tree 5d14b22d1dc22cee63d066961c1bf30dd6c8ee85
parent 5d1b71226dc4d44b4b65766fa9d74492f9d4587b
author Takashi Iwai <tiwai@suse.de> 1579120653 +0100
committer Takashi Iwai <tiwai@suse.de> 1579120698 +0100

ALSA: seq: Fix racy access for queue timer in proc read

snd_seq_info_timer_read() reads the information of the timer assigned
for each queue, but it's done in a racy way which may lead to UAF as
spotted by syzkaller.

This patch applies the missing q->timer_mutex lock while accessing the
timer object as well as a slight code change to adapt the standard
coding style.

Reported-by: syzbot+2b2ef983f973e5c40943@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200115203733.26530-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>