Re: [Resolverless-dns] Paper on Resolver-less DNS

Erik Sy <sy@informatik.uni-hamburg.de> Thu, 29 August 2019 14:36 UTC

Return-Path: <sy@informatik.uni-hamburg.de>
X-Original-To: resolverless-dns@ietfa.amsl.com
Delivered-To: resolverless-dns@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 352E712083B for <resolverless-dns@ietfa.amsl.com>; Thu, 29 Aug 2019 07:36:49 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.2
X-Spam-Level:
X-Spam-Status: No, score=-4.2 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] 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 Sb6iG0h0wyWV for <resolverless-dns@ietfa.amsl.com>; Thu, 29 Aug 2019 07:36:47 -0700 (PDT)
Received: from mailhost.informatik.uni-hamburg.de (mailhost.informatik.uni-hamburg.de [134.100.9.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id BACE812083A for <resolverless-dns@ietf.org>; Thu, 29 Aug 2019 07:36:46 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mailhost.informatik.uni-hamburg.de (Postfix) with ESMTP id E66C05BA for <resolverless-dns@ietf.org>; Thu, 29 Aug 2019 16:36:44 +0200 (CEST)
X-Virus-Scanned: amavisd-new at informatik.uni-hamburg.de
Received: from mailhost.informatik.uni-hamburg.de ([127.0.0.1]) by localhost (mailhost.informatik.uni-hamburg.de [127.0.0.1]) (amavisd-new, port 10024) with LMTP id mPN9gKtKb0Nv for <resolverless-dns@ietf.org>; Thu, 29 Aug 2019 16:36:44 +0200 (CEST)
Received: from svs26.informatik.uni-hamburg.de (svs26.informatik.uni-hamburg.de [134.100.15.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "Erik Sy", Issuer "DFN-Verein Global Issuing CA" (verified OK)) (Authenticated sender: sy) by mailhost.informatik.uni-hamburg.de (Postfix) with ESMTPSA id C263E5B9 for <resolverless-dns@ietf.org>; Thu, 29 Aug 2019 16:36:43 +0200 (CEST)
To: resolverless-dns@ietf.org
References: <CAHbrMsBhR1yaLxQk7wZk54Jdf5nvkS03KC3UTae0Famu2+SV8g@mail.gmail.com> <4568720.uvMTqBdgP4@linux-9daj> <fb12f102-714d-95cc-c6cc-0871a2df9f50@informatik.uni-hamburg.de> <34813218.VKkrhzyXsx@linux-9daj> <ae355776-a1bb-cf23-f380-133439661d1f@informatik.uni-hamburg.de> <1171283855.590.1566558699991@appsuite-gw1.open-xchange.com> <a8d9398b-4fea-0a1e-3fa7-5954d001f9ea@informatik.uni-hamburg.de> <1405682425.665.1566561941610@appsuite-gw1.open-xchange.com> <220061a8-608c-0a87-4656-213c87979284@informatik.uni-hamburg.de> <849BE7D4-A07E-496B-B413-E1C979390DA8@osterweil.net> <b2b3e56a-c577-f08a-627a-f54e2e6fadb6@informatik.uni-hamburg.de> <f093a605-6e7d-0237-df5c-441d6789c66f@erik-sy.de> <54892F22-27E4-4444-9CC8-2D9E84A9668F@dukhovni.org>
From: Erik Sy <sy@informatik.uni-hamburg.de>
Openpgp: preference=signencrypt
Autocrypt: addr=sy@informatik.uni-hamburg.de; prefer-encrypt=mutual; keydata= mQINBFzVyS4BEADnUWBPWNK8CNxDj8QarMioEQsyEiLkpsln4zxw1cxhTnK+ZHd4wTOh1BZf GVmGZ7wdb/NLiQbENv44okX4mYgJjt32gbVg8ssfScfTEO9PVBgLi5SDtLAxLk8TjF7ETIkG NUWgAQm6Pw6EowjLjMJ4y3fahPcypqtfuO1cxF86pPYAsSG+9iuInpBQoZwuvZu3SLUMXB9l +Xwiy77wEpvPg49pNQhbFqlIZXAHTLyEIlrxG41xXbTt7P5kH333c1cRD//EeC2oEjZhgCBh B4ObFpgL4JxSo71MZFdSDOWfiwMq3kXOwJnPNq9xzcWEItVyLK30fXWt5uZ3YfUcZGpGXv1Y Kl4monIru9NFVSW35FlhHtpgUKdQBKJMeuc1ckZr00zRtd1tf/69rdnjJngR+5RJZE3ykDx4 bJ4P75nqeDUe8adc4S0GeExEgsjVl8QZpCgIrjicA4MQERJKaA3bmCWy5YfCqsZYfbFXrcmq sZopkMTI2X5ZsA3y+jjWlmfDo3Tdu9ddfF8BSB0nTbaPLnJCs878T8HE+Lx9y6QyHlfZ0BJx IuepITZInhbH2c/X5Ipw37+YjNCwzlCOozJDZ/tTj8suMpAKdt4qq3OR1PKyhlilUBiQcYDu 4HfGffihD91Bwxz89YsAtej6EvWLjSfF4fUucFMh9N4GSVQK/QARAQABtCZFcmlrIFN5IDxz