From patchwork Wed Dec 2 15:40:06 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 7748021 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E377D9F387 for ; Wed, 2 Dec 2015 15:49:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F0F0B204B5 for ; Wed, 2 Dec 2015 15:49:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6BE120498 for ; Wed, 2 Dec 2015 15:49:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932982AbbLBPte (ORCPT ); Wed, 2 Dec 2015 10:49:34 -0500 Received: from mail-ig0-f170.google.com ([209.85.213.170]:33492 "EHLO mail-ig0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932775AbbLBPmM (ORCPT ); Wed, 2 Dec 2015 10:42:12 -0500 Received: by igcmv3 with SMTP id mv3so120225304igc.0 for ; Wed, 02 Dec 2015 07:42:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=frunC1mLI8jp4dUjS6IRw492nG5EQ5tIehtDLhukJjE=; b=DFQDDJoJxt9re7riH/271zukjGQPLzA4kyyyhCHw+hDByfjM50cY8UC+0th6yhO3eK plPdlXaimzn4zx6un388eB8h+3A/zO00oMfOjtiPpoBH+tZj8f22WGkkL9UQya3+KJAU sFjl7CEAemUDZ/LfWvVVdBScYfkrIPtLwUo3fGllM448zL9IgkXAug3UAl3facMSTP9r 7lnI2vrD05W3fpR7joiCqKYFX+Jn7OMzrzbF0ClD2ltcfWe1srb/3zl3HWpmR4kOSSP8 nX6bARu/cjQmJXwepArWIWDd2fFoVyAAbf9AYxagJ9fJR+ecLAxztmJNObn/X6vOZcn9 FBwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=frunC1mLI8jp4dUjS6IRw492nG5EQ5tIehtDLhukJjE=; b=hj6tVwTHKFXpfu/s73ZvXvtwVpVTsbWdyKmIUJuRpT0Hta25abdM+HZO+7N4x8ObU6 g16KXjHuyZiSXioqR0bSpx424RGl2JVP16nLrQhwzhc02vdjNJ/0w1itVQLQv8CyMVYP 5KKGTHXym1i8OckDFeV2rF23/kxIkORncuYn8Xj20I209AcWouGSfHlhfnVEX/svjqxx hxNznXtSkaQ/5bGzv2UWbSFdWL2WbA6+QUaL2ulnAZiSE6eAHj53DSLJDoeNMFaQegOm zF1HSmqmNq13cBJxBZjCdTDh8+6XqDJm+T9OdezShD46NcToR0dcGPAts6Hx8sW9K3jR A9eQ== X-Gm-Message-State: ALoCoQkuQVTX2dwV450h+T0lha7DVtSpKmOpRjkz8nOWMG+TJLNZCmE6S2LtAX57BUwIYVTCNtyR X-Received: by 10.50.142.40 with SMTP id rt8mr4706142igb.0.1449070931765; Wed, 02 Dec 2015 07:42:11 -0800 (PST) Received: from localhost (199-87-125-144.dyn.kc.surewest.net. [199.87.125.144]) by smtp.gmail.com with ESMTPSA id q17sm11587785igr.3.2015.12.02.07.42.11 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 02 Dec 2015 07:42:11 -0800 (PST) From: Seth Forshee To: "Eric W. Biederman" , Casey Schaufler Cc: Alexander Viro , Serge Hallyn , Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee , James Morris , "Serge E. Hallyn" Subject: [PATCH 06/19] Smack: Handle labels consistently in untrusted mounts Date: Wed, 2 Dec 2015 09:40:06 -0600 Message-Id: <1449070821-73820-7-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> References: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The SMACK64, SMACK64EXEC, and SMACK64MMAP labels are all handled differently in untrusted mounts. This is confusing and potentically problematic. Change this to handle them all the same way that SMACK64 is currently handled; that is, read the label from disk and check it at use time. For SMACK64 and SMACK64MMAP access is denied if the label does not match smk_root. To be consistent with suid, a SMACK64EXEC label which does not match smk_root will still allow execution of the file but will not run with the label supplied in the xattr. Signed-off-by: Seth Forshee Acked-by: Casey Schaufler --- security/smack/smack_lsm.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 16cac04214e2..0e555f64ded0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -921,6 +921,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) struct inode *inode = file_inode(bprm->file); struct task_smack *bsp = bprm->cred->security; struct inode_smack *isp; + struct superblock_smack *sbsp; int rc; if (bprm->cred_prepared) @@ -930,6 +931,11 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; + sbsp = inode->i_sb->s_security; + if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) && + isp->smk_task != sbsp->smk_root) + return 0; + if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { struct task_struct *tracer; rc = 0; @@ -1733,6 +1739,7 @@ static int smack_mmap_file(struct file *file, struct task_smack *tsp; struct smack_known *okp; struct inode_smack *isp; + struct superblock_smack *sbsp; int may; int mmay; int tmay; @@ -1744,6 +1751,10 @@ static int smack_mmap_file(struct file *file, isp = file_inode(file)->i_security; if (isp->smk_mmap == NULL) return 0; + sbsp = file_inode(file)->i_sb->s_security; + if (sbsp->smk_flags & SMK_SB_UNTRUSTED && + isp->smk_mmap != sbsp->smk_root) + return -EACCES; mkp = isp->smk_mmap; tsp = current_security(); @@ -3532,16 +3543,14 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) if (rc >= 0) transflag = SMK_INODE_TRANSMUTE; } - if (!(sbsp->smk_flags & SMK_SB_UNTRUSTED)) { - /* - * Don't let the exec or mmap label be "*" or "@". - */ - skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); - if (IS_ERR(skp) || skp == &smack_known_star || - skp == &smack_known_web) - skp = NULL; - isp->smk_task = skp; - } + /* + * Don't let the exec or mmap label be "*" or "@". + */ + skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + if (IS_ERR(skp) || skp == &smack_known_star || + skp == &smack_known_web) + skp = NULL; + isp->smk_task = skp; skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); if (IS_ERR(skp) || skp == &smack_known_star ||