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| author | Takashi Iwai <tiwai@suse.de> | 2018-04-30 10:06:48 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-04-30 10:06:48 +0200 |
| commit | 76b3421b39bd610546931fc923edcf90c18fa395 (patch) | |
| tree | f27e1ca71c7053ccd68c6ec44163410a6b8ed6a9 /sound/drivers | |
| parent | 52759c0963510a2843774aac9b65ccaed3308dc0 (diff) | |
| download | lwn-76b3421b39bd610546931fc923edcf90c18fa395.tar.gz lwn-76b3421b39bd610546931fc923edcf90c18fa395.zip | |
ALSA: aloop: Add missing cable lock to ctl API callbacks
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>
Diffstat (limited to 'sound/drivers')
| -rw-r--r-- | sound/drivers/aloop.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index 58e349fc893f..eab7f594ebe7 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -831,9 +831,11 @@ static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, { 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; } @@ -865,9 +867,11 @@ static int loopback_notify_get(struct snd_kcontrol *kcontrol, { 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; } @@ -879,12 +883,14 @@ static int loopback_notify_put(struct snd_kcontrol *kcontrol, 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; } @@ -892,15 +898,18 @@ static int loopback_active_get(struct snd_kcontrol *kcontrol, 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; } @@ -943,9 +952,11 @@ static int loopback_rate_get(struct snd_kcontrol *kcontrol, { 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; } @@ -965,9 +976,11 @@ static int loopback_channels_get(struct snd_kcontrol *kcontrol, { 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; } |