From patchwork Fri Jan 16 17:00:01 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Theodore Ts'o X-Patchwork-Id: 19010 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 87BD3DE207 for ; Sat, 17 Jan 2009 04:00:43 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762920AbZAPRAO (ORCPT ); Fri, 16 Jan 2009 12:00:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761099AbZAPRAM (ORCPT ); Fri, 16 Jan 2009 12:00:12 -0500 Received: from thunk.org ([69.25.196.29]:45260 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935508AbZAPRAE (ORCPT ); Fri, 16 Jan 2009 12:00:04 -0500 Received: from root (helo=closure.thunk.org) by thunker.thunk.org with local-esmtp (Exim 4.50 #1 (Debian)) id 1LNs38-0003ds-5M; Fri, 16 Jan 2009 12:00:02 -0500 Received: from tytso by closure.thunk.org with local (Exim 4.69) (envelope-from ) id 1LNs37-0003fT-Ar; Fri, 16 Jan 2009 12:00:01 -0500 From: Theodore Ts'o To: Ext4 Developers List Cc: Theodore Ts'o , stable@kernel.org Subject: [PATCH, RFC 2/2] ext3: Add sanity check to make_indexed_dir Date: Fri, 16 Jan 2009 12:00:01 -0500 Message-Id: <1232125201-14075-2-git-send-email-tytso@mit.edu> X-Mailer: git-send-email 1.6.0.4.8.g36f27.dirty In-Reply-To: <1232125201-14075-1-git-send-email-tytso@mit.edu> References: <1232125201-14075-1-git-send-email-tytso@mit.edu> X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@mit.edu X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Make sure the rec_len field in the '..' entry is sane, lest we overrun the directory block and cause a kernel oops on a purposefully corrupted filesystem. This fixes a bug related to a bug originally reported by Sami Liedes for ext4 at: http://bugzilla.kernel.org/show_bug.cgi?id=12430 Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org --- fs/ext3/namei.c | 20 ++++++++++++++------ 1 files changed, 14 insertions(+), 6 deletions(-) diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c index 69a3d19..4db4ffa 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -1358,7 +1358,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, struct fake_dirent *fde; blocksize = dir->i_sb->s_blocksize; - dxtrace(printk("Creating index\n")); + dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino)); retval = ext3_journal_get_write_access(handle, bh); if (retval) { ext3_std_error(dir->i_sb, retval); @@ -1367,6 +1367,19 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, } root = (struct dx_root *) bh->b_data; + /* The 0th block becomes the root, move the dirents out */ + fde = &root->dotdot; + de = (struct ext3_dir_entry_2 *)((char *)fde + + ext3_rec_len_from_disk(fde->rec_len)); + if ((char *) de >= (((char *) root) + blocksize)) { + ext3_error(dir->i_sb, __func__, + "invalid rec_len for '..' in inode %lu", + dir->i_ino); + brelse(bh); + return -EIO; + } + len = ((char *) root) + blocksize - (char *) de; + bh2 = ext3_append (handle, dir, &block, &retval); if (!(bh2)) { brelse(bh); @@ -1375,11 +1388,6 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, EXT3_I(dir)->i_flags |= EXT3_INDEX_FL; data1 = bh2->b_data; - /* The 0th block becomes the root, move the dirents out */ - fde = &root->dotdot; - de = (struct ext3_dir_entry_2 *)((char *)fde + - ext3_rec_len_from_disk(fde->rec_len)); - len = ((char *) root) + blocksize - (char *) de; memcpy (data1, de, len); de = (struct ext3_dir_entry_2 *) data1; top = data1 + len;