From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755969Ab3B1XCt (ORCPT ); Thu, 28 Feb 2013 18:02:49 -0500 Received: from cantor2.suse.de ([195.135.220.15]:59158 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755748Ab3B1XCp (ORCPT ); Thu, 28 Feb 2013 18:02:45 -0500 Date: Fri, 1 Mar 2013 00:02:43 +0100 (CET) From: Jiri Kosina To: Matthew Garrett Cc: David Howells , Linus Torvalds , jwboyer@redhat.com, pjones@redhat.com, vgoyal@redhat.com, keescook@chromium.org, keyrings@linux-nfs.org, linux-kernel@vger.kernel.org, Greg KH , Florian Weimer , Paolo Bonzini Subject: Re: [GIT PULL] Load keys from signed PE binaries In-Reply-To: <20130228225115.GA12360@srcf.ucam.org> Message-ID: References: <30665.1361461678@warthog.procyon.org.uk> <20130228225115.GA12360@srcf.ucam.org> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Feb 2013, Matthew Garrett wrote: > > Let me formulate my point more clearly -- Microsoft very likely going to > > sign hello world EFI PE binary, no matter the contents of .keylist > > section, as they don't give a damn about this section, as it has zero > > semantic value to them, right? > > > > They sign the binary. By signing the binary, they are *NOT* establishing > > cryptographic chain of trust to the key stored in .keylist, but your > > patchset seems to imply so. > > Mr Evil Blackhat's binary is then a mechanism for circumventing the > Windows trust mechanism, Yes, the "hello world" one. But the real harm is being done by the i_own_your_ring0.ko module, which can be modprobed on all the systems where the signed "hello world" binary has been keyctl-ed before it was blacklisted. In other words -- you blacklist the population of the key on systems by blakclisting the key-carrying binary, but the key remains trusted on whatever system the binary has been processed by keyctl before. Right? If so, that's a clear difference from normal X.509 chain of trust (i.e. the difference between having the key signed, and having the binary signed). -- Jiri Kosina SUSE Labs