_free(struct sock *sk);
 void security_sk_clone(const struct sock *sk, struct sock *newsk);
@@ -1536,7 +1537,9 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
 	return -ENOPROTOOPT;
 }
 
-static inline int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
+static inline int security_socket_getpeersec_dgram(struct socket *sock,
+						   struct sk_buff *skb,
+						   struct lsmblob *blob)
 {
 	return -ENOPROTOOPT;
 }
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
 	kgid_t			gid;
 	struct scm_fp_list	*fp;		/* Passed files		*/
 #ifdef CONFIG_SECURITY_NETWORK
-	u32			secid;		/* Security ID		*/
+	struct lsmblob		lsmblob;	/* Security LSM data	*/
 #endif
 	u32			consumed;
 } __randomize_layout;
diff --git a/include/net/scm.h b/include/net/scm.h
index 1ce365f4c256..e2e71c4bf9d0 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -33,7 +33,7 @@ struct scm_cookie {
 	struct scm_fp_list	*fp;		/* Passed files		*/
 	struct scm_creds	creds;		/* Skb credentials	*/
 #ifdef CONFIG_SECURITY_NETWORK
-	u32			secid;		/* Passed security ID 	*/
+	struct lsmblob		lsmblob;	/* Passed LSM data	*/
 #endif
 };
 
@@ -46,7 +46,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
 #ifdef CONFIG_SECURITY_NETWORK
 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
 {
-	security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
+	security_socket_getpeersec_dgram(sock, NULL, &scm->lsmblob);
 }
 #else
 static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
@@ -97,7 +97,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
+		/* Scaffolding - it has to be element 0 for now */
+		err = security_secid_to_secctx(scm->lsmblob.secid[0],
+					       &secdata, &seclen);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index d2c223554ff7..551dfbc717e9 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -130,15 +130,17 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
+	struct lsmblob lb;
 	char *secdata;
-	u32 seclen, secid;
+	u32 seclen;
 	int err;
 
-	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
+	err = security_socket_getpeersec_dgram(NULL, skb, &lb);
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(secid, &secdata, &seclen);
+	/* Scaffolding - it has to be element 0 */
+	err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
 	if (err)
 		return;
 
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 181ea6fb56a6..c15668b80d1d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -138,17 +138,17 @@ static struct hlist_head *unix_sockets_unbound(void *addr)
 #ifdef CONFIG_SECURITY_NETWORK
 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	UNIXCB(skb).secid = scm->secid;
+	UNIXCB(skb).lsmblob = scm->lsmblob;
 }
 
 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	scm->secid = UNIXCB(skb).secid;
+	scm->lsmblob = UNIXCB(skb).lsmblob;
 }
 
 static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
 {
-	return (scm->secid == UNIXCB(skb).secid);
+	return lsmblob_equal(&scm->lsmblob, &(UNIXCB(skb).lsmblob));
 }
 #else
 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
diff --git a/security/security.c b/security/security.c
index d6d882b1f7d5..c42873876954 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2219,10 +2219,22 @@ int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				optval, optlen, len);
 }
 
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
+int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+				     struct lsmblob *blob)
 {
-	return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock,
-			     skb, secid);
+	struct security_hook_list *hp;
+	int rc = -ENOPROTOOPT;
+
+	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_dgram,
+			     list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.socket_getpeersec_dgram(sock, skb,
+						&blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			break;
+	}
+	return rc;
 }
 EXPORT_SYMBOL(security_socket_getpeersec_dgram);
 
-- 
James Morris
[off-list ref]

Re: [PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes

From: James Morris <jmorris@namei.org>
Date: 2020-09-03 16:32:30 

On Wed, 26 Aug 2020, Casey Schaufler wrote:

Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Paul, can you review/ack the audit changes?
quoted hunk
---
 drivers/android/binder.c                |  2 +-
 include/linux/audit.h                   | 13 +++-
 include/linux/security.h                | 18 ++++-
 include/net/netlabel.h                  |  2 +-
 include/net/scm.h                       |  3 +-
 include/net/xfrm.h                      |  4 +-
 include/uapi/linux/audit.h              |  1 +
 kernel/audit.c                          | 89 ++++++++++++++++++-------
 kernel/auditfilter.c                    |  2 +-
 kernel/auditsc.c                        | 87 ++++++++++++++++++++++--
 net/ipv4/ip_sockglue.c                  |  2 +-
 net/netfilter/nf_conntrack_netlink.c    |  4 +-
 net/netfilter/nf_conntrack_standalone.c |  2 +-
 net/netfilter/nfnetlink_queue.c         |  2 +-
 net/netlabel/netlabel_unlabeled.c       | 16 ++---
 net/netlabel/netlabel_user.c            | 12 ++--
 net/netlabel/netlabel_user.h            |  6 +-
 security/integrity/integrity_audit.c    |  2 +-
 security/security.c                     | 73 +++++++++++++++-----
 security/smack/smackfs.c                |  3 +-
 20 files changed, 259 insertions(+), 84 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 0bde1b96680e..93781dad0c28 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3113,7 +3113,7 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &lsmctx);
+		ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index ba1cd38d601b..fe027df0d9a8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,7 +186,9 @@ extern void		    audit_log_path_denied(int type,
 						  const char *operation);
 extern void		    audit_log_lost(const char *message);
 
-extern int audit_log_task_context(struct audit_buffer *ab);
+extern void audit_log_lsm(struct lsmblob *blob, bool exiting);
+extern int audit_log_task_context(struct audit_buffer *ab,
+				  struct lsmblob *blob);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
 extern int		    audit_update_lsm_rules(void);
@@ -246,7 +248,10 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
 { }
 static inline void audit_log_path_denied(int type, const char *operation)
 { }
-static inline int audit_log_task_context(struct audit_buffer *ab)
+static inline void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{ }
+static inline int audit_log_task_context(struct audit_buffer *ab,
+					 struct lsmblob *blob);
 {
 	return 0;
 }
@@ -305,6 +310,7 @@ extern void audit_seccomp(unsigned long syscall, long signr, int code);
 extern void audit_seccomp_actions_logged(const char *names,
 					 const char *old_names, int res);
 extern void __audit_ptrace(struct task_struct *t);
+extern void audit_stamp_context(struct audit_context *ctx);
 
 static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
 {
@@ -682,6 +688,9 @@ static inline void audit_ntp_log(const struct audit_ntp_data *ad)
 static inline void audit_ptrace(struct task_struct *t)
 { }
 
+static inline void audit_stamp_context(struct audit_context *ctx)
+{ }
+
 static inline void audit_log_nfcfg(const char *name, u8 af,
 				   unsigned int nentries,
 				   enum audit_nfcfgop op, gfp_t gfp)
diff --git a/include/linux/security.h b/include/linux/security.h
index 40260bfc3a0d..3cbe24be1563 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -180,6 +180,8 @@ struct lsmblob {
 #define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
 #define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
 #define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+#define LSMBLOB_DISPLAY		-4	/* Use the "display" slot */
+#define LSMBLOB_FIRST		-5	/* Use the default "display" slot */
 
 /**
  * lsmblob_init - initialize an lsmblob structure.
@@ -242,6 +244,17 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
 	return 0;
 }
 
+const char *security_lsm_slot_name(int slot);
+
+static inline bool lsm_multiple_contexts(void)
+{
+#ifdef CONFIG_SECURITY
+	return security_lsm_slot_name(1) != NULL;
+#else
+	return false;
+#endif
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -554,7 +567,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1372,7 +1386,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   struct lsmcontext *cp)
+					   struct lsmcontext *cp, int display)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 73fc25b4042b..216cb1ffc8f0 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -97,7 +97,7 @@ struct calipso_doi;
 
 /* NetLabel audit information */
 struct netlbl_audit {
-	u32 secid;
+	struct lsmblob lsmdata;
 	kuid_t loginuid;
 	unsigned int sessionid;
 };
diff --git a/include/net/scm.h b/include/net/scm.h
index 4a6ad8caf423..8b5a4737e1b8 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -96,7 +96,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(&scm->lsmblob, &context);
+		err = security_secid_to_secctx(&scm->lsmblob, &context,
+					       LSMBLOB_DISPLAY);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY,
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 2737d24ec244..9e8cac6228b4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -675,11 +675,13 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
+	audit_stamp_context(audit_context());
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
 				    AUDIT_MAC_IPSEC_EVENT);
 	if (audit_buf == NULL)
 		return NULL;
 	audit_log_format(audit_buf, "op=%s", op);
+	audit_log_lsm(NULL, false);
 	return audit_buf;
 }
 
@@ -693,7 +695,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
 		AUDIT_SID_UNSET;
 
 	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
-	audit_log_task_context(audit_buf);
+	audit_log_task_context(audit_buf, NULL);
 }
 
 void xfrm_audit_policy_add(struct xfrm_policy *xp, int result, bool task_valid);
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index cd2d8279a5e4..2a63720e56f6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -139,6 +139,7 @@
 #define AUDIT_MAC_UNLBL_STCDEL	1417	/* NetLabel: del a static label */
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 594b42fc88ff..0e7831c9f321 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -394,10 +394,11 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
 		return rc;
 	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
 	audit_log_session_info(ab);
-	rc = audit_log_task_context(ab);
+	rc = audit_log_task_context(ab, NULL);
 	if (rc)
 		allow_changes = 0; /* Something weird, deny request */
 	audit_log_format(ab, " res=%d", allow_changes);
+	audit_log_lsm(NULL, false);
 	audit_log_end(ab);
 	return rc;
 }
@@ -1070,13 +1071,31 @@ static void audit_log_common_recv_msg(struct audit_context *context,
 		return;
 	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
 	audit_log_session_info(*ab);
-	audit_log_task_context(*ab);
+	audit_log_task_context(*ab, NULL);
 }
 
 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
 					   u16 msg_type)
 {
-	audit_log_common_recv_msg(NULL, ab, msg_type);
+	struct audit_context *context;
+
+	if (!lsm_multiple_contexts()) {
+		audit_log_common_recv_msg(NULL, ab, msg_type);
+		return;
+	}
+
+	context = audit_context();
+	if (context) {
+		if (!context->in_syscall)
+			audit_stamp_context(context);
+		audit_log_common_recv_msg(context, ab, msg_type);
+		return;
+	}
+
+	audit_alloc(current);
+	context = audit_context();
+
+	audit_log_common_recv_msg(context, ab, msg_type);
 }
 
 int is_audit_feature_set(int i)
@@ -1372,6 +1391,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				audit_log_n_untrustedstring(ab, str, data_len);
 			}
 			audit_log_end(ab);
+			audit_log_lsm(NULL, false);
 		}
 		break;
 	case AUDIT_ADD_RULE:
@@ -1444,7 +1464,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			err = security_secid_to_secctx(&audit_sig_lsm,
-						       &context);
+						       &context, LSMBLOB_FIRST);
 			if (err)
 				return err;
 		}
@@ -1572,7 +1592,7 @@ static void audit_log_multicast(int group, const char *op, int err)
 			 tty ? tty_name(tty) : "(none)",
 			 audit_get_sessionid(current));
 	audit_put_tty(tty);
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm); /* exe= */
@@ -1869,6 +1889,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	}
 
 	audit_get_stamp(ab->ctx, &t, &serial);
+	if (type == AUDIT_MAC_TASK_CONTEXTS && ab->ctx->serial == 0) {
+		audit_stamp_context(ab->ctx);
+		audit_get_stamp(ab->ctx, &t, &serial);
+	}
 	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
 			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
 
@@ -2126,30 +2150,47 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 		audit_log_format(ab, "(null)");
 }
 
-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob)
 {
+	int i;
 	int error;
-	struct lsmblob blob;
-	struct lsmcontext context;
+	struct lsmblob localblob;
+	struct lsmcontext lsmdata;
 
-	security_task_getsecid(current, &blob);
-	if (!lsmblob_is_set(&blob))
+	/*
+	 * If there is more than one security module that has a
+	 * subject "context" it's necessary to put the subject data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		audit_log_format(ab, " subj=?");
 		return 0;
+	}
 
-	error = security_secid_to_secctx(&blob, &context);
-	if (error) {
-		if (error != -EINVAL)
-			goto error_path;
-		return 0;
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob)) {
+			audit_log_format(ab, " subj=?");
+			return 0;
+		}
+		blob = &localblob;
 	}
 
-	audit_log_format(ab, " subj=%s", context.context);
-	security_release_secctx(&context);
-	return 0;
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_task_context");
+			return error;
+		}
 
-error_path:
-	audit_panic("error in audit_log_task_context");
-	return error;
+		audit_log_format(ab, " subj=%s", lsmdata.context);
+		security_release_secctx(&lsmdata);
+		break;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
@@ -2221,7 +2262,7 @@ void audit_log_task_info(struct audit_buffer *ab)
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 }
 EXPORT_SYMBOL(audit_log_task_info);
 
