kernel.git/sound/core/seq/seq_clientmgr.c, branch linux-5.0.y

ALSA: seq: Fix OOB-reads from strlcpy

2019-04-17T06:39:47Z

commit 212ac181c158c09038c474ba68068be49caecebb upstream. When ioctl calls are made with non-null-terminated userspace strings, strlcpy causes an OOB-read from within strlen. Fix by changing to use strscpy instead. Signed-off-by: Zubin Mithra Reviewed-by: Guenter Roeck Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57Z

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

ALSA: seq: Use no intrruptible mutex_lock

2018-08-01T20:54:36Z

All usages of mutex in ALSA sequencer core would take too long, hence we don't have to care about the user interruption that makes things complicated. Let's replace them with simpler mutex_lock(). Signed-off-by: Takashi Iwai

ALSA: seq: Fix leftovers at probe error path

2018-08-01T20:54:36Z

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 poll() error return

2018-07-26T06:23:26Z

The sanity checks in ALSA sequencer and OSS sequencer emulation codes return falsely -ENXIO from poll callback. They should be EPOLLERR instead. This was caught thanks to the recent change to the return value. Cc: Signed-off-by: Takashi Iwai

ALSA: seq: Fix UBSAN warning at SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT ioctl

2018-06-25T09:18:04Z

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

ALSA: seq: Clear client entry before deleting else at closing

2018-03-10T16:30:01Z

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: Signed-off-by: Takashi Iwai

ALSA: seq: Remove superfluous snd_seq_queue_client_leave_cells() call

2018-03-08T11:06:07Z

With the previous two fixes for the write / ioctl races: ALSA: seq: Don't allow resizing pool in use ALSA: seq: More protection for concurrent write and ioctl races the cells aren't any longer in queues at the point calling snd_seq_pool_done() in snd_seq_ioctl_set_client_pool(). Hence the function call snd_seq_queue_client_leave_cells() can be dropped safely from there. Suggested-by: Nicolai Stange Signed-off-by: Takashi Iwai

ALSA: seq: More protection for concurrent write and ioctl races

2018-03-08T11:05:37Z

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 Reported-by: Nicolai Stange Reviewed-and-tested-by: Nicolai Stange Cc: Signed-off-by: Takashi Iwai

ALSA: seq: Don't allow resizing pool in use

2018-03-08T07:59:26Z

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