Re: FAILED: patch "[PATCH] ALSA: usb-audio: Fix OOB access of mixer element list" failed to apply to 4.14-stable tree

[Sasha Levin <sashal@kernel.org>]

On Sun, Jun 28, 2020 at 05:31:00PM +0200, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.14-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 220345e98f1cdc768eeb6e3364a0fa7ab9647fe7 Mon Sep 17 00:00:00 2001
>From: Takashi Iwai <tiwai@suse.de>
>Date: Wed, 24 Jun 2020 14:23:40 +0200
>Subject: [PATCH] ALSA: usb-audio: Fix OOB access of mixer element list
>
>The USB-audio mixer code holds a linked list of usb_mixer_elem_list,
>and several operations are performed for each mixer element.  A few of
>them (snd_usb_mixer_notify_id() and snd_usb_mixer_interrupt_v2())
>assume each mixer element being a usb_mixer_elem_info object that is a
>subclass of usb_mixer_elem_list, cast via container_of() and access it
>members.  This may result in an out-of-bound access when a
>non-standard list element has been added, as spotted by syzkaller
>recently.
>
>This patch adds a new field, is_std_info, in usb_mixer_elem_list to
>indicate that the element is the usb_mixer_elem_info type or not, and
>skip the access to such an element if needed.
>
>Reported-by: syzbot+fb14314433463ad51625@syzkaller.appspotmail.com
>Reported-by: syzbot+2405ca3401e943c538b5@syzkaller.appspotmail.com
>Cc: <stable@vger.kernel.org>
>Link: https://lore.kernel.org/r/20200624122340.9615-1-tiwai@suse.de
>Signed-off-by: Takashi Iwai <tiwai@suse.de>

I took these two additional commits:

8c558076c740 ("ALSA: usb-audio: Clean up mixer element list traverse")
b2500b584cfd ("ALSA: usb-audio: uac1: Invalidate ctl on interrupt")

and queued all 3 for 4.14, 4.9, and 4.4

-- 
Thanks,
Sasha