commit 94ffb030b6d31ec840bb811be455dd2e26a4f43e upstream.
stream is indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
sound/core/pcm.c:140 snd_pcm_control_ioctl() warn: potential spectre issue 'pcm->streams' [r] (local cap)
Fix this by sanitizing stream before using it to index pcm->streams
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b51abed8355e5556886623b2772fa6b7598d2282 upstream.
Currently the PCM core calls snd_pcm_unlink() always unconditionally
at closing a stream. However, since snd_pcm_unlink() invokes the
global rwsem down, the lock can be easily contended. More badly, when
a thread runs in a high priority RT-FIFO, it may stall at spinning.
Basically the call of snd_pcm_unlink() is required only for the linked
streams that are already rare occasion. For normal use cases, this
code path is fairly superfluous.
As an optimization (and also as a workaround for the RT problem
above in normal situations without linked streams), this patch adds a
check before calling snd_pcm_unlink() and calls it only when needed.
Reported-by: Chanho Min <chanho.min@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b888a5f713e4d17faaaff24316585a4eb07f35b7 upstream.
Commit 67ec1072b053 ("ALSA: pcm: Fix rwsem deadlock for non-atomic PCM
stream") fixes deadlock for non-atomic PCM stream. But, This patch
causes antother stuck.
If writer is RT thread and reader is a normal thread, the reader
thread will be difficult to get scheduled. It may not give chance to
release readlocks and writer gets stuck for a long time if they are
pinned to single cpu.
The deadlock described in the previous commit is because the linux
rwsem queues like a FIFO. So, we might need non-FIFO writelock, not
non-block one.
My suggestion is that the writer gives reader a chance to be scheduled
by using the minimum msleep() instaed of spinning without blocking by
writer. Also, The *_nonblock may be changed to *_nonfifo appropriately
to this concept.
In terms of performance, when trylock is failed, this minimum periodic
msleep will have the same performance as the tick-based
schedule()/wake_up_q().
[ Although this has a fairly high performance penalty, the relevant
code path became already rare due to the previous commit ("ALSA:
pcm: Call snd_pcm_unlink() conditionally at closing"). That is, now
this unconditional msleep appears only when using linked streams,
and this must be a rare case. So we accept this as a quick
workaround until finding a more suitable one -- tiwai ]
Fixes: 67ec1072b053 ("ALSA: pcm: Fix rwsem deadlock for non-atomic PCM stream")
Suggested-by: Wonmin Jung <wonmin.jung@lge.com>
Signed-off-by: Chanho Min <chanho.min@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e1a7bfe3807974e66f971f2589d4e0197ec0fced upstream.
The procedure for adding a user control element has some window opened
for race against the concurrent removal of a user element. This was
caught by syzkaller, hitting a KASAN use-after-free error.
This patch addresses the bug by wrapping the whole procedure to add a
user control element with the card->controls_rwsem, instead of only
around the increment of card->user_ctl_count.
This required a slight code refactoring, too. The function
snd_ctl_add() is split to two parts: a core function to add the
control element and a part calling it. The former is called from the
function for adding a user control element inside the controls_rwsem.
One change to be noted is that snd_ctl_notify() for adding a control
element gets called inside the controls_rwsem as well while it was
called outside the rwsem. But this should be OK, as snd_ctl_notify()
takes another (finer) rwlock instead of rwsem, and the call of
snd_ctl_notify() inside rwsem is already done in another code path.
Reported-by: syzbot+dc09047bce3820621ba2@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 65766ee0bf7fe8b3be80e2e1c3ef54ad59b29476 upstream.
PCM OSS layer may allocate a few temporary buffers, one for the core
read/write and another for the conversions via plugins. Currently
both are allocated via vmalloc(). But as the allocation size is
equivalent with the PCM period size, the required size might be quite
small, depending on the application.
This patch replaces these vmalloc() calls with kvzalloc() for covering
small period sizes better. Also, we use "z"-alloc variant here for
addressing the possible uninitialized access reported by syzkaller.
