Re: [babel] babel-dtls: verifying "authentication"

David Schinazi <dschinazi.ietf@gmail.com> Mon, 14 January 2019 22:03 UTC

Return-Path: <dschinazi.ietf@gmail.com>
X-Original-To: babel@ietfa.amsl.com
Delivered-To: babel@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C0CF11313A4 for <babel@ietfa.amsl.com>; Mon, 14 Jan 2019 14:03:59 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.998
X-Spam-Level:
X-Spam-Status: No, score=-1.998 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
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 Nd-t_P5LRgO3 for <babel@ietfa.amsl.com>; Mon, 14 Jan 2019 14:03:57 -0800 (PST)
Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) (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 D1A511313AC for <babel@ietf.org>; Mon, 14 Jan 2019 14:03:57 -0800 (PST)
Received: by mail-pg1-x533.google.com with SMTP id y4so234374pgc.12 for <babel@ietf.org>; Mon, 14 Jan 2019 14:03:57 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Jmi+UG7A6XL9XMoH/bvo10jH4W3UN1m/eaNsd1FYiZ4=; b=ePnRlPJ4t0tQtzDYve+zIW7O/M0gB0lr9lDKt859cXEkwlIKNIBuSckaZn1PWGXOIL sC8fyfY/fTE+CNlMVKdo7TD70WV2RzkTbd7ZG2Gob7/Jy288u8gttFM569YtPZ4Kec1w d+IOsNNZP8bEhn7Z1BFPCnpEYjmz+KJKlFhWAnGOALmbsLa/GWcfJ4SDxv8pdcmYlpcE wI0HfZ7nhRa63Vxl2KWAGLlqZdKm4V6NcmndTzlCw+gnLuNXBccTz/6roN3eZ32Y6r8b f8fWFl/ZtNBYCkqyxNcdCGTHlchl7ieUBIPa7U2SG4gOqrDdXwimaCwNEHcVziU+fVeb ZxBA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Jmi+UG7A6XL9XMoH/bvo10jH4W3UN1m/eaNsd1FYiZ4=; b=m9/Y0UFxNbsKN7/S3H/r6DlQCjtgWJuo7pZIBO9PbVc1jw188Fg1ULCTsg5owz56sP CppLn+GkbRarJADfDYDT5UdI1lgSFGC4gJ9TvC+w4MVeJ8iW4Zmva65lPIm32K8HhtBn Ted7Hb/eCNB9CrIPY8SCA/9nOG7HlbKL6BtMN9gjDQrG5K0apDCv3aDEVlWuqO/3y5jJ gkE66Six6A7pnBWeLUW2RrPyvzOjVXwuFjBJnL8FLPUJiS3RVqmVTqQ0HgZ9Lu5/S+qM 1+ligXHpnFRbGiJOorkCaYxAC+PQBUR3ppjViJVWE9YNzZhM5FgqGuaW59lmeJs6sSkN cjjQ==
X-Gm-Message-State: AJcUukemUMxHSGT9yu+c9DZ2E61/obdGZMz6lHjmSXNVV+zBAMy0RaX0 tAgXCeDhsMR8cacA2W4KcDaSsG0Ecq4sB2JPm7s=
X-Google-Smtp-Source: ALg8bN6SNhIeKZrHs3ePSnWZeBuh8G55os/RaqIQ4UmyC8CFHz8a2DU1Q+XEX24DDj37sP71INcumHTYXoNKhoGFhxQ=
X-Received: by 2002:a63:7e1a:: with SMTP id z26mr639262pgc.216.1547503437241; Mon, 14 Jan 2019 14:03:57 -0800 (PST)
MIME-Version: 1.0
References: <2D09D61DDFA73D4C884805CC7865E6114DF8A154@GAALPA1MSGUSRBF.ITServices.sbc.com> <CAPDSy+6cuAJ1m1-DJAHVNjmsQHP6SOJoFSZx6bF6x8o48xs71Q@mail.gmail.com> <2D09D61DDFA73D4C884805CC7865E6114DF8A9A3@GAALPA1MSGUSRBF.ITServices.sbc.com> <875zuuw0yo.wl-jch@irif.fr> <2D09D61DDFA73D4C884805CC7865E6114DF9C5D7@GAALPA1MSGUSRBF.ITServices.sbc.com> <87imyqgbqw.wl-jch@irif.fr>
In-Reply-To: <87imyqgbqw.wl-jch@irif.fr>
From: David Schinazi <dschinazi.ietf@gmail.com>
Date: Mon, 14 Jan 2019 14:03:46 -0800
Message-ID: <CAPDSy+54rPEiLpAujcLLbYKJCEPGCmkF4OCJp-UgeLnZ47w1oQ@mail.gmail.com>
To: Juliusz Chroboczek <jch@irif.fr>
Cc: "STARK, BARBARA H" <bs7652@att.com>, Babel at IETF <babel@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000aa645a057f7238a1"
Archived-At: <https://mailarchive.ietf.org/arch/msg/babel/abT4Wby3f8c9kd5aP02xxvNBJWI>
Subject: Re: [babel] babel-dtls: verifying "authentication"
X-BeenThere: babel@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "A list for discussion of the Babel Routing Protocol." <babel.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/babel>, <mailto:babel-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/babel/>
List-Post: <mailto:babel@ietf.org>
List-Help: <mailto:babel-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/babel>, <mailto:babel-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 14 Jan 2019 22:04:00 -0000

