From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758305Ab2HQPjH (ORCPT ); Fri, 17 Aug 2012 11:39:07 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:45079 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758274Ab2HQPjD (ORCPT ); Fri, 17 Aug 2012 11:39:03 -0400 Date: Fri, 17 Aug 2012 12:38:55 -0300 From: Herton Ronaldo Krzesinski To: Paul Gortmaker Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Carlos Maiolino , Alex Elder , Jan Kara , Ben Myers , Dave Chinner Subject: Re: [v2.6.34-stable 013/165] xfs: Fix possible memory corruption in xfs_readlink Message-ID: <20120817153855.GC4039@herton-Z68MA-D2H-B3> References: <1345060109-9187-1-git-send-email-paul.gortmaker@windriver.com> <1345060109-9187-14-git-send-email-paul.gortmaker@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1345060109-9187-14-git-send-email-paul.gortmaker@windriver.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 15, 2012 at 03:45:57PM -0400, Paul Gortmaker wrote: > From: Carlos Maiolino > > ------------------- > This is a commit scheduled for the next v2.6.34 longterm release. > http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git > If you see a problem with using this for longterm, please comment. > ------------------- > > commit b52a360b2aa1c59ba9970fb0f52bbb093fcc7a24 upstream. > > Fixes a possible memory corruption when the link is larger than > MAXPATHLEN and XFS_DEBUG is not enabled. This also remove the > S_ISLNK assert, since the inode mode is checked previously in > xfs_readlink_by_handle() and via VFS. > > Updated to address concerns raised by Ben Hutchings about the loose > attention paid to 32- vs 64-bit values, and the lack of handling a > potentially negative pathlen value: > - Changed type of "pathlen" to be xfs_fsize_t, to match that of > ip->i_d.di_size > - Added checking for a negative pathlen to the too-long pathlen > test, and generalized the message that gets reported in that case > to reflect the change > As a result, if a negative pathlen were encountered, this function > would return EFSCORRUPTED (and would fail an assertion for a debug > build)--just as would a too-long pathlen. > > Signed-off-by: Alex Elder > Signed-off-by: Carlos Maiolino > Reviewed-by: Christoph Hellwig > [PG: no xfs_alert in 2.6.34; use xfs_fs_cmn_err(CE_ALERT, ...) instead] > Signed-off-by: Paul Gortmaker [...] commit 9b025eb3a89e041bab6698e3858706be2385d692 ("xfs: Fix missing xfs_iunlock() on error recovery path in xfs_readlink()") addresses a regression with this change, something to consider for inclusion too. -- []'s Herton