Reported-by: syzbot+1cb36954e127c98dd037@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ff2d6acdf6f13d9f8fdcd890844c6d7535ac1f10 ]
Without this commit the following intervals [x y), (x y) were be
replaced to (y-1 y) by snd_interval_refine_last(). This was also done
if y-1 is part of the previous interval.
With this changes it will be replaced with [y-1 y) in case of y-1 is
part of the previous interval. A similar behavior will be used for
snd_interval_refine_first().
This commit adapts the changes for alsa-lib of commit
9bb985c ("pcm: snd_interval_refine_first/last: exclude value only if
also excluded before")
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit c9a4c63888dbb79ce4d068ca1dd8b05bc3f156b1 ]
The kernel may spew a WARNING with UBSAN undefined behavior at
handling ALSA sequencer ioctl SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT:
UBSAN: Undefined behaviour in sound/core/seq/seq_clientmgr.c:2007:14
signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x122/0x1c8 lib/dump_stack.c:113
ubsan_epilogue+0x12/0x86 lib/ubsan.c:159
handle_overflow+0x1c2/0x21f lib/ubsan.c:190
__ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:198
snd_seq_ioctl_query_next_client+0x1ac/0x1d0 sound/core/seq/seq_clientmgr.c:2007
snd_seq_ioctl+0x264/0x3d0 sound/core/seq/seq_clientmgr.c:2144
....
It happens only when INT_MAX is passed there, as we're incrementing it
unconditionally. So the fix is trivial, check the value with
INT_MAX. Although the bug itself is fairly harmless, it's better to
fix it so that fuzzers won't hit this again later.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200211
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dfef01e150824b0e6da750cacda8958188d29aea upstream.
snd_dma_alloc_pages_fallback() tries to allocate pages again when the
allocation fails with reduced size. But the first try actually
*increases* the size to power-of-two, which may give back a larger
chunk than the requested size. This confuses the callers, e.g. sgbuf
assumes that the size is equal or less, and it may result in a bad
loop due to the underflow and eventually lead to Oops.
The code of this function seems incorrectly assuming the usage of
get_order(). We need to decrease at first, then align to
power-of-two.
Reported-and-tested-by: he, bo <bo.he@intel.com>
Reported-by: zhang jun <jun.zhang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 50e9ffb1996a5d11ff5040a266585bad4ceeca0a upstream.
The virmidi output trigger tries to parse the all available bytes and
process sequencer events as much as possible. In a normal situation,
this is supposed to be relatively short, but a program may give a huge
buffer and it'll take a long time in a single spin lock, which may
eventually lead to a soft lockup.
This patch simply adds a workaround, a cond_resched() call in the loop
if applicable. A better solution would be to move the event processor
into a work, but let's put a duct-tape quickly at first.
Reported-and-tested-by: Dae R. Jeong <threeearcat@gmail.com>
Reported-by: syzbot+619d9f40141d826b097e@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 39675f7a7c7e7702f7d5341f1e0d01db746543a0 upstream.
The SNDRV_RAWMIDI_IOCTL_PARAMS ioctl may resize the buffers and the
current code is racy. For example, the sequencer client may write to
buffer while it being resized.
As a simple workaround, let's switch to the resized buffer inside the
stream runtime lock.
Reported-by: syzbot+52f83f0ea8df16932f7f@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b41f794f284966fd6ec634111e3b40d241389f96 upstream.
The kernel may spew a WARNING about UBSAN undefined behavior at
handling ALSA timer ioctl SNDRV_TIMER_IOCTL_NEXT_DEVICE:
UBSAN: Undefined behaviour in sound/core/timer.c:1524:19
signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x122/0x1c8 lib/dump_stack.c:113
ubsan_epilogue+0x12/0x86 lib/ubsan.c:159
handle_overflow+0x1c2/0x21f lib/ubsan.c:190
__ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:198
snd_timer_user_next_device sound/core/timer.c:1524 [inline]
__snd_timer_user_ioctl+0x204d/0x2520 sound/core/timer.c:1939
snd_timer_user_ioctl+0x67/0x95 sound/core/timer.c:1994
....
