Patch "ALSA: usb-audio: Add sanity checks to FE parser" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

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

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     alsa-usb-audio-add-sanity-checks-to-fe-parser.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d937cd6790a2bef2d07b500487646bd794c039bb Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 21 Nov 2017 16:55:51 +0100
Subject: ALSA: usb-audio: Add sanity checks to FE parser

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
@@ -1463,6 +1463,12 @@ 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,
@@ -1480,6 +1486,12 @@ 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;


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-4.9/alsa-usb-audio-fix-potential-zero-division-at-parsing-fu.patch
queue-4.9/alsa-timer-remove-kernel-warning-at-compat-ioctl-error-paths.patch
queue-4.9/alsa-hda-add-raven-pci-id.patch
queue-4.9/alsa-usb-audio-add-sanity-checks-in-v2-clock-parsers.patch
queue-4.9/alsa-hda-fix-too-short-hdmi-dp-chmap-reporting.patch
queue-4.9/alsa-hda-realtek-fix-alc700-family-no-sound-issue.patch
queue-4.9/alsa-usb-audio-fix-potential-out-of-bound-access-at-parsing-su.patch
queue-4.9/alsa-pcm-update-tstamp-only-if-audio_tstamp-changed.patch
queue-4.9/alsa-usb-audio-add-sanity-checks-to-fe-parser.patch