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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 0911DC43463 for ; Fri, 18 Sep 2020 23:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9E4321707 for ; Fri, 18 Sep 2020 23:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726152AbgIRXZU (ORCPT ); Fri, 18 Sep 2020 19:25:20 -0400 Received: from mga11.intel.com ([192.55.52.93]:32638 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726009AbgIRXZU (ORCPT ); Fri, 18 Sep 2020 19:25:20 -0400 IronPort-SDR: qSksG/9yLCgvd3Gxdw3DYCD0lXRxcUr/6e3YTtxTc0PCsio/6p2MgxiSALV5BcPtgKmizDSMLP 4NhzbzI/CRnA== X-IronPort-AV: E=McAfee;i="6000,8403,9748"; a="157444944" X-IronPort-AV: E=Sophos;i="5.77,276,1596524400"; d="scan'208";a="157444944" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2020 16:25:09 -0700 IronPort-SDR: bwQl4yFHMgKEVeADmPLf3YddIA9jvYk9OyDQiQiin4hc6P/CFDEWDJIJlPKkoifvB7h/HuS3xt xZ7bK1/tc/YA== X-IronPort-AV: E=Sophos;i="5.77,276,1596524400"; d="scan'208";a="484421587" Received: from pbaltus-mobl.ger.corp.intel.com (HELO localhost) ([10.252.48.234]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2020 16:25:02 -0700 Date: Sat, 19 Sep 2020 02:24:58 +0300 From: Jarkko Sakkinen To: Andy Lutomirski Cc: X86 ML , linux-sgx@vger.kernel.org, LKML , Sean Christopherson , Linux-MM , Andrew Morton , Matthew Wilcox , Jethro Beekman , Darren Kenny , Andy Shevchenko , asapek@google.com, Borislav Petkov , "Xing, Cedric" , chenalexchen@google.com, Conrad Parker , cyhanish@google.com, Dave Hansen , "Huang, Haitao" , Josh Triplett , "Huang, Kai" , "Svahn, Kai" , Keith Moyer , Christian Ludloff , Neil Horman , Nathaniel McCallum , Patrick Uiterwijk , David Rientjes , Thomas Gleixner , yaozhangx@google.com Subject: Re: [PATCH v38 10/24] mm: Add vm_ops->mprotect()' Message-ID: <20200918232458.GA6175@linux.intel.com> References: <20200915112842.897265-1-jarkko.sakkinen@linux.intel.com> <20200915112842.897265-11-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 18, 2020 at 08:09:04AM -0700, Andy Lutomirski wrote: > On Tue, Sep 15, 2020 at 4:28 AM Jarkko Sakkinen > wrote: > > > > From: Sean Christopherson > > > > Add vm_ops()->mprotect() for additional constraints for a VMA. > > > > Intel Software Guard eXtensions (SGX) will use this callback to add two > > constraints: > > > > 1. Verify that the address range does not have holes: each page address > > must be filled with an enclave page. > > 2. Verify that VMA permissions won't surpass the permissions of any enclave > > page within the address range. Enclave cryptographically sealed > > permissions for each page address that set the upper limit for possible > > VMA permissions. Not respecting this can cause #GP's to be emitted. > > It's been awhile since I looked at this. Can you remind us: is this > just preventing userspace from shooting itself in the foot or is this > something more important? > > --Andy Haitao found this: https://patchwork.kernel.org/patch/10978327/ The way I understand it, for an LSM hook it makes sense that the mprotect() can deduce a single permission for an enclave address range. With those constraints it is possible. /Jarkko