diff options
| author | Takashi Iwai <tiwai@suse.de> | 2022-03-22 18:07:17 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2022-03-22 20:56:07 +0100 |
| commit | 92ee3c60ec9fe64404dc035e7c41277d74aa26cb (patch) | |
| tree | 495dbd456ef721512b0113483cc62e34879e6d6c /sound/core/pcm.c | |
| parent | 646b907e1559f006c79a752ee3eebe220ceb983d (diff) | |
ALSA: pcm: Fix races among concurrent hw_params and hw_free calls
Currently we have neither proper check nor protection against the
concurrent calls of PCM hw_params and hw_free ioctls, which may result
in a UAF. Since the existing PCM stream lock can't be used for
protecting the whole ioctl operations, we need a new mutex to protect
those racy calls.
This patch introduced a new mutex, runtime->buffer_mutex, and applies
it to both hw_params and hw_free ioctl code paths. Along with it, the
both functions are slightly modified (the mmap_count check is moved
into the state-check block) for code simplicity.
Reported-by: Hu Jiahui <kirin.say@gmail.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20220322170720.3529-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/pcm.c')
| -rw-r--r-- | sound/core/pcm.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sound/core/pcm.c b/sound/core/pcm.c index ba4a987ed1c6..edd9849210f2 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -969,6 +969,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream, init_waitqueue_head(&runtime->tsleep); runtime->status->state = SNDRV_PCM_STATE_OPEN; + mutex_init(&runtime->buffer_mutex); substream->runtime = runtime; substream->private_data = pcm->private_data; @@ -1002,6 +1003,7 @@ void snd_pcm_detach_substream(struct snd_pcm_substream *substream) } else { substream->runtime = NULL; } + mutex_destroy(&runtime->buffer_mutex); kfree(runtime); put_pid(substream->pid); substream->pid = NULL; |