ALSA: seq: timer: Use guard() for locking

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-17-tiwai@suse.de

ALSA: seq: Fix race of snd_seq_timer_open()

The timer instance per queue is exclusive, and snd_seq_timer_open()
should have managed the concurrent accesses. It looks as if it's
checking the already existing timer instance at the beginning, but
it's not right, because there is no protection, hence any later
concurrent call of snd_seq_timer_open() may override the timer
instance easily. This may result in UAF, as the leftover timer
instance can keep running while the queue itself gets closed, as
spotted by syzkaller recently.

For avoiding the race, add a proper check at the assignment of
tmr->timeri again, and return -EBUSY if it's been already registered.

Reported-by: syzbot+ddc1260a83ed1cbf6fb5@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/000000000000dce34f05c42f110c@google.com
Link: https://lore.kernel.org/r/20210610152059.24633-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq: Fix concurrent access to queue current tick/time

snd_seq_check_queue() passes the current tick and time of the given
queue as a pointer to snd_seq_prioq_cell_out(), but those might be
updated concurrently by the seq timer update.

Fix it by retrieving the current tick and time via the proper helper
functions at first, and pass those values to snd_seq_prioq_cell_out()
later in the loops.

snd_seq_timer_get_cur_time() takes a new argument and adjusts with the
current system time only when it's requested so; this update isn't
needed for snd_seq_check_queue(), as it's called either from the
interrupt handler or right after queuing.

Also, snd_seq_timer_get_cur_tick() is changed to read the value in the
spinlock for the concurrency, too.

Reported-by: syzbot+fd5e0eaa1a32999173b2@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20200214111316.26939-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq: Fix racy access for queue timer in proc read

snd_seq_info_timer_read() reads the information of the timer assigned
for each queue, but it's done in a racy way which may lead to UAF as
spotted by syzkaller.

This patch applies the missing q->timer_mutex lock while accessing the
timer object as well as a slight code change to adapt the standard
coding style.

Reported-by: syzbot+2b2ef983f973e5c40943@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200115203733.26530-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: timer: Fix possible race at assigning a timer instance

When a new timer instance is created and assigned to the active link
in snd_timer_open(), the caller still doesn't (can't) set its callback
and callback data. In both the user-timer and the sequencer-timer
code, they do manually set up the callbacks after calling
snd_timer_open(). This has a potential risk of race when the timer
instance is added to the already running timer target, as the callback
might get triggered during setting up the callback itself.

This patch tries to address it by changing the API usage slightly:

- An empty timer instance is created at first via the new function
snd_timer_instance_new(). This object isn't linked to the timer
list yet.
- The caller sets up the callbacks and others stuff for the new timer
instance.
- The caller invokes snd_timer_open() with this instance, so that it's
linked to the target timer.

For closing, do similarly:

- Call snd_timer_close(). This unlinks the timer instance from the
timer list.
- Free the timer instance via snd_timer_instance_free() after that.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20191107192008.32331-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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

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 <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ALSA: seq: Avoid open-code for getting timer resolution

Instead of open-coding for getting the timer resolution, use the
standard snd_timer_resolution() helper.

The original code falls back to the callback function when the
resolution is zero, but it must be always so when the callback
function is defined. So this should be no functional change.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

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

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 <tiwai@suse.de>

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

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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq: Fix time account regression

The recent rewrite of the sequencer time accounting using timespec64
in the commit [3915bf294652: ALSA: seq_timer: use monotonic times
internally] introduced a bad regression. Namely, the time reported
back doesn't increase but goes back and forth.

The culprit was obvious: the delta is stored to the result (cur_time =
delta), instead of adding the delta (cur_time += delta)!

Let's fix it.

Fixes: 3915bf294652 ('ALSA: seq_timer: use monotonic times internally')
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=177571
Reported-by: Yves Guillemot <yc.guillemot@wanadoo.fr>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq_timer: use monotonic times internally

The sequencer client manager reports timestamps in units of unsigned
32-bit seconds/nanoseconds, but that does not suffer from the y2038
overflow because it stores only the delta since the 'last_update'
time was recorded.

However, the use of the do_gettimeofday() function is problematic
and we have to replace it to avoid the overflow on on 32-bit
architectures.

This uses 'struct timespec64' to record 'last_update', and changes
the code to use monotonic timestamps that do not suffer from leap
seconds and settimeofday updates.

As a side-effect, the code can now use the timespec64_sub() helper
and become more readable and also avoid a multiplication to convert
from microseconds to nanoseconds.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq: Fix yet another races among ALSA timer accesses

ALSA sequencer may open/close and control ALSA timer instance
dynamically either via sequencer events or direct ioctls. These are
done mostly asynchronously, and it may call still some timer action
like snd_timer_start() while another is calling snd_timer_close().
Since the instance gets removed by snd_timer_close(), it may lead to
a use-after-free.

This patch tries to address such a race by protecting each
snd_timer_*() call via the existing spinlock and also by avoiding the
access to timer during close call.

