Commit 7303cb5b authored Jul 31, 2020 by Jan Kara Committed by Theodore Ts'o Aug 07, 2020

ext4: fix checking of directory entry validity for inline directories



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: 109ba779 ("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>

parent 377254b2

fs/ext4/namei.c

+3 −3

Original line number	Original line	Diff line number	Diff line
	@@ -1396,8 +1396,8 @@ int ext4_search_dir(struct buffer_head bh, char search_buf, int buf_size,
	ext4_match(dir, fname, de)) {		ext4_match(dir, fname, de)) {
	/* found a match - just to be sure, do		/* found a match - just to be sure, do
	* a full check */		* a full check */
	if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,		if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
	bh->b_size, offset))		buf_size, offset))
	return -1;		return -1;
	*res_dir = de;		*res_dir = de;
	return 1;		return 1;
	@@ -2482,7 +2482,7 @@ int ext4_generic_delete_entry(handle_t *handle,
	de = (struct ext4_dir_entry_2 *)entry_buf;		de = (struct ext4_dir_entry_2 *)entry_buf;
	while (i < buf_size - csum_size) {		while (i < buf_size - csum_size) {
	if (ext4_check_dir_entry(dir, NULL, de, bh,		if (ext4_check_dir_entry(dir, NULL, de, bh,
	bh->b_data, bh->b_size, i))		entry_buf, buf_size, i))
	return -EFSCORRUPTED;		return -EFSCORRUPTED;
	if (de == de_del) {		if (de == de_del) {
	if (pde)		if (pde)