audit: add subj creds to NETFILTER_CFG record to

Some table unregister actions seem to be initiated by the kernel to garbage collect unused tables that are not initiated by any userspace actions. It was found to be necessary to add the subject credentials to cover this case to reveal the source of these actions. A sample record: The uid, auid, tty, ses and exe fields have not been included since they are in the SYSCALL record and contain nothing useful in the non-user context. Here are two sample orphaned records: type=NETFILTER_CFG msg=audit(2020-05-20 12:14:36.505:5) : table=filter family=ipv4 entries=0 op=register pid=1 subj=kernel comm=swapper/0 type=NETFILTER_CFG msg=audit(2020-05-20 12:15:27.701:301) : table=nat family=bridge entries=0 op=unregister pid=30 subj=system_u:system_r:kernel_t:s0 comm=kworker/u4:1 Signed-off-by: Richard Guy Briggs <[email protected]> Signed-off-by: Paul Moore <[email protected]>
xdp-project · May 20, 2020 · 9d44a12 · 9d44a12
1 parent 0090c1e
commit 9d44a12
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
@@ -2557,12 +2557,18 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 		       enum audit_nfcfgop op)
 {
 	struct audit_buffer *ab;
+	char comm[sizeof(current->comm)];
 
 	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_NETFILTER_CFG);
 	if (!ab)
 		return;
 	audit_log_format(ab, "table=%s family=%u entries=%u op=%s",
 			 name, af, nentries, audit_nfcfgs[op].s);
+
+	audit_log_format(ab, " pid=%u", task_pid_nr(current));
+	audit_log_task_context(ab); /* subj= */
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_end(ab);
 }
 EXPORT_SYMBOL_GPL(__audit_log_nfcfg);