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ALSA: usb-audio: Add sanity checks to FE parser

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commit d937cd6790 upstream.

When the usb-audio descriptor contains the malformed feature unit
description with a too short length, the driver may access
out-of-bounds.  Add a sanity check of the header size at the beginning
of parse_audio_feature_unit().

Fixes: 23caaf19b1 ("ALSA: usb-mixer: Add support for Audio Class v2.0")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: use snd_printk() for logging]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Takashi Iwai 2017-11-21 16:55:51 +01:00 committed by Ben Hutchings
parent fe37537fcb
commit 76747915c1
1 changed files with 12 additions and 0 deletions
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12
sound/usb/mixer.c
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@ -1255,6 +1255,12 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
__u8 *bmaControls;
if (state->mixer->protocol == UAC_VERSION_1) {
if (hdr->bLength < 7) {
snd_printk(KERN_ERR
"usbaudio: unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
unitid);
return -EINVAL;
}
csize = hdr->bControlSize;
if (!csize) {
snd_printdd(KERN_ERR "usbaudio: unit %u: "
@ -1271,6 +1277,12 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
}
} else {
struct uac2_feature_unit_descriptor *ftr = _ftr;
if (hdr->bLength < 6) {
snd_printk(KERN_ERR
"usbaudio: unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
unitid);
return -EINVAL;
}
csize = 4;
channels = (hdr->bLength - 6) / 4 - 1;
bmaControls = ftr->bmaControls;