linux-stable.git/sound/drivers, branch v4.1.44

ALSA: dummy: Fix a use-after-free at closing

2016-07-11T00:20:04+00:00

[ Upstream commit d5dbbe6569481bf12dcbe3e12cff72c5f78d272c ]

syzkaller fuzzer spotted a potential use-after-free case in snd-dummy
driver when hrtimer is used as backend:
> ==================================================================
> BUG: KASAN: use-after-free in rb_erase+0x1b17/0x2010 at addr ffff88005e5b6f68
>  Read of size 8 by task syz-executor/8984
> =============================================================================
> BUG kmalloc-192 (Not tainted): kasan: bad access detected
> -----------------------------------------------------------------------------
>
> Disabling lock debugging due to kernel taint
> INFO: Allocated in 0xbbbbbbbbbbbbbbbb age=18446705582212484632
> ....
> [<      none      >] dummy_hrtimer_create+0x49/0x1a0 sound/drivers/dummy.c:464
> ....
> INFO: Freed in 0xfffd8e09 age=18446705496313138713 cpu=2164287125 pid=-1
> [<      none      >] dummy_hrtimer_free+0x68/0x80 sound/drivers/dummy.c:481
> ....
> Call Trace:
>  [] __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:333
>  [<     inline     >] rb_set_parent include/linux/rbtree_augmented.h:111
>  [<     inline     >] __rb_erase_augmented include/linux/rbtree_augmented.h:218
>  [] rb_erase+0x1b17/0x2010 lib/rbtree.c:427
>  [] timerqueue_del+0x78/0x170 lib/timerqueue.c:86
>  [] __remove_hrtimer+0x90/0x220 kernel/time/hrtimer.c:903
>  [<     inline     >] remove_hrtimer kernel/time/hrtimer.c:945
>  [] hrtimer_try_to_cancel+0x22a/0x570 kernel/time/hrtimer.c:1046
>  [] hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1066
>  [] dummy_hrtimer_stop+0x91/0xb0 sound/drivers/dummy.c:417
>  [] dummy_pcm_trigger+0x17f/0x1e0 sound/drivers/dummy.c:507
>  [] snd_pcm_do_stop+0x160/0x1b0 sound/core/pcm_native.c:1106
>  [] snd_pcm_action_single+0x76/0x120 sound/core/pcm_native.c:956
>  [] snd_pcm_action+0x231/0x290 sound/core/pcm_native.c:974
>  [<     inline     >] snd_pcm_stop sound/core/pcm_native.c:1139
>  [] snd_pcm_drop+0x12d/0x1d0 sound/core/pcm_native.c:1784
>  [] snd_pcm_common_ioctl1+0xfae/0x2150 sound/core/pcm_native.c:2805
>  [] snd_pcm_capture_ioctl1+0x2a1/0x5e0 sound/core/pcm_native.c:2976
>  [] snd_pcm_kernel_ioctl+0x11c/0x160 sound/core/pcm_native.c:3020
>  [] snd_pcm_oss_sync+0x3a4/0xa30 sound/core/oss/pcm_oss.c:1693
>  [] snd_pcm_oss_release+0x1ad/0x280 sound/core/oss/pcm_oss.c:2483
>  .....

A workaround is to call hrtimer_cancel() in dummy_hrtimer_sync() which
is called certainly before other blocking ops.

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

ALSA: dummy: Implement timer backend switching more safely

2016-02-28T05:09:52+00:00

[ Upstream commit ddce57a6f0a2d8d1bfacfa77f06043bc760403c2 ]

Currently the selected timer backend is referred at any moment from
the running PCM callbacks.  When the backend is switched, it's
possible to lead to inconsistency from the running backend.  This was
pointed by syzkaller fuzzer, and the commit [7ee96216c31a: ALSA:
dummy: Disable switching timer backend via sysfs] disabled the dynamic
switching for avoiding the crash.

