From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755156Ab3BUQjo (ORCPT ); Thu, 21 Feb 2013 11:39:44 -0500 Received: from terminus.zytor.com ([198.137.202.10]:41926 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754950Ab3BUQjn (ORCPT ); Thu, 21 Feb 2013 11:39:43 -0500 Date: Thu, 21 Feb 2013 08:38:25 -0800 From: tip-bot for Tejun Heo Message-ID: Cc: linux-kernel@vger.kernel.org, sasha.levin@oracle.com, hpa@zytor.com, mingo@kernel.org, akpm@linux-foundation.org, tj@kernel.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, sasha.levin@oracle.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tj@kernel.org, tglx@linutronix.de In-Reply-To: <20130220232412.GL3570@htj.dyndns.org> References: <20130220232412.GL3570@htj.dyndns.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] posix-timer: Don't call idr_find() with out-of-range ID Git-Commit-ID: e182bb38d7db7494fa5dcd82da17fe0dedf60ecf X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Thu, 21 Feb 2013 08:38:30 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e182bb38d7db7494fa5dcd82da17fe0dedf60ecf Gitweb: http://git.kernel.org/tip/e182bb38d7db7494fa5dcd82da17fe0dedf60ecf Author: Tejun Heo AuthorDate: Wed, 20 Feb 2013 15:24:12 -0800 Committer: Thomas Gleixner CommitDate: Thu, 21 Feb 2013 17:28:29 +0100 posix-timer: Don't call idr_find() with out-of-range ID When idr_find() was fed a negative ID, it used to look up the ID ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c") patch. Now a negative ID triggers a WARN_ON_ONCE(). __lock_timer() feeds timer_id from userland directly to idr_find() without sanitizing it which can trigger the above malfunctions. Add a range check on @timer_id before invoking idr_find() in __lock_timer(). While timer_t is defined as int by all archs at the moment, Andrew worries that it may be defined as a larger type later on. Make the test cover larger integers too so that it at least is guaranteed to not return the wrong timer. Note that WARN_ON_ONCE() in idr_find() on id < 0 is transitional precaution while moving away from ignoring MSB. Once it's gone we can remove the guard as long as timer_t isn't larger than int. Signed-off-by: Tejun Heo nnn Reported-by: Sasha Levin Cc: Andrew Morton Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20130220232412.GL3570@htj.dyndns.org Signed-off-by: Thomas Gleixner --- kernel/posix-timers.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 10349d5..7edfe4b 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -639,6 +639,13 @@ static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags) { struct k_itimer *timr; + /* + * timer_t could be any type >= int and we want to make sure any + * @timer_id outside positive int range fails lookup. + */ + if ((unsigned long long)timer_id > INT_MAX) + return NULL; + rcu_read_lock(); timr = idr_find(&posix_timers_id, (int)timer_id); if (timr) {