After the call to hfs_bnode_read on line 356 of fs/hfs/super.c, the struct hfs_cat_rec, which is supposed to be for the root dir, has type HFS_CDR_FIL. Only the first 70 bytes of that struct are then initialized, because the entrylength passed into hfs_bnode_read is 70, corresponding to the size of struct hfs_cat_dir. This causes uninitialized values to be used later on when the hfs_cat_rec union is treated as a hfs_cat_file. Add a check to make sure the retrieved record has the correct type for the root directory (HFS_CDR_DIR). #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master --- fs/hfs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/hfs/super.c b/fs/hfs/super.c index 3bee9b5dba5e..02d78992eefd 100644 --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -354,6 +354,8 @@ static int hfs_fill_super(struct super_block *sb, struct fs_context *fc) goto bail_hfs_find; } hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength); + if (rec.type != HFS_CDR_DIR) + res = -EIO; } if (res) goto bail_hfs_find; -- 2.43.0
