Subject: [Emu] Late WGLC Comment on draft-ietf-emu-eap-tls13

From: Russ Housley <[email-masked]>
Date: Mon, 13 Jan 2020 12:29:13 -0500

John:

Section 2.1.1 says:

   Pre-Shared Key (PSK) authentication SHALL NOT be used except
   for resumption.

I would rather this say:

   Pre-Shared Key (PSK) authentication SHALL NOT be used except
   for resumption or in conjunction with the "tls_cert_with_extern_psk"
   extension [ID-ietf-tls-tls13-cert-with-extern-psk].

Russ

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From: "Eliot Lear (elear)" <[email-masked]>
Date: Wed, 15 Jan 2020 09:17:10 +0000

Hi Michael,

> 
> Owen, do we have a need to recognize that a device needs to perform
> onboarding again after a movement?
> 
> i.e. device A enrolls on network 1, gets an LDevID usable on network 1,
> uses that with EAP-FOOBAR.
> 
> device A then is moved to network 2, it tries to use same LDevID,
> receives an error and then recognizes that it needs to perform another
> enrollment.
> 

I think that is up to the device manufacturer and relates to a number of factors, such as whether the device is mobile, whether it has a reset button, the nature of the device, privacy considerations, whether there are federated capabilities on the device, etc.

> What is that error, and is it recognizeable?  Do we need a new error
> code to distinguish from "I reject you" from "I reject you but, you
> could try enrolling with BRSKI-TEAP"

I think that can already be detected in the draft based on the action request frames.

Eliot
> 
> 
> (hoping re-installed laptop works)
> 
> 
> <pEpkey.asc>_______________________________________________
> Emu mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/emu

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From: Michael Richardson <[email-masked]>
Date: Wed, 15 Jan 2020 10:10:36 -0500

Eliot Lear (elear) <[email-masked]> wrote:
    >> i.e. device A enrolls on network 1, gets an LDevID usable on network
    >> 1, uses that with EAP-FOOBAR.
    >>

    > I think that is up to the device manufacturer and relates to a number
    > of factors, such as whether the device is mobile, whether it has a
    > reset button, the nature of the device, privacy considerations, whether
    > there are federated capabilities on the device, etc.

I can see that some of these are important to the device.
The device may have reasons why it would like to enroll again, but I think
the question is more about when the network recognizes that it does not need
to enroll again.
An example would be a device which was originally enrolled with BRSKI-TEAP,
but is then provided with roaming credentials (EDU-ROAM).

How would it know it was on network 2?

    > I think that can already be detected in the draft based on the action

To clear, it would be doing TEAP (or EAP-TLS) to connect to the network,
because it is already enrolled.   If there are BRSKI-specific responses
defined in TEAP, then I'm surprised.

--
Michael Richardson <[email-masked]>, Sandelman Software Works
 -= IPv6 IoT consulting =-

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From: "Eliot Lear (elear)" <[email-masked]>
Date: Wed, 15 Jan 2020 15:26:44 +0000

> On 15 Jan 2020, at 16:10, Michael Richardson <[email-masked]> wrote:
> 
> 

Ah.  I misread your note the first time.  The example of 2 is precisely eduroam, and this becomes a matter of configuration.  We were talking about this at one point, and there is a need to configure a realm as part of all of this.  That is something that could be easily be included in TEAP but isn’t there today.  It could also be included in DPP in the configuration frame.

> defined in TEAP, then I'm surprised.

That is what draft-lear-eap-teap-brski is really about.

Eliot

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From: Michael Richardson <[email-masked]>
Date: Thu, 16 Jan 2020 16:02:36 -0500

> Ah.  I misread your note the first time.  The example of 2 is precisely
    > eduroam, and this becomes a matter of configuration.  We were talking
    > about this at one point, and there is a need to configure a realm as
    > part of all of this.  That is something that could be easily be
    > included in TEAP but isn’t there today.  It could also be included in
    > DPP in the configuration frame.

Yes, so eduroam is an explicit configuration (the end user picks it, and
tells their laptop to use it, Yes they could tell it prefer it, which turns
into a kind of auto-magic selection).  Eduroam is a bit unusual at present.

Consider the case of a device (an expensive 3D virtual reality projector with
a wifi interface, let's say) which if onboarded onto ESSID:
Enterprise.Example.com using BRSKI-TEAP. It then expects to use *TEAP* to
authenticate, and the projector could be carried around the building, and
maybe even travels sometimes to other buildings.  Either on an ad-hoc basis,
or because devices are reassigned.   During that period, it needs to refresh
it's Enterprise-WPA certificate, i.e. it's LDevID, and it just uses EST.

One day, you take it to a show to use in the booth.  At this point, you need
to get it to onboard to the show WiFi.   How does that work?

    > That is what draft-lear-eap-teap-brski is really about.

well, that assumes that EAP-TEAP is used.
Few enterprises use EAP-TEAP today, so how does EAP-TLS (WPA-Enterprise) tell
the device that it needs to enroll?