[PATCH 5.8 026/148] ext4: fix checking of directory entry validity for inline directories

Greg Kroah-Hartman
2020-08-24T09:58:42Z

From: Jan Kara <jack@suse.cz>

commit 7303cb5bfe845f7d43cd9b2dbd37dbb266efda9b upstream.

ext4_search_dir() and ext4_generic_delete_entry() can be called both for
standard director blocks and for inline directories stored inside inode
or inline xattr space. For the second case we didn't call
ext4_check_dir_entry() with proper constraints that could result in
accepting corrupted directory entry as well as false positive filesystem
errors like:

EXT4-fs error (device dm-0): ext4_search_dir:1395: inode #28320400:
block 113246792: comm dockerd: bad entry in directory: directory entry too
close to block end - offset=0, inode=28320403, rec_len=32, name_len=8,
size=4096

Fix the arguments passed to ext4_check_dir_entry().

Fixes: 109ba779d6cc ("ext4: check for directory entries too close to block end")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200731162135.8080-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/namei.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1396,8 +1396,8 @@ int ext4_search_dir(struct buffer_head *
ext4_match(dir, fname, de)) {
/* found a match - just to be sure, do
* a full check */
- if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
- bh->b_size, offset))
+ if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
+ buf_size, offset))
return -1;
*res_dir = de;
return 1;
@@ -2472,7 +2472,7 @@ int ext4_generic_delete_entry(handle_t *
de = (struct ext4_dir_entry_2 *)entry_buf;
while (i < buf_size - csum_size) {
if (ext4_check_dir_entry(dir, NULL, de, bh,
- bh->b_data, bh->b_size, i))
+ entry_buf, buf_size, i))
return -EFSCORRUPTED;
if (de == de_del) {
if (pde)