ALSA: seq: Fix race at timer setup and close
commit6e29b1cc3071f1c41a943e8e873f34e454428bda
authorTakashi Iwai <tiwai@suse.de>
Tue, 12 Jan 2016 14:36:27 +0000 (12 15:36 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 29 Jan 2016 05:49:30 +0000 (28 21:49 -0800)
tree9f137c8f2991bf9d5cead95bb950bc2392036f02
parentb85a6198e28f573d6df99522782aa09948258d19
ALSA: seq: Fix race at timer setup and close

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 <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/core/seq/seq_queue.c