From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759914Ab3BYPpy (ORCPT ); Mon, 25 Feb 2013 10:45:54 -0500 Received: from cavan.codon.org.uk ([93.93.128.6]:57194 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757049Ab3BYPpx (ORCPT ); Mon, 25 Feb 2013 10:45:53 -0500 Date: Mon, 25 Feb 2013 15:45:49 +0000 From: Matthew Garrett To: Florian Weimer Cc: Linus Torvalds , David Howells , Josh Boyer , Peter Jones , Vivek Goyal , Kees Cook , keyrings@linux-nfs.org, Linux Kernel Mailing List Subject: Re: [GIT PULL] Load keys from signed PE binaries Message-ID: <20130225154549.GD13605@srcf.ucam.org> References: <30665.1361461678@warthog.procyon.org.uk> <20130221164244.GA19625@srcf.ucam.org> <87ppzo79in.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ppzo79in.fsf@mid.deneb.enyo.de> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 25, 2013 at 03:28:32PM +0100, Florian Weimer wrote: > But what puzzles me most is why anyone would assume that the UEFI > application signing process somehow ensures that the embedded > certificate is non-malicious. We cannot even track it back to the > submitter because the third-pary market place UEFI authority only > issues pseudonymous proxy certificates. This utterly useless for any > purpose whatsoever, with the notable exception of avoding one > additional step when setting up a dual-boot machine (which will not > even work reliably until we switch to overwriting the Windows boot > loader, like in the pre-UEFI days). If your firmware trusts objects signed by Microsoft, you have to assume that objects signed by Microsoft are trustworthy. There's no way to build a security model otherwise. Are Microsoft trustworthy? We don't know. If you don't trust Microsoft, remove their key from db. > Seriously, folks, can we go back one step and discuss what problem you > are trying to solve? Is it about allowing third-party kernel modules > in an environment which does not allow unsigned ring 0 code execution? The problem I'm trying to solve is "Don't permit Linux to be used as a bootloader for backdoored versions of other operating systems". Any other security benefit is a happy side effect. -- Matthew Garrett | mjg59@srcf.ucam.org