Re: [DNSOP] Resolver behaviour with multiple trust anchors

Joe Abley <jabley@hopcount.ca> Thu, 02 November 2017 16:38 UTC

Return-Path: <jabley@hopcount.ca>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4276813F4F4 for <dnsop@ietfa.amsl.com>; Thu, 2 Nov 2017 09:38:26 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Level:
X-Spam-Status: No, score=-2.7 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=hopcount.ca
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 XE3u3OKlYSlC for <dnsop@ietfa.amsl.com>; Thu, 2 Nov 2017 09:38:24 -0700 (PDT)
Received: from mail-io0-x236.google.com (mail-io0-x236.google.com [IPv6:2607:f8b0:4001:c06::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 21D9D13B262 for <dnsop@ietf.org>; Thu, 2 Nov 2017 09:38:24 -0700 (PDT)
Received: by mail-io0-x236.google.com with SMTP id p186so252492ioe.12 for <dnsop@ietf.org>; Thu, 02 Nov 2017 09:38:24 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hopcount.ca; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=H7z8sALIMF+cSCF+rqefREjQ0npJh5m7X0FvqzrSZyI=; b=ULhpz3VfOy/UcMaT46pZQdedhL2mktFyn62FX64ePPFWngQYNqZvqSPPQHC/sdhBU/ fqv+Fy390E5igjOeibGWqd9bqYUZMFjuIp2ms6vH0dsHRmh/tO+PHsyvKu/mlR19IjqX /SIbXm26AUfKyX5rnTkIok7DvSru99xpRJO8w=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=H7z8sALIMF+cSCF+rqefREjQ0npJh5m7X0FvqzrSZyI=; b=OLg2R6GGE681NCxzdOTxHtcV1QmPiHNjnfYlXfAS9pgmh+oxpPZaZXizd9YxSg6a+M SJa9gpV4HWQ8ZGYsJODPDcVIDcBWuv4oX4PJqOFbeTghrvPfDew/nODY+GA03C0+BEZX YTK93MW52PgyMLd2CXSS5p9ziJK4nWFczu/h48KPDSkWtUt8P47plImTrVCi6d8QjnPz 8kDgN08QoFnykH4yp0NipHNzzm+WFT1RfnuKK6zfoWOizpKx/kacIdQ+2SWHg1UtY1c1 aNkrEyCrgg9eQTBOo05wZTHoK/xdP1m9Z+HM1slTwp9EeSRqD+LcwaaxY5Vf7hkWJ3Rs j/ow==
X-Gm-Message-State: AMCzsaW5NER58xHN2GoEPd+d70W/M0lnrvhjqEdBtSCfEW9uPkbEieQ/ DvjQWZrdC9fiNfNbuBG8Ukwixw==
X-Google-Smtp-Source: ABhQp+TaHIqxWM6T5etZVjvhIHtGxHD+FBqicz1uI0Xqn+R64NIXC4b3/aFd6Cuc2SEzp9naofkYUw==
X-Received: by 10.36.0.207 with SMTP id 198mr3375526ita.128.1509640703395; Thu, 02 Nov 2017 09:38:23 -0700 (PDT)
Received: from node-131fec9w2t6im3n57e.ipv6.teksavvy.com ([2607:f2c0:101:202:546:52b9:e331:151a]) by smtp.gmail.com with ESMTPSA id b13sm1798632iod.16.2017.11.02.09.38.21 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Nov 2017 09:38:22 -0700 (PDT)
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 11.0 \(3445.1.7\))
From: Joe Abley <jabley@hopcount.ca>
In-Reply-To: <CA+nkc8CqoX87L9YPoJfx7dSOZY4Pm5RXKNvKVBkFB_KX+EK4KQ@mail.gmail.com>
Date: Thu, 2 Nov 2017 12:38:18 -0400
Cc: Larson Matt <matt@kahlerlarson.org>, Ed Lewis <edward.lewis@icann.org>, Moritz Muller <moritz.muller@sidn.nl>, =?utf-8?Q?=C3=93lafur_Gu=C3=B0mundsson?= <olafur@cloudflare.com>, Paul Wouters <paul@nohats.ca>, "dnsop@ietf.org" <dnsop@ietf.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <956BA758-D584-44BB-8E7C-7F0843F4CA99@hopcount.ca>
References: <121CDBC2-D68C-48EE-A56E-46C61FC21538@sidn.nl> <CAN6NTqxy4SWxsUNZyBA=1TZxdhWtVxaTDYLoA1qO2nKf202g9w@mail.gmail.com> <E94AE36A-CA69-47DB-A2B7-41D0C3644855@nohats.ca> <4678D8A8-1AA0-4684-BFD1-40C969305C49@icann.org> <alpine.LRH.2.21.1710311541090.23568@bofh.nohats.ca> <54030D6D-0B7D-4408-A50A-FDBD66A940B4@kahlerlarson.org> <CA+nkc8CqoX87L9YPoJfx7dSOZY4Pm5RXKNvKVBkFB_KX+EK4KQ@mail.gmail.com>
To: Bob Harold <rharolde@umich.edu>
X-Mailer: Apple Mail (2.3445.1.7)
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsop/k__843hA-g3Gqoln7ZRmv8UDuJU>
Subject: Re: [DNSOP] Resolver behaviour with multiple trust anchors
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Nov 2017 16:38:26 -0000

On 2 Nov 2017, at 11:04, Bob Harold <rharolde@umich.edu>; wrote:

> I generally agree with you, but wonder if there is a performance penalty to searching every possible path before failing.  Is that a reasonable concern?

I think there's a much bigger performance penalty from returning an error to an application and requiring an end-user to do something; the small delay introduced by validating a signature chain against a different trust anchor is likely smaller than that in the event that validation subsequently succeeds and irrelevant in the case that it fails.

I think that the performance angle, whilst always worth considering e.g. for impact on scaling properties, is a red herring in this particular case. I think the focus on what policy makes sense and where it should be applied is the right one.


Joe