ALSA: control: Handle numid overflow
authorLars-Peter Clausen <lars@metafoo.de>
Wed, 18 Jun 2014 11:32:34 +0000 (13:32 +0200)
committerTakashi Iwai <tiwai@suse.de>
Wed, 18 Jun 2014 13:13:23 +0000 (15:13 +0200)
commitac902c112d90a89e59916f751c2745f4dbdbb4bd
treedcf1e049671b65d03cce48a8a9d836c3fa6d14f0
parentfd9f26e4eca5d08a27d12c0933fceef76ed9663d
ALSA: control: Handle numid overflow

Each control gets automatically assigned its numids when the control is created.
The allocation is done by incrementing the numid by the amount of allocated
numids per allocation. This means that excessive creation and destruction of
controls (e.g. via SNDRV_CTL_IOCTL_ELEM_ADD/REMOVE) can cause the id to
eventually overflow. Currently when this happens for the control that caused the
overflow kctl->id.numid + kctl->count will also over flow causing it to be
smaller than kctl->id.numid. Most of the code assumes that this is something
that can not happen, so we need to make sure that it won't happen

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jaroslav Kysela <perex@perex.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/core/control.c