Subject: [lisp] Nonce in PubSub

From: Alberto Rodriguez-Natal <[email-masked]>
Date: Thu, 16 Nov 2017 18:49:11 -0800

Just to clarify what was discussed in the meeting. The nonce used in
the Map-Request requesting the subscription will be used in the
Map-Notify that confirms the subscription. This is at top of page 6 in
the draft.

Similarly, a Map-Notify sent as publication will be ack'ed by a
Map-Notify-Ack using its nonce.

https://tools.ietf.org/html/draft-rodrigueznatal-lisp-pubsub-01

Thanks,
Alberto

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From: Erik Nordmark <[email-masked]>
Date: Fri, 17 Nov 2017 15:17:08 +0800

> Map-Notify-Ack using its nonce.

Albero,

My understanding from Dino's comment at the make was that in his 
implementation the map-notify has the nonce from the original map-request.

The reason I asked about this is that there are some additional security 
benefits if the map-notify has a nonce which corresponds to what the xTR 
had sent in the map-request. Otherwise you need some other mechanism to 
guard against receiving spoofed map-notifies.

    Erik

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From: Alberto Rodriguez-Natal <[email-masked]>
Date: Fri, 17 Nov 2017 10:57:21 -0800

Hi Erik,

I see your point. The draft assumes a security association between the
ITR and the MS in order to authenticate the Map-Notifies. I think this
addresses your valid concern on spoofed Map-Notifies. How this
security association is established is a different discussion :)

Note also that, ideally, the Map-Notifies sent as publications should
each have a different nonce so the MS can easily correlate them with
the Map-Notify-Acks received as responses.

Best,
Alberto

On Thu, Nov 16, 2017 at 11:17 PM, Erik Nordmark <[email-masked]> wrote:
> benefits if the map-notify has a nonce which corresponds to what the xTR had
> sent in the map-request. Otherwise you need some other mechanism to guard
> against receiving spoofed map-notifies.
>
>    Erik
>
>>

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From: Dino Farinacci <[email-masked]>
Date: Sat, 18 Nov 2017 07:10:46 +0800

> ITR and the MS in order to authenticate the Map-Notifies. I think this

We can’t assume this. That is, a subscriber may not register its EID-prefixes to the same map-server that the EID-prefix it
Is Map-Requesting is registered to. So there would be no security association between the two. 

> security association is established is a different discussion :)

You need to store the nonce in the Mao-server. See Fabio’s slide of our demo. My implementation does it the way Erik is suggesting. 

> the Map-Notify-Acks received as responses.

It can do that with the Map-Request nonce as well. 

Dino

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From: Alberto Rodriguez-Natal <[email-masked]>
Date: Fri, 17 Nov 2017 16:03:55 -0800

Then I'm afraid that your implementation is not following the current
specification. But worry not, we can update -02 with Erik's suggestion
so your implementation and the draft are in sync :)

Alberto

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From: Dino Farinacci <[email-masked]>
Date: Sat, 18 Nov 2017 09:10:20 +0800

> Then I'm afraid that your implementation is not following the current

Well there is one of two ways to fix that. :-)

> so your implementation and the draft are in sync :)

Thanks a bunch. 

Dino