linux-toradex.git/sound/core, branch v4.4.108

ALSA: seq: Remove spurious WARN_ON() at timer check

2017-12-16T09:33:49+00:00

commit 43a3542870328601be02fcc9d27b09db467336ef upstream.

The use of snd_BUG_ON() in ALSA sequencer timer may lead to a spurious
WARN_ON() when a slave timer is deployed as its backend and a
corresponding master timer stops meanwhile.  The symptom was triggered
by syzkaller spontaneously.

Since the NULL timer is valid there, rip off snd_BUG_ON().

Reported-by: syzbot 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: prevent UAF in snd_pcm_info

2017-12-16T09:33:48+00:00

commit 362bca57f5d78220f8b5907b875961af9436e229 upstream.

When the device descriptor is closed, the `substream->runtime` pointer
is freed. But another thread may be in the ioctl handler, case
SNDRV_CTL_IOCTL_PCM_INFO. This case calls snd_pcm_info_user() which
calls snd_pcm_info() which accesses the now freed `substream->runtime`.

Note: this fixes CVE-2017-0861

Signed-off-by: Robb Glasser 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: timer: Remove kernel warning at compat ioctl error paths

2017-11-30T08:37:22+00:00

commit 3d4e8303f2c747c8540a0a0126d0151514f6468b upstream.

Some timer compat ioctls have NULL checks of timer instance with
snd_BUG_ON() that bring up WARN_ON() when the debug option is set.
Actually the condition can be met in the normal situation and it's
confusing and bad to spew kernel warnings with stack trace there.
Let's remove snd_BUG_ON() invocation and replace with the simple
checks.  Also, correct the error code to EBADFD to follow the native
ioctl error handling.

Reported-by: syzbot 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: update tstamp only if audio_tstamp changed

2017-11-30T08:37:21+00:00

commit 20e3f985bb875fea4f86b04eba4b6cc29bfd6b71 upstream.

commit 3179f6200188 ("ALSA: core: add .get_time_info") had a side effect
of changing the behaviour of the PCM runtime tstamp.  Prior to this
change tstamp was not updated by snd_pcm_update_hw_ptr0() unless the
hw_ptr had moved, after this change tstamp was always updated.

For an application using alsa-lib, doing snd_pcm_readi() followed by
snd_pcm_status() to estimate the age of the read samples by subtracting
status->avail * [sample rate] from status->tstamp this change degraded
the accuracy of the estimate on devices where the pcm hw does not
provide a granular hw_ptr, e.g., devices using
soc-generic-dmaengine-pcm.c and a dma-engine with residue_granularity
DMA_RESIDUE_GRANULARITY_DESCRIPTOR.  The accuracy of the estimate
depended on the latency between the PCM hw completing a period and the
driver called snd_pcm_period_elapsed() to notify ALSA core, typically
determined by interrupt handling latency.  After the change the accuracy
of the estimate depended on the latency between the PCM hw completing a
period and the application calling snd_pcm_status(), determined by the
scheduling of the application process.  The maximum error of the
estimate is one period length in both cases, but the error average and
variance is smaller when it depends on interrupt latency.

Instead of always updating tstamp, update it only if audio_tstamp
changed.

Fixes: 3179f6200188 ("ALSA: core: add .get_time_info")
Suggested-by: Pierre-Louis Bossart 
Signed-off-by: Henrik Eriksson 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Cancel pending autoload work at unbinding device

2017-11-18T10:11:05+00:00

commit fc27fe7e8deef2f37cba3f2be2d52b6ca5eb9d57 upstream.

ALSA sequencer core has a mechanism to load the enumerated devices
automatically, and it's performed in an off-load work.  This seems
causing some race when a sequencer is removed while the pending
autoload work is running.  As syzkaller spotted, it may lead to some
use-after-free:
  BUG: KASAN: use-after-free in snd_rawmidi_dev_seq_free+0x69/0x70
  sound/core/rawmidi.c:1617
  Write of size 8 at addr ffff88006c611d90 by task kworker/2:1/567

