4.4-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
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: 23caaf19b11e ("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
--- sound/usb/mixer.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1397,6 +1397,12 @@ static int parse_audio_feature_unit(stru __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(stru } } 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;