linux/sound/core/seq
Takashi Iwai 8f22e52528 ALSA: seq: Fix races at MIDI encoding in snd_virmidi_output_trigger()
The sequencer virmidi code has an open race at its output trigger
callback: namely, virmidi keeps only one event packet for processing
while it doesn't protect for concurrent output trigger calls.

snd_virmidi_output_trigger() tries to process the previously
unfinished event before starting encoding the given MIDI stream, but
this is done without any lock.  Meanwhile, if another rawmidi stream
starts the output trigger, this proceeds further, and overwrites the
event package that is being processed in another thread.  This
eventually corrupts and may lead to the invalid memory access if the
event type is like SYSEX.

The fix is just to move the spinlock to cover both the pending event
and the new stream.

The bug was spotted by a new fuzzer, RaceFuzzer.

BugLink: http://lkml.kernel.org/r/20180426045223.GA15307@dragonet.kaist.ac.kr
Reported-by: DaeRyong Jeong <threeearcat@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-04-27 17:50:37 +02:00
..
oss ALSA: seq: oss: Hardening for potential Spectre v1 2018-04-25 10:37:45 +02:00
Kconfig ALSA: seq: Fix CONFIG_SND_SEQ_MIDI dependency 2017-08-11 09:51:41 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
seq_clientmgr.c ALSA: seq: Clear client entry before deleting else at closing 2018-03-10 17:30:01 +01:00
seq_clientmgr.h ALSA: seq: Make ioctls race-free 2018-01-11 14:37:51 +01:00
seq_compat.c ALSA: seq: fix passing wrong pointer in function call of compatibility layer 2016-10-12 20:09:36 +02:00
seq_dummy.c ALSA: seq: Drop snd_seq_autoload_lock() and _unlock() 2015-02-12 14:42:31 +01:00
seq_fifo.c ALSA: seq: More protection for concurrent write and ioctl races 2018-03-08 12:05:37 +01:00
seq_fifo.h
seq_info.c ALSA: core: Build conditionally and remove superfluous ifdefs 2015-04-24 17:31:07 +02:00
seq_info.h ALSA: replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS 2015-05-27 21:25:19 +02:00
seq_lock.c ALSA: seq: Enable 'use' locking in all configurations 2017-10-18 08:01:46 +02:00
seq_lock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
seq_memory.c ALSA: seq: More protection for concurrent write and ioctl races 2018-03-08 12:05:37 +01:00
seq_memory.h ALSA: seq: More protection for concurrent write and ioctl races 2018-03-08 12:05:37 +01:00
seq_midi_emul.c ALSA: seq: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:03 +02:00
seq_midi_event.c ALSA: seq: Follow standard EXPORT_SYMBOL() declarations 2017-06-16 16:19:03 +02:00
seq_midi.c ALSA: seq: Drop snd_seq_autoload_lock() and _unlock() 2015-02-12 14:42:31 +01:00
seq_ports.c ALSA: seq: Fix use-after-free at creating a port 2017-10-11 09:58:18 +02:00
seq_ports.h ALSA: seq: remove unused callback_all field 2015-01-26 13:56:58 +01:00
seq_prioq.c ALSA: seq: Fix possible UAF in snd_seq_check_queue() 2018-03-10 17:29:49 +01:00
seq_prioq.h ALSA: seq: Fix possible UAF in snd_seq_check_queue() 2018-03-10 17:29:49 +01:00
seq_queue.c ALSA: seq: Fix possible UAF in snd_seq_check_queue() 2018-03-10 17:29:49 +01:00
seq_queue.h ALSA: seq: 2nd attempt at fixing race creating a queue 2017-08-15 08:02:35 +02:00
seq_system.c sound: Add export.h for THIS_MODULE/EXPORT_SYMBOL where needed 2011-10-31 19:31:22 -04:00
seq_system.h
seq_timer.c ALSA: seq: Process queue tempo/ppq change in a shot 2018-01-15 16:48:36 +01:00
seq_timer.h ALSA: seq: Process queue tempo/ppq change in a shot 2018-01-15 16:48:36 +01:00
seq_virmidi.c ALSA: seq: Fix races at MIDI encoding in snd_virmidi_output_trigger() 2018-04-27 17:50:37 +02:00
seq.c ALSA: timer: remove legacy rtctimer 2016-04-25 10:41:46 +02:00