This patch improves the handling of timer backend switching.  It keeps
the reference to the selected backend during the whole operation of an
opened stream so that it won't be changed by other streams.

Together with this change, the hrtimer parameter is reenabled as
writable now.

NOTE: this patch also turned out to fix the still remaining race.
Namely, ops was still replaced dynamically at dummy_pcm_open:

  static int dummy_pcm_open(struct snd_pcm_substream *substream)
  {
  ....
          dummy->timer_ops = &dummy_systimer_ops;
          if (hrtimer)
                  dummy->timer_ops = &dummy_hrtimer_ops;

Since dummy->timer_ops is common among all streams, and when the
replacement happens during accesses of other streams, it may lead to a
crash.  This was actually triggered by syzkaller fuzzer and KASAN.

This patch rewrites the code not to use the ops shared by all streams
any longer, too.

BugLink: http://lkml.kernel.org/r/CACT4Y+aZ+xisrpuM6cOXbL21DuM0yVxPYXf4cD4Md9uw0C3dBQ@mail.gmail.com
Reported-by: Dmitry Vyukov 
Cc: 
Signed-off-by: Takashi Iwai 
Signed-off-by: Sasha Levin

ALSA: dummy: Disable switching timer backend via sysfs

2016-02-15T20:45:26+00:00

[ Upstream commit 7ee96216c31aabe1eb42fb91ff50dae9fcd014b2 ]

ALSA dummy driver can switch the timer backend between system timer
and hrtimer via its hrtimer module option.  This can be also switched
dynamically via sysfs, but it may lead to a memory corruption when
switching is done while a PCM stream is running; the stream instance
for the newly switched timer method tries to access the memory that
was allocated by another timer method although the sizes differ.

As the simplest fix, this patch just disables the switch via sysfs by
dropping the writable bit.

BugLink: http://lkml.kernel.org/r/CACT4Y+ZGEeEBntHW5WHn2GoeE0G_kRrCmUh6=dWyy-wfzvuJLg@mail.gmail.com
Reported-by: Dmitry Vyukov 
Cc: 
Signed-off-by: Takashi Iwai 
Signed-off-by: Sasha Levin

Merge branch 'for-linus' into for-next

2015-03-09T07:42:00+00:00

Merging the HD-audio fixes back to base devel branch for further
working on it.

ALSA: opl3: small array underflow

2015-03-06T12:04:42+00:00

There is a missing lower bound check on "pitchbend" so it means we can
read up to 6 elements before the start of the opl3_note_table[] array.

Thanks to Clemens Ladisch for his help with this patch.

Signed-off-by: Dan Carpenter 
Signed-off-by: Takashi Iwai

ALSA: seq: Define driver object in each driver

2015-02-12T13:15:54+00:00

This patch moves the driver object initialization and allocation to
each driver's module init/exit code like other normal drivers.  The
snd_seq_driver struct is now published in seq_device.h, and each
driver is responsible to define it with proper driver attributes
(name, probe and remove) with snd_seq_driver specific attributes as id
and argsize fields.  The helper functions snd_seq_driver_register(),
snd_seq_driver_unregister() and module_snd_seq_driver() are used for
simplifying codes.

Signed-off-by: Takashi Iwai

ALSA: Include linux/uaccess.h and linux/bitopts.h instead of asm/*

2015-01-28T16:25:07+00:00

Signed-off-by: Takashi Iwai

ALSA: Include linux/io.h instead of asm/io.h

2015-01-28T15:49:33+00:00

Nowadays it's recommended.  Replace all in a shot.

Signed-off-by: Takashi Iwai

ALSA: serial-u16550: Use setup_timer() and mod_timer()

2015-01-19T10:32:26+00:00

No functional change, refactoring with the standard helpers.

Signed-off-by: Takashi Iwai

ALSA: opl3: Use setup_timer() and mod_timer()

2015-01-19T10:32:26+00:00

No functional change, refactoring with the standard helpers.

Signed-off-by: Takashi Iwai