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=-2.2 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 41A89C3B1B3 for ; Fri, 14 Feb 2020 17:52:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27116206D7 for ; Fri, 14 Feb 2020 17:52:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388840AbgBNRwO (ORCPT ); Fri, 14 Feb 2020 12:52:14 -0500 Received: from mga01.intel.com ([192.55.52.88]:14459 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388300AbgBNRwN (ORCPT ); Fri, 14 Feb 2020 12:52:13 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Feb 2020 09:52:11 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,441,1574150400"; d="scan'208";a="238425267" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by orsmga006.jf.intel.com with ESMTP; 14 Feb 2020 09:52:11 -0800 Date: Fri, 14 Feb 2020 09:52:11 -0800 From: Sean Christopherson To: Andy Lutomirski Cc: Jethro Beekman , Jarkko Sakkinen , linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com, linux-security-module@vger.kernel.org, Haitao Huang Subject: Re: [PATCH v26 10/22] x86/sgx: Linux Enclave Driver Message-ID: <20200214175211.GE20690@linux.intel.com> References: <20200214171146.GD20690@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Fri, Feb 14, 2020 at 09:40:00AM -0800, Andy Lutomirski wrote: > > > > On Feb 14, 2020, at 9:11 AM, Sean Christopherson wrote: > > > > On Fri, Feb 14, 2020 at 10:24:10AM +0100, Jethro Beekman wrote: > >>> On 2020-02-13 19:07, Sean Christopherson wrote: > >>> On Thu, Feb 13, 2020 at 02:59:52PM +0100, Jethro Beekman wrote: > >>>> On 2020-02-09 22:25, Jarkko Sakkinen wrote: > >>>>> +/** > >>>>> + * struct sgx_enclave_add_pages - parameter structure for the > >>>>> + * %SGX_IOC_ENCLAVE_ADD_PAGE ioctl > >>>>> + * @src: start address for the page data > >>>>> + * @offset: starting page offset > >>>>> + * @length: length of the data (multiple of the page size) > >>>>> + * @secinfo: address for the SECINFO data > >>>>> + * @flags: page control flags > >>>>> + * @count: number of bytes added (multiple of the page size) > >>>>> + */ > >>>>> +struct sgx_enclave_add_pages { > >>>>> + __u64 src; > >>>>> + __u64 offset; > >>>>> + __u64 length; > >>>>> + __u64 secinfo; > >>>>> + __u64 flags; > >>>>> + __u64 count; > >>>>> +}; > >>>> > >>>> Compared to the last time I looked at the patch set, this API removes the > >>>> ability to measure individual pages chunks. That is not acceptable. > >>> > >>> Why is it not acceptable? E.g. what specific use case do you have that > >>> _requires_ on measuring partial 4k pages of an enclave? > >> > >> The use case is someone gives me an enclave and I want to load it. If I don't > >> load it exactly as the enclave author specified, the enclave hash will be > >> different, and it won't work. > > > > And if our ABI says "thou shall measure in 4k chunks", then it's an invalid > > enclave if its author generated MRENCLAVE using a different granularity. > > ISTM, unless there’s a particularly compelling reason, if an enclave is > valid, we should be able to load it. That means we have to have a separate ioctl() for EEXTEND, otherwise we can't handle EADD[0]->EADD[1]->EADD[2]->EEXTEND[0]->EEXTEND[1]->EEXTEND[2]. I think we'd still want to keep the MEASURE flag for SGX_IOC_ENCLAVE_ADD_PAGE so that we can optimize EADD[0]->EEXTEND[0]->EADD[1]->EEXTEND[1].