From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755869AbaCNWEo (ORCPT ); Fri, 14 Mar 2014 18:04:44 -0400 Received: from mail-by2lp0240.outbound.protection.outlook.com ([207.46.163.240]:49058 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754397AbaCNWEm (ORCPT ); Fri, 14 Mar 2014 18:04:42 -0400 From: Matthew Garrett To: "gnomes@lxorguk.ukuu.org.uk" CC: "linux-kernel@vger.kernel.org" , "jmorris@namei.org" , "keescook@chromium.org" , "linux-security-module@vger.kernel.org" , "akpm@linux-foundation.org" , "hpa@zytor.com" , "jwboyer@fedoraproject.org" , "linux-efi@vger.kernel.org" , "gregkh@linuxfoundation.org" Subject: Re: Trusted kernel patchset for Secure Boot lockdown Thread-Topic: Trusted kernel patchset for Secure Boot lockdown Thread-Index: AQHPP9CXgdFEpLbAD0ahQ2OJgthmsZrhIyiA Date: Fri, 14 Mar 2014 22:04:39 +0000 Message-ID: <1394834679.1286.16.camel@x230> References: <1393445473-15068-1-git-send-email-matthew.garrett@nebula.com> <1394686919.25122.2.camel@x230> <1394726363.25122.16.camel@x230> <20140313212450.67f1de8e@alan.etchedpixels.co.uk> <1394746248.27846.3.camel@x230> <20140313232140.03bdaac3@alan.etchedpixels.co.uk> <1394762250.6416.24.camel@x230.lan> <20140314122231.17b9ca8a@alan.etchedpixels.co.uk> <1394801518.6416.38.camel@x230.lan> <20140314170655.0ce398a3@alan.etchedpixels.co.uk> <1394820664.26846.18.camel@x230.mview.int.nebula.com> <1394825094.1286.1.camel@x230> <20140314215854.50ec186a@alan.etchedpixels.co.uk> In-Reply-To: <20140314215854.50ec186a@alan.etchedpixels.co.uk> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [2001:470:1f07:1371:6267:20ff:fec3:2318] x-forefront-prvs: 0150F3F97D x-forefront-antispam-report: SFV:NSPM;SFS:(10009001)(6009001)(428001)(51704005)(377424004)(199002)(189002)(24454002)(81686001)(83322001)(19580405001)(81816001)(80976001)(85852003)(92726001)(19580395003)(90146001)(92566001)(83072002)(74662001)(56816005)(53806001)(54356001)(77096001)(76796001)(56776001)(76786001)(54316002)(76482001)(4396001)(46102001)(49866001)(31966008)(93136001)(94316002)(69226001)(74876001)(74366001)(33716001)(74706001)(85306002)(33646001)(86362001)(93516002)(47446002)(59766001)(81342001)(77982001)(74502001)(80022001)(63696002)(51856001)(81542001)(97336001)(50986001)(47736001)(47976001)(95666003)(95416001)(94946001)(97186001)(2656002)(79102001)(20776003)(87266001)(87936001)(65816001);DIR:OUT;SFP:1101;SCL:1;SRVR:BN1PR05MB124;H:BN1PR05MB423.namprd05.prod.outlook.com;FPR:FEC0F03E.AF545B2B.78F08398.48987E41.201C5;MLV:sfv;PTR:InfoNoRecords;A:1;MX:1;LANG:en; Content-Type: text/plain; charset="utf-8" Content-ID: <4B9940B633CC2049901F7815B7789244@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 s2EM5OpH019905 On Fri, 2014-03-14 at 21:58 +0000, One Thousand Gnomes wrote: > On Fri, 14 Mar 2014 19:24:55 +0000 > Matthew Garrett wrote: > > As an example, imagine a platform with the bootloader and kernel on > > read-only media. The platform can assert that the kernel is trusted even > > if there's no measurement of the kernel. > > Only if you have a secure signed path through the controller firmware and > physical security of the hardware. If not I can reprogram your BIOS, your > GPU firmware, your USB stick or your CD-ROM controller to lie. Sure, and then the trust that the firmware placed in the kernel would be misplaced. You can subvert Secure Boot with an SPI flasher, just as you can subvert selinux with a firewire dongle. Those attacks are outside the threat model. If you're in a situation where you have to care about threats outside that threat model then you need to choose a more appropriate solution. -- Matthew Garrett {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I