Subject: [Homenet-babel-sec] Security Design Team - July is coming!

From: Mark Townsley <[email-masked]>
Date: Tue, 23 May 2017 16:21:14 +0200

Dear Babel Security Design Team,

At IETF 98 in Chicago, after the presentation on draft-ietf-homenet-babel-profile, the issue of what to do about routing security was brought up:

https://www.ietf.org/proceedings/98/minutes/minutes-98-homenet-00.txt <https://www.ietf.org/proceedings/98/minutes/minutes-98-homenet-00.txt>
We ended with the action to create a “Small work team to look at issue led by Ted. 5 people raised hands, including Ted, Pierre, Barbara Stark…”. We don’t want to dictate specifically all of the “issues” at hand in this email, but they included such items as:

Network-wide shared keys vs bilateral key exchange
Determination of the network perimeter

If you are receiving this email, you have either been volunteered yourself by signing up to this list or been cordially invited by your chairs  to be in the homenet security design team. If you signed up in error or cannot participate, please unsubscribe.

Ted has agreed to lead the group, including getting you together for online meetings if that is necessary, edit documents, etc. He even said something about writing code, which as pointed out by Juliusz in the meeting, has been a hallmark of all homenet work published thus far. It’s also a good way to ensure that the design team’s recommendation is correct.

The submission deadline for internet drafts is the 3rd of July, about 6 weeks away.  Before then it is highly desirable that the team spend some time between now and then to write up a preliminary design, either in the form of edits to the babel-profile document or (if the design is substantial) as a standalone Homenet Perimeter Security document per our milestones. We would expect to schedule substantive time during our face to face meeting in Prague to discuss your design recommendation. 

Sincerely,

Mark & Ray

Members of the Design Security Team:

Original list of volunteers from Chicago:
STARK, BARBARA H <[email-masked]>
David Schinazi <[email-masked]>
Pierre Pfister <[email-masked]>
Chris Wood <[email-masked]>
Ted Lemon <[email-masked] <mailto:[email-masked]>>
Russ White <[email-masked]>
Juliusz Chroboczek <[email-masked]>
James Woodyatt <[email-masked]>
Donald Eastlake <[email-masked]>
Jennifer Richards <[email-masked]>
Margaret Cullen <[email-masked]>

Others that have signed up to the list since:
[email-masked]
[email-masked]
[email-masked]
[email-masked]
[email-masked]
[email-masked]

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From: Ted Lemon <[email-masked]>
Date: Tue, 23 May 2017 10:41:16 -0400

Thanks, Mark.

To be honest, I do not know where the discussion has landed at this point.   One of the key requirements for me to write any code is that there be a conclusion on how to do unicast hellos.   I sort of thought that that had happened, but I didn't see a clear conclusion because I got busy on some other stuff right when that discussion seemed to stop.

Can anybody else on the team talk about what's going on there?

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From: Ray Bellis <[email-masked]>
Date: Tue, 23 May 2017 16:54:34 +0100

On 23/05/2017 15:41, Ted Lemon wrote:

> To be honest, I do not know where the discussion has landed at this
> point.   One of the key requirements for me to write any code is that
> there be a conclusion on how to do unicast hellos.

At a higher level, ISTR there was some contention as to whether
bilateral key exchange (AIUI requiring unicast hellos) is even necessary
and/or appropriate for the Homenet profile?

Ray

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From: David Schinazi <[email-masked]>
Date: Tue, 23 May 2017 09:00:26 -0700

Ted,

Juliusz can correct me if he disagrees,
but my understanding of the current status of unicast hellos in Babel is:
1) The community agrees that we want to support them
2) The community hasn't yet come to a consensus on how to encode them,
proposals included a new TLV, a flag in the existing TLV, and a sub-TLV.

I think we were waiting for proponents of each alternative to write code.
I'm hoping to work on that in a couple weeks after our developer conference.

While the Homenet Babel profile could technically be achieved without
unicast hellos, I think they expand our options, and since they are at the
top of the Babel WG's agenda, it's worth waiting for them.

David

> On May 23, 2017, at 07:41, Ted Lemon <[email-masked]> wrote:
> 
> Thanks, Mark.
> 
> _______________________________________________
> Homenet-babel-sec mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/homenet-babel-sec

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From: Juliusz Chroboczek <[email-masked]>
Date: Tue, 23 May 2017 19:00:36 +0200

CC-ing the Babel list, at least Matthieu is interested and not subscribed
to h-b-s.

> there be a conclusion on how to do unicast hellos.

Ted, please assume that we (the Babel community) will do the Babel
security work in a reasonably timely manner.  What somebody needs to do is
work out the HNCP-related details, notably signalling the requirement for
auth on a given link and the authentication keys.

