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| author | Takashi Iwai <tiwai@suse.de> | 2020-12-09 11:45:52 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-12-14 11:10:39 +0300 |
| commit | 175b8d89fe292796811fdee87fa39799a5b6b87a (patch) | |
| tree | 2188693002fdf3c7e765d78be8a83b8c289f35c4 /sound | |
| parent | 43d5ca88dfcd35e43010fdd818e067aa9a55f5ba (diff) | |
| download | linux-175b8d89fe292796811fdee87fa39799a5b6b87a.tar.xz | |
ALSA: pcm: oss: Fix potential out-of-bounds shift
syzbot spotted a potential out-of-bounds shift in the PCM OSS layer
where it calculates the buffer size with the arbitrary shift value
given via an ioctl.
Add a range check for avoiding the undefined behavior.
As the value can be treated by a signed integer, the max shift should
be 30.
Reported-by: syzbot+df7dc146ebdd6435eea3@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201209084552.17109-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/core/oss/pcm_oss.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index 327ec42a36b0..de1917484647 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1935,11 +1935,15 @@ static int snd_pcm_oss_set_subdivide(struct snd_pcm_oss_file *pcm_oss_file, int static int snd_pcm_oss_set_fragment1(struct snd_pcm_substream *substream, unsigned int val) { struct snd_pcm_runtime *runtime; + int fragshift; runtime = substream->runtime; if (runtime->oss.subdivision || runtime->oss.fragshift) return -EINVAL; - runtime->oss.fragshift = val & 0xffff; + fragshift = val & 0xffff; + if (fragshift >= 31) + return -EINVAL; + runtime->oss.fragshift = fragshift; runtime->oss.maxfrags = (val >> 16) & 0xffff; if (runtime->oss.fragshift < 4) /* < 16 */ runtime->oss.fragshift = 4; |