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 64970C11D25 for ; Thu, 20 Feb 2020 22:16:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B64220801 for ; Thu, 20 Feb 2020 22:16:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729141AbgBTWQU (ORCPT ); Thu, 20 Feb 2020 17:16:20 -0500 Received: from mga12.intel.com ([192.55.52.136]:20659 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727656AbgBTWQT (ORCPT ); Thu, 20 Feb 2020 17:16:19 -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 fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2020 14:16:19 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,465,1574150400"; d="scan'208";a="240154208" Received: from evieschw-mobl.ger.corp.intel.com (HELO localhost) ([10.251.86.197]) by orsmga006.jf.intel.com with ESMTP; 20 Feb 2020 14:16:08 -0800 Date: Fri, 21 Feb 2020 00:16:07 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: Jordan Hand , 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, Suresh Siddha , Haitao Huang Subject: Re: [PATCH v26 10/22] x86/sgx: Linux Enclave Driver Message-ID: <20200220221607.GB26618@linux.intel.com> References: <20200209212609.7928-1-jarkko.sakkinen@linux.intel.com> <20200209212609.7928-11-jarkko.sakkinen@linux.intel.com> <15074c16-4832-456d-dd12-af8548e46d6d@linux.microsoft.com> <20200220181345.GD3972@linux.intel.com> <7738b3cf-fb32-5306-5740-59974444e327@linux.microsoft.com> <20200220184842.GE3972@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220184842.GE3972@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 20, 2020 at 10:48:42AM -0800, Sean Christopherson wrote: > My biggest concern for allowing PROT_EXEC if RIE is that it would result > in #PF(SGX) (#GP on Skylake) due to an EPCM violation if the enclave > actually tried to execute from such a page. This isn't a problem for the > kernel as the fault will be reported cleanly through the vDSO (or get > delivered as a SIGSEGV if the enclave isn't entered through the vDSO), but > it's a bit weird for userspace as userspace will see the #PF(SGX) and > likely assume the EPC was lost, e.g. silently restart the enclave instead > of logging an error that the enclave is broken. I think right way to fix the current implementation is to -EACCES mmap() (and mprotect) when !!(current->personality & READ_IMPLIES_EXEC). This way supporting RIE can be reconsidered later on without any potential ABI bottlenecks. /Jarkko