diff options
| author | Takashi Iwai <tiwai@suse.de> | 2018-12-19 12:36:27 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2019-01-07 10:46:26 +0100 |
| commit | f4351a199cc120ff9d59e06d02e8657d08e6cc46 (patch) | |
| tree | b3d38fbd367555c5a905dc37954a4af73dd74bf6 /sound | |
| parent | bfeffd155283772bbe78c6a05dec7c0128ee500c (diff) | |
| download | lwn-f4351a199cc120ff9d59e06d02e8657d08e6cc46.tar.gz lwn-f4351a199cc120ff9d59e06d02e8657d08e6cc46.zip | |
ALSA: usb-audio: Avoid access before bLength check in build_audio_procunit()
The parser for the processing unit reads bNrInPins field before the
bLength sanity check, which may lead to an out-of-bound access when a
malformed descriptor is given. Fix it by assignment after the bLength
check.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/usb/mixer.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index c63c84b54969..0131de348cf6 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2314,7 +2314,7 @@ static int build_audio_procunit(struct mixer_build *state, int unitid, char *name) { struct uac_processing_unit_descriptor *desc = raw_desc; - int num_ins = desc->bNrInPins; + int num_ins; struct usb_mixer_elem_info *cval; struct snd_kcontrol *kctl; int i, err, nameid, type, len; @@ -2329,7 +2329,13 @@ static int build_audio_procunit(struct mixer_build *state, int unitid, 0, NULL, default_value_info }; - if (desc->bLength < 13 || desc->bLength < 13 + num_ins || + if (desc->bLength < 13) { + usb_audio_err(state->chip, "invalid %s descriptor (id %d)\n", name, unitid); + return -EINVAL; + } + + num_ins = desc->bNrInPins; + if (desc->bLength < 13 + num_ins || desc->bLength < num_ins + uac_processing_unit_bControlSize(desc, state->mixer->protocol)) { usb_audio_err(state->chip, "invalid %s descriptor (id %d)\n", name, unitid); return -EINVAL; |