Re: [Suit] intentional rollback of firmware

Michael Richardson <mcr+ietf@sandelman.ca> Wed, 11 December 2019 19:00 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 4292F1200D6 for <suit@ietfa.amsl.com>; Wed, 11 Dec 2019 11:00:50 -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 ZHmQ2nqcqcdj for <suit@ietfa.amsl.com>; Wed, 11 Dec 2019 11:00:48 -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 111F6120052 for <suit@ietf.org>; Wed, 11 Dec 2019 11:00:47 -0800 (PST)
Received: from sandelman.ca (obiwan.sandelman.ca [209.87.249.21]) by tuna.sandelman.ca (Postfix) with ESMTP id E7FF338989 for <suit@ietf.org>; Wed, 11 Dec 2019 13:56:58 -0500 (EST)
Received: from localhost (localhost [IPv6:::1]) by sandelman.ca (Postfix) with ESMTP id D1334A91 for <suit@ietf.org>; Wed, 11 Dec 2019 14:00:46 -0500 (EST)
From: Michael Richardson <mcr+ietf@sandelman.ca>
To: "suit\@ietf.org" <suit@ietf.org>
In-Reply-To: <MWHPR21MB07843D8D21C1A01336E8EFEBA35A0@MWHPR21MB0784.namprd21.prod.outlook.com>
References: <19658.1576089434@localhost> <MWHPR21MB07843D8D21C1A01336E8EFEBA35A0@MWHPR21MB0784.namprd21.prod.outlook.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: Wed, 11 Dec 2019 14:00:46 -0500
Message-ID: <25447.1576090846@localhost>
Archived-At: <https://mailarchive.ietf.org/arch/msg/suit/rBiO2dwo9YosCbxOJxtEeFuirMA>
Subject: Re: [Suit] intentional rollback of firmware
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: Wed, 11 Dec 2019 19:00:50 -0000

Dave Thaler <dthaler@microsoft.com> wrote:
    > https://tools.ietf.org/html/draft-ietf-suit-information-model-04#section-4.3.1 says:
    >> Note: This is not a firmware version.  It is a manifest sequence
    >> number.  A firmware version may be rolled back by creating a new
    >> manifest for the old firmware version with a later sequence number.

    > The information model doc is referenced in several places in the
    > architecture, but maybe it should be explicit about the threat model is
    > covered in detail in the information model document.

Thank you for this pointer.
I didn't think I'd find it in the info model, but in hindsight, it makes
sense.  It shows that I haven't paid enough attention to the information
model document. (Damn WG conflicts. I see it's in WGLC, which I had spaced too)

I want to suggest a tweak to the abstract:

OLD:
   One component of such a firmware update is a concise and machine-
   processable meta-data document, or manifest, that describes the
   firmware image(s) and offers appropriate protection.  This document
   describes the information that must be present in the manifest.

NEW:
   One component of such a firmware update is a concise and machine-
   processable meta-data document, or manifest, that describes the
   firmware image(s) and offers appropriate protection.  This document
   describes a series of security threats, along with the types of
   information that must be present in the manifest in order to deal
   with the threats.



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