BugLink: http://lkml.kernel.org/r/CACT4Y+Z6RzW5MBr-HUdV-8zwg71WQfKTdPpYGvOeS7v4cyurNQ@mail.gmail.com
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS

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 <yang.jie@intel.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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

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 <tiwai@suse.de>

ALSA: seq: Use standard printk helpers

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

Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: seq: Fix missing error handling in snd_seq_timer_open()

snd_seq_timer_open() didn't catch the whole error path but let through
if the timer id is a slave. This may lead to Oops by accessing the
uninitialized pointer.

BUG: unable to handle kernel NULL pointer dereference at 00000000000002ae
IP: [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130
PGD 785cd067 PUD 76964067 PMD 0
Oops: 0002 [#4] SMP
CPU 0
Pid: 4288, comm: trinity-child7 Tainted: G D W 3.9.0-rc1+ #100 Bochs Bochs
RIP: 0010:[<ffffffff819b3477>] [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130
RSP: 0018:ffff88006ece7d38 EFLAGS: 00010246
RAX: 0000000000000286 RBX: ffff88007851b400 RCX: 0000000000000000
RDX: 000000000000ffff RSI: ffff88006ece7d58 RDI: ffff88006ece7d38
RBP: ffff88006ece7d98 R08: 000000000000000a R09: 000000000000fffe
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8800792c5400 R14: 0000000000e8f000 R15: 0000000000000007
FS: 00007f7aaa650700(0000) GS:ffff88007f800000(0000) GS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000002ae CR3: 000000006efec000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process trinity-child7 (pid: 4288, threadinfo ffff88006ece6000, task ffff880076a8a290)
Stack:
0000000000000286 ffffffff828f2be0 ffff88006ece7d58 ffffffff810f354d
65636e6575716573 2065756575712072 ffff8800792c0030 0000000000000000
ffff88006ece7d98 ffff8800792c5400 ffff88007851b400 ffff8800792c5520
Call Trace:
[<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff819b17e9>] snd_seq_queue_timer_open+0x29/0x70
[<ffffffff819ae01a>] snd_seq_ioctl_set_queue_timer+0xda/0x120
[<ffffffff819acb9b>] snd_seq_do_ioctl+0x9b/0xd0
[<ffffffff819acbe0>] snd_seq_ioctl+0x10/0x20
[<ffffffff811b9542>] do_vfs_ioctl+0x522/0x570
[<ffffffff8130a4b3>] ? file_has_perm+0x83/0xa0
[<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff811b95ed>] sys_ioctl+0x5d/0xa0
[<ffffffff813663fe>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81faed69>] system_call_fastpath+0x16/0x1b

Reported-and-tested-by: Tommi Rantala <tt.rantala@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound: seq_timer: simplify snd_seq_timer_set_tick_resolution() parameters

As snd_seq_timer_set_tick_resolution() is always called with the same
three fields of struct snd_seq_timer, it suffices to give that as the
only parameter.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

ALSA: Kill snd_assert() in sound/core/*

Kill snd_assert() in sound/core/*, either removed or replaced with
if () with snd_BUG_ON().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

[ALSA] Remove sound/driver.h

This header file exists only for some hacks to adapt alsa-driver
tree. It's useless for building in the kernel. Let's move a few
lines in it to sound/core.h and remove it.
With this patch, sound/driver.h isn't removed but has just a single
compile warning to include it. This should be really killed in
future.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

[ALSA] sound/core/seq: move declarations of globally visible variables to proper headers

sound/core/seq: move declarations of globally visible variables to proper headers

Signed-off-by: Marcin Ślusarz <marcin.slusarz@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

[ALSA] Changed Jaroslav Kysela's e-mail from perex@suse.cz to perex@perex.cz


Signed-off-by: Jaroslav Kysela <perex@perex.cz>

[ALSA] Optimize for config without PROC_FS (seq and oss parts)

Modules: ALSA<-OSS emulation,ALSA sequencer,ALSA<-OSS sequencer

Optimize the code when compiled without CONFIG_PROC_FS (in seq and oss
emulation parts).

Signed-off-by: Takashi Iwai <tiwai@suse.de>

[ALSA] Remove xxx_t typedefs: Sequencer

Modules: ALSA sequencer

Remove xxx_t typedefs from the core sequencer codes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

[ALSA] seq-timer: restrict timer frequencies

Modules: ALSA sequencer

When no default timer frequency has been set, initialize_timer() just
uses the maximum frequency supported by the timer, which is ridiculously
high on 96 kHz timers.

This patch introduces a default frequency of 1000 Hz for this case, and
makes sure that a frequency set by the user isn't too high.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

[ALSA] sequencer: remove superfluous function parameter

Modules: ALSA sequencer

Remove the last parameter of snd_seq_timer_set_tick_resolution()
because it is always one.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

[ALSA] Replace with kzalloc() - seq stuff

ALSA sequencer,Instrument layer,ALSA<-OSS sequencer
Replace kcalloc(1,..) with kzalloc().

Signed-off-by: Takashi Iwai <tiwai@suse.de>

[ALSA] sound/core/: possible cleanups

PCM Midlevel,ALSA Core,Timer Midlevel,ALSA sequencer,Virtual Midi
This patch contains the following possible cleanups:
- make needlessly global code static
- #if 0 the following unused global functions
- remove the following unneeded EXPORT_SYMBOL's

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!