eUBpbmZvcm1hdGlrLnVpbi1oYW1idXJnLmRlPokCVgQTAQoAQQIbAwUJB4YfgAULCQgHAwUV CgkICwUWAgMBAAIeAQIXgBYhBADP3q0kgaL0XCmyn7pmQSEb9ifsBQJc1dhqAhkBAAoJELpm QSEb9ifs580P9AiLD49H+bZhNwXZYAXD236D6mKBimXo7EnM8D+v6TXiBKweH35XkKjkHtfU nosHYybfQoV8Rjcdg4lZ8+E/N/7Jk0dcQ6N6gUY1YvMw+t5AiEXMZdz6tQEjwrU+FVlBMN7j WKDpumE4PjkKlxh4IPc9HCgmI0G3uq859nIBvHEpPyCc6z1++9zq+oqP8vUtFLqmuAhQJoOc JSyKv7FYnGhGRnGJGPwkdqwGfS6fZaavhKDXgBcvULXKF7gThZp6kAHG7QhEeNmwL4l/UTOA oAu1pwTfelMwkRWwXyZjgnSqY59ejD6lcFdxZ51O4qIfPmxViaORhNcguD9SvdGw6kdEGNIA az+bd8UfVltz2EkWb+KPbDi6bpa12Zr2Sz+8AakDRhEQ6gSLHicK1cyimhsf66i4SjlUMefX Gq2ImH2xJTMSZi2GN/0JtK/KaBfwArvxoNlWfp3aP97fmXeqNWZVJo2T0+Vvr3hKs00XhU/S 82sbVeFmAJMho5SL4GO+CYEYBQUuIUj131JBfgw3o/YB/WuTD+ELuM+VKP0loXPcgfE4UlEM Ik8yJmzKbRRXfwhCpvoc5T0GFtmQ9szMO9cnll+BiDK3qHNtfMsY09PgjCHnOzwhvYMf7H+3 g0dH3HyIY5Id1YPS88GANpqiG+K1d3vwr2dTER5ZUBuu+pq5Ag0EXNXJLgEQAKRNM1sPfiLC nEVME84YDsek0M+5svW6T1ggJL4dAgUdwYyujSrDdEujBr1AJaVHuJzMKLvqAIQqSvid0qVM zH32rx70LIkaLJE6iGbf/ckHHA1bpgzDRY9dcLj/J/B0F94BFx1oSavnP6uD1qRODnc4c9rZ s/GfmdnTxaC84MG26SWua2ckk81+ZP2qenXnebz1Krv0oRvObGW3QzAAjyg7Fdlb9UqRApmI FbM8xtTtNyls+ISruC8KbYTxv5wPegm817iLox9WpXkkJNbM6I/Nn887yvxsZghbiuoJaqJl OQqkm1wlMroQEIVIfZbe9+iSB7wc9KisxAOxsoFTfOeIwNfgH6HMvzNo+yffLnvjNO3v/Yzx utfP4FL00lVl53aTWj+Hq6Bym1EX+ZSSb+LhDW5MzXig4PYJKgZf2L+fr2SfDoiZMY6Nbirt DMAS2TpKaV4Jgc8576qkhwhG7o9GKPmNWV55lo+sFsGIXCsVB5zWjCq/FUJLg+dE+FR6aIR7 q2npur4rz9os69POEbTcIKn3vfbQ8ytaTuRfFGeTq2VjHXzi/qH49+i5sWLgvZug31f0dDhs PKDFdSTKrv2DFaKW9OsAbPoqqT3krqE0ho8iMbOaPqpEUn8z+cR7Ozuz3BE/ZedetOh/W8Kx K04rYuWGo4bZmf42QoKfWM6vABEBAAGJAjwEGAEKACYWIQQAz96tJIGi9Fwpsp+6ZkEhG/Yn 7AUCXNXJLgIbDAUJB4YfgAAKCRC6ZkEhG/Yn7HwtD/98u7M3mR5ktzk2aCkS7grO7PMbEFqS 0ycCOV+3P3u6gMy0conDgywA+niXVmzO4UsD2u7ncE8Y27Gc+nx0Q0MgmZ7Nju/rlLc/xisU Q++0MLhvwWQU6NRIO9hhaPK8gQzkvTtxRWxKljh7fDqlb9L02rCJ5jZ7zpRxGrRanQxkB7Z6 StY2AAaI6SMH6RDV45J2uVT+Fg5qenA3wqgxeY/V2avEFNHMwbs1v3pUmnPo5KTLvaMbMDaf PKu8akQezpO4CK3ugxV3tMQ43RFT4kdl1XQyaKEffLQUyoUyFHGJfq66+01t4cMu4/CEC7D+ S7pkOn7ANuwgilfINHVZ95Z1HOdadMYvt1Q37qmOaK34K6kHLbTglBIb2eBEp/OcUlOcrFEu 7yq1TU6QSvGA9QZVeAfttyA9YqEawB3j11uJm3xMknqS3SzTE0JxZNyz1Qri6OLnP3uVaXJj BCiiGZf6sgnCa7/JlYrrEIF3ukWQutUfG+1XVq85/gPYnmTlenp4PCIuQVJT+ldG3hPNS1un qX0iEGiV8XdwXy9Gg49QAhNOFn6llW17VP279NvEVa6eRAm5w4mp4L3FgpbFlKkCHZXzMx/7 wuYPd9pj+olW2uDid279lKsUGt0I7MVyad311Fd1WnQQrAuEw6ZduDNZMxnhRV4x0PxwnGEY Ye+WbA==
X-Enigmail-Draft-Status: N11101
Reply-To: sy@informatik.uni-hamburg.de
Message-ID: <4ec7dd1d-e914-0adb-4240-296f2f762b5f@informatik.uni-hamburg.de>
Date: Thu, 29 Aug 2019 16:36:42 +0200
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <54892F22-27E4-4444-9CC8-2D9E84A9668F@dukhovni.org>
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="------------ms020109000008020902090005"
Archived-At: <https://mailarchive.ietf.org/arch/msg/resolverless-dns/06NwrdTwhaBCdIIjPA-kbHUkipI>
Subject: Re: [Resolverless-dns] Paper on Resolver-less DNS
X-BeenThere: resolverless-dns@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Resolverless DNS <resolverless-dns.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/resolverless-dns>, <mailto:resolverless-dns-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/resolverless-dns/>
List-Post: <mailto:resolverless-dns@ietf.org>
List-Help: <mailto:resolverless-dns-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/resolverless-dns>, <mailto:resolverless-dns-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 29 Aug 2019 14:36:49 -0000