It happens only when a value with INT_MAX is passed, as we're
incrementing it unconditionally. So the fix is trivial, check the
value with INT_MAX. Although the bug itself is fairly harmless, it's
better to fix it so that fuzzers won't hit this again later.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200213
Reported-and-tested-by: Team OWL337 <icytxw@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2e2c177ca84aff092c3c96714b0f6a12900f3946 ]
In slave_update() of vmaster code ignores the error from the slave
get() callback and copies the values. It's not only about the missing
error code but also that this may potentially lead to a leak of
uninitialized variables when the slave get() don't clear them.
This patch fixes slave_update() not to copy the potentially
uninitialized values when an error is returned from the slave get()
callback, and to propagate the error value properly.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3ae180972564846e6d794e3615e1ab0a1e6c4ef9 upstream.
Commit f65e0d299807 ("ALSA: timer: Call notifier in the same spinlock")
combined the start/continue and stop/pause functions, and in doing so
changed the event code for the pause case to SNDRV_TIMER_EVENT_CONTINUE.
Change it back to SNDRV_TIMER_EVENT_PAUSE.
Fixes: f65e0d299807 ("ALSA: timer: Call notifier in the same spinlock")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3f12888dfae2a48741c4caa9214885b3aaf350f9 upstream.
In snd_ctl_elem_add_compat(), the fields of the struct 'data' need to be
copied from the corresponding fields of the struct 'data32' in userspace.
This is achieved by invoking copy_from_user() and get_user() functions. The
problem here is that the 'type' field is copied twice. One is by
copy_from_user() and one is by get_user(). Given that the 'type' field is
not used between the two copies, the second copy is *completely* redundant
and should be removed for better performance and cleanup. Also, these two
copies can cause inconsistent data: as the struct 'data32' resides in
userspace and a malicious userspace process can race to change the 'type'
field between the two copies to cause inconsistent data. Depending on how
the data is used in the future, such an inconsistency may cause potential
security risks.
For above reasons, we should take out the second copy.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8f22e52528cc372b218b5f100457469615c733ce upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f13876e2c33a657a71bcbb10f767c0951b165020 upstream.
Since snd_pcm_ioctl_xfern_compat() has no PCM state check, it may go
further and hit the sanity check pcm_sanity_check() when the ioctl is
called right after open. It may eventually spew a kernel warning, as
triggered by syzbot, depending on kconfig.
The lack of PCM state check there was just an oversight. Although
it's no real crash, the spurious kernel warning is annoying, so let's
add the proper check.
Reported-by: syzbot+1dac3a4f6bc9c1c675d4@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8d218dd8116695ecda7164f97631c069938aa22e upstream.
As Smatch recently suggested, a few places in OSS sequencer codes may
expand the array directly from the user-space value with speculation,
namely there are a significant amount of references to either
info->ch[] or dp->synths[] array:
sound/core/seq/oss/seq_oss_event.c:315 note_on_event() warn: potential spectre issue 'info->ch' (local cap)
sound/core/seq/oss/seq_oss_event.c:362 note_off_event() warn: potential spectre issue 'info->ch' (local cap)
sound/core/seq/oss/seq_oss_synth.c:470 snd_seq_oss_synth_load_patch() warn: potential spectre issue 'dp->synths' (local cap)
sound/core/seq/oss/seq_oss_event.c:293 note_on_event() warn: potential spectre issue 'dp->synths'
sound/core/seq/oss/seq_oss_event.c:353 note_off_event() warn: potential spectre issue 'dp->synths'
sound/core/seq/oss/seq_oss_synth.c:506 snd_seq_oss_synth_sysex() warn: potential spectre issue 'dp->synths'
sound/core/seq/oss/seq_oss_synth.c:580 snd_seq_oss_synth_ioctl() warn: potential spectre issue 'dp->synths'
Although all these seem doing only the first load without further
reference, we may want to stay in a safer side, so hardening with
array_index_nospec() would still make sense.
We may put array_index_nospec() at each place, but here we take a
different approach:
- For dp->synths[], change the helpers to retrieve seq_oss_synthinfo
pointer directly instead of the array expansion at each place
- For info->ch[], harden in a normal way, as there are only a couple
of places
As a result, the existing helper, snd_seq_oss_synth_is_valid() is
replaced with snd_seq_oss_synth_info(). Also, we cover MIDI device
where a similar array expansion is done, too, although it wasn't
reported by Smatch.
BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f5e94b4c6ebdabe0f602d796e0430180927521a0 upstream.
When get_synthdev() is called for a MIDI device, it returns the fixed
midi_synth_dev without the use refcounting. OTOH, the caller is
supposed to unreference unconditionally after the usage, so this would
lead to unbalanced refcount.
This patch corrects the behavior and keep up the refcount balance also
for the MIDI synth device.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f853dcaae2f5bbe021161e421bd1576845bae8f6 upstream.
It looks like a simple mistake that this struct member
was forgotten.
Audio_tstamp isn't used much, and on some archs (such as x86) this
ioctl is not used by default, so that might be the reason why this
has slipped for so long.
Fixes: 4eeaaeaea1ce ("ALSA: core: add hooks for audio timestamps")
Signed-off-by: David Henningsson <diwic@ubuntu.com>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: <stable@vger.kernel.org> # v3.8+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 912e4c332037e7ed063c164985c36fb2b549ea3a upstream.
The commit c2c86a97175f ("ALSA: pcm: Remove set_fs() in PCM core code")
changed SNDRV_PCM_IOCTL_DELAY to return an inconsistent error instead of a
negative delay. Originally the call would succeed and return the negative
delay. The Chromium OS Audio Server (CRAS) gets confused and hangs when
the error is returned instead of the negative delay.
Help CRAS avoid the issue by rolling back the behavior to return a
negative delay instead of an error.
Fixes: c2c86a97175f ("ALSA: pcm: Remove set_fs() in PCM core code")
Signed-off-by: Jeffery Miller <jmiller@neverware.com>
Cc: <stable@vger.kernel.org> # v4.13+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8a56ef4f3ffba9ebf4967b61ef600b0a7ba10f11 upstream.
Some rawmidi compat ioctls lack of the input substream checks
(although they do check only for rfile->output). This many eventually
lead to an Oops as NULL substream is passed to the rawmidi core
functions.
Fix it by adding the proper checks before each function call.
The bug was spotted by syzkaller.
Reported-by: syzbot+f7a0348affc3b67bc617@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e15dc99dbb9cf99f6432e8e3c0b3a8f7a3403a86 upstream.
The commit 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS
ioctls and read/write") split the PCM preparation code to a locked
version, and it added a sanity check of runtime->oss.prepare flag
along with the change. This leaded to an endless loop when the stream
gets XRUN: namely, snd_pcm_oss_write3() and co call
snd_pcm_oss_prepare() without setting runtime->oss.prepare flag and
the loop continues until the PCM state reaches to another one.
As the function is supposed to execute the preparation
unconditionally, drop the invalid state check there.
The bug was triggered by syzkaller.
Fixes: 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS ioctls and read/write")
Reported-by: syzbot+150189c103427d31a053@syzkaller.appspotmail.com
Reported-by: syzbot+7e3f31a52646f939c052@syzkaller.appspotmail.com
Reported-by: syzbot+4f2016cf5185da7759dc@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f6d297df4dd47ef949540e4a201230d0c5308325 upstream.
The previous fix 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS
ioctls changing busy streams") introduced some mutex unbalance; the
check of runtime->oss.rw_ref was inserted in a wrong place after the
mutex lock.
This patch fixes the inconsistency by rewriting with the helper
functions to lock/unlock parameters with the stream check.
Fixes: 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 40cab6e88cb0b6c56d3f30b7491a20e803f948f6 upstream.
OSS PCM stream management isn't modal but it allows ioctls issued at
any time for changing the parameters. In the previous hardening
patch ("ALSA: pcm: Avoid potential races between OSS ioctls and
read/write"), we covered these races and prevent the corruption by
protecting the concurrent accesses via params_lock mutex. However,
this means that some ioctls that try to change the stream parameter
(e.g. channels or format) would be blocked until the read/write
finishes, and it may take really long.