  CPU: 2 PID: 567 Comm: kworker/2:1 Not tainted 4.13.0+ #29
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Workqueue: events autoload_drivers
  Call Trace:
   __dump_stack lib/dump_stack.c:16 [inline]
   dump_stack+0x192/0x22c lib/dump_stack.c:52
   print_address_description+0x78/0x280 mm/kasan/report.c:252
   kasan_report_error mm/kasan/report.c:351 [inline]
   kasan_report+0x230/0x340 mm/kasan/report.c:409
   __asan_report_store8_noabort+0x1c/0x20 mm/kasan/report.c:435
   snd_rawmidi_dev_seq_free+0x69/0x70 sound/core/rawmidi.c:1617
   snd_seq_dev_release+0x4f/0x70 sound/core/seq_device.c:192
   device_release+0x13f/0x210 drivers/base/core.c:814
   kobject_cleanup lib/kobject.c:648 [inline]
   kobject_release lib/kobject.c:677 [inline]
   kref_put include/linux/kref.h:70 [inline]
   kobject_put+0x145/0x240 lib/kobject.c:694
   put_device+0x25/0x30 drivers/base/core.c:1799
   klist_devices_put+0x36/0x40 drivers/base/bus.c:827
   klist_next+0x264/0x4a0 lib/klist.c:403
   next_device drivers/base/bus.c:270 [inline]
   bus_for_each_dev+0x17e/0x210 drivers/base/bus.c:312
   autoload_drivers+0x3b/0x50 sound/core/seq_device.c:117
   process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
   worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
   kthread+0x324/0x3f0 kernel/kthread.c:231
   ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425

The fix is simply to assure canceling the autoload work at removing
the device.

Reported-by: Andrey Konovalov 
Tested-by: Andrey Konovalov 
Signed-off-by: Takashi Iwai 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix OSS sysex delivery in OSS emulation

2017-11-15T16:13:12+00:00

commit 132d358b183ac6ad8b3fea32ad5e0663456d18d1 upstream.

The SYSEX event delivery in OSS sequencer emulation assumed that the
event is encoded in the variable-length data with the straight
buffering.  This was the normal behavior in the past, but during the
development, the chained buffers were introduced for carrying more
data, while the OSS code was left intact.  As a result, when a SYSEX
event with the chained buffer data is passed to OSS sequencer port,
it may end up with the wrong memory access, as if it were having a too
large buffer.

This patch addresses the bug, by applying the buffer data expansion by
the generic snd_seq_dump_var_event() helper function.

Reported-by: syzbot 
Reported-by: Mark Salyzyn 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix nested rwsem annotation for lockdep splat

2017-11-08T09:06:27+00:00

commit 1f20f9ff57ca23b9f5502fca85ce3977e8496cb1 upstream.

syzkaller reported the lockdep splat due to the possible deadlock of
grp->list_mutex of each sequencer client object.  Actually this is
rather a false-positive report due to the missing nested lock
annotations.  The sequencer client may deliver the event directly to
another client which takes another own lock.

For addressing this issue, this patch replaces the simple down_read()
with down_read_nested().  As a lock subclass, the already existing
"hop" can be re-used, which indicates the depth of the call.

Reference: http://lkml.kernel.org/r/089e082686ac9b482e055c832617@google.com
Reported-by: syzbot 
Reported-by: Dmitry Vyukov 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: timer: Add missing mutex lock for compat ioctls

2017-11-08T09:06:27+00:00

commit 79fb0518fec8c8b4ea7f1729f54f293724b3dbb0 upstream.

The races among ioctl and other operations were protected by the
commit af368027a49a ("ALSA: timer: Fix race among timer ioctls") and
later fixes, but one code path was forgotten in the scenario: the
32bit compat ioctl.  As syzkaller recently spotted, a very similar
use-after-free may happen with the combination of compat ioctls.

The fix is simply to apply the same ioctl_lock to the compat_ioctl
callback, too.

Fixes: af368027a49a ("ALSA: timer: Fix race among timer ioctls")
Reference: http://lkml.kernel.org/r/089e082686ac9b482e055c832617@google.com
Reported-by: syzbot 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Enable 'use' locking in all configurations

2017-10-27T08:23:16+00:00

commit 8009d506a1dd00cf436b0c4cca0dcec130580a21 upstream.

The 'use' locking macros are no-ops if neither SMP or SND_DEBUG is
enabled.  This might once have been OK in non-preemptible
configurations, but even in that case snd_seq_read() may sleep while
relying on a 'use' lock.  So always use the proper implementations.

Signed-off-by: Ben Hutchings 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix copy_from_user() call inside lock

2017-10-18T07:20:42+00:00

commit 5803b023881857db32ffefa0d269c90280a67ee0 upstream.

The event handler in the virmidi sequencer code takes a read-lock for
the linked list traverse, while it's calling snd_seq_dump_var_event()
in the loop.  The latter function may expand the user-space data
depending on the event type.  It eventually invokes copy_from_user(),
which might be a potential dead-lock.

The sequencer core guarantees that the user-space data is passed only
with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it
and always takes read-lock().  For avoiding the problem above, this
patch introduces rwsem for non-atomic case, while keeping rwlock for
atomic case.

Also while we're at it: the superfluous irq flags is dropped in
snd_virmidi_input_open().

Reported-by: Jia-Ju Bai 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman