diff options
| author | Hui Peng <benquike@gmail.com> | 2018-12-03 16:09:34 +0100 |
|---|---|---|
| committer | Todd Kjos <tkjos@google.com> | 2019-10-04 14:42:06 -0700 |
| commit | dab1e837772d0472c7545eb3e1fca0a23384f7d6 (patch) | |
| tree | 85cd1ef5f469752adfbf8ab15e6b3cd43441773c | |
| parent | 527a528f89b9469c45e2375c7f530792bb329919 (diff) | |
ALSA: usb-audio: Fix UAF decrement if card has no live interfaces in card.cASB-2019-10-05_3.18-o-release
commit 5f8cf712582617d523120df67d392059eaf2fc4b upstream.
If a USB sound card reports 0 interfaces, an error condition is triggered
and the function usb_audio_probe errors out. In the error path, there was a
use-after-free vulnerability where the memory object of the card was first
freed, followed by a decrement of the number of active chips. Moving the
decrement above the atomic_dec fixes the UAF.
[ The original problem was introduced in 3.1 kernel, while it was
developed in a different form. The Fixes tag below indicates the
original commit but it doesn't mean that the patch is applicable
cleanly. -- tiwai ]
Fixes: 362e4e49abe5 ("ALSA: usb-audio - clear chip->probing on error exit")
Reported-by: Hui Peng <benquike@gmail.com>
Reported-by: Mathias Payer <mathias.payer@nebelwelt.net>
Signed-off-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Mathias Payer <mathias.payer@nebelwelt.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[surenb@google.com: resolve 3.18 differences]
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I54aecb9fe09beb178bc5d48f18ffa9ca13cf26e0
| -rw-r--r-- | sound/usb/card.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/sound/usb/card.c b/sound/usb/card.c index f7dbdc10bf77..59fb1ef3cd55 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -593,9 +593,12 @@ snd_usb_audio_probe(struct usb_device *dev, __error: if (chip) { + /* chip->probing is inside the chip->card object, + * reset before memory is possibly returned. + */ + chip->probing = 0; if (!chip->num_interfaces) snd_card_free(chip->card); - chip->probing = 0; } mutex_unlock(®ister_mutex); __err_val: |