@@ -2279,6 +2320,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	if (!audit_enabled)
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
 	if (!ab)
 		return;
@@ -2289,11 +2331,12 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	tty = audit_get_tty();
 
 	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
 			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
 			 oldsessionid, sessionid, !rc);
 	audit_put_tty(tty);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 31732023b689..6c03e463668e 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1107,7 +1107,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 	if (!ab)
 		return;
 	audit_log_session_info(ab);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s", action);
 	audit_log_key(ab, rule->filterkey);
 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4af5861bcb9a..cf5dbd0e3a3d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -473,7 +473,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 {
 	const struct cred *cred;
 	int i, need_sid = 1;
-	struct lsmblob blob;
+	struct lsmblob blob = { };
 	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
@@ -962,10 +962,12 @@ int audit_alloc(struct task_struct *tsk)
 		return 0; /* Return if not auditing. */
 
 	state = audit_filter_task(tsk, &key);
-	if (state == AUDIT_DISABLED) {
+	if (!lsm_multiple_contexts() && state == AUDIT_DISABLED) {
 		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 		return 0;
 	}
+	if (state == AUDIT_DISABLED)
+		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 
 	if (!(context = audit_alloc_context(state))) {
 		kfree(key);
@@ -1009,7 +1011,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx)) {
+		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1254,7 +1256,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt,
+						     LSMBLOB_FIRST)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1406,7 +1409,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx)) {
+		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
@@ -1483,6 +1486,52 @@ static void audit_log_proctitle(void)
 	audit_log_end(ab);
 }
 
+void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{
+	struct audit_context *context = audit_context();
+	struct lsmcontext lsmdata;
+	struct audit_buffer *ab;
+	struct lsmblob localblob;
+	bool sep = false;
+	int error;
+	int i;
+
+	if (!lsm_multiple_contexts())
+		return;
+
+	if (context && context->in_syscall && !exiting)
+		return;
+
+	ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
+	if (!ab)
+		return;	/* audit_panic or being filtered */
+
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob))
+			return;
+		blob = &localblob;
+	}
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_lsm");
+			return;
+		}
+
+		audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
+				 security_lsm_slot_name(i), lsmdata.context);
+		sep = true;
+
+		security_release_secctx(&lsmdata);
+	}
+
+	audit_log_end(ab);
+}
+
 static void audit_log_exit(void)
 {
 	int i, call_panic = 0;
@@ -1606,6 +1655,7 @@ static void audit_log_exit(void)
 	}
 
 	audit_log_proctitle();
+	audit_log_lsm(NULL, true);
 
 	/* Send end of event record to help user space know we are finished */
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
@@ -2217,6 +2267,21 @@ void __audit_inode_child(struct inode *parent,
 }
 EXPORT_SYMBOL_GPL(__audit_inode_child);
 
+/**
+ * audit_stamp_context - set the timestamp+serial in an audit context
+ * @ctx: audit_context to set
+ */
+void audit_stamp_context(struct audit_context *ctx)
+{
+	/* ctx will be NULL unless lsm_multiple_contexts() is true */
+	if (!ctx)
+		return;
+
+	ktime_get_coarse_real_ts64(&ctx->ctime);
+	ctx->serial = audit_serial();
+	ctx->current_state = AUDIT_BUILD_CONTEXT;
+}
+ 
 /**
  * auditsc_get_stamp - get local copies of audit_context values
  * @ctx: audit_context for the task
@@ -2228,6 +2293,12 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 int auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec64 *t, unsigned int *serial)
 {
+	if (ctx->serial && !ctx->in_syscall) {
+		t->tv_sec  = ctx->ctime.tv_sec;
+		t->tv_nsec = ctx->ctime.tv_nsec;
+		*serial    = ctx->serial;
+		return 1;
+	}
 	if (!ctx->in_syscall)
 		return 0;
 	if (!ctx->serial)
@@ -2622,7 +2693,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 			 name, af, nentries, audit_nfcfgs[op].s);
 
 	audit_log_format(ab, " pid=%u", task_pid_nr(current));
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_end(ab);
@@ -2645,7 +2716,7 @@ static void audit_log_task(struct audit_buffer *ab)
 			 from_kuid(&init_user_ns, uid),
 			 from_kgid(&init_user_ns, gid),
 			 sessionid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
@@ -2668,11 +2739,13 @@ void audit_core_dumps(long signr)
 	if (signr == SIGQUIT)	/* don't care for those */
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
 	if (unlikely(!ab))
 		return;
 	audit_log_task(ab);
 	audit_log_format(ab, " sig=%ld res=1", signr);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 58bf1f3532ae..16fa8f1fb4e0 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -138,7 +138,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(&lb, &context);
+	err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index e38b5182e301..3c90b9a488d5 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -339,7 +339,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
@@ -655,7 +655,7 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 	struct lsmblob blob;
 	struct lsmcontext context;
 
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 71bec249d23b..ca01bf2b73c2 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -177,7 +177,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index c830401f7792..9c557f9091ab 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -316,7 +316,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, context);
+		security_secid_to_secctx(&blob, context, LSMBLOB_DISPLAY);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index c14a485ff045..99579fa49293 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -437,7 +437,8 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(lsmblob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -492,7 +493,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -552,7 +554,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -1122,7 +1125,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-	ret_val = security_secid_to_secctx(lsmb, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context, LSMBLOB_FIRST);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1521,14 +1524,11 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
-	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid(current, &blob);
-	/* scaffolding until audit_info.secid is converted */
-	audit_info.secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info.lsmdata);
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..4e9064754b5f 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,12 +84,12 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
-	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
 
+	audit_stamp_context(audit_context());
+
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
 	if (audit_buf == NULL)
 		return NULL;
@@ -98,12 +98,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
-	lsmblob_init(&blob, audit_info->secid);
-	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &context) == 0) {
-		audit_log_format(audit_buf, " subj=%s", context.context);
-		security_release_secctx(&context);
-	}
+	audit_log_task_context(audit_buf, &audit_info->lsmdata);
+	audit_log_lsm(&audit_info->lsmdata, false);
 
 	return audit_buf;
 }
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 438b5db6c714..bd4335443b87 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,11 +34,7 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	struct lsmblob blob;
-
-	security_task_getsecid(current, &blob);
-	/* scaffolding until secid is converted */
-	audit_info->secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info->lsmdata);
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index f25e7df099c8..418f7e45753d 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -50,7 +50,7 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
 			 from_kuid(&init_user_ns, current_cred()->uid),
 			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
 			 audit_get_sessionid(current));
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s cause=%s comm=", op, cause);
 	audit_log_untrustedstring(ab, get_task_comm(name, current));
 	if (fname) {
diff --git a/security/security.c b/security/security.c
index 95b48721fb17..4752291376bf 100644
--- a/security/security.c
+++ b/security/security.c
@@ -480,7 +480,31 @@ static int lsm_append(const char *new, char **result)
  * Pointers to the LSM id structures for local use.
  */
 static int lsm_slot __lsm_ro_after_init;
-static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES];
+static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES] __lsm_ro_after_init;
+
+/**
+ * security_lsm_slot_name - Get the name of the security module in a slot
+ * @slot: index into the "display" slot list.
+ *
+ * Provide the name of the security module associated with
+ * a display slot.
+ *
+ * If @slot is LSMBLOB_INVALID return the value
+ * for slot 0 if it has been set, otherwise NULL.
+ *
+ * Returns a pointer to the name string or NULL.
+ */
+const char *security_lsm_slot_name(int slot)
+{
+	if (slot == LSMBLOB_INVALID)
+		slot = 0;
+	else if (slot >= LSMBLOB_ENTRIES || slot < 0)
+		return NULL;
+
+	if (lsm_slotlist[slot] == NULL)
+		return NULL;
+	return lsm_slotlist[slot]->lsm;
+}
 
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
@@ -2175,7 +2199,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
 				     list) {
 			rc = hp->hook.setprocattr(name, value, size);
-			if (rc < 0)
+			if (rc < 0 && rc != -EINVAL)
 				return rc;
 		}
 
@@ -2220,13 +2244,32 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display)
 {
 	struct security_hook_list *hp;
-	int display = lsm_task_display(current);
 
 	memset(cp, 0, sizeof(*cp));
 
+	/*
+	 * display either is the slot number use for formatting
+	 * or an instruction on which relative slot to use.
+	 */
+	if (display == LSMBLOB_DISPLAY)
+		display = lsm_task_display(current);
+	else if (display == LSMBLOB_FIRST)
+		display = LSMBLOB_INVALID;
+	else if (display < 0) {
+		WARN_ONCE(true,
+			"LSM: %s unknown display\n", __func__);
+		display = LSMBLOB_INVALID;
+	} else if (display >= lsm_slot) {
+		WARN_ONCE(true,
+			"LSM: %s invalid display\n", __func__);
+		display = LSMBLOB_INVALID;
+	}
+
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
@@ -2256,7 +2299,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			return hp->hook.secctx_to_secid(secdata, seclen,
 						&blob->secid[hp->lsmid->slot]);
 	}
-	return 0;
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2757,23 +2800,17 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
 	struct security_hook_list *hp;
-	bool one_is_good = false;
-	int rc = 0;
-	int trc;
+	int display = lsm_task_display(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		trc = hp->hook.audit_rule_init(field, op, rulestr,
-					       &lsmrule[hp->lsmid->slot]);
-		if (trc == 0)
-			one_is_good = true;
-		else
-			rc = trc;
+		if (display != LSMBLOB_INVALID && display != hp->lsmid->slot)
+			continue;
+		return hp->hook.audit_rule_init(field, op, rulestr,
+						&lsmrule[hp->lsmid->slot]);
 	}
-	if (one_is_good)
-		return 0;
-	return rc;
+	return 0;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2805,6 +2842,8 @@ int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			continue;
 		if (lsmrule[hp->lsmid->slot] == NULL)
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
 					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index dcabf6bd8faa..15fa4b7eb2e6 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -185,7 +185,8 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap)
 
 	nap->loginuid = audit_get_loginuid(current);
 	nap->sessionid = audit_get_sessionid(current);
-	nap->secid = skp->smk_secid;
+	lsmblob_init(&nap->lsmdata, 0);
+	nap->lsmdata.secid[smack_lsmid.slot] = skp->smk_secid;
 }
 
 /*
-- 
James Morris
[off-list ref]

Re: [PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes

From: John Johansen <john.johansen@canonical.com>
Date: 2020-09-03 17:00:26 

On 9/3/20 9:32 AM, James Morris wrote:
On Wed, 26 Aug 2020, Casey Schaufler wrote:
quoted
Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Paul, can you review/ack the audit changes?
I am working on reviewing them as well, but I can't/won't ack them.
quoted
---
 drivers/android/binder.c                |  2 +-
 include/linux/audit.h                   | 13 +++-
 include/linux/security.h                | 18 ++++-
 include/net/netlabel.h                  |  2 +-
 include/net/scm.h                       |  3 +-
 include/net/xfrm.h                      |  4 +-
 include/uapi/linux/audit.h              |  1 +
 kernel/audit.c                          | 89 ++++++++++++++++++-------
 kernel/auditfilter.c                    |  2 +-
 kernel/auditsc.c                        | 87 ++++++++++++++++++++++--
 net/ipv4/ip_sockglue.c                  |  2 +-
 net/netfilter/nf_conntrack_netlink.c    |  4 +-
 net/netfilter/nf_conntrack_standalone.c |  2 +-
 net/netfilter/nfnetlink_queue.c         |  2 +-
 net/netlabel/netlabel_unlabeled.c       | 16 ++---
 net/netlabel/netlabel_user.c            | 12 ++--
 net/netlabel/netlabel_user.h            |  6 +-
 security/integrity/integrity_audit.c    |  2 +-
 security/security.c                     | 73 +++++++++++++++-----
 security/smack/smackfs.c                |  3 +-
 20 files changed, 259 insertions(+), 84 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 0bde1b96680e..93781dad0c28 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3113,7 +3113,7 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 
 		security_task_getsecid(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &lsmctx);
+		ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index ba1cd38d601b..fe027df0d9a8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,7 +186,9 @@ extern void		    audit_log_path_denied(int type,
 						  const char *operation);
 extern void		    audit_log_lost(const char *message);
 
-extern int audit_log_task_context(struct audit_buffer *ab);
+extern void audit_log_lsm(struct lsmblob *blob, bool exiting);
+extern int audit_log_task_context(struct audit_buffer *ab,
+				  struct lsmblob *blob);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
 extern int		    audit_update_lsm_rules(void);
@@ -246,7 +248,10 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
 { }
 static inline void audit_log_path_denied(int type, const char *operation)
 { }
-static inline int audit_log_task_context(struct audit_buffer *ab)
+static inline void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{ }
+static inline int audit_log_task_context(struct audit_buffer *ab,
+					 struct lsmblob *blob);
 {
 	return 0;
 }
@@ -305,6 +310,7 @@ extern void audit_seccomp(unsigned long syscall, long signr, int code);
 extern void audit_seccomp_actions_logged(const char *names,
 					 const char *old_names, int res);
 extern void __audit_ptrace(struct task_struct *t);
+extern void audit_stamp_context(struct audit_context *ctx);
 
 static inline void audit_set_context(struct task_struct *task, struct audit_context *ctx)
 {
@@ -682,6 +688,9 @@ static inline void audit_ntp_log(const struct audit_ntp_data *ad)
 static inline void audit_ptrace(struct task_struct *t)
 { }
 
