ALSA: seq: Fix race at closing in virmidi driver
authorTakashi Iwai <tiwai@suse.de>
Mon, 1 Feb 2016 11:06:42 +0000 (12:06 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 19 Feb 2016 22:22:39 +0000 (14:22 -0800)
commit14bdca3fa46eb56d2f042ce9f0a8b42f800a9a12
tree1223e15503bc1261e55eeace114cb68f9b9f0a41
parent4df6314c220c4943f82fdcb882b48561f5ffebbc
ALSA: seq: Fix race at closing in virmidi driver

commit 2d1b5c08366acd46c35a2e9aba5d650cb5bf5c19 upstream.

The virmidi driver has an open race at closing its assigned rawmidi
device, and this may lead to use-after-free in
snd_seq_deliver_single_event().

Plug the hole by properly protecting the linked list deletion and
calling in the right order in snd_virmidi_input_close().

BugLink: http://lkml.kernel.org/r/CACT4Y+Zd66+w12fNN85-425cVQT=K23kWbhnCEcMB8s3us-Frw@mail.gmail.com
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/core/seq/seq_virmidi.c