Subject: [Anima] x5bag in pledge->registrar

From: Michael Richardson <[email-masked]>
Date: Mon, 26 Jul 2021 22:15:17 -0400

In the hackathon work a Registrar implementor noticed an x5bag on the
BRSKI-EST link (Pledge->Registrar)

I think that the DTLS Client Certificate (and chain) is always better.
But, I guess we should say something about why the Registrar should prefer to
use that instead.

So pledge can put stuff in that doesn't belong, but it will get ignored.

  https://github.com/anima-wg/constrained-voucher/issues/145

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Michael Richardson <[email-masked]>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide

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From: Peter van der Stok <[email-masked]>
Date: Tue, 27 Jul 2021 10:25:42 +0200

Fully agree

peter
Michael Richardson schreef op 2021-07-27 04:15:

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From: Toerless Eckert <[email-masked]>
Date: Tue, 27 Jul 2021 19:13:35 +0200

This goes back to your observation from the content-type discussion:

"Data items not mentioned SHOULD be ignored."

BUT: Vendors (running MASA) could be very curious. Lightbulbs enrolling
may want to encode in some opague data of the VR (such as the cert)
information spoofed about the environment, such as the wifi BSSIDs
it sees, aka: Mac Addresses of WiFi APs. This is what google for example
uses to guess where you are on the planet.

Given how some ANIMA observers are concerned about MASA/Vendors,
i think we should do our best to avoid unnecessary side channel
opportunities.

So: Why would we not want to specify that pledge MUST NOT include
into the voucher elements not explicitly mentioned in the document ?

Cheers
    Toerless

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[email-masked]

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From: Michael Richardson <[email-masked]>
Date: Wed, 28 Jul 2021 16:47:03 -0400

> "Data items not mentioned SHOULD be ignored."

Postel Principal:  be liberal in what you accept.

I can't stop people putting extra stuff in their objects, but we can tell
receivers what to do when they see that stuff.

In this case, we have reasons why a library might include x5bag support (for
the voucher).   My Voucher-Request class is a subclass of Voucher, for instance.
I can easily goof here and include x5bag on the voucher-request.

    > uses to guess where you are on the planet.

Uhm. Sure.

    > i think we should do our best to avoid unnecessary side channel

But, there are lots of other places, and I'm working on a document, for
instance, on carrying RATS EAT Evidence through the VR.

    > into the voucher elements not explicitly mentioned in the document ?

Because it's not enforceable, and it results in failures to interoperate when
we introduce new things.

If we say that anything new causes the VR to be dropped, then we can never
add new things, because it causes interoperation issues if the pledge
starts adding them before the Registrar is ready.

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        |    IoT architect   [
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