[PATCH v5 5/5] Audit: Add record for multiple object contexts
From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2025-08-16 16:42:05
Also in:
lkml, selinux
Subsystem:
audit subsystem, security subsystem, selinux security module, smack security module, the rest · Maintainers:
Paul Moore, Eric Paris, James Morris, "Serge E. Hallyn", Stephen Smalley, Casey Schaufler, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2025-07-16 · [PATCH v5 5/5] Audit: Add record for multiple object contexts · Casey Schaufler <casey@schaufler-ca.com>
Create a new audit record AUDIT_MAC_OBJ_CONTEXTS.
An example of the MAC_OBJ_CONTEXTS record is:
type=MAC_OBJ_CONTEXTS
msg=audit(1601152467.009:1050):
obj_selinux=unconfined_u:object_r:user_home_t:s0
When an audit event includes a AUDIT_MAC_OBJ_CONTEXTS record
the "obj=" field in other records in the event will be "obj=?".
An AUDIT_MAC_OBJ_CONTEXTS record is supplied when the system has
multiple security modules that may make access decisions based
on an object security context.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
include/linux/audit.h | 7 +++++
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 58 +++++++++++++++++++++++++++++++++++++-
kernel/auditsc.c | 38 +++++--------------------
security/selinux/hooks.c | 4 ++-
security/smack/smack_lsm.c | 4 ++-
6 files changed, 78 insertions(+), 34 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index fb54c1119947..56944fbc1e58 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h@@ -151,6 +151,7 @@ extern unsigned compat_signal_class[]; /* bit values for audit_cfg_lsm */ #define AUDIT_CFG_LSM_SECCTX_SUBJECT BIT(0) +#define AUDIT_CFG_LSM_SECCTX_OBJECT BIT(1) struct filename;
@@ -191,6 +192,7 @@ extern void audit_log_path_denied(int type, extern void audit_log_lost(const char *message); extern int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop); +extern int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop); extern int audit_log_task_context(struct audit_buffer *ab); extern void audit_log_task_info(struct audit_buffer *ab);
@@ -258,6 +260,11 @@ static inline int audit_log_subj_ctx(struct audit_buffer *ab, { return 0; } +static inline int audit_log_obj_ctx(struct audit_buffer *ab, + struct lsm_prop *prop) +{ + return 0; +} static inline int audit_log_task_context(struct audit_buffer *ab) { return 0;
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 8cad2f307719..14a1c1fe013a 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h@@ -149,6 +149,7 @@ #define AUDIT_LANDLOCK_ACCESS 1423 /* Landlock denial */ #define AUDIT_LANDLOCK_DOMAIN 1424 /* Landlock domain status */ #define AUDIT_MAC_TASK_CONTEXTS 1425 /* Multiple LSM task contexts */ +#define AUDIT_MAC_OBJ_CONTEXTS 1426 /* Multiple LSM objext 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 c7dea6bfacdd..63c69db43172 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c@@ -85,7 +85,9 @@ static unsigned int audit_net_id; /* Number of modules that provide a security context. List of lsms that provide a security context */ static u32 audit_subj_secctx_cnt; +static u32 audit_obj_secctx_cnt; static const struct lsm_id *audit_subj_lsms[MAX_LSM_COUNT]; +static const struct lsm_id *audit_obj_lsms[MAX_LSM_COUNT]; /** * struct audit_net - audit private network namespace data
@@ -305,6 +307,12 @@ void audit_cfg_lsm(const struct lsm_id *lsmid, int flags) return; audit_subj_lsms[audit_subj_secctx_cnt++] = lsmid; } + if (flags & AUDIT_CFG_LSM_SECCTX_OBJECT) { + for (i = 0 ; i < audit_obj_secctx_cnt; i++) + if (audit_obj_lsms[i] == lsmid) + return; + audit_obj_lsms[audit_obj_secctx_cnt++] = lsmid; + } } /**
@@ -1142,7 +1150,6 @@ static int is_audit_feature_set(int i) return af.features & AUDIT_FEATURE_TO_MASK(i); } - static int audit_get_feature(struct sk_buff *skb) { u32 seq;
