From: Zhang Yi yi.zhang@huawei.com
hulk inclusion category: bugfix bugzilla: 109205 CVE: NA ---------------------------
After commit 5946d089379a ("ext4: check for overlapping extents in ext4_valid_extent_entries()"), we can check out the overlapping extent entry in leaf extent blocks. But the out-of-order extent entry in index extent blocks could also trigger bad things if the filesystem is inconsistent. So this patch add a check to figure out the out-of-order index extents and return error.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Theodore Ts'o tytso@mit.edu Link: https://lore.kernel.org/r/20210908120850.4012324-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Reviewed-by: Yang Erkun yangerkun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/ext4/extents.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index f4a3b814fc66e..bb7024e0d5509 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -405,6 +405,9 @@ static int ext4_valid_extent_entries(struct inode *inode, ext4_fsblk_t *pblk, int depth) { unsigned short entries; + ext4_lblk_t lblock = 0; + ext4_lblk_t prev = 0; + if (eh->eh_entries == 0) return 1;
@@ -413,31 +416,35 @@ static int ext4_valid_extent_entries(struct inode *inode, if (depth == 0) { /* leaf entries */ struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); - 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) { *pblk = ext4_ext_pblock(ext); return 0; } + prev = lblock + ext4_ext_get_actual_len(ext) - 1; ext++; entries--; - prev = lblock + len - 1; } } else { struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); while (entries) { if (!ext4_valid_extent_idx(inode, ext_idx)) return 0; + + /* Check for overlapping index extents */ + lblock = le32_to_cpu(ext_idx->ei_block); + if ((lblock <= prev) && prev) { + *pblk = ext4_idx_pblock(ext_idx); + return 0; + } ext_idx++; entries--; + prev = lblock; } } return 1;