Basically changing the parameter while reading/writing is an invalid
operation, hence it's even more user-friendly from the API POV if it
returns -EBUSY in such a situation.
This patch adds such checks in the relevant ioctls with the addition
of read/write access refcount.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 02a5d6925cd34c3b774bdb8eefb057c40a30e870 upstream.
Although we apply the params_lock mutex to the whole read and write
operations as well as snd_pcm_oss_change_params(), we may still face
some races.
First off, the params_lock is taken inside the read and write loop.
This is intentional for avoiding the too long locking, but it allows
the in-between parameter change, which might lead to invalid
pointers. We check the readiness of the stream and set up via
snd_pcm_oss_make_ready() at the beginning of read and write, but it's
called only once, by assuming that it remains ready in the rest.
Second, many ioctls that may change the actual parameters
(i.e. setting runtime->oss.params=1) aren't protected, hence they can
be processed in a half-baked state.
This patch is an attempt to plug these holes. The stream readiness
check is moved inside the read/write inner loop, so that the stream is
always set up in a proper state before further processing. Also, each
ioctl that may change the parameter is wrapped with the params_lock
for avoiding the races.
The issues were triggered by syzkaller in a few different scenarios,
particularly the one below appearing as GPF in loopback_pos_update.
Reported-by: syzbot+c4227aec125487ec3efa@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c64ed5dd9feba193c76eb460b451225ac2a0d87b upstream.
Fix the last standing EINTR in the whole subsystem. Use more correct
ERESTARTSYS for pending signals.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a820ccbe21e8ce8e86c39cd1d3bc8c7d1cbb949b upstream.
The PCM runtime object is created and freed dynamically at PCM stream
open / close time. This is tracked via substream->runtime, and it's
cleared at snd_pcm_detach_substream().
The runtime object assignment is protected by PCM open_mutex, so for
all PCM operations, it's safely handled. However, each PCM substream
provides also an ALSA timer interface, and user-space can access to
this while closing a PCM substream. This may eventually lead to a
UAF, as snd_pcm_timer_resolution() tries to access the runtime while
clearing it in other side.
Fortunately, it's the only concurrent access from the PCM timer, and
it merely reads runtime->timer_resolution field. So, we can avoid the
race by reordering kfree() and wrapping the substream->runtime
clearance with the corresponding timer lock.
Reported-by: syzbot+8e62ff4e07aa2ce87826@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5607dddbfca774fb38bffadcb077fe03aa4ac5c6 upstream.
Smatch complains that "tmp" can be uninitialized if we do a zero size
write.
Fixes: 02a5d6925cd3 ("ALSA: pcm: Avoid potential races between OSS ioctls and read/write")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9066ae7ff5d89c0b5daa271e2d573540097a94fa upstream.
When trying to use the driver (e.g. aplay *.wav), the 4MiB DMA buffer
will get mmapp'ed in 16KiB chunks. But this fails with the 2nd 16KiB
area, as the page offset is outside of the VMA range (size), which is
currently used as size parameter in snd_pcm_lib_default_mmap(). By
using the DMA buffer size (dma_bytes) instead, the complete DMA buffer
can be mmapp'ed and the issue is fixed.
This issue was detected on an ARM platform (TI AM57xx) using the RME
HDSP MADI PCIe soundcard.
Fixes: 657b1989dacf ("ALSA: pcm - Use dma_mmap_coherent() if available")
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a2ff19f7b70118ced291a28d5313469914de451b upstream.
When releasing a client, we need to clear the clienttab[] entry at
first, then call snd_seq_queue_client_leave(). Otherwise, the
in-flight cell in the queue might be picked up by the timer interrupt
via snd_seq_check_queue() before calling snd_seq_queue_client_leave(),
and it's delivered to another queue while the client is clearing
queues. This may eventually result in an uncleared cell remaining in
a queue, and the later snd_seq_pool_delete() may need to wait for a
long time until the event gets really processed.
