ext3: Fix format string issues

ext3_msg() takes the printk prefix as the second parameter and the
format string as the third parameter. Two callers of ext3_msg omit the
prefix and pass the format string as the second parameter and the first
parameter to the format string as the third parameter. In both cases
this string comes from an arbitrary source. Which means the string may
contain format string characters, which will
lead to undefined and potentially harmful behavior.

The issue was introduced in commit 4cf46b67eb("ext3: Unify log messages
in ext3") and is fixed by this patch.

CC: stable@vger.kernel.org
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext3/super.c

@@ -353,7 +353,7 @@ static struct block_device *ext3_blkdev_get(dev_t dev, struct super_block *sb)
 	return bdev;
 
 fail:
-	ext3_msg(sb, "error: failed to open journal device %s: %ld",
+	ext3_msg(sb, KERN_ERR, "error: failed to open journal device %s: %ld",
 		__bdevname(dev, b), PTR_ERR(bdev));
 
 	return NULL;
@@ -887,7 +887,7 @@ static ext3_fsblk_t get_sb_block(void **data, struct super_block *sb)
 	/*todo: use simple_strtoll with >32bit ext3 */
 	sb_block = simple_strtoul(options, &options, 0);
 	if (*options && *options != ',') {
-		ext3_msg(sb, "error: invalid sb specification: %s",
+		ext3_msg(sb, KERN_ERR, "error: invalid sb specification: %s",
 		       (char *) *data);
 		return 1;
 	}