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| author | Takashi Iwai <tiwai@suse.de> | 2020-06-24 14:23:40 +0200 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2020-06-30 15:36:50 -0400 |
| commit | 25e1bb1e6c368d09da13007b60f0c92b1c4101b4 (patch) | |
| tree | 0dc62dcec686215ba6ee1e5d9b9702bed41c2650 /sound/usb/mixer_quirks.c | |
| parent | 1cc2d29710c2e9c96b6d026f71b5cfc09d96ea8c (diff) | |
ALSA: usb-audio: Fix OOB access of mixer element list
commit 220345e98f1cdc768eeb6e3364a0fa7ab9647fe7 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound/usb/mixer_quirks.c')
| -rw-r--r-- | sound/usb/mixer_quirks.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c index dc181066c799..d39bf5b648d1 100644 --- a/sound/usb/mixer_quirks.c +++ b/sound/usb/mixer_quirks.c @@ -157,7 +157,8 @@ static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer, return -ENOMEM; } kctl->private_free = snd_usb_mixer_elem_free; - return snd_usb_mixer_add_control(list, kctl); + /* don't use snd_usb_mixer_add_control() here, this is a special list element */ + return snd_usb_mixer_add_list(list, kctl, false); } /* |