Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752019AbaJYSn0 (ORCPT ); Sat, 25 Oct 2014 14:43:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56374 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751565AbaJYSnZ (ORCPT ); Sat, 25 Oct 2014 14:43:25 -0400 Date: Sat, 25 Oct 2014 01:45:50 -0700 From: tip-bot for Mathias Krause Message-ID: Cc: hpa@zytor.com, tglx@linutronix.de, mingo@kernel.org, oleg@redhat.com, minipli@googlemail.com, pageexec@freemail.hu, spender@grsecurity.net, linux-kernel@vger.kernel.org Reply-To: tglx@linutronix.de, hpa@zytor.com, minipli@googlemail.com, mingo@kernel.org, oleg@redhat.com, pageexec@freemail.hu, linux-kernel@vger.kernel.org, spender@grsecurity.net In-Reply-To: <1412456799-32339-1-git-send-email-minipli@googlemail.com> References: <1412456799-32339-1-git-send-email-minipli@googlemail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] posix-timers: Fix stack info leak in timer_create() Git-Commit-ID: 6891c4509c792209c44ced55a60f13954cb50ef4 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6891c4509c792209c44ced55a60f13954cb50ef4 Gitweb: http://git.kernel.org/tip/6891c4509c792209c44ced55a60f13954cb50ef4 Author: Mathias Krause AuthorDate: Sat, 4 Oct 2014 23:06:39 +0200 Committer: Thomas Gleixner CommitDate: Sat, 25 Oct 2014 10:43:15 +0200 posix-timers: Fix stack info leak in timer_create() If userland creates a timer without specifying a sigevent info, we'll create one ourself, using a stack local variable. Particularly will we use the timer ID as sival_int. But as sigev_value is a union containing a pointer and an int, that assignment will only partially initialize sigev_value on systems where the size of a pointer is bigger than the size of an int. On such systems we'll copy the uninitialized stack bytes from the timer_create() call to userland when the timer actually fires and we're going to deliver the signal. Initialize sigev_value with 0 to plug the stack info leak. Found in the PaX patch, written by the PaX Team. Fixes: 5a9fa7307285 ("posix-timers: kill ->it_sigev_signo and...") Signed-off-by: Mathias Krause Cc: Oleg Nesterov Cc: Brad Spengler Cc: PaX Team Cc: # v2.6.28+ Link: http://lkml.kernel.org/r/1412456799-32339-1-git-send-email-minipli@googlemail.com Signed-off-by: Thomas Gleixner --- kernel/time/posix-timers.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 42b463a..31ea01f 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -636,6 +636,7 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock, goto out; } } else { + memset(&event.sigev_value, 0, sizeof(event.sigev_value)); event.sigev_notify = SIGEV_SIGNAL; event.sigev_signo = SIGALRM; event.sigev_value.sival_int = new_timer->it_id; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/