+static inline void audit_stamp_context(struct audit_context *ctx)
+{ }
+
 static inline void audit_log_nfcfg(const char *name, u8 af,
 				   unsigned int nentries,
 				   enum audit_nfcfgop op, gfp_t gfp)
diff --git a/include/linux/security.h b/include/linux/security.h
index 40260bfc3a0d..3cbe24be1563 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -180,6 +180,8 @@ struct lsmblob {
 #define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
 #define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
 #define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+#define LSMBLOB_DISPLAY		-4	/* Use the "display" slot */
+#define LSMBLOB_FIRST		-5	/* Use the default "display" slot */
 
 /**
  * lsmblob_init - initialize an lsmblob structure.
@@ -242,6 +244,17 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
 	return 0;
 }
 
+const char *security_lsm_slot_name(int slot);
+
+static inline bool lsm_multiple_contexts(void)
+{
+#ifdef CONFIG_SECURITY
+	return security_lsm_slot_name(1) != NULL;
+#else
+	return false;
+#endif
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -554,7 +567,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1372,7 +1386,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   struct lsmcontext *cp)
+					   struct lsmcontext *cp, int display)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 73fc25b4042b..216cb1ffc8f0 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -97,7 +97,7 @@ struct calipso_doi;
 
 /* NetLabel audit information */
 struct netlbl_audit {
-	u32 secid;
+	struct lsmblob lsmdata;
 	kuid_t loginuid;
 	unsigned int sessionid;
 };
diff --git a/include/net/scm.h b/include/net/scm.h
index 4a6ad8caf423..8b5a4737e1b8 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -96,7 +96,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(&scm->lsmblob, &context);
+		err = security_secid_to_secctx(&scm->lsmblob, &context,
+					       LSMBLOB_DISPLAY);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY,
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 2737d24ec244..9e8cac6228b4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -675,11 +675,13 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
+	audit_stamp_context(audit_context());
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
 				    AUDIT_MAC_IPSEC_EVENT);
 	if (audit_buf == NULL)
 		return NULL;
 	audit_log_format(audit_buf, "op=%s", op);
+	audit_log_lsm(NULL, false);
 	return audit_buf;
 }
 
@@ -693,7 +695,7 @@ static inline void xfrm_audit_helper_usrinfo(bool task_valid,
 		AUDIT_SID_UNSET;
 
 	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
-	audit_log_task_context(audit_buf);
+	audit_log_task_context(audit_buf, NULL);
 }
 
 void xfrm_audit_policy_add(struct xfrm_policy *xp, int result, bool task_valid);
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index cd2d8279a5e4..2a63720e56f6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -139,6 +139,7 @@
 #define AUDIT_MAC_UNLBL_STCDEL	1417	/* NetLabel: del a static label */
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 594b42fc88ff..0e7831c9f321 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -394,10 +394,11 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
 		return rc;
 	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
 	audit_log_session_info(ab);
-	rc = audit_log_task_context(ab);
+	rc = audit_log_task_context(ab, NULL);
 	if (rc)
 		allow_changes = 0; /* Something weird, deny request */
 	audit_log_format(ab, " res=%d", allow_changes);
+	audit_log_lsm(NULL, false);
 	audit_log_end(ab);
 	return rc;
 }
@@ -1070,13 +1071,31 @@ static void audit_log_common_recv_msg(struct audit_context *context,
 		return;
 	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
 	audit_log_session_info(*ab);
-	audit_log_task_context(*ab);
+	audit_log_task_context(*ab, NULL);
 }
 
 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
 					   u16 msg_type)
 {
-	audit_log_common_recv_msg(NULL, ab, msg_type);
+	struct audit_context *context;
+
+	if (!lsm_multiple_contexts()) {
+		audit_log_common_recv_msg(NULL, ab, msg_type);
+		return;
+	}
+
+	context = audit_context();
+	if (context) {
+		if (!context->in_syscall)
+			audit_stamp_context(context);
+		audit_log_common_recv_msg(context, ab, msg_type);
+		return;
+	}
+
+	audit_alloc(current);
+	context = audit_context();
+
+	audit_log_common_recv_msg(context, ab, msg_type);
 }
 
 int is_audit_feature_set(int i)
@@ -1372,6 +1391,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				audit_log_n_untrustedstring(ab, str, data_len);
 			}
 			audit_log_end(ab);
+			audit_log_lsm(NULL, false);
 		}
 		break;
 	case AUDIT_ADD_RULE:
@@ -1444,7 +1464,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			err = security_secid_to_secctx(&audit_sig_lsm,
-						       &context);
+						       &context, LSMBLOB_FIRST);
 			if (err)
 				return err;
 		}
@@ -1572,7 +1592,7 @@ static void audit_log_multicast(int group, const char *op, int err)
 			 tty ? tty_name(tty) : "(none)",
 			 audit_get_sessionid(current));
 	audit_put_tty(tty);
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm); /* exe= */
@@ -1869,6 +1889,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 	}
 
 	audit_get_stamp(ab->ctx, &t, &serial);
+	if (type == AUDIT_MAC_TASK_CONTEXTS && ab->ctx->serial == 0) {
+		audit_stamp_context(ab->ctx);
+		audit_get_stamp(ab->ctx, &t, &serial);
+	}
 	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
 			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
 
@@ -2126,30 +2150,47 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 		audit_log_format(ab, "(null)");
 }
 
-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob)
 {
+	int i;
 	int error;
-	struct lsmblob blob;
-	struct lsmcontext context;
+	struct lsmblob localblob;
+	struct lsmcontext lsmdata;
 
-	security_task_getsecid(current, &blob);
-	if (!lsmblob_is_set(&blob))
+	/*
+	 * If there is more than one security module that has a
+	 * subject "context" it's necessary to put the subject data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		audit_log_format(ab, " subj=?");
 		return 0;
+	}
 
-	error = security_secid_to_secctx(&blob, &context);
-	if (error) {
-		if (error != -EINVAL)
-			goto error_path;
-		return 0;
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob)) {
+			audit_log_format(ab, " subj=?");
+			return 0;
+		}
+		blob = &localblob;
 	}
 
-	audit_log_format(ab, " subj=%s", context.context);
-	security_release_secctx(&context);
-	return 0;
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_task_context");
+			return error;
+		}
 
-error_path:
-	audit_panic("error in audit_log_task_context");
-	return error;
+		audit_log_format(ab, " subj=%s", lsmdata.context);
+		security_release_secctx(&lsmdata);
+		break;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
@@ -2221,7 +2262,7 @@ void audit_log_task_info(struct audit_buffer *ab)
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 }
 EXPORT_SYMBOL(audit_log_task_info);
 
@@ -2279,6 +2320,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	if (!audit_enabled)
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
 	if (!ab)
 		return;
@@ -2289,11 +2331,12 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	tty = audit_get_tty();
 
 	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
 			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
 			 oldsessionid, sessionid, !rc);
 	audit_put_tty(tty);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 31732023b689..6c03e463668e 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1107,7 +1107,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 	if (!ab)
 		return;
 	audit_log_session_info(ab);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s", action);
 	audit_log_key(ab, rule->filterkey);
 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4af5861bcb9a..cf5dbd0e3a3d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -473,7 +473,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 {
 	const struct cred *cred;
 	int i, need_sid = 1;
-	struct lsmblob blob;
+	struct lsmblob blob = { };
 	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
@@ -962,10 +962,12 @@ int audit_alloc(struct task_struct *tsk)
 		return 0; /* Return if not auditing. */
 
 	state = audit_filter_task(tsk, &key);
-	if (state == AUDIT_DISABLED) {
+	if (!lsm_multiple_contexts() && state == AUDIT_DISABLED) {
 		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 		return 0;
 	}
+	if (state == AUDIT_DISABLED)
+		clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
 
 	if (!(context = audit_alloc_context(state))) {
 		kfree(key);
@@ -1009,7 +1011,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx)) {
+		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1254,7 +1256,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt,
+						     LSMBLOB_FIRST)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1406,7 +1409,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx)) {
+		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
@@ -1483,6 +1486,52 @@ static void audit_log_proctitle(void)
 	audit_log_end(ab);
 }
 
+void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{
+	struct audit_context *context = audit_context();
+	struct lsmcontext lsmdata;
+	struct audit_buffer *ab;
+	struct lsmblob localblob;
+	bool sep = false;
+	int error;
+	int i;
+
+	if (!lsm_multiple_contexts())
+		return;
+
+	if (context && context->in_syscall && !exiting)
+		return;
+
+	ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
+	if (!ab)
+		return;	/* audit_panic or being filtered */
+
+	if (blob == NULL) {
+		security_task_getsecid(current, &localblob);
+		if (!lsmblob_is_set(&localblob))
+			return;
+		blob = &localblob;
+	}
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_lsm");
+			return;
+		}
+
+		audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
+				 security_lsm_slot_name(i), lsmdata.context);
+		sep = true;
+
+		security_release_secctx(&lsmdata);
+	}
+
+	audit_log_end(ab);
+}
+
 static void audit_log_exit(void)
 {
 	int i, call_panic = 0;
@@ -1606,6 +1655,7 @@ static void audit_log_exit(void)
 	}
 
 	audit_log_proctitle();
+	audit_log_lsm(NULL, true);
 
 	/* Send end of event record to help user space know we are finished */
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
@@ -2217,6 +2267,21 @@ void __audit_inode_child(struct inode *parent,
 }
 EXPORT_SYMBOL_GPL(__audit_inode_child);
 
+/**
+ * audit_stamp_context - set the timestamp+serial in an audit context
+ * @ctx: audit_context to set
+ */
+void audit_stamp_context(struct audit_context *ctx)
+{
+	/* ctx will be NULL unless lsm_multiple_contexts() is true */
+	if (!ctx)
+		return;
+
+	ktime_get_coarse_real_ts64(&ctx->ctime);
+	ctx->serial = audit_serial();
+	ctx->current_state = AUDIT_BUILD_CONTEXT;
+}
+ 
 /**
  * auditsc_get_stamp - get local copies of audit_context values
  * @ctx: audit_context for the task
@@ -2228,6 +2293,12 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 int auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec64 *t, unsigned int *serial)
 {
+	if (ctx->serial && !ctx->in_syscall) {
+		t->tv_sec  = ctx->ctime.tv_sec;
+		t->tv_nsec = ctx->ctime.tv_nsec;
+		*serial    = ctx->serial;
+		return 1;
+	}
 	if (!ctx->in_syscall)
 		return 0;
 	if (!ctx->serial)
@@ -2622,7 +2693,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 			 name, af, nentries, audit_nfcfgs[op].s);
 
 	audit_log_format(ab, " pid=%u", task_pid_nr(current));
-	audit_log_task_context(ab); /* subj= */
+	audit_log_task_context(ab, NULL); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_end(ab);
@@ -2645,7 +2716,7 @@ static void audit_log_task(struct audit_buffer *ab)
 			 from_kuid(&init_user_ns, uid),
 			 from_kgid(&init_user_ns, gid),
 			 sessionid);
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
@@ -2668,11 +2739,13 @@ void audit_core_dumps(long signr)
 	if (signr == SIGQUIT)	/* don't care for those */
 		return;
 
+	audit_stamp_context(audit_context());
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
 	if (unlikely(!ab))
 		return;
 	audit_log_task(ab);
 	audit_log_format(ab, " sig=%ld res=1", signr);
+	audit_log_lsm(NULL, true);
 	audit_log_end(ab);
 }
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 58bf1f3532ae..16fa8f1fb4e0 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -138,7 +138,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(&lb, &context);
+	err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index e38b5182e301..3c90b9a488d5 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -339,7 +339,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
@@ -655,7 +655,7 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 	struct lsmblob blob;
 	struct lsmcontext context;
 
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 71bec249d23b..ca01bf2b73c2 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -177,7 +177,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index c830401f7792..9c557f9091ab 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -316,7 +316,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, context);
+		security_secid_to_secctx(&blob, context, LSMBLOB_DISPLAY);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index c14a485ff045..99579fa49293 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -437,7 +437,8 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(lsmblob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -492,7 +493,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -552,7 +554,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -1122,7 +1125,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-	ret_val = security_secid_to_secctx(lsmb, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context, LSMBLOB_FIRST);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1521,14 +1524,11 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
-	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid(current, &blob);
-	/* scaffolding until audit_info.secid is converted */
-	audit_info.secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info.lsmdata);
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..4e9064754b5f 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,12 +84,12 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
-	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
 
