From: Darrick J. Wong darrick.wong@oracle.com
[ 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 --- fs/ext4/fsmap.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/ext4/fsmap.c b/fs/ext4/fsmap.c index 7ec3408985980..1a4d42a1b161d 100644 --- a/fs/ext4/fsmap.c +++ b/fs/ext4/fsmap.c @@ -121,6 +121,9 @@ 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++;