block: do not pass disk names as format strings

block: do not pass disk names as format strings

Disk names may contain arbitrary strings, so they must not be interpreted
as format strings. It seems that only md allows arbitrary strings to be
used for disk names, but this could allow for a local memory corruption
from uid 0 into ring 0.

CVE-2013-2851

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>