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authorZheng Liu <wenqing.lz@taobao.com>2013-03-11 04:48:59 +0400
committerTheodore Ts'o <tytso@mit.edu>2013-03-11 04:48:59 +0400
commitbd384364c1185ecb01f3b8242c915ccb5921c60d (patch)
treed6badf52d7d389180b1557fdaac856f1952031ce /fs/ext4/extents_status.c
parent6ca470d7b5e7639b7925b3202e796282703b6d5d (diff)
downloadlinux-bd384364c1185ecb01f3b8242c915ccb5921c60d.tar.xz
ext4: avoid a potential overflow in ext4_es_can_be_merged()
Check the length of an extent to avoid a potential overflow in ext4_es_can_be_merged(). Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Diffstat (limited to 'fs/ext4/extents_status.c')
-rw-r--r--fs/ext4/extents_status.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 95796a1b7522..37f9a2d8fd04 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -333,17 +333,27 @@ static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
static int ext4_es_can_be_merged(struct extent_status *es1,
struct extent_status *es2)
{
- if (es1->es_lblk + es1->es_len != es2->es_lblk)
+ if (ext4_es_status(es1) != ext4_es_status(es2))
return 0;
- if (ext4_es_status(es1) != ext4_es_status(es2))
+ if (((__u64) es1->es_len) + es2->es_len > 0xFFFFFFFFULL)
return 0;
- if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
- (ext4_es_pblock(es1) + es1->es_len != ext4_es_pblock(es2)))
+ if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk)
return 0;
- return 1;
+ if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
+ (ext4_es_pblock(es1) + es1->es_len == ext4_es_pblock(es2)))
+ return 1;
+
+ if (ext4_es_is_hole(es1))
+ return 1;
+
+ /* we need to check delayed extent is without unwritten status */
+ if (ext4_es_is_delayed(es1) && !ext4_es_is_unwritten(es1))
+ return 1;
+
+ return 0;
}
static struct extent_status *