By moving the clienttab[] clearance at the beginning of release, any
event delivery of a cell belonging to this client will fail at a later
point, since snd_seq_client_ptr() returns NULL. Thus the cell that
was picked up by the timer interrupt will be returned immediately
without further delivery, and the long stall of snd_seq_delete_pool()
can be avoided, too.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d0f833065221cbfcbadf19fd4102bcfa9330006a upstream.
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 <nstange@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 01c0b4265cc16bc1f43f475c5944c55c10d5768f upstream.
snd_pcm_oss_get_formats() has an obvious use-after-free around
snd_mask_test() calls, as spotted by syzbot. The passed format_mask
argument is a pointer to the hw_params object that is freed before the
loop. What a surprise that it has been present since the original
code of decades ago...
Reported-by: syzbot+4090700a4f13fccaf648@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7bd80091567789f1c0cb70eb4737aac8bcd2b6b9 upstream.
This patch is an attempt for further hardening against races between
the concurrent write and ioctls. The previous fix d15d662e89fc
("ALSA: seq: Fix racy pool initializations") covered the race of the
pool initialization at writer and the pool resize ioctl by the
client->ioctl_mutex (CVE-2018-1000004). However, basically this mutex
should be applied more widely to the whole write operation for
avoiding the unexpected pool operations by another thread.
The only change outside snd_seq_write() is the additional mutex
argument to helper functions, so that we can unlock / relock the given
mutex temporarily during schedule() call for blocking write.
Fixes: d15d662e89fc ("ALSA: seq: Fix racy pool initializations")
Reported-by: 范龙飞 <long7573@126.com>
Reported-by: Nicolai Stange <nstange@suse.de>
Reviewed-and-tested-by: Nicolai Stange <nstange@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d85739367c6d56e475c281945c68fdb05ca74b4c upstream.
This is a fix for a (sort of) fallout in the recent commit
d15d662e89fc ("ALSA: seq: Fix racy pool initializations") for
CVE-2018-1000004.
As the pool resize deletes the existing cells, it may lead to a race
when another thread is writing concurrently, eventually resulting a
UAF.
A simple workaround is not to allow the pool resizing when the pool is
in use. It's an invalid behavior in anyway.
Fixes: d15d662e89fc ("ALSA: seq: Fix racy pool initializations")
Reported-by: 范龙飞 <long7573@126.com>
Reported-by: Nicolai Stange <nstange@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5a23699a39abc5328921a81b89383d088f6ba9cc upstream.
The patch "ALSA: control: code refactoring for ELEM_READ/ELEM_WRITE
operations" introduced a potential for kernel memory corruption due
to an incorrect if statement allowing non-readable controls to fall
through and call the get function. For TLV controls a driver can omit
SNDRV_CTL_ELEM_ACCESS_READ to ensure that only the TLV get function
can be called. Instead the normal get() can be invoked unexpectedly
and as the driver expects that this will only be called for controls
<= 512 bytes, potentially try to copy >512 bytes into the 512 byte
return array, so corrupting kernel memory.
The problem is an attempt to refactor the snd_ctl_elem_read function
to invert the logic so that it conditionally aborted if the control
is unreadable instead of conditionally executing. But the if statement
wasn't inverted correctly.
The correct inversion of
if (a && !b)
is
if (!a || b)
Fixes: becf9e5d553c2 ("ALSA: control: code refactoring for ELEM_READ/ELEM_WRITE operations")
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d15d662e89fc667b90cd294b0eb45694e33144da upstream.
ALSA sequencer core initializes the event pool on demand by invoking
snd_seq_pool_init() when the first write happens and the pool is
empty. Meanwhile user can reset the pool size manually via ioctl
concurrently, and this may lead to UAF or out-of-bound accesses since
the function tries to vmalloc / vfree the buffer.
A simple fix is to just wrap the snd_seq_pool_init() call with the
recently introduced client->ioctl_mutex; as the calls for
snd_seq_pool_init() from other side are always protected with this
mutex, we can avoid the race.
