--- v19
+++ v38
@@ -1,57 +1,326 @@
-Verify that the tasks on the ends of a binder transaction
-use the same "display" security module. This prevents confusion
-of security "contexts".
+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 <keescook@chromium.org>
-Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
+Reviewed-by: John Johansen <john.johansen@canonical.com>
+Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
+Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
+Cc: linux-integrity@vger.kernel.org
+Cc: linux-audit@redhat.com
---
- security/security.c | 29 +++++++++++++++++++++++++++++
- 1 file changed, 29 insertions(+)
+ drivers/android/binder.c | 12 +----------
+ include/linux/security.h | 7 ++++---
+ kernel/audit.c | 25 +++++++----------------
+ kernel/audit.h | 3 ++-
+ kernel/auditsc.c | 33 +++++++++++--------------------
+ security/integrity/ima/ima_main.c | 4 +---
+ security/security.c | 12 ++++++++---
+ 7 files changed, 36 insertions(+), 60 deletions(-)
+diff --git a/drivers/android/binder.c b/drivers/android/binder.c
+index 0ab1d5179fc4..6e1e35de1fcb 100644
+--- a/drivers/android/binder.c
++++ b/drivers/android/binder.c
+@@ -3171,18 +3171,8 @@ static void binder_transaction(struct binder_proc *proc,
+ if (target_node && target_node->txn_security_ctx) {
+ struct lsmblob blob;
+ size_t added_size;
+- u32 secid;
+
+- security_cred_getsecid(proc->cred, &secid);
+- /*
+- * Later in this patch set security_cred_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_cred_getsecid(),
+- * which means that the one expected by
+- * security_secid_to_secctx() will be set.
+- */
+- lsmblob_init(&blob, secid);
++ security_cred_getsecid(proc->cred, &blob);
+ ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
+ if (ret) {
+ binder_txn_error("%d:%d failed to get security context\n",
+diff --git a/include/linux/security.h b/include/linux/security.h
+index ca5dcaee7c23..9f80b685542d 100644
+--- a/include/linux/security.h
++++ b/include/linux/security.h
+@@ -521,7 +521,7 @@ 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);
+@@ -1162,9 +1162,10 @@ static inline void security_transfer_creds(struct cred *new,
+ {
+ }
+
+-static inline void security_cred_getsecid(const struct cred *c, u32 *secid)
++static inline void security_cred_getsecid(const struct cred *c,
++ struct lsmblob *blob)
+ {
+- *secid = 0;
++ lsmblob_init(blob, 0);
+ }
+
+ static inline int security_kernel_act_as(struct cred *cred,
+diff --git a/kernel/audit.c b/kernel/audit.c
+index 4e13e48afc06..3d026013e6eb 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. */
+ static kuid_t audit_sig_uid = INVALID_UID;
+ static pid_t audit_sig_pid = -1;
+-static u32 audit_sig_sid;
++static struct lsmblob audit_sig_lsm;
+
+ /* Records can be lost in several ways:
+ 0) [suppressed in audit_alloc]
+@@ -1463,29 +1463,21 @@ 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(struct_size(sig_data, ctx, 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);
+ }
+@@ -2392,7 +2384,6 @@ 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 ||
+@@ -2403,9 +2394,7 @@ int audit_signal_info(int sig, struct task_struct *t)
+ audit_sig_uid = auid;
+ else
+ audit_sig_uid = uid;
+- security_current_getsecid_subj(&blob);
+- /* scaffolding until audit_sig_sid is converted */
+- audit_sig_sid = lsmblob_first(&blob);
++ security_current_getsecid_subj(&audit_sig_lsm);
+ }
+
+ return audit_signal_info_syscall(t);
+diff --git a/kernel/audit.h b/kernel/audit.h
+index 58b66543b4d5..316fac62d5f7 100644
+--- a/kernel/audit.h
++++ b/kernel/audit.h
+@@ -12,6 +12,7 @@
+ #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>
+ #include <uapi/linux/openat2.h> // struct open_how
+@@ -143,7 +144,7 @@ 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;
+diff --git a/kernel/auditsc.c b/kernel/auditsc.c
+index ad5f33af3b50..092aba46a9b3 100644
+--- a/kernel/auditsc.c
++++ b/kernel/auditsc.c
+@@ -99,7 +99,7 @@ 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;
+ };
+@@ -1018,7 +1018,7 @@ static void audit_reset_context(struct audit_context *ctx)
+ ctx->target_pid = 0;
+ ctx->target_auid = ctx->target_uid = KUIDT_INIT(0);
+ ctx->target_sessionid = 0;
+- ctx->target_sid = 0;
++ lsmblob_init(&ctx->target_lsm, 0);
+ ctx->target_comm[0] = '\0';
+ unroll_tree_refs(ctx, NULL, 0);
+ WARN_ON(!list_empty(&ctx->killed_trees));
+@@ -1091,14 +1091,14 @@ 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)
+@@ -1107,9 +1107,8 @@ 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 {
+@@ -1789,7 +1788,7 @@ 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;
+ }
+@@ -1798,7 +1797,7 @@ 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) {
+@@ -2740,15 +2739,12 @@ 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_obj(t, &blob);
+- /* scaffolding - until target_sid is converted */
+- context->target_sid = lsmblob_first(&blob);
++ security_task_getsecid_obj(t, &context->target_lsm);
+ memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
+ }
+
+@@ -2764,7 +2760,6 @@ 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;
+@@ -2776,9 +2771,7 @@ 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_obj(t, &blob);
+- /* scaffolding until target_sid is converted */
+- ctx->target_sid = lsmblob_first(&blob);
++ security_task_getsecid_obj(t, &ctx->target_lsm);
+ memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
+ return 0;
+ }
+@@ -2799,9 +2792,7 @@ 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_obj(t, &blob);
+- /* scaffolding until target_sid is converted */
+- axp->target_sid[axp->pid_count] = lsmblob_first(&blob);
++ security_task_getsecid_obj(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 25870eb422d9..ecaa0b96bb26 100644
+--- a/security/integrity/ima/ima_main.c
++++ b/security/integrity/ima/ima_main.c
+@@ -488,7 +488,6 @@ 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_current_getsecid_subj(&blob);
+@@ -497,8 +496,7 @@ int ima_bprm_check(struct linux_binprm *bprm)
+ if (ret)
+ return ret;
+
+- security_cred_getsecid(bprm->cred, &secid);
+- lsmblob_init(&blob, secid);
++ security_cred_getsecid(bprm->cred, &blob);
+ return process_measurement(bprm->file, bprm->cred, &blob, NULL, 0,
+ MAY_EXEC, CREDS_CHECK);
+ }
diff --git a/security/security.c b/security/security.c
-index ddbaf2073b02..95b48721fb17 100644
+index 563452000729..80133d6e982c 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);
+@@ -1829,10 +1829,16 @@ 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;
+
-+ /*
-+ * 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);
- }
++ 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
+2.37.3