diff options
| author | Takashi Iwai <tiwai@suse.de> | 2022-04-20 15:02:47 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2022-04-20 15:13:45 +0200 |
| commit | 0665886ad1392e6b5bae85d7a6ccbed48dca1522 (patch) | |
| tree | 9a00a5473e824803beff2336a41ed2d05619a5f1 | |
| parent | 0aea30a07ec6b50de0fc5f5b2ec34a68ead86b61 (diff) | |
ALSA: usb-audio: Clear MIDI port active flag after draining
When a rawmidi output stream is closed, it calls the drain at first,
then does trigger-off only when the drain returns -ERESTARTSYS as a
fallback. It implies that each driver should turn off the stream
properly after the drain. Meanwhile, USB-audio MIDI interface didn't
change the port->active flag after the drain. This may leave the
output work picking up the port that is closed right now, which
eventually leads to a use-after-free for the already released rawmidi
object.
This patch fixes the bug by properly clearing the port->active flag
after the output drain.
Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/00000000000011555605dceaff03@google.com
Link: https://lore.kernel.org/r/20220420130247.22062-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/usb/midi.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 2c01649c70f6..7c6ca2b433a5 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1194,6 +1194,7 @@ static void snd_usbmidi_output_drain(struct snd_rawmidi_substream *substream) } while (drain_urbs && timeout); finish_wait(&ep->drain_wait, &wait); } + port->active = 0; spin_unlock_irq(&ep->buffer_lock); } |