From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932846Ab0G3SJT (ORCPT ); Fri, 30 Jul 2010 14:09:19 -0400 Received: from kroah.org ([198.145.64.141]:59199 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932772Ab0G3R5i (ORCPT ); Fri, 30 Jul 2010 13:57:38 -0400 X-Mailbox-Line: From gregkh@clark.site Fri Jul 30 10:51:50 2010 Message-Id: <20100730175150.183301109@clark.site> User-Agent: quilt/0.48-11.2 Date: Fri, 30 Jul 2010 10:53:16 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Dan Rosenberg Subject: [179/205] xfs: prevent swapext from operating on write-only files In-Reply-To: <20100730175238.GA3924@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.34-stable review patch. If anyone has any objections, please let us know. ------------------ From: Dan Rosenberg commit 1817176a86352f65210139d4c794ad2d19fc6b63 upstream. This patch prevents user "foo" from using the SWAPEXT ioctl to swap a write-only file owned by user "bar" into a file owned by "foo" and subsequently reading it. It does so by checking that the file descriptors passed to the ioctl are also opened for reading. Signed-off-by: Dan Rosenberg Reviewed-by: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_dfrag.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -69,7 +69,9 @@ xfs_swapext( goto out; } - if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) { + if (!(file->f_mode & FMODE_WRITE) || + !(file->f_mode & FMODE_READ) || + (file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_file; } @@ -81,6 +83,7 @@ xfs_swapext( } if (!(tmp_file->f_mode & FMODE_WRITE) || + !(tmp_file->f_mode & FMODE_READ) || (tmp_file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_tmp_file;