Commit bb3d132a authored May 28, 2012 by Dan Carpenter Committed by Theodore Ts'o May 28, 2012

ext4: fix potential NULL dereference in ext4_free_inodes_counts()



The ext4_get_group_desc() function returns NULL on error, and
ext4_free_inodes_count() function dereferences it without checking.
There is a check on the next line, but it's too late.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

parent e93376c2

fs/ext4/ialloc.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -508,12 +508,14 @@ static int find_group_orlov(struct super_block sb, struct inode parent,
		for (i = 0; i < ngroups; i++) {
		grp = (parent_group + i) % ngroups;
		desc = ext4_get_group_desc(sb, grp, NULL);
		if (desc) {
		grp_free = ext4_free_inodes_count(sb, desc);
		if (desc && grp_free && grp_free >= avefreei) {
		if (grp_free && grp_free >= avefreei) {
		*group = grp;
		return 0;
		}
		}
		}

		if (avefreei) {
		/*