> Can anybody else on the team talk about what's going on there?

Will reply to David's mail.

-- Juliusz

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From: Juliusz Chroboczek <[email-masked]>
Date: Tue, 23 May 2017 19:05:04 +0200

> 1) The community agrees that we want to support them

I think there's a fair number of people who are.  I, for one, would like
to see them defined, although I'm not sure if they are really necessary --
I don't see an attack model that targets Hellos specifically.

> proposals included a new TLV, a flag in the existing TLV, and a sub-TLV.

I don't think we considered sub-TLVs, although this might be an option now
that we have mandatory bits.

> top of the Babel WG's agenda, it's worth waiting for them.

Agreed.

Antonin Décimo (in copy of this mail) will be doing an internship on Babel
this July.  The plan is to have him implement a prototype of
Stenberg-Schinazi security for Babel (unicast everything, protect using
DTLS).

My current plan is to ask him to do without unicast Hellos for now (this
means that Hellos will be unprotected), although it's up to Antonin --
perhaps he'll want to work on unicast Hellos first.

-- Juliusz

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From: Juliusz Chroboczek <[email-masked]>
Date: Tue, 23 May 2017 19:09:09 +0200

> I think we were waiting for proponents of each alternative to write code.

Oh, I missed this bit.

I was going to bully everyone into working on that, but then Gwendoline
and Matthieu convinced me to add mandatory bits to the spec, so I've been
working on that, as I'd like the mandatory bits work to be ready before we
introduce more changes.

FWIW, mandatory bits are implemented in both babeld and sbabeld, and I've
got the spec written down.  Unfortunately, I did it in an obsolete git
branch, so I need to do some merging and wordsmithing before I can push.
(Automatic git merges on natural language documents are not quite reliable.)

-- Juliusz

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From: Jehan Tremback <[email-masked]>
Date: Tue, 23 May 2017 11:55:09 -0700

Hey, I just read through the minutes, wondering if someone has a concise
definition of the threat model we are trying to guard against. I assume
it's to prevent attackers from showing up and sending out bogus routing
messages to bork or DOS the network?

-Jehan

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From: Ted Lemon <[email-masked]>
Date: Tue, 23 May 2017 15:01:08 -0400

> auth on a given link and the authentication keys.

Okay, thanks, that's good feedback.   I will focus on that.

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From: Ted Lemon <[email-masked]>
Date: Tue, 23 May 2017 15:04:02 -0400

On May 23, 2017, at 2:55 PM, Jehan Tremback <[email-masked]> wrote:
> Hey, I just read through the minutes, wondering if someone has a concise definition of the threat model we are trying to guard against. I assume it's to prevent attackers from showing up and sending out bogus routing messages to bork or DOS the network?

I don't think it's necessarily going to be possible to _prevent_ attackers from showing up and sending out bogus routing messages.   However, what we probably _can_ do is to be able to know which router sent which update, so that we can see, if there is an attack, where it is coming from.

It would be good to game this out more, though.   We had a pretty good discussion in the meeting, and I think I sent out a summary message about it afterwards, but we haven't gone past that.

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From: Ted Lemon <[email-masked]>
Date: Tue, 23 May 2017 15:06:51 -0400

> Hey, I just read through the minutes, wondering if someone has a concise definition of the threat model we are trying to guard against. I assume it's to prevent attackers from showing up and sendin…

Here are the notes that we took in the break-out session after the main meeting:

https://github.com/bhstark2/babel-security/blob/master/chicago-notes.md <https://github.com/bhstark2/babel-security/blob/master/chicago-notes.md>

There's also a file there where we were going to put in our thoughts about the threat model, so that we could try to come up with an idea of what we are all talking about.   However, it looks like nobody's actually done anything to that document.

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From: Toke Høiland-Jørgensen <[email-masked]>
Date: Tue, 23 May 2017 22:28:49 +0200

> proposals included a new TLV, a flag in the existing TLV, and a

This is definitely on my list on things to add to the Bird babel code...
Haven't gotten around to it as of yet, though.

-Toke

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From: "STARK, BARBARA H" <[email-masked]>
Date: Wed, 24 May 2017 17:37:46 +0000

> https://github.com/bhstark2/babel-security/blob/master/chicago-notes.md 

Please let me know if I should add anyone to this github.
BTW, I'm on vacation this week and will not be particularly responsive during this time.
Barbara

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From: Ted Lemon <[email-masked]>
Date: Wed, 24 May 2017 15:02:34 -0400

If you add me as a maintainer, I can do updates.