Hi Barbara,

I think we might be interpreting the TLS document differently from one
another, but I'm sure we'll find agreement on what to change in Babel-DTLS.

Regarding the type of credentials, I'm fine with the information model
restricting configuration to X509 certificates, but I do not think that
should belong in Babel-DTLS as there might be non-certificate based
use-cases for Babel-DTLS.

Responding inline to your text proposals:

On Mon, Jan 14, 2019 at 11:35 AM STARK, BARBARA H <bs7652@att.com> wrote:

> Here are some possible authentication requirements that might be
> reasonable for babel-dtls. I'm strongly in favor of the first of these. I
> also think the CA requirement is a good idea. The others I'm presenting to
> provide an idea of what else we might say, but I do think it's good to
> provide at least one (optional) method for associating credentials with a
> specific router-id or IP address.
>

Requiring a CA would break the homenet use-case for example. In my opinion,
if I buy a bunch of homenet routers I should be able to setup my network
even if I don't currently have Internet access to get a CA to sign my
certificates.


> MUST authenticate received credentials against an internal store of
> credentials.
>

I'm not sure how this differs from the current text "Nodes MUST use mutual
authentication" - authenticating a peer implies it is done against a store
of credentials, but perhaps adding a line of clarification is worthwhile.


> SHOULD associate router-id with credentials and ensure credentials are
> only used for that router (this would require additional requirements for
> how to express router-id in certain types of credentials -- like X.509
> subjectAltName).
>

I don't think we should necessarily bind ourselves to the router-ID, as
that could inhibit future innovation - I could run a router that uses two
router IDs to do <insert magic new feature here>.
Having a way to tie router-IDs to X509 certificates makes sense to me, but
I see that as a separate document (similar to how subjectAltName is not
defined or mentioned in the TLS spec).


> MAY ensure same IP address is used to send a particular cert, after first
> use of cert
>

There are devices out there rotating MAC addresses and IP addresses
periodically to improve user privacy, I don't want Babel-DTLS to get in the
way of that.


> MAY support validation by certificate authority (CA) credentials (requires
> an internal store of CA credentials) used to sign received credentials.
> MAY support trust-on-first-use for first time an IP address is seen
>

I'm not sure how these MAYs improve the document. These mechanisms will be
defined by the profiles that use Babel-DTLS. If you feel strongly about
this we could add an appendix providing options for what credentials would
make sense, but I would remove the normative language.

All this said, it might be simplest to have a phone call / video chat of
some kind to discuss this in real time.

Thanks,
David


On Mon, Jan 14, 2019 at 1:39 PM Juliusz Chroboczek <jch@irif.fr> wrote:

> > No. (D)TLS ecosystems have to specify what "authentication" means within
> > that ecosystem.
>
> [...]
>
> > As far as (D)TLS is concerned, received certificates can be
> > automatically accepted without question (i.e., without authentication),
> > and (D)TLS will work just fine.
>
> Right.  Thanks for the explanation.
>