Re: [tram] Adam Roach's Discuss on draft-ietf-tram-stunbis-16: (with DISCUSS and COMMENT)
Rohan Mahy <rohan.mahy@gmail.com> Sun, 07 October 2018 20:37 UTC
Return-Path: <rohan.mahy@gmail.com>
X-Original-To: tram@ietfa.amsl.com
Delivered-To: tram@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 591AF130DEF; Sun, 7 Oct 2018 13:37:25 -0700 (PDT)
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 b_GDJ6h2iVYk; Sun, 7 Oct 2018 13:37:21 -0700 (PDT)
Received: from mail-ua1-x92b.google.com (mail-ua1-x92b.google.com [IPv6:2607:f8b0:4864:20::92b]) (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 0C62F124D68; Sun, 7 Oct 2018 13:37:21 -0700 (PDT)
Received: by mail-ua1-x92b.google.com with SMTP id g18-v6so6459585uam.6; Sun, 07 Oct 2018 13:37:20 -0700 (PDT)
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=9Zhw2ip7iPwAsN+7vVKl362nVGD6b0/zAOUQq9AvHJw=; b=Kf5rlbOrKCAX2u8175/O0DtyJkOr3oGbq9nO02uDzRmxa223ul8ullFfLexKhojCMw jjDN7+/l/P+w9kxjc305QbCcc3oTsosnojlOQx3urDpkEr74g5R7oz15W19JQJuXVUtc ClsWHJUZrk2uZymvQdYVYJ+eB3zl2kZVPI3hHibuYjTCLCHIE/uFhXEaJyyb0QDYsU4V SAuOovP6NFrzonvoZU1662MXhz+Fl2phmhzrKvoI7JiPzrqCPjU+Fpu4fPxbIGj1BJwj w/4/VQDXYzLwlL6hn+qMYRZPD6T3QDj0RW9l5FLQ3QhgLZXZF302rnz9Tcq8KWzM2Yj2 AgMg==
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=9Zhw2ip7iPwAsN+7vVKl362nVGD6b0/zAOUQq9AvHJw=; b=IG+JFEek7icRqq3x3OsSaOJCQDAj/adz+hanKDsaFJTQ7KiQsIJS3ONEjC4ihdHqeh 187eKhoEMwFpFIBHxs6YDQMWnUiXfiTfDXkPpWcFUlSM2DlsbS65N7i4aUVMy/V91apy yPXHTedFHM03pz8VY44UwctEiDHdjHzdPJG8EQjJEn3hj7J9aLlYsxggObKACRO6Jz1y rP5n/EvWWsmZmA0a2z0UF2+Ruz3YzcgGvJmE0Pu/arDrszDkgFm7jSjup3Xe/RTWy4iV /h5hzvYgN1TB0aoGjjzv4XDCHRJW7msDPPD/rbkiuAYciLDUR6mqs1NgLBNn4s+uMspP CGHg==
X-Gm-Message-State: ABuFfoi4o/GeJ4XGTcyBzcQA6Hn1jpUX9XN1AAF2bxoxXK0FrkBBVU5I wLU9z45slG3sMvYINggdazN8HXUrDKcMI1KjIhc=
X-Google-Smtp-Source: ACcGV605yRjmCf2DOvOEH8SfMb803Bb4bqPWrbis+y3F704K0o3IGzKb/XEVMJZA12VHZfyj+WAAanUd4I8Cgoia+4g=
X-Received: by 2002:ab0:2101:: with SMTP id d1mr7732463ual.108.1538944639836; Sun, 07 Oct 2018 13:37:19 -0700 (PDT)
MIME-Version: 1.0
References: <152403138853.31946.14807823535362928987.idtracker@ietfa.amsl.com> <27cb2f70-d907-b61f-bb5a-6b19053238fe@petit-huguenin.org> <1e8cd5de-06de-6745-fc4d-d15fcdd0b4d9@petit-huguenin.org> <df27ff82-bb5a-8c83-f119-a6f4e9f65a53@nostrum.com> <a5da7dc3-472c-8dcf-27e0-7e334d6590f6@ericsson.com> <5ff10fb0-301e-5d97-01b0-f15296bae0d3@nostrum.com> <b845eb08-7974-ec9d-0a98-e04d6071b2e1@petit-huguenin.org> <20180909014711.GT73164@kduck.kaduk.org> <49512499-0e71-1f5b-e12c-213a3dd88d91@petit-huguenin.org> <CAKoiRuacSP_FuXouxfSbbZ5fN_9O1gxBPwUomranS_Cz5YawMA@mail.gmail.com> <7aacd118-e726-320b-2083-5ee89746c042@petit-huguenin.org>
In-Reply-To: <7aacd118-e726-320b-2083-5ee89746c042@petit-huguenin.org>
From: Rohan Mahy <rohan.mahy@gmail.com>
Date: Sun, 07 Oct 2018 13:37:08 -0700
Message-ID: <CAKoiRub8vo+X419QgbiyvQKUoc4nGJdKfEJTM+CUGKpV_7x-rA@mail.gmail.com>
To: Marc Petit-Huguenin <marc@petit-huguenin.org>
Cc: Benjamin Kaduk <kaduk@mit.edu>, Adam Roach <adam@nostrum.com>, Gonzalo Camarillo <Gonzalo.Camarillo@ericsson.com>, The IESG <iesg@ietf.org>, tram-chairs@ietf.org, draft-ietf-tram-stunbis@ietf.org, Tolga Asveren <tasveren@rbbn.com>, tram@ietf.org
Content-Type: multipart/alternative; boundary="0000000000009628650577a978bf"
Archived-At: <https://mailarchive.ietf.org/arch/msg/tram/wyGvsmQmUAz0Ok4tpNQtslI2FcU>
Subject: Re: [tram] Adam Roach's Discuss on draft-ietf-tram-stunbis-16: (with DISCUSS and COMMENT)
X-BeenThere: tram@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Discussing the creation of a Turn Revised And Modernized \(TRAM\) WG, which goal is to consolidate the various initiatives to update TURN and STUN." <tram.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tram>, <mailto:tram-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tram/>
List-Post: <mailto:tram@ietf.org>
