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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
rawmidi devices expose the card number via IOCTLs, which allows to
find the corresponding device in sysfs.
The sequencer provides no identifing data. Chromium works around this
issue by scanning rawmidi as well as sequencer devices and matching
them by using assumtions, how the kernel register sequencer devices.
This changes adds support for exposing the card number for kernel clients
as well as the PID for user client.
The minor of the API version is changed to distinguish between the zero
initialised reserved field and card number 0.
[minor coding style fixes by tiwai]
Signed-off-by: Martin Koegler <martin.koegler@chello.at>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The fields of struct snd_seq_client_callback either aren't used or are
always set to the same value, so we can get rid of it altogether.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Modules: ALSA sequencer
None of the fields of struct snd_seq_kernel_client was actually used, so
remove them.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
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!
Takashi Iwai