From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754685AbdJINBm (ORCPT ); Mon, 9 Oct 2017 09:01:42 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41889 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754373AbdJIMpQ (ORCPT ); Mon, 9 Oct 2017 08:45:16 -0400 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, "Jan Kara" , "Ernesto A. =?UTF-8?Q?Fern=C3=A1ndez?=" Date: Mon, 09 Oct 2017 13:30:34 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 51/74] ext3: preserve i_mode if ext2_set_acl() fails In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.94-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings Based on Ernesto A. Fernández's fix for ext2 (commit fe26569eb919), from which the following description is taken: > When changing a file's acl mask, ext2_set_acl() will first set the group > bits of i_mode to the value of the mask, and only then set the actual > extended attribute representing the new acl. > > If the second part fails (due to lack of space, for example) and the file > had no acl attribute to begin with, the system will from now on assume > that the mask permission bits are actual group permission bits, potentially > granting access to the wrong users. > > Prevent this by only changing the inode mode after the acl has been set. Cc: Ernesto A. Fernández Cc: Jan Kara Signed-off-by: Ben Hutchings --- fs/ext3/acl.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/ext3/acl.c +++ b/fs/ext3/acl.c @@ -231,15 +231,22 @@ ext3_set_acl(handle_t *handle, struct in struct posix_acl *acl) { int error; + int update_mode = 0; + umode_t mode = inode->i_mode; if (type == ACL_TYPE_ACCESS && acl) { - error = posix_acl_update_mode(inode, &inode->i_mode, &acl); + error = posix_acl_update_mode(inode, &mode, &acl); if (error) return error; + update_mode = 1; + } + error = __ext3_set_acl(handle, inode, type, acl); + if (!error && update_mode) { + inode->i_mode = mode; inode->i_ctime = CURRENT_TIME_SEC; ext3_mark_inode_dirty(handle, inode); } - return __ext3_set_acl(handle, inode, type, acl); + return error; } /*