List-Help: <mailto:tram-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tram>, <mailto:tram-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 07 Oct 2018 20:37:25 -0000
If we think this might happen we could add: "A future STUN extension or usage may relax this requirement provided it demonstrates how to authenticate the STUN server and prevent man in the middle attacks." Thanks, -rohan On Sun, Oct 7, 2018, 08:17 Marc Petit-Huguenin <marc@petit-huguenin.org> wrote: > On 10/07/2018 08:05 AM, Rohan Mahy wrote: > > [snip] > >>> using https, that the hostname verification for the https certificate > >>> implies that the stuns URI embedded in the document are receiving > >>> adequate protection and can be used without worrying about the lack of > >>> certificate verification for the stuns URI. > >>> > >>> Now that is an assumption that we made, and we'd very much like to hear > >>> if that assumption is incorrect. > >> > >> Note that I may be lacking full context, but based just on your > > description > >> above and § 8.1 of the -18, I am concerned about your statement "without > >> worrying about the lack of certificate verification for the stuns URI". > > My > >> understanding is, that given a stuns URI with an IP address for the host > >> and some domain name specified by the same mechanism that provided the > > URI, > >> is that this domain name would then be used as input to the servername > >> verification process for the new connection using this stuns URI. Your > >> statement that I quote here makes it sound like no certificate > > verification > >> is done on this second connection, which would seem to make it > vulnerable > >> to a MITM attack (and thus be a bad idea). > > > > Probably too late now, but if you wanted to be able use a stuns: URI > safely > > with an IP address, you could use a fingerprint URI parameter to prevent > > MITM. This would work as long as you received the URI over an > authenticated > > channel (ex: https:, sip: + S/MIME, and possibly sips:). > > Yes but, as you said, it is too late now for stunbis and TRAM. Maybe in a > draft in 2019... > > > Thanks, > > -rohan > > > > On Sun, Oct 7, 2018 at 5:48 AM Marc Petit-Huguenin < > marc@petit-huguenin.org> > > wrote: > > > >> Hi Benjamin, > >> > >> See inline. > >> > >> On 09/08/2018 06:52 PM, Benjamin Kaduk wrote: > >>> Hi Marc, > >>> > >>> On Sat, Sep 08, 2018 at 02:59:41PM -0700, Marc Petit-Huguenin wrote: > >>>> Hi Adam, > >>>> > >>>> Apologies for the delay in working on that. > >>>> > >>>> For the first issue, the fix is in my copy of the draft. > >>>> > >>>> As for the second issue, Section 8.1 says: > >>>> > >>>> 'A "stuns" URI > >>>> containing an IP address MUST be rejected, unless the domain name is > >>>> provided by the same mechanism that provided the STUN URI, and that > >>>> domain name can be passed to the verification code.' > >>>> > >>>> That text was never about IP addresses in certificates, but about the > >> way a STUN (or TURN really, but that draft does not care about TURN) > server > >> IP address is passed to a WebRTC browser. RFC 7064 permits to store an > IP > >> address directly inside a stun URI, and RFC 7350 extended that to stuns > >> URI, and in fact the text above is directly copied from RFC 7350. > >>>> > >>>> The idea is that a stun URI can be provisioned by a JavaScript program > >>>> downloaded by a WebRTC browser as part of the initialization of a > WebRTC > >>>> application. A security assumption is that using a stuns URI that > >>>> contains an API address is safe if the Javascript program was > downloaded > >>> ^^^ > >>> (I assume this is autocorrect picking the wrong thing to fix a typo and > >>> should be "IP Address") > >> > >> Yes. But no auto-correct feature was to blame in that case. > >> > >>> > >>>> using https, that the hostname verification for the https certificate > >>>> implies that the stuns URI embedded in the document are receiving > >>>> adequate