iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ext4: limit entries returned when counting fsmap records

Browse Source 
[ Upstream commit af8c53c8bc087459b1aadd4c94805d8272358d79 ]

If userspace asked fsmap to try to count the number of entries, we cannot
return more than UINT_MAX entries because fmh_entries is u32.
Therefore, stop counting if we hit this limit or else we will waste time
to return truncated results.

Fixes: 0c9ec4beecac ("ext4: support GETFSMAP ioctls")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20201001222148.GA49520@magnolia
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Darrick J. Wong 2020-10-01 15:21:48 -07:00 committed by Greg Kroah-Hartman
parent 9c27185e12
commit f2f616f3e3
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/ext4/fsmap.c
View File

@ -108,6 +108,9 @@ static int ext4_getfsmap_helper(struct super_block *sb,
/* Are we just counting mappings? */
if (info->gfi_head->fmh_count == 0) {
if (info->gfi_head->fmh_entries == UINT_MAX)
return EXT4_QUERY_RANGE_ABORT;
if (rec_fsblk > info->gfi_next_fsblk)
info->gfi_head->fmh_entries++;