+	audit_stamp_context(audit_context());
+
 	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
 	if (audit_buf == NULL)
 		return NULL;
@@ -98,12 +98,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
-	lsmblob_init(&blob, audit_info->secid);
-	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &context) == 0) {
-		audit_log_format(audit_buf, " subj=%s", context.context);
-		security_release_secctx(&context);
-	}
+	audit_log_task_context(audit_buf, &audit_info->lsmdata);
+	audit_log_lsm(&audit_info->lsmdata, false);
 
 	return audit_buf;
 }
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 438b5db6c714..bd4335443b87 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,11 +34,7 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	struct lsmblob blob;
-
-	security_task_getsecid(current, &blob);
-	/* scaffolding until secid is converted */
-	audit_info->secid = blob.secid[0];
+	security_task_getsecid(current, &audit_info->lsmdata);
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index f25e7df099c8..418f7e45753d 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -50,7 +50,7 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
 			 from_kuid(&init_user_ns, current_cred()->uid),
 			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
 			 audit_get_sessionid(current));
-	audit_log_task_context(ab);
+	audit_log_task_context(ab, NULL);
 	audit_log_format(ab, " op=%s cause=%s comm=", op, cause);
 	audit_log_untrustedstring(ab, get_task_comm(name, current));
 	if (fname) {
diff --git a/security/security.c b/security/security.c
index 95b48721fb17..4752291376bf 100644
--- a/security/security.c
+++ b/security/security.c
@@ -480,7 +480,31 @@ static int lsm_append(const char *new, char **result)
  * Pointers to the LSM id structures for local use.
  */
 static int lsm_slot __lsm_ro_after_init;
-static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES];
+static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES] __lsm_ro_after_init;
+
+/**
+ * security_lsm_slot_name - Get the name of the security module in a slot
+ * @slot: index into the "display" slot list.
+ *
+ * Provide the name of the security module associated with
+ * a display slot.
+ *
+ * If @slot is LSMBLOB_INVALID return the value
+ * for slot 0 if it has been set, otherwise NULL.
+ *
+ * Returns a pointer to the name string or NULL.
+ */
+const char *security_lsm_slot_name(int slot)
+{
+	if (slot == LSMBLOB_INVALID)
+		slot = 0;
+	else if (slot >= LSMBLOB_ENTRIES || slot < 0)
+		return NULL;
+
+	if (lsm_slotlist[slot] == NULL)
+		return NULL;
+	return lsm_slotlist[slot]->lsm;
+}
 
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
@@ -2175,7 +2199,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
 				     list) {
 			rc = hp->hook.setprocattr(name, value, size);
-			if (rc < 0)
+			if (rc < 0 && rc != -EINVAL)
 				return rc;
 		}
 
@@ -2220,13 +2244,32 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display)
 {
 	struct security_hook_list *hp;
-	int display = lsm_task_display(current);
 
 	memset(cp, 0, sizeof(*cp));
 
+	/*
+	 * display either is the slot number use for formatting
+	 * or an instruction on which relative slot to use.
+	 */
+	if (display == LSMBLOB_DISPLAY)
+		display = lsm_task_display(current);
+	else if (display == LSMBLOB_FIRST)
+		display = LSMBLOB_INVALID;
+	else if (display < 0) {
+		WARN_ONCE(true,
+			"LSM: %s unknown display\n", __func__);
+		display = LSMBLOB_INVALID;
+	} else if (display >= lsm_slot) {
+		WARN_ONCE(true,
+			"LSM: %s invalid display\n", __func__);
+		display = LSMBLOB_INVALID;
+	}
+
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
@@ -2256,7 +2299,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			return hp->hook.secctx_to_secid(secdata, seclen,
 						&blob->secid[hp->lsmid->slot]);
 	}
-	return 0;
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2757,23 +2800,17 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
 	struct security_hook_list *hp;
-	bool one_is_good = false;
-	int rc = 0;
-	int trc;
+	int display = lsm_task_display(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		trc = hp->hook.audit_rule_init(field, op, rulestr,
-					       &lsmrule[hp->lsmid->slot]);
-		if (trc == 0)
-			one_is_good = true;
-		else
-			rc = trc;
+		if (display != LSMBLOB_INVALID && display != hp->lsmid->slot)
+			continue;
+		return hp->hook.audit_rule_init(field, op, rulestr,
+						&lsmrule[hp->lsmid->slot]);
 	}
-	if (one_is_good)
-		return 0;
-	return rc;
+	return 0;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2805,6 +2842,8 @@ int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			continue;
 		if (lsmrule[hp->lsmid->slot] == NULL)
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
 					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index dcabf6bd8faa..15fa4b7eb2e6 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -185,7 +185,8 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap)
 
 	nap->loginuid = audit_get_loginuid(current);
 	nap->sessionid = audit_get_sessionid(current);
-	nap->secid = skp->smk_secid;
+	lsmblob_init(&nap->lsmdata, 0);
+	nap->lsmdata.secid[smack_lsmid.slot] = skp->smk_secid;
 }
 
 /*





  

    
Re: [PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-03 21:49:44 
    

  

  
On Thu, Sep 3, 2020 at 12:32 PM James Morris [off-list ref] wrote:
On Wed, 26 Aug 2020, Casey Schaufler wrote:

quoted
Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Paul, can you review/ack the audit changes?
I did a previous version at some point in the past, I'll take a look
at v20 tomorrow or this weekend.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 03/23] LSM: Use lsmblob in security_audit_rule_match

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 18:54:00 
    

  

  
On Wed, Aug 26, 2020 at 11:04 AM Casey Schaufler [off-list ref] wrote:
Change the secid parameter of security_audit_rule_match
to a lsmblob structure pointer. Pass the entry from the
lsmblob structure for the approprite slot to the LSM hook.

Change the users of security_audit_rule_match to use the
lsmblob instead of a u32. The scaffolding function lsmblob_init()
fills the blob with the value of the old secid, ensuring that
it is available to the appropriate module hook. The sources of
the secid, security_task_getsecid() and security_inode_getsecid(),
will be converted to use the blob structure later in the series.
At the point the use of lsmblob_init() is dropped.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h            |  7 ++++---
 kernel/auditfilter.c                |  6 ++++--
 kernel/auditsc.c                    | 14 ++++++++++----
 security/integrity/ima/ima.h        |  4 ++--
 security/integrity/ima/ima_policy.c |  7 +++++--
 security/security.c                 | 10 ++++++++--
 6 files changed, 33 insertions(+), 15 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 04/23] LSM: Use lsmblob in security_kernel_act_as

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 19:46:55 
    

  

  
On Wed, Aug 26, 2020 at 11:05 AM Casey Schaufler [off-list ref] wrote:
Change the security_kernel_act_as interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its only caller, set_security_override,
to do the same. Change that one's only caller,
set_security_override_from_ctx, to call it with the new
parameter type.

The security module hook is unchanged, still taking a secid.
The infrastructure passes the correct entry from the lsmblob.
lsmblob_init() is used to fill the lsmblob structure, however
this will be removed later in the series when security_secctx_to_secid()
is undated to provide a lsmblob instead of a secid.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/cred.h     |  3 ++-
 include/linux/security.h |  5 +++--
 kernel/cred.c            | 10 ++++++----
 security/security.c      | 14 ++++++++++++--
 4 files changed, 23 insertions(+), 9 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 20:09:00 
    

  

  
On Wed, Aug 26, 2020 at 11:07 AM Casey Schaufler [off-list ref] wrote:
Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)
...

quoted hunk
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
        kgid_t                  gid;
        struct scm_fp_list      *fp;            /* Passed files         */
 #ifdef CONFIG_SECURITY_NETWORK
-       u32                     secid;          /* Security ID          */
+       struct lsmblob          lsmblob;        /* Security LSM data    */
As mentioned in a previous revision, I remain concerned that this is
going to become a problem due to the size limit on unix_skb_parms.  I
would need to redo the math to be certain, but if I recall correctly
this would limit us to five LSMs assuming both that we don't need to
grow the per-LSM size of lsmblob *and* the netdev folks don't decide
to add more fields to the unix_skb_parms.

I lost track of that earlier discussion so I'm not sure where it ended
up, but if there is a viable alternative it might be a good idea to
pursue it.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 06/23] LSM: Use lsmblob in security_secctx_to_secid

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 21:29:35 
    

  

  
On Wed, Aug 26, 2020 at 11:08 AM Casey Schaufler [off-list ref] wrote:
Change security_secctx_to_secid() to fill in a lsmblob instead
of a u32 secid. Multiple LSMs may be able to interpret the
string, and this allows for setting whichever secid is
appropriate. Change security_secmark_relabel_packet() to use a
lsmblob instead of a u32 secid. In some other cases there is
scaffolding where interfaces have yet to be converted.

Reviewed-by: Kees Cook <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 include/linux/security.h          | 30 +++++++++++++++++++++++----
 include/net/scm.h                 |  7 +++++--
 kernel/cred.c                     |  4 +---
 net/ipv4/ip_sockglue.c            |  6 ++++--
 net/netfilter/nft_meta.c          | 18 +++++++++-------
 net/netfilter/xt_SECMARK.c        |  9 ++++++--
 net/netlabel/netlabel_unlabeled.c | 23 +++++++++++++--------
 security/security.c               | 34 ++++++++++++++++++++++++++-----
 8 files changed, 98 insertions(+), 33 deletions(-)
I imagine there may be ways around the xt_secmark_target_info
limitation, but that would require userspace changes to take advantage
of it, and the way forward is clearly nftables so it probably isn't
worth the effort.

I'm okay with this patch with the understanding that several chunks in
the patch are replaced by later patches in the series.

Acked-by: Paul Moore <paul@paul-moore.com>

quoted hunk
diff --git a/include/linux/security.h b/include/linux/security.h
index ae623b89cdf4..f8770c228356 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -190,6 +190,27 @@ static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
        return !memcmp(bloba, blobb, sizeof(*bloba));
 }

+/**
+ * lsmblob_value - find the first non-zero value in an lsmblob structure.
+ * @blob: Pointer to the data
+ *
+ * This needs to be used with extreme caution, as the cases where
+ * it is appropriate are rare.
+ *
+ * Return the first secid value set in the lsmblob.
+ * There should only be one.
+ */
+static inline u32 lsmblob_value(const struct lsmblob *blob)
+{
+       int i;
+
+       for (i = 0; i < LSMBLOB_ENTRIES; i++)
+               if (blob->secid[i])
+                       return blob->secid[i];
+
+       return 0;
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
                       int cap, unsigned int opts);
@@ -503,7 +524,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+                            struct lsmblob *blob);
 void security_release_secctx(char *secdata, u32 seclen);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1322,7 +1344,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle

 static inline int security_secctx_to_secid(const char *secdata,
                                           u32 seclen,
-                                          u32 *secid)
+                                          struct lsmblob *blob)
 {
        return -EOPNOTSUPP;
 }
@@ -1412,7 +1434,7 @@ void security_inet_csk_clone(struct sock *newsk,
                        const struct request_sock *req);
 void security_inet_conn_established(struct sock *sk,
                        struct sk_buff *skb);
-int security_secmark_relabel_packet(u32 secid);
+int security_secmark_relabel_packet(struct lsmblob *blob);
 void security_secmark_refcount_inc(void);
 void security_secmark_refcount_dec(void);
 int security_tun_dev_alloc_security(void **security);
@@ -1585,7 +1607,7 @@ static inline void security_inet_conn_established(struct sock *sk,
 {
 }

-static inline int security_secmark_relabel_packet(u32 secid)
+static inline int security_secmark_relabel_packet(struct lsmblob *blob)
 {
        return 0;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index e2e71c4bf9d0..c09f2dfeec88 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -97,8 +97,11 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
        int err;

        if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-               /* Scaffolding - it has to be element 0 for now */
-               err = security_secid_to_secctx(scm->lsmblob.secid[0],
+               /* There can currently be only one value in the lsmblob,
+                * so getting it from lsmblob_value is appropriate until
+                * security_secid_to_secctx() is converted to taking a
+                * lsmblob directly. */
+               err = security_secid_to_secctx(lsmblob_value(&scm->lsmblob),
                                               &secdata, &seclen);

                if (!err) {
diff --git a/kernel/cred.c b/kernel/cred.c
index 22e0e7cbefde..848306c7d823 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -757,14 +757,12 @@ EXPORT_SYMBOL(set_security_override);
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
        struct lsmblob blob;
-       u32 secid;
        int ret;

-       ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
+       ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
        if (ret < 0)
                return ret;

-       lsmblob_init(&blob, secid);
        return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 551dfbc717e9..c568574abfae 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -139,8 +139,10 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
        if (err)
                return;

