From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947353Ab3BHX1G (ORCPT ); Fri, 8 Feb 2013 18:27:06 -0500 Received: from va3ehsobe005.messaging.microsoft.com ([216.32.180.31]:41557 "EHLO va3outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757638Ab3BHX1D (ORCPT ); Fri, 8 Feb 2013 18:27:03 -0500 X-Forefront-Antispam-Report: CIP:157.56.236.101;KIP:(null);UIP:(null);IPV:NLI;H:BY2PRD0510HT004.namprd05.prod.outlook.com;RD:none;EFVD:NLI X-SpamScore: -3 X-BigFish: PS-3(zz98dI936eI1432Izz1f42h1ee6h1de0h1202h1e76h1d1ah1d2ahzzz2fh2a8h668h839h93fhd24he5bhf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1155h) From: Matthew Garrett To: Borislav Petkov CC: "H. Peter Anvin" , Kees Cook , LKML , Thomas Gleixner , Ingo Molnar , "x86@kernel.org" , "linux-efi@vger.kernel.org" , linux-security-module Subject: Re: [PATCH] x86: Lock down MSR writing in secure boot Thread-Topic: [PATCH] x86: Lock down MSR writing in secure boot Thread-Index: AQHOBjA7mQsIMlqU/k+EElzc7Yz1iZhwVXgAgAAAbACAAAawAIAACLcAgAABPICAAAKrAIAAAdKAgAAHwICAABjCAIAAChOAgAAFkwA= Date: Fri, 8 Feb 2013 23:26:53 +0000 Message-ID: <1360366012.18083.21.camel@x230.lan> References: <20130208191213.GA25081@www.outflux.net> <00780235-deac-4f80-b936-867834e05661@email.android.com> <5115553A.5000708@zytor.com> <1360355671.18083.18.camel@x230.lan> <51157C9C.6030501@zytor.com> <20130208230655.GB28990@pd.tnic> In-Reply-To: <20130208230655.GB28990@pd.tnic> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.255.84.4] Content-Type: text/plain; charset="utf-8" Content-ID: <4F44BB0DA4EB914D8ED1146AA9048BE8@namprd05.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: nebula.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id r18NR9XK006673 On Sat, 2013-02-09 at 00:06 +0100, Borislav Petkov wrote: > On Fri, Feb 08, 2013 at 02:30:52PM -0800, H. Peter Anvin wrote: > > Also, keep in mind that there is a very simple way to deny MSR access > > completely, which is to not include the driver in your kernel (and not > > allow module loading, but if you can load modules you can just load a > > module to muck with whatever MSR you want.) > > I was contemplating that too. What is the use case of having > msr.ko in a secure boot environment? Isn't that an all-no-tools, > you-can't-do-sh*t-except-what-you're-explicitly-allowed-to environment which > simply doesn't need to write MSRs in the first place? Well, sure, distributions could build every kernel twice. That seems a little excessive, though. {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I