Re: Benjamin Kaduk's No Objection on draft-ietf-rtgwg-enterprise-pa-multihoming-08: (with COMMENT)

Benjamin Kaduk <kaduk@mit.edu> Wed, 10 July 2019 00:17 UTC

Return-Path: <kaduk@mit.edu>
X-Original-To: rtgwg@ietfa.amsl.com
Delivered-To: rtgwg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id EBBBF120098; Tue, 9 Jul 2019 17:17:02 -0700 (PDT)
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 cG4Q878AAXPv; Tue, 9 Jul 2019 17:17:00 -0700 (PDT)
Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (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 5B91E120094; Tue, 9 Jul 2019 17:17:00 -0700 (PDT)
Received: from kduck.mit.edu ([24.16.140.251]) (authenticated bits=56) (User authenticated as kaduk@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x6A0Gs5A005527 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 9 Jul 2019 20:16:57 -0400
Date: Tue, 9 Jul 2019 19:16:54 -0500
From: Benjamin Kaduk <kaduk@mit.edu>
To: Jen Linkova <furry13@gmail.com>
Cc: Chris Bowers <chrisbowers.ietf@gmail.com>, The IESG <iesg@ietf.org>, Ronald Bonica <rbonica@juniper.net>, rtgwg-chairs <rtgwg-chairs@ietf.org>, draft-ietf-rtgwg-enterprise-pa-multihoming@ietf.org, Routing WG <rtgwg@ietf.org>
Subject: Re: Benjamin Kaduk's No Objection on draft-ietf-rtgwg-enterprise-pa-multihoming-08: (with COMMENT)
Message-ID: <20190710001653.GF24351@kduck.mit.edu>
References: <156158728441.20135.9632421726659042986.idtracker@ietfa.amsl.com> <CAFU7BASqGX1u4hiaVNxBcMi+7y6fHnP5=xi=phJeOWoymy7Rjg@mail.gmail.com> <CAHzoHbuiP9cqOv5KAkYN=oDhrU_Og98AuN_kbE73Ao9ns5ZquQ@mail.gmail.com> <20190703185314.GL13810@kduck.mit.edu> <CAFU7BAQGhT4FH5ia97QvmKKiz=2QerXxemg1qXxG5A=DBB9hbA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAFU7BAQGhT4FH5ia97QvmKKiz=2QerXxemg1qXxG5A=DBB9hbA@mail.gmail.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtgwg/s6uTq3R79fbDUssQn8-zouvQSso>
X-BeenThere: rtgwg@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Routing Area Working Group <rtgwg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtgwg>, <mailto:rtgwg-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rtgwg/>
List-Post: <mailto:rtgwg@ietf.org>
List-Help: <mailto:rtgwg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtgwg>, <mailto:rtgwg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 10 Jul 2019 00:17:03 -0000

On Thu, Jul 04, 2019 at 10:42:35AM +1000, Jen Linkova wrote:
> Hi Ben,
> 
> I've just submitted -10 version which has Chris's changes integrated
> as well as all suggestions you made.
> 
> The diff:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-rtgwg-enterprise-pa-multihoming-10
> 
> Full text:
> https://tools.ietf.org/html/draft-ietf-rtgwg-enterprise-pa-multihoming-10
> 
> A few comments below:
> 
> On Thu, Jul 4, 2019 at 6:12 AM Benjamin Kaduk <kaduk@mit.edu>; wrote:
> > > > >    To fully benefit from the RA-based solution, first-hop routers need
> > > > >    to implement SADR and be able to send dedicated RAs per scoped
> > > > >
> > > > > It's not just the first-hop routers, though -- won't all the first-hops
> > > > > need to be part of the same connected SADR domain?
> > > >
> > > > They are. By design/definition.
> >
> > Perhaps I'm still confused, but I thought other parts of this document
> > admitted the possibility of having multiple SADR-capable routers that are
> > not all in a connected domain, if only to say "don't do that".  For
> > example, all the  SERs need to be in the same domain.  But if I look at,
> > e.g., Figure 1's topology, R3 would be a first-hop router for H41, and if I
> > read the quoted text literally, having R3 and the SERs support SADR but not
> > R5 would seem to produce a disconnected domain and thus problems.
> 
> That's why we are saying:
> "Therefore all SADR-capable routers within the domain MUST be
> logically connected."
> Having R3 and SERs in the SADR domain with non-SADR capable R5 between
> them might lead to a routing loop.
> 
> The changes made in -10 to clarify this:
> 1) Replaced:
> "To fully benefit from the RA-based solution, first-hop routers need
> to implement SADR and be able to send dedicated RAs per scoped
> forwarding table as discussed above,"
> 
> with
> "To fully benefit from the RA-based solution, first-hop routers need
> to implement SADR, belong to the SADR domain and be able to send
> dedicated RAs per scoped forwarding table as discussed above.."
> 
> 2) Added another item to the Deployment Considerations section:
> https://tools.ietf.org/html/draft-ietf-rtgwg-enterprise-pa-multihoming-10#section-7.1
> "During the incremental SADR domain expansion from the SERs down
> towards first-hop routers it's important to ensure that at any
> moment of time all SADR-capable routers within the domain are
> logically connected (see Section 5)."
> 
> Is it less confusing now?

Greatly so; thank you!

> > That's one type of attack, yes.  I think there may be another one where the
> > attacker has some wiretap in ISP_A but not ISP_B, and they can use the
> > ICMPv6 message to tell the sender to use the source address from ISP_A when
> > traffic would otherwise go to ISP_B or elsewhere -- the forged message
> > causes the traffic to be routed where the attacker can do other things to
> > it.
> >
> > > > I think that if such messages are required to be sent from the
> > > > link-local address and the GTSM is enforced, then the attack vector is
> > > > limited to the same L2 domain which is a bit better..I'll add the text
> > > > to clarify it tomorrow.
> 
> After thinking about it I've realized that GTSM would not help here.
> Those messages could be sent from SERs (which are a few hops away).
> I've moved all security considerations from that section to Section 10:
> https://tools.ietf.org/html/draft-ietf-rtgwg-enterprise-pa-multihoming-10#section-10
> 
> Please let me know if you have any comments for -10 version.

It looks good here (just one typo "tra ffic" that may be my fault anyway).

Thanks again,

Ben