cdrom: fix bad cgc.buflen assignment (CVE-2006-2935)

The code really means to mask off the high bits, not assign 0xff.

Reported by Marcus Meissner <meissner@suse.de>.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

drivers/cdrom/cdrom.c

@@ -1837,7 +1837,7 @@ static int dvd_read_bca(struct cdrom_device_info *cdi, dvd_struct *s)
 	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
 	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;
 	cgc.cmd[7] = s->type;
-	cgc.cmd[9] = cgc.buflen = 0xff;
+	cgc.cmd[9] = cgc.buflen & 0xff;
 
 	if ((ret = cdo->generic_packet(cdi, &cgc)))
 		return ret;