On 8/27/19 23:39, Viktor Dukhovni wrote:
>> On Aug 27, 2019, at 5:18 PM, Erik Sy <email@erik-sy.de>; wrote:
>>
>> It seems to me, that both of you are OK with the risk of DNSSEC + DANE
>> TLSA leading to hard failures.
> I also deny beating my spouse...  Seriously, the premise of the question
> "are you OK with the risk of DANE leading to hard failures" is flawed.
> Hard failures are the purpose of security mechanisms.  Of course I am
> OK with a security mechanism that may deny access, that's not the
> right question.

I disagree, that this question is flawed. It assumes that DNSSEC + DANE
is an optional security mechanism in the context of web browsers. Note,
that for example a valid TLS certificate is considered a mandatory
security mechanism and should be enforced by hard failures. Thus, the
question is more like "are you OK with optional security mechanisms
leading to hard failures".

>
> The right question is whether a given mechanism is sufficiently robust
> to be usable. 
At least the given mechanism needs also to provide a significant
security benefit. In my view, the additional benefit of DNSSEC+ DANE
compared to Certificate Transparency + Strict Transport Security (HSTS
or MTA-STS) is for the majority of server operators or users not relevant.
>> I like to point out, that resolver-less DNS can be extended to support
>> DNSSEC + DANE TLSA as a validation mechanism for DNS records. Thus, in
>> case browser vendors decide to support DNSSEC + DANE TLSA the browsers
>> can receive the corresponding records also via resolver-less DNS.
> Actually, we've been down that road already (TLS DNSSEC chain
> extension fiasco).  There is no clean way to provide downgrade
> resistance in such a protocol, or even properly ensure that
> answers are in bailiwick.  I doubt you are proposing that servers
> MUST always return a full DNSSEC validation chain for the returned
> RRsets (or denial of existence proofs for the associated DS RRs).

In my view, supporting DNSSEC + DANE TLSA in resolver-less DNS makes
only sense if the server provides a full DNSSEC validation chain because
everything else seems to introduce significant delays. However, given
the significant size of full DNSSEC validation chains such feature
should be deactivated in a default configuration of resolver-less DNS.
Anyway, as long as no web browser intends to support a validation of DNS
records via DNSSEC + DANE TLSA, there is no requirement for
resolver-less DNS to support this practice.

Erik