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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 1ACB4C3A5A1 for ; Thu, 22 Aug 2019 16:59:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEC6F23401 for ; Thu, 22 Aug 2019 16:59:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730411AbfHVQ7h (ORCPT ); Thu, 22 Aug 2019 12:59:37 -0400 Received: from mga06.intel.com ([134.134.136.31]:59259 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726844AbfHVQ7h (ORCPT ); Thu, 22 Aug 2019 12:59:37 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Aug 2019 09:59:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,417,1559545200"; d="scan'208";a="208240577" Received: from greathea-mobl2.ger.corp.intel.com ([10.252.39.37]) by fmsmga002.fm.intel.com with ESMTP; 22 Aug 2019 09:59:34 -0700 Message-ID: <6a5fb735e795c25ceb075d4a6f4db20653b731af.camel@linux.intel.com> Subject: Re: [PATCH 4/5] x86/sgx: Validate TCS permssions in sgx_validate_secinfo() From: Jarkko Sakkinen To: "Ayoun, Serge" , "linux-sgx@vger.kernel.org" Cc: "Christopherson, Sean J" Date: Thu, 22 Aug 2019 19:59:34 +0300 In-Reply-To: References: <20190819152544.7296-1-jarkko.sakkinen@linux.intel.com> <20190819152544.7296-5-jarkko.sakkinen@linux.intel.com> <20190821184544.ii37h7hhxjiocbb4@linux.intel.com> <88B7642769729B409B4A93D7C5E0C5E7C661E7A7@hasmsx108.ger.corp.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.2-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Thu, 2019-08-22 at 19:46 +0300, Jarkko Sakkinen wrote: > On Thu, 2019-08-22 at 11:33 +0000, Ayoun, Serge wrote: > > Also replying to Sean. > > Sean is right that never mind the value in secsinfo->flags, HW will reset RWX > > For TCS pages. > > So basically you may not enforce and and could not check those but... The signature depends > > On those flags, so if you put a non-zero flag value, eadd will pass but if you > > compute the signature according to this non zero value then you will have > > a delta between ur signature and HW's signature: einit will fail. > > So this is tricky and more a usability issue. > > I vote for checking the flag is zeroed. > > As I responded to Sean that as long as the ioctl does not adjust > prot bits I'm cool with any sane solution. What do you think of > requiring at minimum RW? > > Doing that kind of adjusting is just doing fixup's for corrupted > data from the user space. Kind of missed your comment about EINIT in rush! A valid point and good catch. I still think my 2nd proposal would be more appropriate than this patch. Signatures will work and we don't need special cases anywhere. /Jarkko