IETF Logo Mail Archive

Re: [Suit] Wording for integrated payload size

Michael Richardson <mcr+ietf@sandelman.ca> Tue, 17 December 2019 19:38 UTC

Return-Path: <mcr+ietf@sandelman.ca>
X-Original-To: suit@ietfa.amsl.com
Delivered-To: suit@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1B485120CE6 for <suit@ietfa.amsl.com>; Tue, 17 Dec 2019 11:38:09 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.199
X-Spam-Level:
X-Spam-Status: No, score=-4.199 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tTLQe-lfX2F1 for <suit@ietfa.amsl.com>; Tue, 17 Dec 2019 11:38:04 -0800 (PST)
Received: from tuna.sandelman.ca (tuna.sandelman.ca [209.87.249.19]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 0ED37120D55 for <suit@ietf.org>; Tue, 17 Dec 2019 11:38:03 -0800 (PST)
Received: from sandelman.ca (obiwan.sandelman.ca [IPv6:2607:f0b0:f:2::247]) by tuna.sandelman.ca (Postfix) with ESMTP id 45A8E38981; Tue, 17 Dec 2019 14:37:59 -0500 (EST)
Received: from localhost (localhost [IPv6:::1]) by sandelman.ca (Postfix) with ESMTP id 3F6E2D36; Tue, 17 Dec 2019 14:38:02 -0500 (EST)
From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Brendan Moran <Brendan.Moran@arm.com>
cc: Dave Thaler <dthaler@microsoft.com>, suit <suit@ietf.org>
In-Reply-To: <3EC3D5C9-1475-4659-BCE5-FEFFD7144248@arm.com>
References: <734509A8-7562-4B47-AAE5-54F840C4A298@arm.com> <MWHPR21MB0784F574BE1FFD50743040FCA35A0@MWHPR21MB0784.namprd21.prod.outlook.com> <3EC3D5C9-1475-4659-BCE5-FEFFD7144248@arm.com>
X-Mailer: MH-E 8.6; nmh 1.7+dev; GNU Emacs 24.5.1
X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m<nPbLgmtKK-5dC@#:k
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha256"; protocol="application/pgp-signature"
Date: Tue, 17 Dec 2019 14:38:02 -0500
Message-ID: <16551.1576611482@localhost>
Archived-At: <https://mailarchive.ietf.org/arch/msg/suit/goJm19BQjzZxA0pLTQiChP6dWeg>
Subject: Re: [Suit] Wording for integrated payload size
X-BeenThere: suit@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Software Updates for Internet of Things <suit.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/suit>, <mailto:suit-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/suit/>
List-Post: <mailto:suit@ietf.org>
List-Help: <mailto:suit-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/suit>, <mailto:suit-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 17 Dec 2019 19:38:09 -0000

Brendan Moran <Brendan.Moran@arm.com> wrote:
    > I see why the use of RAM as a requirement is surprising. There are two
    > requirements here. I believe that one of them is required and one is
    > optional.

    > It is required that the manifest be held invariant between verification and
    > processing. This could mean storing in internal RAM or NVRAM, storing in a
    > secure external memory, etc.

I think that you are also attempting to defend against hardware attacks where
the contents of memory get changed mid-process.  That's not *explicitely*
stated in the text.

But, it's why you speak about internal RAM (vs RAM), and I guess "secure
external memory" means that it has some cryptographic checks not attackable
From outside the SoC.

Maybe the attempt to abstract the text is detracting from understanding?

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-

v2.23.0 | Report a Bug | By Email