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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A7943C73C53 for ; Tue, 9 Jul 2019 20:41:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 881F02073D for ; Tue, 9 Jul 2019 20:41:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729763AbfGIUl3 (ORCPT ); Tue, 9 Jul 2019 16:41:29 -0400 Received: from mga18.intel.com ([134.134.136.126]:10570 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728955AbfGIUl3 (ORCPT ); Tue, 9 Jul 2019 16:41:29 -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 orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Jul 2019 13:41:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,471,1557212400"; d="scan'208";a="168099604" Received: from bxing-desk.ccr.corp.intel.com (HELO [134.134.148.187]) ([134.134.148.187]) by orsmga003.jf.intel.com with ESMTP; 09 Jul 2019 13:41:27 -0700 Subject: Re: [RFC PATCH v4 00/12] security: x86/sgx: SGX vs. LSM To: Sean Christopherson , Jarkko Sakkinen Cc: linux-sgx@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, Bill Roberts , Casey Schaufler , James Morris , Dave Hansen , Andy Lutomirski , Jethro Beekman , "Dr . Greg Wettstein" , Stephen Smalley References: <20190619222401.14942-1-sean.j.christopherson@intel.com> <20190705160549.tzsck5ho5kvtdhit@linux.intel.com> <20190708172930.GA20791@linux.intel.com> <20190709162203.gzyvulah5u7eksip@linux.intel.com> <20190709170917.GD25369@linux.intel.com> From: "Xing, Cedric" Message-ID: <512391ba-fe0d-e758-ae32-09660c1264f7@intel.com> Date: Tue, 9 Jul 2019 13:41:28 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190709170917.GD25369@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On 7/9/2019 10:09 AM, Sean Christopherson wrote: > On Tue, Jul 09, 2019 at 07:22:03PM +0300, Jarkko Sakkinen wrote: >> On Mon, Jul 08, 2019 at 10:29:30AM -0700, Sean Christopherson wrote: >>> On Fri, Jul 05, 2019 at 07:05:49PM +0300, Jarkko Sakkinen wrote: >>>> On Wed, Jun 19, 2019 at 03:23:49PM -0700, Sean Christopherson wrote: >>>> >>>> I still don't get why we need this whole mess and do not simply admit >>>> that there are two distinct roles: >>>> >>>> 1. Creator >>>> 2. User >>> >>> Because SELinux has existing concepts of EXECMEM and EXECMOD. >> >> What is the official documentation for those? I've only found some >> explanations from discussions and some RHEL sysadmin guides. > > No clue. My knowledge was gleaned from the code and from Stephen's > feedback. > > > The high level breakdown: > > - FILE__EXECUTE: required to gain X on a mapping to a regular file > > > - FILE__EXECUTE + FILE__WRITE: required to gain WX or W->X on a shared > mapping to a regular file > > - FILE__EXECMOD: required to gain W->X on a private mapping of a regular > file > > - PROCESS__EXECMEM: required to gain WX on a private mapping to a regular > file, OR to gain X on an anonymous mapping. > > > Translating those to SGX, with a lot of input from Stephen, I ended up > with the following: > > - FILE__ENCLAVE_EXECUTE: equivalent to FILE__EXECUTE, required to gain X > on an enclave page loaded from a regular file > > - PROCESS2__ENCLAVE_EXECDIRTY: hybrid of EXECMOD and EXECUTE+WRITE, > required to gain W->X on an enclave page EXECMOD basically indicates a file containing self-modifying code. Your ENCLAVE_EXECDIRTY is however a process permission, which is illogical. > - PROCESS2__ENCLAVE_EXECANON: subset of EXECMEM, required to gain X on > an enclave page that is loaded from an > anonymous mapping > > - PROCESS2__ENCLAVE_MAPWX: subset of EXECMEM, required to gain WX on an > enclave page > > > >>> That being said, we can do so without functional changes to the SGX uapi, >>> e.g. add reserved fields so that the initial uapi can be extended *if* we >>> decide to go with the "userspace provides maximal protections" path, and >>> use the EPCM permissions as the maximal protections for the initial >>> upstreaming. >>> >>> That'd give us a minimal implemenation for initial upstreaming and would >>> eliminate Cedric's blocking complaint. The "whole mess" of whitelisting, >>> blacklisting and SGX2 support would be deferred until post-upstreaming. >> >> I'd like that approach more too. >> >> /Jarkko