-       /* Scaffolding - it has to be element 0 */
-       err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
+       /* There can only be one secid in the lsmblob at this point,
+        * so getting it using lsmblob_value() is sufficient until
+        * security_secid_to_secctx() is changed to use a lsmblob */
+       err = security_secid_to_secctx(lsmblob_value(&lb), &secdata, &seclen);
        if (err)
                return;

diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index 7bc6537f3ccb..7db487d93618 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -801,7 +801,7 @@ struct nft_expr_type nft_meta_type __read_mostly = {

 #ifdef CONFIG_NETWORK_SECMARK
 struct nft_secmark {
-       u32 secid;
+       struct lsmblob lsmdata;
        char *ctx;
 };

@@ -811,21 +811,21 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {

 static int nft_secmark_compute_secid(struct nft_secmark *priv)
 {
-       u32 tmp_secid = 0;
+       struct lsmblob blob;
        int err;

-       err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
+       err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
        if (err)
                return err;

-       if (!tmp_secid)
+       if (!lsmblob_is_set(&blob))
                return -ENOENT;

-       err = security_secmark_relabel_packet(tmp_secid);
+       err = security_secmark_relabel_packet(&blob);
        if (err)
                return err;

-       priv->secid = tmp_secid;
+       priv->lsmdata = blob;
        return 0;
 }

@@ -835,7 +835,11 @@ static void nft_secmark_obj_eval(struct nft_object *obj, struct nft_regs *regs,
        const struct nft_secmark *priv = nft_obj_data(obj);
        struct sk_buff *skb = pkt->skb;

-       skb->secmark = priv->secid;
+       /* It is not possible for more than one secid to be set in
+        * the lsmblob structure because it is set using
+        * security_secctx_to_secid(). Any secid that is set must therefore
+        * be the one that should go in the secmark. */
+       skb->secmark = lsmblob_value(&priv->lsmdata);
 }

 static int nft_secmark_obj_init(const struct nft_ctx *ctx,
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index 75625d13e976..5a268707eeda 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -43,13 +43,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)

 static int checkentry_lsm(struct xt_secmark_target_info *info)
 {
+       struct lsmblob blob;
        int err;

        info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
        info->secid = 0;

        err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
-                                      &info->secid);
+                                      &blob);
        if (err) {
                if (err == -EINVAL)
                        pr_info_ratelimited("invalid security context \'%s\'\n",
@@ -57,13 +58,17 @@ static int checkentry_lsm(struct xt_secmark_target_info *info)
                return err;
        }

+       /* xt_secmark_target_info can't be changed to use lsmblobs because
+        * it is exposed as an API. Use lsmblob_value() to get the one
+        * value that got set by security_secctx_to_secid(). */
+       info->secid = lsmblob_value(&blob);
        if (!info->secid) {
                pr_info_ratelimited("unable to map security context \'%s\'\n",
                                    info->secctx);
                return -ENOENT;
        }

-       err = security_secmark_relabel_packet(info->secid);
+       err = security_secmark_relabel_packet(&blob);
        if (err) {
                pr_info_ratelimited("unable to obtain relabeling permission\n");
                return err;
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 77bb1bb22c3b..8948557eaebb 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -882,7 +882,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
        void *addr;
        void *mask;
        u32 addr_len;
-       u32 secid;
+       struct lsmblob blob;
        struct netlbl_audit audit_info;

        /* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -906,13 +906,18 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
        ret_val = security_secctx_to_secid(
                                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
                                  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-                                 &secid);
+                                 &blob);
        if (ret_val != 0)
                return ret_val;

+       /* netlbl_unlhsh_add will be changed to pass a struct lsmblob *
+        * instead of a u32 later in this patch set. security_secctx_to_secid()
+        * will only be setting one entry in the lsmblob struct, so it is
+        * safe to use lsmblob_value() to get that one value. */
+
        return netlbl_unlhsh_add(&init_net,
-                                dev_name, addr, mask, addr_len, secid,
-                                &audit_info);
+                                dev_name, addr, mask, addr_len,
+                                lsmblob_value(&blob), &audit_info);
 }

 /**
@@ -933,7 +938,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
        void *addr;
        void *mask;
        u32 addr_len;
-       u32 secid;
+       struct lsmblob blob;
        struct netlbl_audit audit_info;

        /* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -955,13 +960,15 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
        ret_val = security_secctx_to_secid(
                                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
                                  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-                                 &secid);
+                                 &blob);
        if (ret_val != 0)
                return ret_val;

+       /* security_secctx_to_secid() will only put one secid into the lsmblob
+        * so it's safe to use lsmblob_value() to get the secid. */
        return netlbl_unlhsh_add(&init_net,
-                                NULL, addr, mask, addr_len, secid,
-                                &audit_info);
+                                NULL, addr, mask, addr_len,
+                                lsmblob_value(&blob), &audit_info);
 }

 /**
diff --git a/security/security.c b/security/security.c
index c42873876954..5c2ed1db0658 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2065,10 +2065,22 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 }
 EXPORT_SYMBOL(security_secid_to_secctx);

-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+                            struct lsmblob *blob)
 {
-       *secid = 0;
-       return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
+       struct security_hook_list *hp;
+       int rc;
+
+       lsmblob_init(blob, 0);
+       hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
+               if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+                       continue;
+               rc = hp->hook.secctx_to_secid(secdata, seclen,
+                                             &blob->secid[hp->lsmid->slot]);
+               if (rc != 0)
+                       return rc;
+       }
+       return 0;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);

@@ -2301,9 +2313,21 @@ void security_inet_conn_established(struct sock *sk,
 }
 EXPORT_SYMBOL(security_inet_conn_established);

-int security_secmark_relabel_packet(u32 secid)
+int security_secmark_relabel_packet(struct lsmblob *blob)
 {
-       return call_int_hook(secmark_relabel_packet, 0, secid);
+       struct security_hook_list *hp;
+       int rc = 0;
+
+       hlist_for_each_entry(hp, &security_hook_heads.secmark_relabel_packet,
+                            list) {
+               if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+                       continue;
+               rc = hp->hook.secmark_relabel_packet(
+                                               blob->secid[hp->lsmid->slot]);
+               if (rc != 0)
+                       break;
+       }
+       return rc;
 }
 EXPORT_SYMBOL(security_secmark_relabel_packet);

--
2.24.1

--
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Casey Schaufler <casey@schaufler-ca.com>

      Date: 2020-09-04 21:35:56 
    

  

  
On 9/4/2020 1:08 PM, Paul Moore wrote:
On Wed, Aug 26, 2020 at 11:07 AM Casey Schaufler [off-list ref] wrote:
quoted
Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)
...

quoted
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
        kgid_t                  gid;
        struct scm_fp_list      *fp;            /* Passed files         */
 #ifdef CONFIG_SECURITY_NETWORK
-       u32                     secid;          /* Security ID          */
+       struct lsmblob          lsmblob;        /* Security LSM data    */
As mentioned in a previous revision, I remain concerned that this is
going to become a problem due to the size limit on unix_skb_parms.  I
would need to redo the math to be certain, but if I recall correctly
this would limit us to five LSMs assuming both that we don't need to
grow the per-LSM size of lsmblob *and* the netdev folks don't decide
to add more fields to the unix_skb_parms.

I lost track of that earlier discussion so I'm not sure where it ended
up, but if there is a viable alternative it might be a good idea to
pursue it.
Stephen had concerns about the lifecycle management involved. He also
pointed out that I had taken a cowards way out when allocations failed.
That could result in unexpected behavior when an allocation failed.
Fixing that would have required a major re-write of the currently simple
UDS attribute code, which I suspect would be as hard a sell to netdev as
expanding the secid to a lsmblob. I also thought I'd gotten netdev on the
CC: for this patch, but it looks like I missed it.

I did start on the UDS attribute re-do, and discovered that I was going
to have to introduce new failure paths, and that it might not be possible
to maintain compatibility for all cases because of the new possibilities
of failure.






  

    
Re: [PATCH v20 02/23] LSM: Create and manage the lsmblob data structure.

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 21:50:22 
    

  

  
On Wed, Aug 26, 2020 at 11:03 AM Casey Schaufler [off-list ref] wrote:
When more than one security module is exporting data to
audit and networking sub-systems a single 32 bit integer
is no longer sufficient to represent the data. Add a
structure to be used instead.

The lsmblob structure is currently an array of
u32 "secids". There is an entry for each of the
security modules built into the system that would
use secids if active. The system assigns the module
a "slot" when it registers hooks. If modules are
compiled in but not registered there will be unused
slots.

A new lsm_id structure, which contains the name
of the LSM and its slot number, is created. There
is an instance for each LSM, which assigns the name
and passes it to the infrastructure to set the slot.

The audit rules data is expanded to use an array of
security module data rather than a single instance.
Because IMA uses the audit rule functions it is
affected as well.

Acked-by: Stephen Smalley <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/audit.h               |  4 +-
 include/linux/lsm_hooks.h           | 12 ++++-
 include/linux/security.h            | 67 +++++++++++++++++++++++++--
 kernel/auditfilter.c                | 24 +++++-----
 kernel/auditsc.c                    | 12 ++---
 security/apparmor/lsm.c             |  7 ++-
 security/bpf/hooks.c                | 12 ++++-
 security/commoncap.c                |  7 ++-
 security/integrity/ima/ima_policy.c | 40 +++++++++++-----
 security/loadpin/loadpin.c          |  8 +++-
 security/lockdown/lockdown.c        |  7 ++-
 security/safesetid/lsm.c            |  8 +++-
 security/security.c                 | 72 ++++++++++++++++++++++++-----
 security/selinux/hooks.c            |  8 +++-
 security/smack/smack_lsm.c          |  7 ++-
 security/tomoyo/tomoyo.c            |  8 +++-
 security/yama/yama_lsm.c            |  7 ++-
 17 files changed, 254 insertions(+), 56 deletions(-)
...

quoted hunk
diff --git a/include/linux/security.h b/include/linux/security.h
index 0a0a03b36a3b..c91389d7aebc 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -131,6 +131,65 @@ enum lockdown_reason {

 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];

+/*
+ * Data exported by the security modules
+ *
+ * Any LSM that provides secid or secctx based hooks must be included.
+ */
+#define LSMBLOB_ENTRIES ( \
+       (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
+       (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
+       (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
+       (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0))
+
+struct lsmblob {
+       u32     secid[LSMBLOB_ENTRIES];
+};
+
+#define LSMBLOB_INVALID                -1      /* Not a valid LSM slot number */
+#define LSMBLOB_NEEDED         -2      /* Slot requested on initialization */
+#define LSMBLOB_NOT_NEEDED     -3      /* Slot not requested */
+
+/**
+ * lsmblob_init - initialize an lsmblob structure.
+ * @blob: Pointer to the data to initialize
+ * @secid: The initial secid value
+ *
+ * Set all secid for all modules to the specified value.
+ */
+static inline void lsmblob_init(struct lsmblob *blob, u32 secid)
+{
+       int i;
+
+       for (i = 0; i < LSMBLOB_ENTRIES; i++)
+               blob->secid[i] = secid;
+}
As I'm going through the v20 draft of these patches it occurs to me,
at least in the intermediate patches, that there is a pretty common
pattern involving lsmblob_init():

  lsmblob_init(blob, secid);
  func(blob, ...);

... would it make sense to have lsmblob_init() return *blob instead of
void?  It doesn't really matter too much, but it seems like it could
help cleanup some of the code:

  func(lsmblob_init(blob, secid), ...);

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 21:53:35 
    

  

  
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
On 9/4/2020 1:08 PM, Paul Moore wrote:
quoted
On Wed, Aug 26, 2020 at 11:07 AM Casey Schaufler [off-list ref] wrote:
quoted
Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)
...

quoted
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
        kgid_t                  gid;
        struct scm_fp_list      *fp;            /* Passed files         */
 #ifdef CONFIG_SECURITY_NETWORK
-       u32                     secid;          /* Security ID          */
+       struct lsmblob          lsmblob;        /* Security LSM data    */
As mentioned in a previous revision, I remain concerned that this is
going to become a problem due to the size limit on unix_skb_parms.  I
would need to redo the math to be certain, but if I recall correctly
this would limit us to five LSMs assuming both that we don't need to
grow the per-LSM size of lsmblob *and* the netdev folks don't decide
to add more fields to the unix_skb_parms.

I lost track of that earlier discussion so I'm not sure where it ended
up, but if there is a viable alternative it might be a good idea to
pursue it.
Stephen had concerns about the lifecycle management involved. He also
pointed out that I had taken a cowards way out when allocations failed.
That could result in unexpected behavior when an allocation failed.
Fixing that would have required a major re-write of the currently simple
UDS attribute code, which I suspect would be as hard a sell to netdev as
expanding the secid to a lsmblob. I also thought I'd gotten netdev on the
CC: for this patch, but it looks like I missed it.

