ALSA: control: Handle numid overflow
authorLars-Peter Clausen <lars@metafoo.de>
Wed, 18 Jun 2014 11:32:34 +0000 (13:32 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 26 Jun 2014 19:12:43 +0000 (15:12 -0400)
commit0255758b24b94398786df97623849a81a7d5b2ef
tree026280077159d54ee1aac306ca6526270d76b1b0
parent9abd94862196476a80dbfc07d3f8a01418fa36d8
ALSA: control: Handle numid overflow

commit ac902c112d90a89e59916f751c2745f4dbdbb4bd upstream.

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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/core/control.c