Reported-by: 范龙飞 <long7573@126.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 23b19b7b50fe1867da8d431eea9cd3e4b6328c2c upstream.
muldiv32() contains a snd_BUG_ON() (which is morphed as WARN_ON() with
debug option) for checking the case of 0 / 0. This would be helpful
if this happens only as a logical error; however, since the hw refine
is performed with any data set provided by user, the inconsistent
values that can trigger such a condition might be passed easily.
Actually, syzbot caught this by passing some zero'ed old hw_params
ioctl.
So, having snd_BUG_ON() there is simply superfluous and rather
harmful to give unnecessary confusions. Let's get rid of it.
Reported-by: syzbot+7e6ee55011deeebce15d@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b3defb791b26ea0683a93a4f49c77ec45ec96f10 upstream.
The ALSA sequencer ioctls have no protection against racy calls while
the concurrent operations may lead to interfere with each other. As
reported recently, for example, the concurrent calls of setting client
pool with a combination of write calls may lead to either the
unkillable dead-lock or UAF.
As a slightly big hammer solution, this patch introduces the mutex to
make each ioctl exclusive. Although this may reduce performance via
parallel ioctl calls, usually it's not demanded for sequencer usages,
hence it should be negligible.
Reported-by: Luo Quan <a4651386@163.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 900498a34a3ac9c611e9b425094c8106bdd7dc1c upstream.
PCM OSS read/write loops keep taking the mutex lock for the whole
read/write, and this might take very long when the exceptionally high
amount of data is given. Also, since it invokes with mutex_lock(),
the concurrent read/write becomes unbreakable.
This patch tries to address these issues by replacing mutex_lock()
with mutex_lock_interruptible(), and also splits / re-takes the lock
at each read/write period chunk, so that it can switch the context
more finely if requested.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 29159a4ed7044c52e3e2cf1a9fb55cec4745c60b upstream.
The loops for read and write in PCM OSS emulation have no proper check
of pending signals, and they keep processing even after user tries to
break. This results in a very long delay, often seen as RCU stall
when a huge unprocessed bytes remain queued. The bug could be easily
triggered by syzkaller.
As a simple workaround, this patch adds the proper check of pending
signals and aborts the loop appropriately.
Reported-by: syzbot+993cb4cfcbbff3947c21@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6708913750344a900f2e73bfe4a4d6dbbce4fe8d upstream.
In the OSS emulation plugin builder where the frame size is parsed in
the plugin chain, some places miss the possible errors returned from
the plugin src_ or dst_frames callback.
This patch papers over such places.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fb51f1cd06f9ced7b7085a2a4636375d520431ca upstream.
The commit 9027c4639ef1 ("ALSA: pcm: Call ack() whenever appl_ptr is
updated") introduced the possible error code returned from the PCM
rewind ioctl. Basically the change was for handling the indirect PCM
more correctly, but ironically, it caused rather a side-effect:
PulseAudio gets pissed off when receiving an error from rewind, throws
everything away and stops processing further, resulting in the
silence.
It's clearly a failure in the application side, so the best would be
to fix that bug in PA. OTOH, PA is mostly the only user of the rewind
feature, so it's not good to slap the sole customer.
This patch tries to mitigate the situation: instead of returning an
error, now the rewind ioctl returns zero when the driver can't rewind.
It indicates that no rewind was performed, so the behavior is
consistent, at least.
Fixes: 9027c4639ef1 ("ALSA: pcm: Call ack() whenever appl_ptr is updated")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fe08f34d066f4404934a509b6806db1a4f700c86 upstream.
syzkaller triggered kernel warnings through PCM OSS emulation at
closing a stream:
WARNING: CPU: 0 PID: 3502 at sound/core/pcm_lib.c:1635
snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635
Call Trace:
....
snd_pcm_hw_param_near.constprop.27+0x78d/0x9a0 sound/core/oss/pcm_oss.c:457
snd_pcm_oss_change_params+0x17d3/0x3720 sound/core/oss/pcm_oss.c:969
snd_pcm_oss_make_ready+0xaa/0x130 sound/core/oss/pcm_oss.c:1128
snd_pcm_oss_sync+0x257/0x830 sound/core/oss/pcm_oss.c:1638
snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431
__fput+0x327/0x7e0 fs/file_table.c:210
....
