2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Takashi Iwai <[email protected]> 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 <[email protected]> Tested-by: Dmitry Vyukov <[email protected]> Signed-off-by: Takashi Iwai <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> Signed-off-by: Willy Tarreau <[email protected]> --- 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 e7a8e9e..a5d191e 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... */ -- 1.7.12.2.21.g234cd45.dirty