I did start on the UDS attribute re-do, and discovered that I was going
to have to introduce new failure paths, and that it might not be possible
to maintain compatibility for all cases because of the new possibilities
of failure.
... and you're hoping to not be responsible for this code by the time
this becomes a limiting issue? ;)

I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 07/23] LSM: Use lsmblob in security_secid_to_secctx

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-04 21:59:23 
    

  

  
On Wed, Aug 26, 2020 at 11:09 AM Casey Schaufler [off-list ref] wrote:
Change security_secid_to_secctx() to take a lsmblob as input
instead of a u32 secid. It will then call the LSM hooks
using the lsmblob element allocated for that module. The
callers have been updated as well. This allows for the
possibility that more than one module may be called upon
to translate a secid to a string, as can occur in the
audit code.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 drivers/android/binder.c                | 12 +++++++++-
 include/linux/security.h                |  5 +++--
 include/net/scm.h                       |  8 ++-----
 kernel/audit.c                          | 20 +++++++++++++++--
 kernel/auditsc.c                        | 28 +++++++++++++++++++----
 net/ipv4/ip_sockglue.c                  |  5 +----
 net/netfilter/nf_conntrack_netlink.c    | 14 ++++++++++--
 net/netfilter/nf_conntrack_standalone.c |  4 +++-
 net/netfilter/nfnetlink_queue.c         | 11 +++++++--
 net/netlabel/netlabel_unlabeled.c       | 30 +++++++++++++++++++++----
 net/netlabel/netlabel_user.c            |  6 ++---
 security/security.c                     | 11 +++++----
 12 files changed, 117 insertions(+), 37 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Casey Schaufler <casey@schaufler-ca.com>

      Date: 2020-09-04 23:58:54 
    

  

  
On 9/4/2020 2:53 PM, Paul Moore wrote:
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
quoted
On Wed, Aug 26, 2020 at 11:07 AM Casey Schaufler [off-list ref] wrote:
quoted
Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 +++++--
 include/net/af_unix.h    |  2 +-
 include/net/scm.h        |  8 +++++---
 net/ipv4/ip_sockglue.c   |  8 +++++---
 net/unix/af_unix.c       |  6 +++---
 security/security.c      | 18 +++++++++++++++---
 6 files changed, 34 insertions(+), 15 deletions(-)
...

quoted
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
        kgid_t                  gid;
        struct scm_fp_list      *fp;            /* Passed files         */
 #ifdef CONFIG_SECURITY_NETWORK
-       u32                     secid;          /* Security ID          */
+       struct lsmblob          lsmblob;        /* Security LSM data    */
As mentioned in a previous revision, I remain concerned that this is
going to become a problem due to the size limit on unix_skb_parms.  I
would need to redo the math to be certain, but if I recall correctly
this would limit us to five LSMs assuming both that we don't need to
grow the per-LSM size of lsmblob *and* the netdev folks don't decide
to add more fields to the unix_skb_parms.

I lost track of that earlier discussion so I'm not sure where it ended
up, but if there is a viable alternative it might be a good idea to
pursue it.
Stephen had concerns about the lifecycle management involved. He also
pointed out that I had taken a cowards way out when allocations failed.
That could result in unexpected behavior when an allocation failed.
Fixing that would have required a major re-write of the currently simple
UDS attribute code, which I suspect would be as hard a sell to netdev as
expanding the secid to a lsmblob. I also thought I'd gotten netdev on the
CC: for this patch, but it looks like I missed it.

I did start on the UDS attribute re-do, and discovered that I was going
to have to introduce new failure paths, and that it might not be possible
to maintain compatibility for all cases because of the new possibilities
of failure.
... and you're hoping to not be responsible for this code by the time
this becomes a limiting issue? ;)
Well, maybe. More likely that full dementia will have set in by the
time I get the alternative done correctly. It's a _lot_ more complicated.
I'm carefully watching what the BPF people are doing with their
memory management schemes in the hope they will come up with something
useful. 

I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.






  

    
Re: [PATCH v20 08/23] LSM: Use lsmblob in security_ipc_getsecid

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-05 13:13:04 
    

  

  
On Wed, Aug 26, 2020 at 11:10 AM Casey Schaufler [off-list ref] wrote:
There may be more than one LSM that provides IPC data
for auditing. Change security_ipc_getsecid() to fill in
a lsmblob structure instead of the u32 secid. The
audit data structure containing the secid will be updated
later, so there is a bit of scaffolding here.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  7 ++++---
 kernel/auditsc.c         |  7 ++++++-
 security/security.c      | 12 +++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 09/23] LSM: Use lsmblob in security_task_getsecid

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-05 13:18:50 
    

  

  
On Wed, Aug 26, 2020 at 11:11 AM Casey Schaufler [off-list ref] wrote:
Change the security_task_getsecid() interface to fill in
a lsmblob structure instead of a u32 secid in support of
LSM stacking. Audit interfaces will need to collect all
possible secids for possible reporting.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
 drivers/android/binder.c              | 12 +------
 include/linux/security.h              |  7 ++--
 kernel/audit.c                        | 16 ++++-----
 kernel/auditfilter.c                  |  4 +--
 kernel/auditsc.c                      | 25 +++++++-------
 net/netlabel/netlabel_unlabeled.c     |  5 ++-
 net/netlabel/netlabel_user.h          |  6 +++-
 security/integrity/ima/ima_appraise.c | 10 +++---
 security/integrity/ima/ima_main.c     | 49 +++++++++++++++------------
 security/security.c                   | 12 +++++--
 10 files changed, 76 insertions(+), 70 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 10/23] LSM: Use lsmblob in security_inode_getsecid

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-05 13:21:17 
    

  

  
On Wed, Aug 26, 2020 at 11:12 AM Casey Schaufler [off-list ref] wrote:
Change the security_inode_getsecid() interface to fill in a
lsmblob structure instead of a u32 secid. This allows for its
callers to gather data from all registered LSMs. Data is provided
for IMA and audit.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Stephen Smalley <redacted>
cc: linux-integrity@vger.kernel.org
---
 include/linux/security.h            |  7 ++++---
 kernel/auditsc.c                    |  6 +++++-
 security/integrity/ima/ima_policy.c |  4 +---
 security/security.c                 | 11 +++++++++--
 4 files changed, 19 insertions(+), 9 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-05 13:25:29 
    

  

  
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?

I was sorta hoping for something a bit better.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Casey Schaufler <casey@schaufler-ca.com>

      Date: 2020-09-05 18:13:43 
    

  

  
On 9/5/2020 6:25 AM, Paul Moore wrote:
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.

Thank you 






  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: John Johansen <john.johansen@canonical.com>

      Date: 2020-09-05 19:05:44 
    

  

  
On 9/5/20 11:13 AM, Casey Schaufler wrote:
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.






  

    
Re: [PATCH v20 12/23] IMA: Change internal interfaces to use lsmblobs

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 02:28:24 
    

  

  
On Wed, Aug 26, 2020 at 11:14 AM Casey Schaufler [off-list ref] wrote:
The IMA interfaces ima_get_action() and ima_match_policy()
call LSM functions that use lsmblobs. Change the IMA functions
to pass the lsmblob to be compatible with the LSM functions.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
 security/integrity/ima/ima.h          | 11 +++++----
 security/integrity/ima/ima_api.c      | 10 ++++----
 security/integrity/ima/ima_appraise.c |  6 ++---
 security/integrity/ima/ima_main.c     | 35 +++++++++++----------------
 security/integrity/ima/ima_policy.c   | 14 +++++------
 5 files changed, 34 insertions(+), 42 deletions(-)
...

quoted hunk
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index a86b35dad4fa..b057c758b430 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -519,7 +519,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
                case LSM_SUBJ_USER:
                case LSM_SUBJ_ROLE:
                case LSM_SUBJ_TYPE:
-                       lsmblob_init(&lsmdata, secid);
                        rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
                                                   Audit_equal,
                                                   rule->lsm[i].rules);
I'm jumping across patches in this patchset so I may have missed
something, but I think the ima_filter_rule_match() call should be
using the passed "blob" pointer and not the local "lsmdata" right?  If
this is correct, I think this patch can also remove the local
"lsmdata" as well.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 14/23] LSM: Ensure the correct LSM context releaser

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 02:46:16 
    

  

  
On Wed, Aug 26, 2020 at 11:16 AM Casey Schaufler [off-list ref] wrote:
Add a new lsmcontext data structure to hold all the information
about a "security context", including the string, its size and
which LSM allocated the string. The allocation information is
necessary because LSMs have different policies regarding the
lifecycle of these strings. SELinux allocates and destroys
them on each use, whereas Smack provides a pointer to an entry
in a list that never goes away.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 drivers/android/binder.c                | 10 ++++---
 fs/ceph/xattr.c                         |  6 ++++-
 fs/nfs/nfs4proc.c                       |  8 ++++--
 fs/nfsd/nfs4xdr.c                       |  7 +++--
 include/linux/security.h                | 35 +++++++++++++++++++++++--
 include/net/scm.h                       |  5 +++-
 kernel/audit.c                          | 14 +++++++---
 kernel/auditsc.c                        | 12 ++++++---
 net/ipv4/ip_sockglue.c                  |  4 ++-
 net/netfilter/nf_conntrack_netlink.c    |  4 ++-
 net/netfilter/nf_conntrack_standalone.c |  4 ++-
 net/netfilter/nfnetlink_queue.c         | 13 ++++++---
 net/netlabel/netlabel_unlabeled.c       | 19 +++++++++++---
 net/netlabel/netlabel_user.c            |  4 ++-
 security/security.c                     | 11 ++++----
 15 files changed, 121 insertions(+), 35 deletions(-)
One small comment below, but otherwise ...

Acked-by: Paul Moore <paul@paul-moore.com>

+/**
+ * lsmcontext_init - initialize an lsmcontext structure.
+ * @cp: Pointer to the context to initialize
+ * @context: Initial context, or NULL
+ * @size: Size of context, or 0
+ * @slot: Which LSM provided the context
+ *
+ * Fill in the lsmcontext from the provided information.
+ * This is a scaffolding function that will be removed when
+ * lsmcontext integration is complete.
+ */
+static inline void lsmcontext_init(struct lsmcontext *cp, char *context,
+                                  u32 size, int slot)
+{
+       cp->slot = slot;
+       cp->context = context;
+       cp->len = size;
+}
Here is another case where some of the intermediate code, and perhaps
some of the final code, can probably be simplified if
lsmcontext_init() returns the lsmcontext pointer.

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 16/23] LSM: Use lsmcontext in security_inode_getsecctx

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 02:56:02 
    

  

  
On Wed, Aug 26, 2020 at 11:19 AM Casey Schaufler [off-list ref] wrote:
Change the security_inode_getsecctx() interface to fill
a lsmcontext structure instead of data and length pointers.
This provides the information about which LSM created the
context so that security_release_secctx() can use the
correct hook.

Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 fs/nfsd/nfs4xdr.c        | 23 +++++++++--------------
 include/linux/security.h |  5 +++--
 security/security.c      | 13 +++++++++++--
 3 files changed, 23 insertions(+), 18 deletions(-)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 17/23] LSM: security_secid_to_secctx in netlink netfilter

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 03:11:38 
    

  

  
On Wed, Aug 26, 2020 at 11:20 AM Casey Schaufler [off-list ref] wrote:
Change netlink netfilter interfaces to use lsmcontext
pointers, and remove scaffolding.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: netdev@vger.kernel.org
---
 net/netfilter/nfnetlink_queue.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)
...

quoted hunk
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index d3f8e808c5d3..c830401f7792 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -401,8 +399,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
        enum ip_conntrack_info ctinfo;
        struct nfnl_ct_hook *nfnl_ct;
        bool csum_verify;
-       struct lsmcontext scaff; /* scaffolding */
-       char *secdata = NULL;
+       struct lsmcontext context = { };
        u32 seclen = 0;

        size = nlmsg_total_size(sizeof(struct nfgenmsg))
@@ -469,7 +466,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
        }

        if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) {
-               seclen = nfqnl_get_sk_secctx(entskb, &secdata);
+               seclen = nfqnl_get_sk_secctx(entskb, &context);
                if (seclen)
                        size += nla_total_size(seclen);
        }
I think we can get rid of the local "seclen" variable, right?  We can
embed the nfqnl_get_sk_secctx() in the conditional and then simply
reference "context.len" everywhere else, yes?  For example:

  if (nfqnl_get_sk_secctx(..., &context))
    size += nla_total_size(context.len);

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 18/23] NET: Store LSM netlabel data in a lsmblob

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 03:28:12 
    

  

  
On Wed, Aug 26, 2020 at 11:21 AM Casey Schaufler [off-list ref] wrote:
Netlabel uses LSM interfaces requiring an lsmblob and
the internal storage is used to pass information between
these interfaces, so change the internal data from a secid
to a lsmblob. Update the netlabel interfaces and their
callers to accommodate the change. This requires that the
modules using netlabel use the lsm_id.slot to access the
correct secid when using netlabel.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 include/net/netlabel.h              |  8 +--
 net/ipv4/cipso_ipv4.c               | 27 ++++++----
 net/netlabel/netlabel_kapi.c        |  6 +--
 net/netlabel/netlabel_unlabeled.c   | 79 +++++++++--------------------
 net/netlabel/netlabel_unlabeled.h   |  2 +-
 security/selinux/hooks.c            |  2 +-
 security/selinux/include/security.h |  1 +
 security/selinux/netlabel.c         |  2 +-
 security/selinux/ss/services.c      |  4 +-
 security/smack/smack.h              |  1 +
 security/smack/smack_lsm.c          |  5 +-
 security/smack/smackfs.c            | 10 ++--
 12 files changed, 65 insertions(+), 82 deletions(-)
Minor change suggested to a comment below, but looks good otherwise.

