From patchwork Fri Jul 29 07:34:39 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9252139 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1245060757 for ; Fri, 29 Jul 2016 07:35:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0775227D76 for ; Fri, 29 Jul 2016 07:35:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F02A027F96; Fri, 29 Jul 2016 07:35:22 +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=-6.9 required=2.0 tests=BAYES_00,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 96C0127D76 for ; Fri, 29 Jul 2016 07:35:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751416AbcG2HfV (ORCPT ); Fri, 29 Jul 2016 03:35:21 -0400 Received: from mga14.intel.com ([192.55.52.115]:17082 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751365AbcG2HfU (ORCPT ); Fri, 29 Jul 2016 03:35:20 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP; 29 Jul 2016 00:35:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,438,1464678000"; d="scan'208";a="855726513" Received: from gliakhov-mobl.ger.corp.intel.com (HELO elena-ThinkPad-X230.ger.corp.intel.com) ([10.252.62.193]) by orsmga003.jf.intel.com with ESMTP; 29 Jul 2016 00:35:17 -0700 From: Elena Reshetova To: kernel-hardening@lists.openwall.com Cc: linux-security-module@vger.kernel.org, keescook@chromium.org, spender@grsecurity.net, jmorris@namei.org, casey.schaufler@intel.com, michael.leibowitz@intel.com, william.c.roberts@intel.com, Elena Reshetova Subject: [RFC] [PATCH 4/5] invoke path_chroot() LSM hook on mntns_install() Date: Fri, 29 Jul 2016 10:34:39 +0300 Message-Id: <1469777680-3687-5-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469777680-3687-1-git-send-email-elena.reshetova@intel.com> References: <1469777680-3687-1-git-send-email-elena.reshetova@intel.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP This adds an additional invocation of the security_path_chroot LSM hook inside mntns_install(). Currently only capabilities are checked at this point, while process root actually changes. Signed-off-by: Elena Reshetova --- fs/namespace.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 419f746..c5dcb09 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3325,6 +3325,7 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) struct fs_struct *fs = current->fs; struct mnt_namespace *mnt_ns = to_mnt_ns(ns); struct path root; + int retval; if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || @@ -3334,10 +3335,6 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) if (fs->users != 1) return -EINVAL; - get_mnt_ns(mnt_ns); - put_mnt_ns(nsproxy->mnt_ns); - nsproxy->mnt_ns = mnt_ns; - /* Find the root */ root.mnt = &mnt_ns->root->mnt; root.dentry = mnt_ns->root->mnt.mnt_root; @@ -3345,6 +3342,16 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) while(d_mountpoint(root.dentry) && follow_down_one(&root)) ; + retval = security_path_chroot(&root); + if (retval) { + path_put(&root); + return retval; + } + + get_mnt_ns(mnt_ns); + put_mnt_ns(nsproxy->mnt_ns); + nsproxy->mnt_ns = mnt_ns; + /* Update the pwd and root */ set_fs_pwd(fs, &root); set_fs_root(fs, &root);