ALSA: aloop: Add missing cable lock to ctl API callbacks
commit 76b3421b39bd610546931fc923edcf90c18fa395 upstream.
Some control API callbacks in aloop driver are too lazy to take the
loopback->cable_lock and it results in possible races of cable access
while it's being freed. It eventually lead to a UAF, as reported by
fuzzer recently.
This patch covers such control API callbacks and add the proper mutex
locks.
Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index 80ec5c6..847f703 100644
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -832,9 +832,11 @@
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
+ mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate_shift;
+ mutex_unlock(&loopback->cable_lock);
return 0;
}
@@ -866,9 +868,11 @@
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
+ mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify;
+ mutex_unlock(&loopback->cable_lock);
return 0;
}
@@ -880,12 +884,14 @@
int change = 0;
val = ucontrol->value.integer.value[0] ? 1 : 0;
+ mutex_lock(&loopback->cable_lock);
if (val != loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify) {
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify = val;
change = 1;
}
+ mutex_unlock(&loopback->cable_lock);
return change;
}
@@ -893,15 +899,18 @@
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
- struct loopback_cable *cable = loopback->cables
- [kcontrol->id.subdevice][kcontrol->id.device ^ 1];
+ struct loopback_cable *cable;
+
unsigned int val = 0;
+ mutex_lock(&loopback->cable_lock);
+ cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
if (cable != NULL) {
unsigned int running = cable->running ^ cable->pause;
val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
}
+ mutex_unlock(&loopback->cable_lock);
ucontrol->value.integer.value[0] = val;
return 0;
}
@@ -944,9 +953,11 @@
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
+ mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate;
+ mutex_unlock(&loopback->cable_lock);
return 0;
}
@@ -966,9 +977,11 @@
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
+ mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].channels;
+ mutex_unlock(&loopback->cable_lock);
return 0;
}