Acked-by: Paul Moore <paul@paul-moore.com>

quoted hunk
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 2eb71579f4d2..8182b923e802 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -106,15 +106,17 @@ int cipso_v4_rbm_strictvalid = 1;
 /* Base length of the local tag (non-standard tag).
  *  Tag definition (may change between kernel versions)
  *
- * 0          8          16         24         32
- * +----------+----------+----------+----------+
- * | 10000000 | 00000110 | 32-bit secid value  |
- * +----------+----------+----------+----------+
- * | in (host byte order)|
- * +----------+----------+
- *
+ * 0          8          16                    16 + sizeof(struct lsmblob)
+ * +----------+----------+---------------------+
+ * | 10000000 | 00000110 | LSM blob data       |
+ * +----------+----------+---------------------+
+ *
+ * All secid and flag fields are in host byte order.
+ * The lsmblob structure size varies depending on which
+ * Linux security modules are built in the kernel.
+ * The data is opaque.
  */
-#define CIPSO_V4_TAG_LOC_BLEN         6
+#define CIPSO_V4_TAG_LOC_BLEN         (2 + sizeof(struct lsmblob))

 /*
  * Helper Functions
@@ -1469,7 +1471,12 @@ static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,

        buffer[0] = CIPSO_V4_TAG_LOCAL;
        buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
-       *(u32 *)&buffer[2] = secattr->attr.secid;
+       /* Ensure that there is sufficient space in the CIPSO header
+        * for the LSM data. This should never become an issue.
+        * The check is made from an abundance of caution. */
+       BUILD_BUG_ON(CIPSO_V4_TAG_LOC_BLEN > CIPSO_V4_OPT_LEN_MAX);
I like the BUILD_BUG_ON() check, but for reasons very similar to the
unix_skb_params changes I don't really like the "should never become
an issue" commentary.  Granted, it is unlikely, but I don't think it
is wise to thumb our nose at fate.

+       memcpy(&buffer[2], &secattr->attr.lsmblob,
+              sizeof(secattr->attr.lsmblob));

        return CIPSO_V4_TAG_LOC_BLEN;
 }
-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 19/23] LSM: Verify LSM display sanity in binder

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 03:30:51 
    

  

  
On Wed, Aug 26, 2020 at 11:22 AM Casey Schaufler [off-list ref] wrote:
Verify that the tasks on the ends of a binder transaction
use the same "display" security module. This prevents confusion
of security "contexts".

Reviewed-by: Kees Cook <redacted>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/security.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
Acked-by: Paul Moore <paul@paul-moore.com>

-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 20/23] Audit: Add new record for multiple process LSM attributes

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-06 16:32:37 
    

  

  
On Wed, Aug 26, 2020 at 11:23 AM Casey Schaufler [off-list ref] wrote:
Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
---
 drivers/android/binder.c                |  2 +-
 include/linux/audit.h                   | 13 +++-
 include/linux/security.h                | 18 ++++-
 include/net/netlabel.h                  |  2 +-
 include/net/scm.h                       |  3 +-
 include/net/xfrm.h                      |  4 +-
 include/uapi/linux/audit.h              |  1 +
 kernel/audit.c                          | 89 ++++++++++++++++++-------
 kernel/auditfilter.c                    |  2 +-
 kernel/auditsc.c                        | 87 ++++++++++++++++++++++--
 net/ipv4/ip_sockglue.c                  |  2 +-
 net/netfilter/nf_conntrack_netlink.c    |  4 +-
 net/netfilter/nf_conntrack_standalone.c |  2 +-
 net/netfilter/nfnetlink_queue.c         |  2 +-
 net/netlabel/netlabel_unlabeled.c       | 16 ++---
 net/netlabel/netlabel_user.c            | 12 ++--
 net/netlabel/netlabel_user.h            |  6 +-
 security/integrity/integrity_audit.c    |  2 +-
 security/security.c                     | 73 +++++++++++++++-----
 security/smack/smackfs.c                |  3 +-
 20 files changed, 259 insertions(+), 84 deletions(-)
Regardless of the code, the audit folks generally ask for an example
of the new audit record in the commit description; it make it easier
for the people not familiar with the kernel to review the record
format/information.

I've also been requiring that a test is added to the audit test suite
for new features added to the kernel.  I recognize this is a big ask
for something like this, but it is something we have been doing for
several years now and I think the benefits far outweigh the costs.

* https://github.com/linux-audit/audit-testsuite

quoted hunk
diff --git a/include/linux/audit.h b/include/linux/audit.h
index ba1cd38d601b..fe027df0d9a8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,7 +186,9 @@ extern void             audit_log_path_denied(int type,
                                                  const char *operation);
 extern void                audit_log_lost(const char *message);

-extern int audit_log_task_context(struct audit_buffer *ab);
+extern void audit_log_lsm(struct lsmblob *blob, bool exiting);
+extern int audit_log_task_context(struct audit_buffer *ab,
+                                 struct lsmblob *blob);
The audit functions tend to get abused, and this is mostly due to a
rather poor design, so I'd prefer to see audit_log_task_context()
remain with just a single argument: the audit buffer.  I believe this
covers the vast majority of the cases and should remain the preferred
option for callers.  This should help shrink the patch and focus it a
bit more.

For the handful of callers that do need to specify a separate task
context, you can create a __audit_log_task_context(ab, blob) that
allows the caller to specify the blob (and obviously you can write
audit_log_task_context() as a one line wrapper around this function).

quoted hunk
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 2737d24ec244..9e8cac6228b4 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -675,11 +675,13 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)

        if (audit_enabled == AUDIT_OFF)
                return NULL;
+       audit_stamp_context(audit_context());
        audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
                                    AUDIT_MAC_IPSEC_EVENT);
Is audit_stamp_context() necessary here?  Generally if the first
argument to audit_log_start() is not NULL then you shouldn't need to
create a "local" audit context.

I wonder if you might be getting mixed up in testing by not having
audit properly enabled (see link below)?  Make sure you don't have any
audit disable rules loaded into the kernel, and you can even add
"audit=1" to the kernel command line.

https://github.com/linux-audit/audit-documentation/wiki/HOWTO-Fedora-Enable-Auditing

        if (audit_buf == NULL)
                return NULL;
        audit_log_format(audit_buf, "op=%s", op);
+       audit_log_lsm(NULL, false);
        return audit_buf;
 }
...

quoted hunk
diff --git a/kernel/audit.c b/kernel/audit.c
index 594b42fc88ff..0e7831c9f321 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1070,13 +1071,31 @@ static void audit_log_common_recv_msg(struct audit_context *context,
                return;
        audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
        audit_log_session_info(*ab);
-       audit_log_task_context(*ab);
+       audit_log_task_context(*ab, NULL);
 }

 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
                                           u16 msg_type)
 {
-       audit_log_common_recv_msg(NULL, ab, msg_type);
+       struct audit_context *context;
+
+       if (!lsm_multiple_contexts()) {
+               audit_log_common_recv_msg(NULL, ab, msg_type);
+               return;
+       }
+
+       context = audit_context();
+       if (context) {
+               if (!context->in_syscall)
+                       audit_stamp_context(context);
+               audit_log_common_recv_msg(context, ab, msg_type);
+               return;
+       }
+
+       audit_alloc(current);
+       context = audit_context();
+
+       audit_log_common_recv_msg(context, ab, msg_type);
 }
Hmm.  Take a look at Richard's patch for adding the audit container ID
record to audit user records, it should give you a better idea of how
to approach this.  The above changes in audit_log_user_recv_msg() are
not really what we want.

https://lore.kernel.org/linux-audit/4a5019ed3cfab416aeb6549b791ac6d8cc9fb8b7.1593198710.git.rgb@redhat.com

quoted hunk
@@ -1869,6 +1889,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
        }

        audit_get_stamp(ab->ctx, &t, &serial);
+       if (type == AUDIT_MAC_TASK_CONTEXTS && ab->ctx->serial == 0) {
+               audit_stamp_context(ab->ctx);
+               audit_get_stamp(ab->ctx, &t, &serial);
+       }
        audit_log_format(ab, "audit(%llu.%03lu:%u): ",
                         (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
Can you walk me through what you are trying to do here?  This doesn't
seem right to me, but I'm sure you put it here for a reason.

quoted hunk
@@ -2126,30 +2150,47 @@ void audit_log_key(struct audit_buffer *ab, char *key)
                audit_log_format(ab, "(null)");
 }

-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob)
 {
+       int i;
        int error;
-       struct lsmblob blob;
-       struct lsmcontext context;
+       struct lsmblob localblob;
+       struct lsmcontext lsmdata;

-       security_task_getsecid(current, &blob);
-       if (!lsmblob_is_set(&blob))
+       /*
+        * If there is more than one security module that has a
+        * subject "context" it's necessary to put the subject data
+        * into a separate record to maintain compatibility.
+        */
+       if (lsm_multiple_contexts()) {
+               audit_log_format(ab, " subj=?");
                return 0;
+       }

-       error = security_secid_to_secctx(&blob, &context);
-       if (error) {
-               if (error != -EINVAL)
-                       goto error_path;
-               return 0;
+       if (blob == NULL) {
+               security_task_getsecid(current, &localblob);
Why is localblob necessary?  You know blob is NULL here, just use it
directly and skip the assignment later in this code block.

+               if (!lsmblob_is_set(&localblob)) {
+                       audit_log_format(ab, " subj=?");
+                       return 0;
+               }
+               blob = &localblob;
        }

-       audit_log_format(ab, " subj=%s", context.context);
-       security_release_secctx(&context);
-       return 0;
+       for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+               if (blob->secid[i] == 0)
+                       continue;
+               error = security_secid_to_secctx(blob, &lsmdata, i);
+               if (error && error != -EINVAL) {
+                       audit_panic("error in audit_log_task_context");
+                       return error;
+               }

-error_path:
-       audit_panic("error in audit_log_task_context");
-       return error;
+               audit_log_format(ab, " subj=%s", lsmdata.context);
+               security_release_secctx(&lsmdata);
+               break;
+       }
+
+       return 0;
 }
 EXPORT_SYMBOL(audit_log_task_context);
...

quoted hunk
@@ -2279,6 +2320,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
        if (!audit_enabled)
                return;

+       audit_stamp_context(audit_context());
        ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
        if (!ab)
                return;
Similar to above, I'm not sure audit_stamp_context() is what we want here.

quoted hunk
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4af5861bcb9a..cf5dbd0e3a3d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -962,10 +962,12 @@ int audit_alloc(struct task_struct *tsk)
                return 0; /* Return if not auditing. */

        state = audit_filter_task(tsk, &key);
-       if (state == AUDIT_DISABLED) {
+       if (!lsm_multiple_contexts() && state == AUDIT_DISABLED) {
                clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
                return 0;
        }
+       if (state == AUDIT_DISABLED)
+               clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
Hmmm.  I think we've hit critical mass on the amount of hacks in the
audit subsystem for this code ... Let's back up a bit and start with
some basic requirements (correct me if I'm wrong on any of these):

1. This patch only deals with LSM process/task/subject contexts.
2. Multiple LSMs may, or may not exist; audit logs and behavior should
remain unchanged in the single LSM case.
3. If multiple LSMs are present, the subject field in existing records
should take the form of "subj=?" and a new audit record is created
containing fields of the format "subj_<LSM>=<context>".

Assuming all of that is true, why not simply keep the basic logic in
audit_log_task_context(), but also stash a lsmblob struct in the
audit_context for later use by audit_log_exit()?  Stashing of the
lsmblob would really only be necessary to handle the few cases where
the current task is not the proper subject.

quoted hunk
@@ -1483,6 +1486,52 @@ static void audit_log_proctitle(void)
        audit_log_end(ab);
 }

+void audit_log_lsm(struct lsmblob *blob, bool exiting)
+{
+       struct audit_context *context = audit_context();
+       struct lsmcontext lsmdata;
+       struct audit_buffer *ab;
+       struct lsmblob localblob;
+       bool sep = false;
+       int error;
+       int i;
+
+       if (!lsm_multiple_contexts())
+               return;
+
+       if (context && context->in_syscall && !exiting)
+               return;
I think the "!lsm_multiple_contexts()" and "!exiting" checks fit well
with my comments about generating the AUDIT_MAC_TASK_CONTEXT record in
audit_log_exit.  This code needs a rethink.

