Commit 117159f0 authored Feb 08, 2016 by Takashi Iwai

ALSA: timer: Fix wrong instance passed to slave callbacks

In snd_timer_notify1(), the wrong timer instance was passed for slave
ccallback function.  This leads to the access to the wrong data when
an incompatible master is handled (e.g. the master is the sequencer
timer and the slave is a user timer), as spotted by syzkaller fuzzer.

This patch fixes that wrong assignment.

BugLink: http://lkml.kernel.org/r/CACT4Y+Y_Bm+7epAb=8Wi=AaWd+DYS7qawX52qxdCfOfY49vozQ@mail.gmail.com


Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent ddce57a6

sound/core/timer.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -422,7 +422,7 @@ static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
		spin_lock_irqsave(&timer->lock, flags);
		list_for_each_entry(ts, &ti->slave_active_head, active_list)
		if (ts->ccallback)
		ts->ccallback(ti, event + 100, &tstamp, resolution);
		ts->ccallback(ts, event + 100, &tstamp, resolution);
		spin_unlock_irqrestore(&timer->lock, flags);
		}

Admin message