sound/oss/opl3: validate voice and channel indexes

sound/oss/opl3: validate voice and channel indexes

commit 4d00135a680727f6c3be78f8befaac009030e4df upstream.

User-controllable indexes for voice and channel values may cause reading
and writing beyond the bounds of their respective arrays, leading to
potentially exploitable memory corruption.  Validate these indexes.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>