From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81B4CC04AB9 for ; Wed, 15 Aug 2018 23:54:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 963092087E for ; Wed, 15 Aug 2018 23:54:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 963092087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731254AbeHPCsh (ORCPT ); Wed, 15 Aug 2018 22:48:37 -0400 Received: from mga09.intel.com ([134.134.136.24]:61125 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731208AbeHPCs3 (ORCPT ); Wed, 15 Aug 2018 22:48:29 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Aug 2018 16:53:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,245,1531810800"; d="scan'208";a="75694071" Received: from cschaufl-mobl.amr.corp.intel.com ([10.252.130.105]) by orsmga003.jf.intel.com with ESMTP; 15 Aug 2018 16:53:58 -0700 From: Casey Schaufler To: kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, SMACK-discuss@lists.01.org, casey.schaufler@intel.com, dave.hansen@intel.com, deneen.t.dock@intel.com, kristen@linux.intel.com, arjan@linux.intel.com Subject: [PATCH RFC 4/5] Smack: Support determination of side-channel vulnerability Date: Wed, 15 Aug 2018 16:53:54 -0700 Message-Id: <20180815235355.14908-5-casey.schaufler@intel.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180815235355.14908-1-casey.schaufler@intel.com> References: <20180815235355.14908-1-casey.schaufler@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Smack considers its private task data safe if the current task has read access to the passed task. Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 91750205a5de..85dc053e610c 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2299,6 +2299,23 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode) isp->smk_inode = skp; } +/** + * smack_task_safe_sidechannel - Are the task and current sidechannel safe? + * @p: task to check on + * + * A crude value for sidechannel safety is that the current task is + * already allowed to read from the other. + * + * Returns 0 if the tasks are sidechannel safe, -EACCES otherwise. + */ +static int smack_task_safe_sidechannel(struct task_struct *p) +{ + struct smack_known *skp = smk_of_task_struct(p); + struct smack_known *ckp = smk_of_task_struct(current); + + return smk_access(ckp, skp, MAY_READ, NULL); +} + /* * Socket hooks. */ @@ -4718,6 +4735,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(task_movememory, smack_task_movememory), LSM_HOOK_INIT(task_kill, smack_task_kill), LSM_HOOK_INIT(task_to_inode, smack_task_to_inode), + LSM_HOOK_INIT(task_safe_sidechannel, smack_task_safe_sidechannel), LSM_HOOK_INIT(ipc_permission, smack_ipc_permission), LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid), -- 2.17.1