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 <[email protected]>
---
 include/linux/audit.h      |  7 +++-
 include/uapi/linux/audit.h |  1 +
 kernel/audit.c             | 51 ++++++++++++++++++++++-
 kernel/auditsc.c           | 85 ++++++++++++--------------------------
 4 files changed, 83 insertions(+), 61 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index ee3e2ce70c45..16b89cbd6ac7 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -186,8 +186,10 @@ extern void                    audit_log_path_denied(int 
type,
                                                  const char *operation);
 extern void                audit_log_lost(const char *message);
 
+extern void audit_log_object_context(struct audit_buffer *ab,
+                                    struct lsm_prop *prop);
 extern int audit_log_subject_context(struct audit_buffer *ab,
-                                    struct lsm_prop *blob);
+                                    struct lsm_prop *prop);
 extern int audit_log_task_context(struct audit_buffer *ab);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
@@ -248,6 +250,9 @@ 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  void audit_log_object_context(struct audit_buffer *ab,
+                                            struct lsm_prop *prop)
+{ }
 static inline int audit_log_subject_context(struct audit_buffer *ab,
                                            struct lsm_prop *prop)
 {
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 49bbae475c35..3e7462f9d80e 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 f58bfa5c9635..62041cea6aba 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1116,7 +1116,6 @@ 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;
@@ -2302,6 +2301,56 @@ int audit_log_task_context(struct audit_buffer *ab)
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
+void audit_log_object_context(struct audit_buffer *ab, struct lsm_prop *prop)
+{
+       int i;
+       int error;
+       bool space = false;
+       struct lsm_context context;
+
+       if (lsm_prop_cnt < 2) {
+               error = security_lsmprop_to_secctx(prop, &context,
+                                                  LSM_ID_UNDEF);
+               if (error < 0) {
+                       if (error != -EINVAL)
+                               goto error_path;
+                       return;
+               }
+               audit_log_format(ab, " obj=%s", context.context);
+               security_release_secctx(&context);
+               return;
+       }
+       audit_log_format(ab, " obj=?");
+       error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS);
+       if (error)
+               goto error_path;
+
+       for (i = 0; i < lsm_prop_cnt; i++) {
+               if (!lsm_idlist[i]->lsmprop)
+                       continue;
+               error = security_lsmprop_to_secctx(prop, &context,
+                                                  lsm_idlist[i]->id);
+               if (error < 0) {
+                       audit_log_format(ab, "%sobj_%s=?",
+                                        space ? " " : "", lsm_idlist[i]->name);
+                       if (error != -EINVAL)
+                               audit_panic("error in 
audit_log_object_context");
+               } else {
+                       audit_log_format(ab, "%sobj_%s=%s",
+                                        space ? " " : "", lsm_idlist[i]->name,
+                                        context.context);
+                       security_release_secctx(&context);
+               }
+               space = true;
+       }
+
+       audit_buffer_aux_end(ab);
+       return;
+
+error_path:
+       audit_panic("error in audit_log_object_context");
+}
+
 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 3fbb1578b820..e5faeab03a56 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1092,36 +1092,24 @@ static inline void audit_free_context(struct 
audit_context *context)
        kfree(context);
 }
 
-static int audit_log_pid_context(struct audit_context *context, pid_t pid,
-                                kuid_t auid, kuid_t uid,
-                                unsigned int sessionid, struct lsm_prop *prop,
-                                char *comm)
+static void audit_log_pid_context(struct audit_context *context, pid_t pid,
+                                 kuid_t auid, kuid_t uid,
+                                 unsigned int sessionid, struct lsm_prop *prop,
+                                 char *comm)
 {
        struct audit_buffer *ab;
-       struct lsm_context ctx;
-       int rc = 0;
 
        ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
        if (!ab)
-               return rc;
+               return;
 
        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);
-               }
-       }
-       audit_log_format(ab, " ocomm=");
-       audit_log_untrustedstring(ab, comm);
-       audit_log_end(ab);
+       if (lsmprop_is_set(prop))
+               audit_log_object_context(ab, prop);
 
-       return rc;
+       return;
 }
 
 static void audit_log_execve_info(struct audit_context *context,
@@ -1391,18 +1379,8 @@ static void show_special(struct audit_context *context, 
int *call_panic)
                                 from_kuid(&init_user_ns, context->ipc.uid),
                                 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) {
-                               *call_panic = 1;
-                       } else {
-                               audit_log_format(ab, " obj=%s", lsmctx.context);
-                               security_release_secctx(&lsmctx);
-                       }
-               }
+               if (lsmprop_is_set(&context->ipc.oprop))
+                       audit_log_object_context(ab, &context->ipc.oprop);
                if (context->ipc.has_perm) {
                        audit_log_end(ab);
                        ab = audit_log_start(context, GFP_KERNEL,
@@ -1558,18 +1536,8 @@ 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 (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_object_context(ab, &n->oprop);
 
        /* log the audit_names record type */
        switch (n->type) {
@@ -1774,21 +1742,20 @@ static void audit_log_exit(void)
                struct audit_aux_data_pids *axs = (void *)aux;
 
                for (i = 0; i < axs->pid_count; i++)
-                       if (audit_log_pid_context(context, axs->target_pid[i],
-                                                 axs->target_auid[i],
-                                                 axs->target_uid[i],
-                                                 axs->target_sessionid[i],
-                                                 &axs->target_ref[i],
-                                                 axs->target_comm[i]))
-                               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;
+                       audit_log_pid_context(context, axs->target_pid[i],
+                                             axs->target_auid[i],
+                                             axs->target_uid[i],
+                                             axs->target_sessionid[i],
+                                             &axs->target_ref[i],
+                                             axs->target_comm[i]);
+       }
+
+       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);
 
        if (context->pwd.dentry && context->pwd.mnt) {
                ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
-- 
2.47.0


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