linux-kernel - [PATCH 3.2 01/34] ext4: FIBMAP ioctl causes BUG_ON due to handle EXT_MAX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <lsq.1400244440.666503446@decadent.org.uk>
Date:	Fri, 16 May 2014 13:47:20 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Kazuya Mio" <k-mio@...jp.nec.com>,
	"Theodore Ts'o" <tytso@....edu>
Subject: [PATCH 3.2 01/34] ext4: FIBMAP ioctl causes BUG_ON due to handle
 EXT_MAX_BLOCKS

3.2.59-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Kazuya Mio <k-mio@...jp.nec.com>

commit 4adb6ab3e0fa71363a5ef229544b2d17de6600d7 upstream.

When we try to get 2^32-1 block of the file which has the extent
(ee_block=2^32-2, ee_len=1) with FIBMAP ioctl, it causes BUG_ON
in ext4_ext_put_gap_in_cache().

To avoid the problem, ext4_map_blocks() needs to check the file logical block
number. ext4_ext_put_gap_in_cache() called via ext4_map_blocks() cannot
handle 2^32-1 because the maximum file logical block number is 2^32-2.

Note that ext4_ind_map_blocks() returns -EIO when the block number is invalid.
So ext4_map_blocks() should also return the same errno.

Signed-off-by: Kazuya Mio <k-mio@...jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -481,6 +481,11 @@ int ext4_map_blocks(handle_t *handle, st
 	ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
 		  "logical block %lu\n", inode->i_ino, flags, map->m_len,
 		  (unsigned long) map->m_lblk);
+
+	/* We can handle the block number less than EXT_MAX_BLOCKS */
+	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
+		return -EIO;
+
 	/*
 	 * Try to see if we can get the block without requesting a new
 	 * file system block.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/