[PATCH] audit: Fix check of return value of strnlen_user()

[Jan Kara]

strnlen_user() returns 0 when it hits fault, not -1. Fix the test in
audit_log_single_execve_arg(). Luckily this shouldn't ever happen unless
there's a kernel bug so it's mostly a cosmetic fix.

CC: Paul Moore <pmoore at redhat.com>
Signed-off-by: Jan Kara <jack at suse.cz>
---
 kernel/auditsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 9fb9d1cb83ce..bb947ceeee4d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1023,7 +1023,7 @@ static int audit_log_single_execve_arg(struct audit_context *context,
 	 * for strings that are too long, we should not have created
 	 * any.
 	 */
-	if (unlikely((len == -1) || len > MAX_ARG_STRLEN - 1)) {
+	if (unlikely((len == 0) || len > MAX_ARG_STRLEN - 1)) {
 		WARN_ON(1);
 		send_sig(SIGKILL, current, 0);
 		return -1;
-- 
2.1.4