ALSA: timer: Fix wrong instance passed to slave callbacks

commit 117159f0b9d392fb433a7871426fad50317f06f7 upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/sound/core/timer.c b/sound/core/timer.c
index 35146c65c46b23d1387ad8ea4695b33bd838089d..d6351b84fd29faafe2fc99d806672cf38b2ae0eb 100644 (file)
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -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);
 }