protection and can be used without worrying about the lack of > >>>> certificate verification for the stuns URI. > >>>> > >>>> Now that is an assumption that we made, and we'd very much like to > hear > >>>> if that assumption is incorrect. > >>> > >>> Note that I may be lacking full context, but based just on your > >> description > >>> above and § 8.1 of the -18, I am concerned about your statement > "without > >>> worrying about the lack of certificate verification for the stuns URI". > >> My > >>> understanding is, that given a stuns URI with an IP address for the > host > >>> and some domain name specified by the same mechanism that provided the > >> URI, > >>> is that this domain name would then be used as input to the servername > >>> verification process for the new connection using this stuns URI. Your > >>> statement that I quote here makes it sound like no certificate > >> verification > >>> is done on this second connection, which would seem to make it > vulnerable > >>> to a MITM attack (and thus be a bad idea). > >> > >> You are right. I am not sure if there is an easy way to fix that but if > >> someone figure that out it can be spelled out in a separate draft. > >> Meanwhile I updated the text in the new version of the draft as follow: > >> > >> "If the <host> part of a "stun" URI contains an IP address, then this > >> IP address is used directly to contact the server. A "stuns" URI > >> containing an IP address MUST be rejected." > >> > >>> > >>> -Benjamin > >>> > >>>> Section 6.2.3 is unrelated - it is about IP addresses provisioned > >> locally (not received from the server), and a matching certificate > >> containing IPAddress. I'll make that more explicit after I receive your > >> response on the subject above. > >>>> > >>>> Also it seems that your DISCUSS is not related to that issue at all, > >> would it be possible to clear it? > >>>> > >>>> Thanks. > >>>> > >>>> On 06/18/2018 10:45 AM, Adam Roach wrote: > >>>>> Gonzalo: > >>>>> > >>>>> TL;DR -- unless someone can find evidence indicating what the WG > >> intended, I believe we are waiting on you and Simon. > >>>>> > >>>>> I had two responses in my most recent message. I presume the first > >> should be uncontroversial. > >>>>> > >>>>> The second point pertains to how the working group intended to treat > >> IP addresses in STUNS URIs. The document right now is ambiguous and > >> self-contradictory. If this has been discussed in the past, then the > >> document simply needs to be updated to reflect the outcome of that > >> conversation. If not, then I believe the WG needs to have a conversation > >> about what is intended. > >>>>> > >>>>> As it stands, the document will lead to various notions about whether > >> (and how) IP addresses can be used, which will be an interop nightmare. > >>>>> > >>>>> /a > >>>>> > >>>>> On 6/18/18 05:41, Gonzalo Camarillo wrote: > >>>>>> Marc, Adam, > >>>>>> > >>>>>> what is the status of this discussion? > >>>>>> > >>>>>> Thanks, > >>>>>> > >>>>>> Gonzalo > >>>>>> > >>>>>> On 21/05/2018 9:11 PM, Adam Roach wrote: > >>>>>>> Sorry for taking so long to get back to you on this. Two responses > >> below > >>>>>>> -- everything else looks good. > >>>>>>> > >>>>>>> On 5/3/18 6:37 PM, Marc Petit-Huguenin wrote: > >>>>>>>> On 04/23/2018 03:37 PM, Marc Petit-Huguenin wrote: > >>>>>>>>>> > >> > --------------------------------------------------------------------------- > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> §17.3.1: > >>>>>>>>>> > >>>>>>>>>>> IANA is requested to update the names for attributes 0x0002, > >> 0x0003, > >>>>>>>>>>> 0x0004, 0x0005, 0x0007, and 0x000B, and the reference from > >> RFC 5389 > >>>>>>>>>>> to RFC-to-be for the following STUN methods: > >>>>>>>>>> ... > >>>>>>>>>>> 0x0003: (Reserved; prior to [RFC5389] this was > CHANGE-REQUEST) > >>>>>>>>>> The attribute 0x0003 is registered by RFC 5780, and should