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| author | Zheng Liu <wenqing.lz@taobao.com> | 2013-03-10 20:48:59 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-03-10 20:48:59 -0400 |
| commit | bd384364c1185ecb01f3b8242c915ccb5921c60d (patch) | |
| tree | d6badf52d7d389180b1557fdaac856f1952031ce /fs | |
| parent | 6ca470d7b5e7639b7925b3202e796282703b6d5d (diff) | |
| download | lwn-bd384364c1185ecb01f3b8242c915ccb5921c60d.tar.gz lwn-bd384364c1185ecb01f3b8242c915ccb5921c60d.zip | |
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')
| -rw-r--r-- | fs/ext4/extents_status.c | 20 |
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 * |