From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754665AbdJINNd (ORCPT ); Mon, 9 Oct 2017 09:13:33 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42021 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754279AbdJIMpA (ORCPT ); Mon, 9 Oct 2017 08:45:00 -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, "=?UTF-8?q?Ernesto=20A=2E=20Fern=C3=A1ndez?=" , "Dave Kleikamp" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 125/192] jfs: preserve i_mode if __jfs_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 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ernesto A. Fernández commit f070e5ac9bc7de71c34402048ce5526dccbd347c upstream. When changing a file's acl mask, __jfs_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. Signed-off-by: Ernesto A. Fernández Signed-off-by: Dave Kleikamp [bwh: Backported to 3.16: keep using CURRENT_TIME] Signed-off-by: Ben Hutchings --- fs/jfs/acl.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/fs/jfs/acl.c +++ b/fs/jfs/acl.c @@ -114,19 +114,26 @@ int jfs_set_acl(struct inode *inode, str { int rc; tid_t tid; + int update_mode = 0; + umode_t mode = inode->i_mode; tid = txBegin(inode->i_sb, 0); mutex_lock(&JFS_IP(inode)->commit_mutex); if (type == ACL_TYPE_ACCESS && acl) { - rc = posix_acl_update_mode(inode, &inode->i_mode, &acl); + rc = posix_acl_update_mode(inode, &mode, &acl); if (rc) goto end_tx; - inode->i_ctime = CURRENT_TIME; - mark_inode_dirty(inode); + update_mode = 1; } rc = __jfs_set_acl(tid, inode, type, acl); - if (!rc) + if (!rc) { + if (update_mode) { + inode->i_mode = mode; + inode->i_ctime = CURRENT_TIME; + mark_inode_dirty(inode); + } rc = txCommit(tid, 1, &inode, 0); + } end_tx: txEnd(tid); mutex_unlock(&JFS_IP(inode)->commit_mutex);