[PATCH] ext4: Fix check for block being out of directory size

Jan Kara
2022-08-22T11:49:14Z

The check in __ext4_read_dirblock() for block being outside of directory
size was wrong because it compared block number against directory size
in bytes. Fix it.

Fixes: 65f8ea4cd57d ("ext4: check if directory block is within i_size")
CVE: CVE-2022-1184
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ext4/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3a31b662f661..bc2e0612ec32 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -126,7 +126,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
struct ext4_dir_entry *dirent;
int is_dx_block = 0;

- if (block >= inode->i_size) {
+ if (block >= inode->i_size >> inode->i_blkbits) {
ext4_error_inode(inode, func, line, block,
"Attempting to read directory block (%u) that is past i_size (%llu)",
block, inode->i_size);
--
2.35.3