Merge tag 'audit-pr-20200422' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

Pull audit fix from Paul Moore:
 "One small audit patch fix, fixing a missing length check on input from
  userspace, nothing crazy"

* tag 'audit-pr-20200422' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: check the length of userspace generated audit records

kernel/audit.c

@@ -1326,6 +1326,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
 		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
 			return 0;
+		/* exit early if there isn't at least one character to print */
+		if (data_len < 2)
+			return -EINVAL;
 
 		err = audit_filter(msg_type, AUDIT_FILTER_USER);
 		if (err == 1) { /* match or error */