not > be > >>>>>>>>>> removed by this document. > >>>>>>>>> Fixed. > >>>>>>> > >>>>>>> Thanks for the change, but the new text still asks IANA to update > the > >>>>>>> table so that 0x0003 points to *this* document, instead of > >> continuing to > >>>>>>> point to RFC 5780. Since this document does not do anything with > >>>>>>> CHANGE-REQUEST, this update does not seem correct. > >>>>>>> > >>>>>>> > >>>>>>>>>> > >> > --------------------------------------------------------------------------- > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> §6.2.3 says: > >>>>>>>>>> > >>>>>>>>>>> Alternatively, a > >>>>>>>>>>> client MAY be configured with a set of IP addresses that are > >>>>>>>>>>> trusted; > >>>>>>>>>>> if a certificate is received that identifies one of those IP > >>>>>>>>>>> addresses, the client considers the identity of the server > to > >> be > >>>>>>>>>>> verified. > >>>>>>>>>> Presumably, this means the server supplies a certificate with > >>>>>>>>>> SubjectAltName > >>>>>>>>>> containing an iPAddress? Please add text to clarify whether > >> that's the > >>>>>>>>>> intention. > >>>>>>>>>> > >>>>>>>>>> If that *is* the intended meaning, then this behavior in §8.1 > >> seems > >>>>>>>>>> unnecessarily restrictive: > >>>>>>>>>> > >>>>>>>>>>> A "stuns" URI > >>>>>>>>>>> containing an IP address MUST be rejected, unless the domain > >> name is > >>>>>>>>>>> provided by the same mechanism that provided the STUN URI, > >> and that > >>>>>>>>>>> domain name can be passed to the verification code. > >>>>>>>>>> Presumably, this is done because certs with iPAddress-form > >>>>>>>>>> SubjectAltNames are > >>>>>>>>>> pretty rare (although CAB Forum baseline requirements do > >> explicitly > >>>>>>>>>> allow > >>>>>>>>>> their issuance) -- but if the text in §6.2.3 is based on > allowing > >>>>>>>>>> the use of > >>>>>>>>>> such certs in a TURN deployment, then it seems that URI > resolution > >>>>>>>>>> should be > >>>>>>>>>> also. > >>>>>>>>>> > >>>>>>>>> I am not sure what was the intent there, so I'll work on that > >> later. > >>>>>>>> We addressed all the other comments, but it would be great if you > >>>>>>>> could suggest some text to address that one. > >>>>>>> I'm not sure what was meant either! > >>>>>>> > >>>>>>> I think we need to untangle what the working group meant to say > >>>>>>> regarding "trusted IP addresses," the way this protocol is intended > >> to > >>>>>>> use certs, and whether the prohibition on using IP addresses in > >> "stuns" > >>>>>>> URIs derives from cert handling or if it has a completely different > >>>>>>> rationale behind it; and, if the former, ensure that those things > >> that > >>>>>>> are prohibited or allowed in certs are similarly prohibited or > >> allowed > >>>>>>> in URIs. > >>>>>>> > >>>>>>> I can suggest some *behavior*, but unless there is some record of > >> what > >>>>>>> the WG meant, any such behavior would need to be discussed by the > >>>>>>> working group, and a consensus would need to be declared by the > >> chairs. > >>>>>>> > >>>>>>> > >>>>>>> /a > >>>>>>> > >>>>> > > > > -- > Marc Petit-Huguenin > Email: marc@petit-huguenin.org > Blog: https://marc.petit-huguenin.org > Profile: https://www.linkedin.com/in/petithug > >
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Adam Roach
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Gonzalo Camarillo
- [tram] Adam Roach's Discuss on draft-ietf-tram-st… Adam Roach
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Adam Roach
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Benjamin Kaduk
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Rohan Mahy
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Benjamin Kaduk
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Rohan Mahy
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Adam Roach
- Re: [tram] Adam Roach's Discuss on draft-ietf-tra… Marc Petit-Huguenin