linux-toradex.git/sound/core/seq/seq_queue.c, branch v5.2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix leftovers at probe error path

2018-08-01T20:54:36+00:00

The sequencer core module doesn't call some destructors in the error
path of the init code, which may leave some resources.

This patch mainly fix these leaks by calling the destructors
appropriately at alsa_seq_init().  Also the patch brings a few
cleanups along with it, namely:

- Expand the old "if ((err = xxx) < 0)" coding style
- Get rid of empty seq_queue_init() and its caller
- Change snd_seq_info_done() to void

Last but not least, a couple of functions lose __exit annotation since
they are called also in alsa_seq_init().

No functional changes but minor code cleanups.

Signed-off-by: Takashi Iwai

ALSA: seq: Fix possible UAF in snd_seq_check_queue()

2018-03-10T16:29:49+00:00

Although we've covered the races between concurrent write() and
ioctl() in the previous patch series, there is still a possible UAF in
the following scenario:

A: user client closed		B: timer irq
  -> snd_seq_release()		  -> snd_seq_timer_interrupt()
    -> snd_seq_free_client()	    -> snd_seq_check_queue()
				      -> cell = snd_seq_prioq_cell_peek()
      -> snd_seq_prioq_leave()
         .... removing all cells
      -> snd_seq_pool_done()
         .... vfree()
				      -> snd_seq_compare_tick_time(cell)
				         ... Oops

So the problem is that a cell is peeked and accessed without any
protection until it's retrieved from the queue again via
snd_seq_prioq_cell_out().

This patch tries to address it, also cleans up the code by a slight
refactoring.  snd_seq_prioq_cell_out() now receives an extra pointer
argument.  When it's non-NULL, the function checks the event timestamp
with the given pointer.  The caller needs to pass the right reference
either to snd_seq_tick or snd_seq_realtime depending on the event
timestamp type.

A good news is that the above change allows us to remove the
snd_seq_prioq_cell_peek(), too, thus the patch actually reduces the
code size.

Reviewed-by: Nicolai Stange 
Cc: 
Signed-off-by: Takashi Iwai

ALSA: seq: Process queue tempo/ppq change in a shot

2018-01-15T15:48:36+00:00

The SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO ioctl sets the tempo and the ppq
in a single call, while the current implementation updates each value
one by one.  This is a bit racy, and also suboptimal from the
performance POV, as each call does re-acquire the lock and invokes
the update of ALSA timer resolution.

This patch reorganizes the code slightly so that we change both the
tempo and the ppq in a shot.  The skew value can be put into the same
lock, but this is rather a rarely used feature and completely
independent from the temp/ppq (it's evaluated only in the interrupt),
so it's left as it was.

Signed-off-by: Takashi Iwai

ALSA: seq: 2nd attempt at fixing race creating a queue

2017-08-15T06:02:35+00:00

commit 4842e98f26dd80be3623c4714a244ba52ea096a8 ("ALSA: seq: Fix race at
creating a queue") attempted to fix a race reported by syzkaller. That
fix has been described as follows:

"
When a sequencer queue is created in snd_seq_queue_alloc(),it adds the
new queue element to the public list before referencing it.  Thus the
queue might be deleted before the call of snd_seq_queue_use(), and it
results in the use-after-free error, as spotted by syzkaller.

The fix is to reference the queue object at the right time.
"

Even with that fix in place, syzkaller reported a use-after-free error.
It specifically pointed to the last instruction "return q->queue" in
snd_seq_queue_alloc(). The pointer q is being used after kfree() has
been called on it.

It turned out that there is still a small window where a race can
happen. The window opens at
snd_seq_ioctl_create_queue()->snd_seq_queue_alloc()->queue_list_add()
and closes at
snd_seq_ioctl_create_queue()->queueptr()->snd_use_lock_use(). Between
these two calls, a different thread could delete the queue and possibly
re-create a different queue in the same location in queue_list.

This change prevents this situation by calling snd_use_lock_use() from
snd_seq_queue_alloc() prior to calling queue_list_add(). It is then the
caller's responsibility to call snd_use_lock_free(&q->use_lock).

Fixes: 4842e98f26dd ("ALSA: seq: Fix race at creating a queue")
Reported-by: Dmitry Vyukov 
Cc: 
Signed-off-by: Daniel Mentz 
Signed-off-by: Takashi Iwai

ALSA: seq: Fix race at creating a queue

2017-02-08T11:42:37+00:00

When a sequencer queue is created in snd_seq_queue_alloc(),it adds the
new queue element to the public list before referencing it.  Thus the
queue might be deleted before the call of snd_seq_queue_use(), and it
results in the use-after-free error, as spotted by syzkaller.

The fix is to reference the queue object at the right time.

Reported-by: Dmitry Vyukov 
Cc: 
Signed-off-by: Takashi Iwai

ALSA: seq: Fix race at timer setup and close

2016-01-12T16:50:41+00:00

ALSA sequencer code has an open race between the timer setup ioctl and
the close of the client.  This was triggered by syzkaller fuzzer, and
a use-after-free was caught there as a result.

This patch papers over it by adding a proper queue->timer_mutex lock
around the timer-related calls in the relevant code path.

Reported-by: Dmitry Vyukov 
Tested-by: Dmitry Vyukov 
Cc: 
Signed-off-by: Takashi Iwai

ALSA: replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS

2015-05-27T19:25:19+00:00

We may disable proc fs only for sound part, to reduce ALSA
memory footprint. So add CONFIG_SND_PROC_FS and replace the
old CONFIG_PROC_FSs in alsa code.

With sound proc fs disabled, we can save about 9KB memory
size on X86_64 platform.

Signed-off-by: Jie Yang 
Reviewed-by: Mark Brown 
Signed-off-by: Takashi Iwai

ALSA: seq: Drop superfluous error/debug messages after malloc failures

2015-03-10T14:41:18+00:00

The kernel memory allocators already report the errors when the
requested allocation fails, thus we don't need to warn it again in
each caller side.

Signed-off-by: Takashi Iwai

ALSA: seq: Use standard printk helpers

2014-02-14T07:14:18+00:00

Use the standard pr_xxx() helpers instead of home-baked snd_print*().

Signed-off-by: Takashi Iwai