aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorEryu Guan <guaneryu@gmail.com>2013-12-03 21:22:21 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-08 09:42:11 -0800
commita1192c0e5d037def6763f3873d3340615c241fe7 (patch)
tree6ea92f29388452b148f2a02c150f3b834c9dcabd
parent510e024d1e74bb0f574d14ee19436a56ed4fc476 (diff)
downloadlinux-linaro-stable-a1192c0e5d037def6763f3873d3340615c241fe7.tar.gz
ext4: check for overlapping extents in ext4_valid_extent_entries()
commit 5946d089379a35dda0e531710b48fca05446a196 upstream. A corrupted ext4 may have out of order leaf extents, i.e. extent: lblk 0--1023, len 1024, pblk 9217, flags: LEAF UNINIT extent: lblk 1000--2047, len 1024, pblk 10241, flags: LEAF UNINIT ^^^^ overlap with previous extent Reading such extent could hit BUG_ON() in ext4_es_cache_extent(). BUG_ON(end < lblk); The problem is that __read_extent_tree_block() tries to cache holes as well but assumes 'lblk' is greater than 'prev' and passes underflowed length to ext4_es_cache_extent(). Fix it by checking for overlapping extents in ext4_valid_extent_entries(). I hit this when fuzz testing ext4, and am able to reproduce it by modifying the on-disk extent by hand. Also add the check for (ee_block + len - 1) in ext4_valid_extent() to make sure the value is not overflow. Ran xfstests on patched ext4 and no regression. Cc: Lukáš Czerner <lczerner@redhat.com> Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/extents.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index b9a3726ea048..c883561e9b61 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -317,8 +317,10 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
{
ext4_fsblk_t block = ext4_ext_pblock(ext);
int len = ext4_ext_get_actual_len(ext);
+ ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
+ ext4_lblk_t last = lblock + len - 1;
- if (len == 0)
+ if (lblock > last)
return 0;
return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
}
@@ -344,11 +346,26 @@ static int ext4_valid_extent_entries(struct inode *inode,
if (depth == 0) {
/* leaf entries */
struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
+ struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
+ ext4_fsblk_t pblock = 0;
+ ext4_lblk_t lblock = 0;
+ ext4_lblk_t prev = 0;
+ int len = 0;
while (entries) {
if (!ext4_valid_extent(inode, ext))
return 0;
+
+ /* Check for overlapping extents */
+ lblock = le32_to_cpu(ext->ee_block);
+ len = ext4_ext_get_actual_len(ext);
+ if ((lblock <= prev) && prev) {
+ pblock = ext4_ext_pblock(ext);
+ es->s_last_error_block = cpu_to_le64(pblock);
+ return 0;
+ }
ext++;
entries--;
+ prev = lblock + len - 1;
}
} else {
struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);