+       ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
+       if (!ab)
+               return; /* audit_panic or being filtered */
+
+       if (blob == NULL) {
+               security_task_getsecid(current, &localblob);
+               if (!lsmblob_is_set(&localblob))
+                       return;
+               blob = &localblob;
+       }
+
+       for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+               if (blob->secid[i] == 0)
+                       continue;
+               error = security_secid_to_secctx(blob, &lsmdata, i);
+               if (error && error != -EINVAL) {
+                       audit_panic("error in audit_log_lsm");
+                       return; fits well with a
+               }
+
+               audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
+                                security_lsm_slot_name(i), lsmdata.context);
+               sep = true;
+
+               security_release_secctx(&lsmdata);
+       }
+
+       audit_log_end(ab);
+}
...

quoted hunk
@@ -2217,6 +2267,21 @@ void __audit_inode_child(struct inode *parent,
 }
 EXPORT_SYMBOL_GPL(__audit_inode_child);

+/**
+ * audit_stamp_context - set the timestamp+serial in an audit context
+ * @ctx: audit_context to set
+ */
+void audit_stamp_context(struct audit_context *ctx)
+{
+       /* ctx will be NULL unless lsm_multiple_contexts() is true */
+       if (!ctx)
+               return;
+
+       ktime_get_coarse_real_ts64(&ctx->ctime);
+       ctx->serial = audit_serial();
+       ctx->current_state = AUDIT_BUILD_CONTEXT;
+}
Based on previous discussions and what I *think* you are trying to do
in this patchset, I believe Richard's audit_alloc_local()
implementation (link below) is a better and cleaner solution.  His
latest revisions needs some minor tweaks (see my feeback), but I think
you could probably work with him to pull that single patch into your
patchset.

To be clear, I'm talking about just that one patch; I'm a firm
believer that tying the LSM stacking and audit container ID patches
beyond this would be a disaster.  I can deal with any merge conflicts
that arise whenever the different patchsets land.

* Richard's audit_alloc_local() patch (07/13 of the latest audit
container ID patchset)
https://lore.kernel.org/linux-audit/21e6c4e1ac179c8dcf35803e603899ccfc69300a.1593198710.git.rgb@redhat.com

quoted hunk
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..4e9064754b5f 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,12 +84,12 @@ struct audit_buffer *netlbl_audit_start_common(int type,
                                               struct netlbl_audit *audit_info)
 {
        struct audit_buffer *audit_buf;
-       struct lsmcontext context;
-       struct lsmblob blob;

        if (audit_enabled == AUDIT_OFF)
                return NULL;

+       audit_stamp_context(audit_context());
Another one.

        audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
        if (audit_buf == NULL)
                return NULL;
-- 
paul moore
www.paul-moore.com





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Stephen Smalley <stephen.smalley.work@gmail.com>

      Date: 2020-09-08 01:29:10 
    

  

  
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.





  

    
Re: [PATCH v20 17/23] LSM: security_secid_to_secctx in netlink netfilter

    

      From: Pablo Neira Ayuso <pablo@netfilter.org>

      Date: 2020-09-08 10:47:08 
    

  

  
On Wed, Aug 26, 2020 at 07:52:41AM -0700, Casey Schaufler wrote:
Change netlink netfilter interfaces to use lsmcontext
pointers, and remove scaffolding.

Reviewed-by: Kees Cook <redacted>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <redacted>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: netdev@vger.kernel.org
---
 net/netfilter/nfnetlink_queue.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)
[...]
quoted hunk
 static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry)
@@ -401,8 +399,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	enum ip_conntrack_info ctinfo;
 	struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
-	struct lsmcontext scaff; /* scaffolding */
-	char *secdata = NULL;
+	struct lsmcontext context = { };
 	u32 seclen = 0;
While at it, please introduce reverse xmas tree in variable
definitions incrementally:

	struct lsmcontext context = { };
  	enum ip_conntrack_info ctinfo;
  	struct nfnl_ct_hook *nfnl_ct;
  	bool csum_verify;
 	u32 seclen = 0;

And Cc: netfilter-devel@vger.kernel.org for patches that update the
Netfilter codebase.

Thanks.





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Stephen Smalley <stephen.smalley.work@gmail.com>

      Date: 2020-09-08 13:53:12 
    

  

  
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Casey Schaufler <casey@schaufler-ca.com>

      Date: 2020-09-08 23:38:07 
    

  

  
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
it earlier and throw in a touch of scaffolding for secid_to_secctx()
we can leave the secid as is for now. This can't be the final solution
as AppArmor will be using the hook someday and we still have the all
modules case to worry about for the next phase. It also assumes that
The BPF module isn't going to suddenly sprout a security context.






  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: John Johansen <john.johansen@canonical.com>

      Date: 2020-09-09 00:18:14 
    

  

  
On 9/8/20 6:35 AM, Stephen Smalley wrote:
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
correct it is not currently needed. I have been playing with code to
handle it but it is not upstream yet.

Regardless this is something that will need to be solved at some
point.





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: John Johansen <john.johansen@canonical.com>

      Date: 2020-09-09 00:21:25 
    

  

  
On 9/8/20 4:37 PM, Casey Schaufler wrote:
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
quoted
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
right but as I said before this is coming, I have been playing with
it and have code. So the series doesn't need it today but sooner than
later it will be needed

it earlier and throw in a touch of scaffolding for secid_to_secctx()
we can leave the secid as is for now. This can't be the final solution
as AppArmor will be using the hook someday and we still have the all
modules case to worry about for the next phase. It also assumes that
The BPF module isn't going to suddenly sprout a security context.
Yep this is something that needs to be dealt with, whether it is now
or kicked down the road a little further ...







  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Stephen Smalley <stephen.smalley.work@gmail.com>

      Date: 2020-09-09 13:23:26 
    

  

  
On Tue, Sep 8, 2020 at 8:21 PM John Johansen
[off-list ref] wrote:
On 9/8/20 4:37 PM, Casey Schaufler wrote:
quoted
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
quoted
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
right but as I said before this is coming, I have been playing with
it and have code. So the series doesn't need it today but sooner than
later it will be needed
I don't understand why.  Is there a userspace component that relies on
SCM_SECURITY today for anything real (more than just blindly passing
it along and maybe writing to a log somewhere)?  And this doesn't
provide support for a composite SCM_SECURITY or SCM_CONTEXT, so it
doesn't really solve the stacking problem for it anyway.  What am I
missing?  Why do you care about this patch?





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Casey Schaufler <casey@schaufler-ca.com>

      Date: 2020-09-09 18:19:46 
    

  

  
On 9/9/2020 6:19 AM, Stephen Smalley wrote:
On Tue, Sep 8, 2020 at 8:21 PM John Johansen
[off-list ref] wrote:
quoted
On 9/8/20 4:37 PM, Casey Schaufler wrote:
quoted
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
quoted
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
right but as I said before this is coming, I have been playing with
it and have code. So the series doesn't need it today but sooner than
later it will be needed
Is sooner like 5.10, or 5.15? It matters.

I don't understand why.  Is there a userspace component that relies on
SCM_SECURITY today for anything real (more than just blindly passing
it along and maybe writing to a log somewhere)?  And this doesn't
provide support for a composite SCM_SECURITY or SCM_CONTEXT, so it
doesn't really solve the stacking problem for it anyway.  What am I
missing?  Why do you care about this patch?





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: John Johansen <john.johansen@canonical.com>

      Date: 2020-09-09 18:33:57 
    

  

  
On 9/9/20 11:19 AM, Casey Schaufler wrote:
On 9/9/2020 6:19 AM, Stephen Smalley wrote:
quoted
On Tue, Sep 8, 2020 at 8:21 PM John Johansen
[off-list ref] wrote:
quoted
On 9/8/20 4:37 PM, Casey Schaufler wrote:
quoted
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
quoted
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
right but as I said before this is coming, I have been playing with
it and have code. So the series doesn't need it today but sooner than
later it will be needed
Is sooner like 5.10, or 5.15? It matters.
I can split SCM_SECURITY off from the rest of the unix mediation and
push it off for a while. So lets call it 5.15 or later.

quoted
I don't understand why.  Is there a userspace component that relies on
SCM_SECURITY today for anything real (more than just blindly passing
it along and maybe writing to a log somewhere)?  And this doesn't
provide support for a composite SCM_SECURITY or SCM_CONTEXT, so it
doesn't really solve the stacking problem for it anyway.  What am I
missing?  Why do you care about this patch?





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: John Johansen <john.johansen@canonical.com>

      Date: 2020-09-09 18:48:01 
    

  

  
On 9/9/20 6:19 AM, Stephen Smalley wrote:
On Tue, Sep 8, 2020 at 8:21 PM John Johansen
[off-list ref] wrote:
quoted
On 9/8/20 4:37 PM, Casey Schaufler wrote:
quoted
On 9/8/2020 6:35 AM, Stephen Smalley wrote:
quoted
On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley
[off-list ref] wrote:
quoted
On Sat, Sep 5, 2020 at 3:07 PM John Johansen
[off-list ref] wrote:
quoted
On 9/5/20 11:13 AM, Casey Schaufler wrote:
quoted
On 9/5/2020 6:25 AM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 2:53 PM, Paul Moore wrote:
quoted
On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler [off-list ref] wrote:
quoted
On 9/4/2020 1:08 PM, Paul Moore wrote:
...

quoted
quoted
I understand the concerns you mention, they are all valid as far as
I'm concerned, but I think we are going to get burned by this code as
it currently stands.
Yes, I can see that. We're getting burned by the non-extensibility
of secids. It will take someone smarter than me to figure out how to
fit N secids into 32bits without danger of either failure or memory
allocation.
Sooo what are the next steps here?  It sounds like there is some
agreement that the currently proposed unix_skb_params approach is a
problem, but it also sounds like you just want to merge it anyway?
There are real problems with all the approaches. This is by far the
least invasive of the lot. If this is acceptable for now I will commit
to including the dynamic allocation version in the full stacking
(e.g. Smack + SELinux) stage. If it isn't, well, this stage is going
to take even longer than it already has. Sigh.


quoted
I was sorta hoping for something a bit better.
I will be looking at alternatives. I am very much open to suggestions.
I'm not even 100% convinced that Stephen's objections to my separate
allocation strategy outweigh its advantages. If you have an opinion on
that, I'd love to hear it.
fwiw I prefer the separate allocation strategy, but as you have already
said it trading off one set of problems for another. I would rather see
this move forward and one set of trade offs isn't significantly worse
than the other to me so, either wfm.
I remain unclear that AppArmor needs this patch at all even when
support for SO_PEERSEC lands.
Contrary to the patch description, it is about supporting SCM_SECURITY
for datagram not SO_PEERSEC.  And I don't know of any actual users of
SCM_SECURITY even for SELinux, just SO_PEERSEC.
I remembered that systemd once tried using SCM_SECURITY but that was a
bug since systemd was using it with stream sockets and that wasn't
supported by the kernel at the time,
https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd
switched over to using SO_PEERSEC.  Subsequently I did fix
SCM_SECURITY to work with stream sockets via kernel commit
37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still
preferred.  Looking around, I see that there is still one usage of
SCM_SECURITY in systemd-journald but it doesn't seem to be required
(if provided, journald will pass the label along but nothing seems to
depend on it AFAICT).  In any event, I don't believe this patch is
needed to support stacking AppArmor.
Stephen is, as is so often the case, correct. AppArmor has a stub
socket_getpeersec_dgram() that gets removed in patch 23. If I remove
right but as I said before this is coming, I have been playing with
it and have code. So the series doesn't need it today but sooner than
later it will be needed
I don't understand why.  Is there a userspace component that relies on
SCM_SECURITY today for anything real (more than just blindly passing
it along and maybe writing to a log somewhere)?  And this doesn't
provide support for a composite SCM_SECURITY or SCM_CONTEXT, so it
doesn't really solve the stacking problem for it anyway.  What am I
missing?  Why do you care about this patch?

personally I don't atm, but there are people who do care about this in
there logs, whether they should or shouldn't is an entirely different
question.

Long term there may be some uses for it that I care about or "have to
care about." For now Casey can drop it from this series.





  

    
Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking

    

      From: Paul Moore <paul@paul-moore.com>

      Date: 2020-09-10 21:22:42 
    

  

  
On Wed, Sep 9, 2020 at 2:47 PM John Johansen
[off-list ref] wrote:
... For now Casey can drop it from this series.
As long as that whenever it reappears there is at the very least some
note of the limits in the commit description and the code (via
comments in the struct).  Of course that assumes we can't find an
alternate solution that we can all agree on which doesn't have these
stacking limits.

-- 
paul moore
www.paul-moore.com




    
  

  
    

      

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