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

ALSA: usb-audio: Fix potential zero-division at parsing FU

to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: alsa-usb-audio-fix-potential-zero-division-at-parsing-fu.patch and it can be found in the queue-3.18 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 8428a8ebde2db1e988e41a58497a28beb7ce1705 Mon Sep 17 00:00:00 2001

From: Takashi Iwai tiwai@suse.de Date: Tue, 21 Nov 2017 17:07:43 +0100 Subject: ALSA: usb-audio: Fix potential zero-division at parsing FU

From: Takashi Iwai tiwai@suse.de

commit 8428a8ebde2db1e988e41a58497a28beb7ce1705 upstream.

parse_audio_feature_unit() contains a code dividing potentially with zero when a malformed FU descriptor is passed. Although there is already a sanity check, it checks only the value zero, hence it can still lead to a zero-division when a value 1 is passed there.

Fix it by correcting the sanity check (and the error message thereof).

Fixes: 23caaf19b11e ("ALSA: usb-mixer: Add support for Audio Class v2.0") Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- sound/usb/mixer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1380,9 +1380,9 @@ static int parse_audio_feature_unit(stru return -EINVAL; } csize = hdr->bControlSize; - if (!csize) { + if (csize <= 1) { usb_audio_dbg(state->chip, - "unit %u: invalid bControlSize == 0\n", + "unit %u: invalid bControlSize <= 1\n", unitid); return -EINVAL; }

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

queue-3.18/alsa-usb-audio-fix-potential-zero-division-at-parsing-fu.patch queue-3.18/alsa-timer-remove-kernel-warning-at-compat-ioctl-error-paths.patch queue-3.18/alsa-hda-add-raven-pci-id.patch queue-3.18/alsa-usb-audio-add-sanity-checks-in-v2-clock-parsers.patch queue-3.18/alsa-usb-audio-fix-potential-out-of-bound-access-at-parsing-su.patch queue-3.18/alsa-usb-audio-add-sanity-checks-to-fe-parser.patch