On Wed, Nov 27, 2019 at 02:44:15PM -0500, Theodore Y. Ts'o wrote: > On Wed, Nov 27, 2019 at 02:12:58PM +0100, Jan Kara wrote: > > Function ext4_empty_dir() doesn't correctly handle directories with > > holes and crashes on bh->b_data dereference when bh is NULL.... > > Hi Jan, > > Thanks for the patch. > > However, it looks like we're still vulnerable to the first block of > the directory being NULL? > > > @@ -2833,19 +2833,25 @@ bool ext4_empty_dir(struct inode *inode) > > return true; > > > > de = (struct ext4_dir_entry_2 *) bh->b_data; > ^^^^^^^^^^^ Ah, never mind. Since we're calling ext4_read_dirblock() with DIRENT_HTREE, if bh is NULL, it will get caught earlier, and ext4_read_dirblock() will return ERR_PTR(-EFSCORRUPTED). - Ted
