From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756521Ab1BJOZM (ORCPT ); Thu, 10 Feb 2011 09:25:12 -0500 Received: from mx1.vsecurity.com ([209.67.252.12]:63274 "EHLO mx1.vsecurity.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756507Ab1BJOZK (ORCPT ); Thu, 10 Feb 2011 09:25:10 -0500 Subject: [PATCH] xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1 From: Dan Rosenberg To: aelder@sgi.com, xfs-masters@oss.sgi.com, xfs@oss.sgi.com Cc: linux-kernel@vger.kernel.org, stable@kernel.org, security@kernel.org Content-Type: text/plain; charset="UTF-8" Date: Thu, 10 Feb 2011 09:25:04 -0500 Message-ID: <1297347904.13370.9.camel@dan> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to xfs_fs_geometry() with a version number of 3. This code path does not fill in the logsunit member of the passed xfs_fsop_geom_t, leading to the leaking of four bytes of uninitialized stack data to potentially unprivileged callers. Since all other members are filled in all code paths and there are no padding bytes in this structure, it's safe to avoid an expensive memset() in favor of just clearing this one field. Signed-off-by: Dan Rosenberg --- fs/xfs/xfs_fsops.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index cec89dd..17c4785 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -102,6 +102,7 @@ xfs_fs_geometry( mp->m_sb.sb_logsectsize : BBSIZE; geo->rtsectsize = mp->m_sb.sb_blocksize; geo->dirblocksize = mp->m_dirblksize; + geo->logsunit = 0; } if (new_version >= 4) { geo->flags |= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p1AEMZoZ137642 for ; Thu, 10 Feb 2011 08:22:35 -0600 Received: from mx1.vsecurity.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id AA80E96D790 for ; Thu, 10 Feb 2011 06:25:09 -0800 (PST) Received: from mx1.vsecurity.com (mx1.vsecurity.com [209.67.252.12]) by cuda.sgi.com with ESMTP id 5DhbBGLYsM65oYmX for ; Thu, 10 Feb 2011 06:25:09 -0800 (PST) Subject: [PATCH] xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1 From: Dan Rosenberg Date: Thu, 10 Feb 2011 09:25:04 -0500 Message-ID: <1297347904.13370.9.camel@dan> Mime-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: aelder@sgi.com, xfs-masters@oss.sgi.com, xfs@oss.sgi.com Cc: security@kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to xfs_fs_geometry() with a version number of 3. This code path does not fill in the logsunit member of the passed xfs_fsop_geom_t, leading to the leaking of four bytes of uninitialized stack data to potentially unprivileged callers. Since all other members are filled in all code paths and there are no padding bytes in this structure, it's safe to avoid an expensive memset() in favor of just clearing this one field. Signed-off-by: Dan Rosenberg --- fs/xfs/xfs_fsops.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index cec89dd..17c4785 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -102,6 +102,7 @@ xfs_fs_geometry( mp->m_sb.sb_logsectsize : BBSIZE; geo->rtsectsize = mp->m_sb.sb_blocksize; geo->dirblocksize = mp->m_dirblksize; + geo->logsunit = 0; } if (new_version >= 4) { geo->flags |= _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs