From patchwork Tue Mar 5 21:17:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 10840135 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 75DF1139A for ; Tue, 5 Mar 2019 21:18:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 62AC62CF56 for ; Tue, 5 Mar 2019 21:18:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 56BB52CF59; Tue, 5 Mar 2019 21:18:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CB3E42CF56 for ; Tue, 5 Mar 2019 21:17:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728738AbfCEVR7 (ORCPT ); Tue, 5 Mar 2019 16:17:59 -0500 Received: from fieldses.org ([173.255.197.46]:40520 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726277AbfCEVR7 (ORCPT ); Tue, 5 Mar 2019 16:17:59 -0500 Received: by fieldses.org (Postfix, from userid 2815) id A6496A9F; Tue, 5 Mar 2019 16:17:58 -0500 (EST) Date: Tue, 5 Mar 2019 16:17:58 -0500 To: Paul Moore , Stephen Smalley , Eric Paris Cc: selinux@vger.kernel.org, Scott Mayhew Subject: [PATCH] security/selinux: fix SECURITY_LSM_NATIVE_LABELS on reused superblock Message-ID: <20190305211758.GA27437@fieldses.org> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "J. Bruce Fields" In the case when we're reusing a superblock, selinux_sb_clone_mnt_opts() fails to set set_kern_flags, with the result that nfs_clone_sb_security() incorrectly clears NFS_CAP_SECURITY_LABEL. The result is that if you mount the same NFS filesystem twice, NFS security labels are turned off, even if they would work fine if you mounted the filesystem only once. ("fixes" may be not exactly the right tag, it may be more like "fixed-other-cases-but-missed-this-one".) Cc: Scott Mayhew Cc: stable@vger.kernel.org Fixes: 0b4d3452b8b4 "security/selinux: allow security_sb_clone_mnt_opts..." Signed-off-by: J. Bruce Fields Acked-by: Stephen Smalley --- security/selinux/hooks.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f0e36c3492ba..5e9304567233 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -959,8 +959,11 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb, BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED)); /* if fs is reusing a sb, make sure that the contexts match */ - if (newsbsec->flags & SE_SBINITIALIZED) + if (newsbsec->flags & SE_SBINITIALIZED) { + if ((kern_flags & SECURITY_LSM_NATIVE_LABELS) && !set_context) + *set_kern_flags |= SECURITY_LSM_NATIVE_LABELS; return selinux_cmp_sb_context(oldsb, newsb); + } mutex_lock(&newsbsec->lock);