commit bf33f87d upstream.

The user can control the size of the next command passed along, but the
value passed to the ioctl isn't checked against the usable max command
size.
Signed-off-by: Peter Chang <dpf@google.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>