From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5CF7EC004D4 for ; Sat, 21 Jan 2023 03:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229609AbjAUD33 (ORCPT ); Fri, 20 Jan 2023 22:29:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229450AbjAUD33 (ORCPT ); Fri, 20 Jan 2023 22:29:29 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11E226E0FE; Fri, 20 Jan 2023 19:29:28 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A6825B82B88; Sat, 21 Jan 2023 03:29:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCBEDC433D2; Sat, 21 Jan 2023 03:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674271765; bh=AYvipXoxxMR9pl1bocKxT+7lCm00qzXfNi41jjeo4Wk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=er5t2tASHFYKk0OJBKJiOnxjFVaDN8aKTqe5xn+MrOB/ee4MvR51nUO9noQhy8ixC 8LVSuNl4hE82lJEJhkGKLcmr8yEWcSg12B5bD78uuFfAlA1a0f45pXWPPELTn7HFsp UmkjL6bAwgo5Mzp7gsQbjKWrawcOdJSsesLK5oMCaPLx0YgEiJ6Xafj9M5heyPYyWM TZ/LAkDLnAjrX5k7svpFn5dDcOlM/5o2Iz1cXdNYtMNGTi+t8zGlOo7kgf1cMpKVwW e1PNaqP2R10Yw8S9ueD/Lkpa75UtJIomzvQZreAZBp/tIjJ9J4W6Fu9r8o1Kl2fj5a bl65PtvH+NoQg== Date: Sat, 21 Jan 2023 03:29:22 +0000 From: Jarkko Sakkinen To: James Bottomley Cc: Matthew Garrett , William Roberts , Evan Green , linux-kernel@vger.kernel.org, corbet@lwn.net, linux-integrity@vger.kernel.org, Eric Biggers , gwendal@chromium.org, dianders@chromium.org, apronin@chromium.org, Pavel Machek , Ben Boeckel , rjw@rjwysocki.net, Kees Cook , dlunev@google.com, zohar@linux.ibm.com, linux-pm@vger.kernel.org, Matthew Garrett , Jason Gunthorpe , Peter Huewe Subject: Re: [PATCH v5 03/11] tpm: Allow PCR 23 to be restricted to kernel-only use Message-ID: References: <20221111231636.3748636-1-evgreen@chromium.org> <20221111151451.v5.3.I9ded8c8caad27403e9284dfc78ad6cbd845bc98d@changeid> <8ae56656a461d7b957b93778d716c6161070383a.camel@linux.ibm.com> <08302ed1c056da86a71aa2e6ca19111075383e75.camel@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08302ed1c056da86a71aa2e6ca19111075383e75.camel@linux.ibm.com> Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Sat, Jan 14, 2023 at 09:55:37AM -0500, James Bottomley wrote: > On Tue, 2023-01-03 at 13:10 -0800, Matthew Garrett wrote: > > On Tue, Jan 3, 2023 at 1:05 PM William Roberts > > wrote: > > > > > What's the use case of using the creation data and ticket in this > > > context? Who gets the creationData and the ticket? > > > Could a user supplied outsideInfo work? IIRC I saw some patches > > > flying around where the sessions will get encrypted and presumably > > > correctly as well. This would allow the transfer of that > > > outsideInfo, like the NV Index PCR value to be included and > > > integrity protected by the session HMAC. > > > > The goal is to ensure that the key was generated by the kernel. In > > the absence of the creation data, an attacker could generate a > > hibernation image using their own key and trick the kernel into > > resuming arbitrary code. We don't have any way to pass secret data > > from the hibernate kernel to the resume kernel, so I don't think > > there's any easy way to do it with outsideinfo. > > Can we go back again to why you can't use locality? It's exactly > designed for this since locality is part of creation data. Currently > everything only uses locality 0, so it's impossible for anyone on Linux > to produce a key with anything other than 0 in the creation data for > locality. However, the dynamic launch people are proposing that the > Kernel should use Locality 2 for all its operations, which would allow > you to distinguish a key created by the kernel from one created by a > user by locality. > > I think the previous objection was that not all TPMs implement > locality, but then not all laptops have TPMs either, so if you ever > come across one which has a TPM but no locality, it's in a very similar > security boat to one which has no TPM. Kernel could try to use locality 2 and use locality 0 as fallback. BR, Jarkko