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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 B4B32C31E41 for ; Mon, 10 Jun 2019 16:05:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87CD420862 for ; Mon, 10 Jun 2019 16:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403848AbfFJQF1 (ORCPT ); Mon, 10 Jun 2019 12:05:27 -0400 Received: from mga12.intel.com ([192.55.52.136]:6422 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403847AbfFJQF1 (ORCPT ); Mon, 10 Jun 2019 12:05:27 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jun 2019 09:05:26 -0700 X-ExtLoop1: 1 Received: from cmargarx-wtg.ger.corp.intel.com (HELO localhost) ([10.249.34.77]) by fmsmga006.fm.intel.com with ESMTP; 10 Jun 2019 09:05:16 -0700 Date: Mon, 10 Jun 2019 19:05:16 +0300 From: Jarkko Sakkinen To: Sean Christopherson Cc: Andy Lutomirski , Cedric Xing , Stephen Smalley , James Morris , "Serge E . Hallyn" , LSM List , Paul Moore , Eric Paris , selinux@vger.kernel.org, Jethro Beekman , Dave Hansen , Thomas Gleixner , Linus Torvalds , LKML , X86 ML , linux-sgx@vger.kernel.org, Andrew Morton , nhorman@redhat.com, npmccallum@redhat.com, Serge Ayoun , Shay Katz-zamir , Haitao Huang , Andy Shevchenko , Kai Svahn , Borislav Petkov , Josh Triplett , Kai Huang , David Rientjes , William Roberts , Philip Tricca Subject: Re: [RFC PATCH v2 4/5] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Message-ID: <20190610160423.GD3752@linux.intel.com> References: <20190606021145.12604-1-sean.j.christopherson@intel.com> <20190606021145.12604-5-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190606021145.12604-5-sean.j.christopherson@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Wed, Jun 05, 2019 at 07:11:44PM -0700, Sean Christopherson wrote: > enclave_load() is roughly analogous to the existing file_mprotect(). > > Due to the nature of SGX and its Enclave Page Cache (EPC), all enclave > VMAs are backed by a single file, i.e. /dev/sgx/enclave, that must be > MAP_SHARED. Furthermore, all enclaves need read, write and execute > VMAs. As a result, the existing/standard call to file_mprotect() does > not provide any meaningful security for enclaves since an LSM can only > deny/grant access to the EPC as a whole. > > security_enclave_load() is called when SGX is first loading an enclave > page, i.e. copying a page from normal memory into the EPC. Although > the prototype for enclave_load() is similar to file_mprotect(), e.g. > SGX could theoretically use file_mprotect() and set reqprot=prot, a > separate hook is desirable as the semantics of an enclave's protection > bits are different than those of vmas, e.g. an enclave page tracks the > maximal set of protections, whereas file_mprotect() operates on the > actual protections being provided. In other words, LSMs will likely > want to implement different policies for enclave page protections. > > Note, extensive discussion yielded no sane alternative to some form of > SGX specific LSM hook[1]. > > [1] https://lkml.kernel.org/r/CALCETrXf8mSK45h7sTK5Wf+pXLVn=Bjsc_RLpgO-h-qdzBRo5Q@mail.gmail.com > > Signed-off-by: Sean Christopherson 4/5 and 5/5 should only be added after upstreaming SGX. /Jarkko