From 45820c294fe1b1a9df495d57f40585ef2d069a39 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 8 Jul 2015 09:33:38 -0700 Subject: [PATCH] Fix broken audit tests for exec arg len The "fix" in commit 0b08c5e5944 ("audit: Fix check of return value of strnlen_user()") didn't fix anything, it broke things. As reported by Steven Rostedt: "Yes, strnlen_user() returns 0 on fault, but if you look at what len is set to, than you would notice that on fault len would be -1" because we just subtracted one from the return value. So testing against 0 doesn't test for a fault condition, it tests against a perfectly valid empty string. Also fix up the usual braindamage wrt using WARN_ON() inside a conditional - make it part of the conditional and remove the explicit unlikely() (which is already part of the WARN_ON*() logic, exactly so that you don't have to write unreadable code. Reported-and-tested-by: Steven Rostedt Cc: Jan Kara Cc: Paul Moore Signed-off-by: Linus Torvalds --- kernel/auditsc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 09c65640cad6..e85bdfd15fed 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1021,8 +1021,7 @@ 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 == 0) || len > MAX_ARG_STRLEN - 1)) { - WARN_ON(1); + if (WARN_ON_ONCE(len < 0 || len > MAX_ARG_STRLEN - 1)) { send_sig(SIGKILL, current, 0); return -1; } -- 2.20.1