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

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commit d937cd6790a2bef2d07b500487646bd794c039bb 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Takashi Iwai 2017-11-21 16:55:51 +01:00 • committed by Greg Kroah-Hartman
parent b71cf750dd
commit d1316b9d83
1 changed files with 12 additions and 0 deletions
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12
sound/usb/mixer.c
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@ -1397,6 +1397,12 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
__u8 *bmaControls;
if (state->mixer->protocol == UAC_VERSION_1) {
if (hdr->bLength < 7) {
usb_audio_err(state->chip,
"unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
unitid);
return -EINVAL;
}
csize = hdr->bControlSize;
if (!csize) {
usb_audio_dbg(state->chip,
@ -1414,6 +1420,12 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
}
} else {
struct uac2_feature_unit_descriptor *ftr = _ftr;
if (hdr->bLength < 6) {
usb_audio_err(state->chip,
"unit %u: invalid UAC_FEATURE_UNIT descriptor\n",
unitid);
return -EINVAL;
}
csize = 4;
channels = (hdr->bLength - 6) / 4 - 1;
bmaControls = ftr->bmaControls;