selinux: call WARN_ONCE() instead of calling audit_log_start()

Two of the conditions in selinux_audit_rule_match() should never happen and
the third indicates a race that should be retried.  Remove the calls to
audit_log() (which call audit_log_start()) and deal with the errors in the
caller, logging only once if the condition is met.  Calling audit_log_start()
in this location makes buffer allocation and locking more complicated in the
calling tree (audit_filter_user()).

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index b4feecc3fe01..f4dda05d7db0 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2938,25 +2938,21 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule,
         struct selinux_audit_rule *rule = vrule;
         int match = 0;
 
-        if (!rule) {
-                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
-                          "selinux_audit_rule_match: missing rule\n");
+        if (unlikely(!rule)) {
+                WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
                 return -ENOENT;
         }
 
         read_lock(&policy_rwlock);
 
         if (rule->au_seqno < latest_granting) {
-                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
-                          "selinux_audit_rule_match: stale rule\n");
                 match = -ESTALE;
                 goto out;
         }
 
         ctxt = sidtab_search(&sidtab, sid);
-        if (!ctxt) {
-                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
-                          "selinux_audit_rule_match: unrecognized SID %d\n",
+        if (unlikely(!ctxt)) {
+                WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
                           sid);
                 match = -ENOENT;
                 goto out;