From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Fabian Yamaguchi" , "Dan Carpenter" , "Nico Golde" , "Ben Myers" , "Dave Chinner" Date: Sun, 29 Dec 2013 03:08:44 +0100 Message-ID: Subject: [PATCH 3.2 179/185] xfs: underflow bug in xfs_attrlist_by_handle() In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.54-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter commit 31978b5cc66b8ba8a7e8eef60b12395d41b7b890 upstream. If we allocate less than sizeof(struct attrlist) then we end up corrupting memory or doing a ZERO_PTR_SIZE dereference. This can only be triggered with CAP_SYS_ADMIN. Reported-by: Nico Golde Reported-by: Fabian Yamaguchi Signed-off-by: Dan Carpenter Reviewed-by: Dave Chinner Signed-off-by: Ben Myers (cherry picked from commit 071c529eb672648ee8ca3f90944bcbcc730b4c06) Signed-off-by: Ben Hutchings --- fs/xfs/xfs_ioctl.c | 3 ++- fs/xfs/xfs_ioctl32.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -404,7 +404,8 @@ xfs_attrlist_by_handle( return -XFS_ERROR(EPERM); if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t))) return -XFS_ERROR(EFAULT); - if (al_hreq.buflen > XATTR_LIST_MAX) + if (al_hreq.buflen < sizeof(struct attrlist) || + al_hreq.buflen > XATTR_LIST_MAX) return -XFS_ERROR(EINVAL); /* --- a/fs/xfs/xfs_ioctl32.c +++ b/fs/xfs/xfs_ioctl32.c @@ -361,7 +361,8 @@ xfs_compat_attrlist_by_handle( if (copy_from_user(&al_hreq, arg, sizeof(compat_xfs_fsop_attrlist_handlereq_t))) return -XFS_ERROR(EFAULT); - if (al_hreq.buflen > XATTR_LIST_MAX) + if (al_hreq.buflen < sizeof(struct attrlist) || + al_hreq.buflen > XATTR_LIST_MAX) return -XFS_ERROR(EINVAL); /*