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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 CAC7AC31E49 for ; Fri, 14 Jun 2019 00:31:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7BF720B7C for ; Fri, 14 Jun 2019 00:31:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725819AbfFNAb2 convert rfc822-to-8bit (ORCPT ); Thu, 13 Jun 2019 20:31:28 -0400 Received: from mga07.intel.com ([134.134.136.100]:52135 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725807AbfFNAb2 (ORCPT ); Thu, 13 Jun 2019 20:31:28 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Jun 2019 17:31:26 -0700 X-ExtLoop1: 1 Received: from orsmsx105.amr.corp.intel.com ([10.22.225.132]) by FMSMGA003.fm.intel.com with ESMTP; 13 Jun 2019 17:31:23 -0700 Received: from orsmsx159.amr.corp.intel.com (10.22.240.24) by ORSMSX105.amr.corp.intel.com (10.22.225.132) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 13 Jun 2019 17:31:08 -0700 Received: from orsmsx116.amr.corp.intel.com ([169.254.7.166]) by ORSMSX159.amr.corp.intel.com ([169.254.11.7]) with mapi id 14.03.0415.000; Thu, 13 Jun 2019 17:31:08 -0700 From: "Xing, Cedric" To: "Christopherson, Sean J" CC: Stephen Smalley , "linux-security-module@vger.kernel.org" , "selinux@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-sgx@vger.kernel.org" , "jarkko.sakkinen@linux.intel.com" , "luto@kernel.org" , "jmorris@namei.org" , "serge@hallyn.com" , "paul@paul-moore.com" , "eparis@parisplace.org" , "jethro@fortanix.com" , "Hansen, Dave" , "tglx@linutronix.de" , "torvalds@linux-foundation.org" , "akpm@linux-foundation.org" , "nhorman@redhat.com" , "pmccallum@redhat.com" , "Ayoun, Serge" , "Katz-zamir, Shay" , "Huang, Haitao" , "andriy.shevchenko@linux.intel.com" , "Svahn, Kai" , "bp@alien8.de" , "josh@joshtriplett.org" , "Huang, Kai" , "rientjes@google.com" , "Roberts, William C" , "Tricca, Philip B" Subject: RE: [RFC PATCH v1 2/3] LSM/x86/sgx: Implement SGX specific hooks in SELinux Thread-Topic: [RFC PATCH v1 2/3] LSM/x86/sgx: Implement SGX specific hooks in SELinux Thread-Index: AQHVH1ilvNGS2ZisK0eWTCWidam/YaaW7RmAgACMWICAAtC5gP//6xkwgAB92oD//55EwA== Date: Fri, 14 Jun 2019 00:31:07 +0000 Message-ID: <960B34DE67B9E140824F1DCDEC400C0F65503F51@ORSMSX116.amr.corp.intel.com> References: <20190611220243.GB3416@linux.intel.com> <8d99d8fb-a921-286a-8cf0-cd522e09b37c@tycho.nsa.gov> <960B34DE67B9E140824F1DCDEC400C0F65503EDD@ORSMSX116.amr.corp.intel.com> <20190613231755.GD18385@linux.intel.com> In-Reply-To: <20190613231755.GD18385@linux.intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiZTM0MmViYzktMDdiZS00YTE1LTgxYTgtZDYzOWY1NzhlOTA5IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiZHhPSUVuNnRUeVpNNWtwUGdBYUVCYUczbU12d2E5VSs4TzBPdWEyZ3B3aUM0S0tGUlQyaldjeFZ0NlwvdlRaQUIifQ== x-ctpclassification: CTP_NT dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [10.22.254.140] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org > From: Christopherson, Sean J > Sent: Thursday, June 13, 2019 4:18 PM > > On Thu, Jun 13, 2019 at 04:03:24PM -0700, Xing, Cedric wrote: > > > From: Stephen Smalley [mailto:sds@tycho.nsa.gov] > > > Sent: Thursday, June 13, 2019 10:02 AM > > > > > > > My RFC series[1] implements #1. My understanding is that Andy > > > > (Lutomirski) prefers #2. Cedric's RFC series implements #3. > > > > > > > > Perhaps the easiest way to make forward progress is to rule out > the > > > > options we absolutely *don't* want by focusing on the potentially > > > > blocking issue with each option: > > > > > > > > #1 - SGX UAPI funkiness > > > > > > > > #2 - Auditing complexity, potential enclave lock contention > > > > > > > > #3 - Pushing SGX details into LSMs and complexity of kernel > > > > implementation > > > > > > > > > > > > [1] > > > > https://lkml.kernel.org/r/20190606021145.12604-1- > sean.j.christopherson > > > > @intel.com > > > > > > Given the complexity tradeoff, what is the clear motivating example > for > > > why #1 isn't the obvious choice? That the enclave loader has no way > of > > > knowing a priori whether the enclave will require W->X or WX? But > > > aren't we better off requiring enclaves to be explicitly marked as > > > needing such so that we can make a more informed decision about > whether > > > to load them in the first place? > > > > Are you asking this question at a) page granularity, b) file > granularity or > > c) enclave (potentially comprised of multiple executable files) > granularity? > > > > #b is what we have on regular executable files and shared objects (i.e. > > FILE__EXECMOD). We all know how to do that. > > > > #c is kind of new but could be done via some proxy file (e.g. > sigstruct file) > > hence reduced to #b. > > > > #a is problematic. It'd require compilers/linkers to generate such > > information, and proper executable image file format to carry that > > information, to be eventually picked up the loader. SELinux doesn't > have > > PAGE__EXECMOD I guess is because it is generally considered > impractical. > > > > Option #1 however requires #a because the driver doesn't track which > page was > > loaded from which file, otherwise it can no longer be qualified > "simple". Or > > we could just implement #c, which will make all options simpler. But I > guess > > #b is still preferred, to be aligned with what SELinux is enforcing > today on > > regular memory pages.o > > Option #1 doesn't require (a). The checks will happen for every page, > but in the RFCs I sent, the policies are still attached to files and > processes, i.e. (b). I was talking at the UAPI level - i.e. your ioctl requires ALLOW_* at page granularity, hence #a.