diff options
| author | Takashi Iwai <tiwai@suse.de> | 2018-07-17 18:26:43 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-07-17 18:33:17 +0300 |
| commit | 39675f7a7c7e7702f7d5341f1e0d01db746543a0 (patch) | |
| tree | 5109d844e69ee0f48e8575f487967a78cb8b9c3c /sound/core/rawmidi.c | |
| parent | 0fca97a29b83e3f315c14ed2372cfd0f9ee0a006 (diff) | |
| download | linux-39675f7a7c7e7702f7d5341f1e0d01db746543a0.tar.xz | |
ALSA: rawmidi: Change resized buffers atomically
The SNDRV_RAWMIDI_IOCTL_PARAMS ioctl may resize the buffers and the
current code is racy. For example, the sequencer client may write to
buffer while it being resized.
As a simple workaround, let's switch to the resized buffer inside the
stream runtime lock.
Reported-by: syzbot+52f83f0ea8df16932f7f@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/rawmidi.c')
| -rw-r--r-- | sound/core/rawmidi.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index 69616d00481c..b53026a72e73 100644 --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -635,7 +635,7 @@ static int snd_rawmidi_info_select_user(struct snd_card *card, int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream, struct snd_rawmidi_params * params) { - char *newbuf; + char *newbuf, *oldbuf; struct snd_rawmidi_runtime *runtime = substream->runtime; if (substream->append && substream->use_count > 1) @@ -648,13 +648,17 @@ int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream, return -EINVAL; } if (params->buffer_size != runtime->buffer_size) { - newbuf = krealloc(runtime->buffer, params->buffer_size, - GFP_KERNEL); + newbuf = kmalloc(params->buffer_size, GFP_KERNEL); if (!newbuf) return -ENOMEM; + spin_lock_irq(&runtime->lock); + oldbuf = runtime->buffer; runtime->buffer = newbuf; runtime->buffer_size = params->buffer_size; runtime->avail = runtime->buffer_size; + runtime->appl_ptr = runtime->hw_ptr = 0; + spin_unlock_irq(&runtime->lock); + kfree(oldbuf); } runtime->avail_min = params->avail_min; substream->active_sensing = !params->no_active_sensing; @@ -665,7 +669,7 @@ EXPORT_SYMBOL(snd_rawmidi_output_params); int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream, struct snd_rawmidi_params * params) { - char *newbuf; + char *newbuf, *oldbuf; struct snd_rawmidi_runtime *runtime = substream->runtime; snd_rawmidi_drain_input(substream); @@ -676,12 +680,16 @@ int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream, return -EINVAL; } if (params->buffer_size != runtime->buffer_size) { - newbuf = krealloc(runtime->buffer, params->buffer_size, - GFP_KERNEL); + newbuf = kmalloc(params->buffer_size, GFP_KERNEL); if (!newbuf) return -ENOMEM; + spin_lock_irq(&runtime->lock); + oldbuf = runtime->buffer; runtime->buffer = newbuf; runtime->buffer_size = params->buffer_size; + runtime->appl_ptr = runtime->hw_ptr = 0; + spin_unlock_irq(&runtime->lock); + kfree(oldbuf); } runtime->avail_min = params->avail_min; return 0; |