Return-path: Received: from mail-ig0-f174.google.com ([209.85.213.174]:36769 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754413AbbETUf6 (ORCPT ); Wed, 20 May 2015 16:35:58 -0400 Received: by igbpi8 with SMTP id pi8so112596011igb.1 for ; Wed, 20 May 2015 13:35:54 -0700 (PDT) From: Kyle McMartin Date: Wed, 20 May 2015 16:35:51 -0400 To: Seth Forshee Cc: "Luis R. Rodriguez" , linux-security-module@vger.kernel.org, james.l.morris@oracle.com, serge@hallyn.com, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, David Howells , David Woodhouse , Greg Kroah-Hartman , Joey Lee , Rusty Russell , zohar@linux.vnet.ibm.com, mricon@kernel.org Subject: Re: [RFD] linux-firmware key arrangement for firmware signing Message-ID: <20150520203551.GA13557@foundry.jkkm.org> (sfid-20150520_223605_965928_5BF37011) References: <20150519200232.GM23057@wotan.suse.de> <20150520140426.GB126473@ubuntu-hedt> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150520140426.GB126473@ubuntu-hedt> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, May 20, 2015 at 09:04:26AM -0500, Seth Forshee wrote: > I raised the question of key revocation when we discussed this on irc, > but it wasn't answered to my satisfaction. If a key signed by the > kernel-embedded key is compromised, how can that key be revoked so that > it is no longer trusted? > > Someone mentioned UEFI blacklists, which I don't know much about, but > not all systems have UEFI. The only reliable option that comes to mind > for me is an in-kernel blacklist of keys which should no longer be > trusted. > I think the solution here is two-fold... first, we'll probably try some to use a HSM for signing, so there's extremely low risk of compromise. Secondly, if we annotate the key such that it can only be used for firmware, a compromise of my key won't allow you to kexec or load kernel modules. regards, --Kyle