From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354AbcBKOoj (ORCPT ); Thu, 11 Feb 2016 09:44:39 -0500 Received: from mx2.suse.de ([195.135.220.15]:49301 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753288AbcBKN7p (ORCPT ); Thu, 11 Feb 2016 08:59:45 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Takashi Iwai , Jiri Slaby Subject: [PATCH 3.12 06/64] ALSA: seq: Fix race at timer setup and close Date: Thu, 11 Feb 2016 14:58:42 +0100 Message-Id: <49386ca9bcb24608ed22e19fb61599e6049f8a44.1455198893.git.jslaby@suse.cz> X-Mailer: git-send-email 2.7.1 In-Reply-To: <74c0820133f1dada0d70c74bc70a9530b2697f86.1455198893.git.jslaby@suse.cz> References: <74c0820133f1dada0d70c74bc70a9530b2697f86.1455198893.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 3567eb6af614dac436c4b16a8d426f9faed639b3 upstream. ALSA sequencer code has an open race between the timer setup ioctl and the close of the client. This was triggered by syzkaller fuzzer, and a use-after-free was caught there as a result. This patch papers over it by adding a proper queue->timer_mutex lock around the timer-related calls in the relevant code path. Reported-by: Dmitry Vyukov Tested-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Jiri Slaby --- sound/core/seq/seq_queue.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/core/seq/seq_queue.c b/sound/core/seq/seq_queue.c index f9077361c119..4c9aa462de9b 100644 --- a/sound/core/seq/seq_queue.c +++ b/sound/core/seq/seq_queue.c @@ -144,8 +144,10 @@ static struct snd_seq_queue *queue_new(int owner, int locked) static void queue_delete(struct snd_seq_queue *q) { /* stop and release the timer */ + mutex_lock(&q->timer_mutex); snd_seq_timer_stop(q->timer); snd_seq_timer_close(q); + mutex_unlock(&q->timer_mutex); /* wait until access free */ snd_use_lock_sync(&q->use_lock); /* release resources... */ -- 2.7.1