@@ -2337,6 +2344,55 @@ int audit_log_task_context(struct audit_buffer *ab) } EXPORT_SYMBOL(audit_log_task_context); +int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop) +{ + int i; + int rc; + int error = 0; + char *space = ""; + struct lsm_context ctx; + + if (audit_obj_secctx_cnt < 2) { + error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF); + if (error < 0) { + if (error != -EINVAL) + goto error_path; + return error; + } + audit_log_format(ab, " obj=%s", ctx.context); + security_release_secctx(&ctx); + return 0; + } + audit_log_format(ab, " obj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS); + if (error) + goto error_path; + + for (i = 0; i < audit_obj_secctx_cnt; i++) { + rc = security_lsmprop_to_secctx(prop, &ctx, + audit_obj_lsms[i]->id); + if (rc < 0) { + audit_log_format(ab, "%sobj_%s=?", space, + audit_obj_lsms[i]->name); + if (rc != -EINVAL) + audit_panic("error in audit_log_obj_ctx"); + error = rc; + } else { + audit_log_format(ab, "%sobj_%s=%s", space, + audit_obj_lsms[i]->name, ctx.context); + security_release_secctx(&ctx); + } + space = " "; + } + + audit_buffer_aux_end(ab); + return error; + +error_path: + audit_panic("error in audit_log_obj_ctx"); + return error; +} + void audit_log_d_path_exe(struct audit_buffer *ab, struct mm_struct *mm) {
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 84173d234d4a..0c28fa33d099 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c@@ -1098,7 +1098,6 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, char *comm) { struct audit_buffer *ab; - struct lsm_context ctx; int rc = 0; ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1108,15 +1107,9 @@ 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 (lsmprop_is_set(prop)) { - if (security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF) < 0) { - audit_log_format(ab, " obj=(none)"); - rc = 1; - } else { - audit_log_format(ab, " obj=%s", ctx.context); - security_release_secctx(&ctx); - } - } + if (lsmprop_is_set(prop) && audit_log_obj_ctx(ab, prop)) + rc = 1; + audit_log_format(ab, " ocomm="); audit_log_untrustedstring(ab, comm); audit_log_end(ab);
@@ -1392,16 +1385,8 @@ static void show_special(struct audit_context *context, int *call_panic) from_kgid(&init_user_ns, context->ipc.gid), context->ipc.mode); if (lsmprop_is_set(&context->ipc.oprop)) { - struct lsm_context lsmctx; - - if (security_lsmprop_to_secctx(&context->ipc.oprop, - &lsmctx, - LSM_ID_UNDEF) < 0) { + if (audit_log_obj_ctx(ab, &context->ipc.oprop)) *call_panic = 1; - } else { - audit_log_format(ab, " obj=%s", lsmctx.context); - security_release_secctx(&lsmctx); - } } if (context->ipc.has_perm) { audit_log_end(ab);
@@ -1558,18 +1543,9 @@ 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 (lsmprop_is_set(&n->oprop)) { - struct lsm_context ctx; - - if (security_lsmprop_to_secctx(&n->oprop, &ctx, - LSM_ID_UNDEF) < 0) { - if (call_panic) - *call_panic = 2; - } else { - audit_log_format(ab, " obj=%s", ctx.context); - security_release_secctx(&ctx); - } - } + if (lsmprop_is_set(&n->oprop) && + audit_log_obj_ctx(ab, &n->oprop)) + *call_panic = 2; /* log the audit_names record type */ switch (n->type) {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 81b66b4d9695..11cd452c970b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c@@ -7595,7 +7595,9 @@ static __init int selinux_init(void) cred_init_security(); /* Inform the audit system that secctx is used */ - audit_cfg_lsm(&selinux_lsmid, AUDIT_CFG_LSM_SECCTX_SUBJECT); + audit_cfg_lsm(&selinux_lsmid, + AUDIT_CFG_LSM_SECCTX_SUBJECT | + AUDIT_CFG_LSM_SECCTX_OBJECT); default_noexec = !(VM_DATA_DEFAULT_FLAGS & VM_EXEC); if (!default_noexec)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 9a76821b7191..5fe4b53fa40b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c@@ -5269,7 +5269,9 @@ static __init int smack_init(void) init_smack_known_list(); /* Inform the audit system that secctx is used */ - audit_cfg_lsm(&smack_lsmid, AUDIT_CFG_LSM_SECCTX_SUBJECT); + audit_cfg_lsm(&smack_lsmid, + AUDIT_CFG_LSM_SECCTX_SUBJECT | + AUDIT_CFG_LSM_SECCTX_OBJECT); return 0; }
--
2.50.1