From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754679AbdJIODT (ORCPT ); Mon, 9 Oct 2017 10:03:19 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41811 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754068AbdJIMo4 (ORCPT ); Mon, 9 Oct 2017 08:44:56 -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, "Aurelien Aptel" , "Sachin Prabhu" , "Steve French" Date: Mon, 09 Oct 2017 13:44:25 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 184/192] Compare prepaths when comparing superblocks 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: Sachin Prabhu commit c1d8b24d18192764fe82067ec6aa8d4c3bf094e0 upstream. The patch fs/cifs: make share unaccessible at root level mountable makes use of prepaths when any component of the underlying path is inaccessible. When mounting 2 separate shares having different prepaths but are other wise similar in other respects, we end up sharing superblocks when we shouldn't be doing so. Signed-off-by: Sachin Prabhu Tested-by: Aurelien Aptel Signed-off-by: Steve French Signed-off-by: Ben Hutchings --- fs/cifs/connect.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -2751,6 +2751,24 @@ compare_mount_options(struct super_block return 1; } +static int +match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data) +{ + struct cifs_sb_info *old = CIFS_SB(sb); + struct cifs_sb_info *new = mnt_data->cifs_sb; + + if (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) { + if (!(new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)) + return 0; + /* The prepath should be null terminated strings */ + if (strcmp(new->prepath, old->prepath)) + return 0; + + return 1; + } + return 0; +} + int cifs_match_super(struct super_block *sb, void *data) { @@ -2778,7 +2796,8 @@ cifs_match_super(struct super_block *sb, if (!match_server(tcp_srv, volume_info) || !match_session(ses, volume_info) || - !match_tcon(tcon, volume_info->UNC)) { + !match_tcon(tcon, volume_info->UNC) || + !match_prepath(sb, mnt_data)) { rc = 0; goto out; }