[PATCH v3 5/5] Audit: Add record for multiple object contexts
From: Casey Schaufler
Date: Wed Mar 19 2025 - 18:38:16 EST
Create a new audit record AUDIT_MAC_OBJ_CONTEXTS.
An example of the MAC_OBJ_CONTEXTS (1424) record is:
type=MAC_OBJ_CONTEXTS[1424]
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@xxxxxxxxxxxxxxxx>
---
include/linux/audit.h | 6 +++++
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 51 +++++++++++++++++++++++++++++++++++++-
kernel/auditsc.c | 45 ++++++++-------------------------
4 files changed, 68 insertions(+), 35 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 3402e3ca43c6..8fdfa2721273 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -188,6 +188,7 @@ 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);
@@ -255,6 +256,11 @@ 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 5ebb5d80363d..8ca58144bcc6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -147,6 +147,7 @@
#define AUDIT_IPE_CONFIG_CHANGE 1421 /* IPE config change */
#define AUDIT_IPE_POLICY_LOAD 1422 /* IPE policy load */
#define AUDIT_MAC_TASK_CONTEXTS 1423 /* Multiple LSM task contexts */
+#define AUDIT_MAC_OBJ_CONTEXTS 1424 /* 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 8ce453f6dc7d..69db0ee09a3f 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1133,7 +1133,6 @@ 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;
@@ -2324,6 +2323,56 @@ 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 context;
+
+ if (audit_secctx_cnt < 2) {
+ error = security_lsmprop_to_secctx(prop, &context,
+ LSM_ID_UNDEF);
+ if (error < 0) {
+ if (error != -EINVAL)
+ goto error_path;
+ return error;
+ }
+ audit_log_format(ab, " obj=%s", context.context);
+ security_release_secctx(&context);
+ 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_secctx_cnt; i++) {
+ rc = security_lsmprop_to_secctx(prop, &context,
+ audit_lsms[i]->id);
+ if (rc < 0) {
+ audit_log_format(ab, "%sobj_%s=?", space,
+ audit_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_lsms[i]->name, context.context);
+ security_release_secctx(&context);
+ }
+ 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 dc3f7e9666f2..e39d7be20c29 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) {
@@ -1780,15 +1756,16 @@ static void audit_log_exit(void)
axs->target_sessionid[i],
&axs->target_ref[i],
axs->target_comm[i]))
- call_panic = 1;
+ call_panic = 1;
}
if (context->target_pid &&
audit_log_pid_context(context, context->target_pid,
context->target_auid, context->target_uid,
context->target_sessionid,
- &context->target_ref, context->target_comm))
- call_panic = 1;
+ &context->target_ref,
+ context->target_comm))
+ call_panic = 1;
if (context->pwd.dentry && context->pwd.mnt) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
--
2.47.0