From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753411Ab3BMGmF (ORCPT ); Wed, 13 Feb 2013 01:42:05 -0500 Received: from db3ehsobe004.messaging.microsoft.com ([213.199.154.142]:6369 "EHLO db3outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752924Ab3BMGmC (ORCPT ); Wed, 13 Feb 2013 01:42:02 -0500 X-Forefront-Antispam-Report: CIP:157.56.236.101;KIP:(null);UIP:(null);IPV:NLI;H:BY2PRD0510HT005.namprd05.prod.outlook.com;RD:none;EFVD:NLI X-SpamScore: -2 X-BigFish: PS-2(zz98dI936eIzz1f42h1ee6h1de0h1202h1e76h1d1ah1d2ahzzz2fh2a8h668h839h93fhd24he5bhf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1155h) From: Matthew Garrett To: "H. Peter Anvin" CC: Borislav Petkov , 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+EElzc7Yz1iZhwVXgAgAAAbACAAAawAIAACLcAgAABPICAAAKrAIAAAdKAgAAHwICAABjCAIAAChOAgAAFkwCAACBDAIAAAhCAgABYQICAAC3GgIAAX64AgAVYBQCAAFFaAIAACSmAgAAEVgCAAAGkAIAAAlCA Date: Wed, 13 Feb 2013 06:41:54 +0000 Message-ID: <1360737709.18083.36.camel@x230.lan> References: <1360355671.18083.18.camel@x230.lan> <51157C9C.6030501@zytor.com> <20130208230655.GB28990@pd.tnic> <1360366012.18083.21.camel@x230.lan> <5115A4CC.3080102@zytor.com> <1360373383.18083.23.camel@x230.lan> <20130209092925.GA17728@pd.tnic> <1360422712.18083.24.camel@x230.lan> <511AE2CC.5040705@zytor.com> <1360733962.18083.30.camel@x230.lan> <511B2EB9.5070406@zytor.com> <1360736860.18083.33.camel@x230.lan> <511B33BC.9080307@zytor.com> In-Reply-To: <511B33BC.9080307@zytor.com> 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: 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 r1D6g6Fd028111 On Tue, 2013-02-12 at 22:33 -0800, H. Peter Anvin wrote: > That is just batshit crazy. If you have CAP_SYS_RAWIO you can do iopl() > which means you can reprogram your northbridge, at which point you most > definitely *can* modify the running kernel. Well right, that's the point of this patchset - it adds some extra permission checks to some of the existing CAP_SYS_RAWIO checks. CAP_SYS_RAWIO hasn't meant "I can perform arbitrary pio and mmio" for years - it means "I can do things that might maybe break something somehow". So sure, removing CAP_SYS_RAWIO would give us basically all the security we want in a secure boot environment, but it would also block things that we *want* to work. {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I