This happens while it tries to open and set up the aloop device
concurrently. The warning above (invoked from snd_BUG_ON() macro) is
to detect the unexpected logical error where snd_pcm_hw_refine() call
shouldn't fail. The theory is true for the case where the hw_params
config rules are static. But for an aloop device, the hw_params rule
condition does vary dynamically depending on the connected target;
when another device is opened and changes the parameters, the device
connected in another side is also affected, and it caused the error
from snd_pcm_hw_refine().
That is, the simplest "solution" for this is to remove the incorrect
assumption of static rules, and treat such an error as a normal error
path. As there are a couple of other places using snd_BUG_ON()
incorrectly, this patch removes these spurious snd_BUG_ON() calls.
Reported-by: syzbot+6f11c7e2a1b91d466432@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c1cfd9025cc394fd137a01159d74335c5ac978ce upstream.
The rawmidi also allows to obtaining the information via ioctl of ctl
API. It means that user can issue an ioctl to the rawmidi device even
when it's being removed as long as the control device is present.
Although the code has some protection via the global register_mutex,
its range is limited to the search of the corresponding rawmidi
object, and the mutex is already unlocked at accessing the rawmidi
object. This may lead to a use-after-free.
For avoiding it, this patch widens the application of register_mutex
to the whole snd_rawmidi_info_select() function. We have another
mutex per rawmidi object, but this operation isn't very hot path, so
it shouldn't matter from the performance POV.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <syzkaller@googlegroups.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <rglasser@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d6c0615f510bc1ee26cfb2b9a3343ac99b9c46fb upstream.
The previous fix for addressing the breakage in vmaster slave
initialization, commit a91d66129fb9 ("ALSA: hda - Fix incorrect TLV
callback check introduced during set_fs() removal"), introduced a new
helper to process over each slave kctl. However, this helper passes
only the original kctl, not the virtual slave kctl. As a result,
HD-audio driver (which is the only user so far) couldn't initialize
the slave correctly because it's trying to update the value directly
with the original kctl, not with the mapped kctl.
This patch fixes the situation again by passing both the mapped slaved
and original slave kctls to the function. Luckily there is a single
caller as of now, so changing the call signature is no big matter.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=197959
Fixes: a91d66129fb9 ("ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <syzkaller@googlegroups.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Henrik Eriksson <henrik.eriksson@axis.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The amount of the changes isn't as quite small as wished, nevertheless
they are straight fixes that deserve merging to 4.14 final.
Most of fixes are about ALSA core bugs spotted by fuzzer: a follow-up
fix for the previous nested rwsem patch, a fix to avoid the resource
hogs due to too many concurrent ALSA timer invocations, and a fix for
a crash with SYSEX MIDI transfer over OSS sequencer emulation that is
used by none but fuzzer.
The rest are usual HD-audio and USB-audio device-specific quirks,
which are safe to apply.
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Merge tag 'sound-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"The amount of the changes isn't as quite small as wished, nevertheless
they are straight fixes that deserve merging to 4.14 final.
Most of fixes are about ALSA core bugs spotted by fuzzer: a follow-up
fix for the previous nested rwsem patch, a fix to avoid the resource
hogs due to too many concurrent ALSA timer invocations, and a fix for
a crash with SYSEX MIDI transfer over OSS sequencer emulation that is
used by none but fuzzer.
The rest are usual HD-audio and USB-audio device-specific quirks,
which are safe to apply"
* tag 'sound-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - fix headset mic problem for Dell machines with alc274
ALSA: seq: Fix OSS sysex delivery in OSS emulation
ALSA: seq: Avoid invalid lockdep class warning
ALSA: timer: Limit max instances per timer
ALSA: usb-audio: support new Amanero Combo384 firmware version
