I am going to consider these 3 errata separately as I think it is clearest:

Errata ID 5767:

I believe Jouni’s differentiation of an “EAP authentication method” vs “EAP 
method” is that an “EAP authentication method” has a type >= 4. Jouni mentions 
this in his errata filing and it is also mentioned in RFC 3748 Section 
2.1<https://tools.ietf.org/html/rfc3748#section-2.1> (possibly other places 
also). Jouni, I apologize if I have misinterpreted – please correct me if so.

So, an EAP-Identity (type 1) request is an “EAP method”, but there is obviously 
no intermediate result TLV or crypto binding TLV exchanged after an 
EAP-Identity exchange.

Jouni has done an excellent job in this errata of identifying where the 
terminology should be updated, and I agree with Jouni’s changes. I think the 
intent of the RFC in the four instances Jouni identified was fairly clear.

Errata ID 5844:

Oleg, your final proposal seems to indicate that an Intermediate-Result TLV 
should NOT be sent after Basic Password Authentication – I’m not sure I follow 
this. Section 3.3.2 outlines that an Intermediate-Result TLV SHOULD be sent 
after Basic Password Authentication.

So I find this errata valid and agree with Jouni that section C.1 and C.2 
should be updated to include the Intermediate-Result TLV in the diagrams.

I agree with the rest of the proposals Jouni has made as well that this should 
be made clearer throughout the document. Most of the time where the 
Intermediate-Result TLV is mentioned, only EAP is discussed and the Basic 
Password Authentication is forgotten. I don’t believe Jouni’s proposals change 
any timings – just clarify the language.

Errata ID 5845:

I find the errata valid and agree with Jouni. The direction in the rest of the 
document seems to be that an Intermediate-Result TLV is always exchanged (after 
both EAP authentication methods and Basic Password Authentications) and the 
text in 3.3.1 is confusing.

*****

In summary – I find all of these errata valid and appreciate Jouni’s 
suggestions for clarifications. I find them all to be language clarifications 
and don’t believe any exchanges need to be altered.

Oleg, your final proposal seems to be removing the exchange of 
Intermediate-Result TLVs in the Basic Password Authentication case – I am not 
sure I follow this but if you believe this is needed for the resolution of this 
errata I would like to better understand why.

Thanks,
Jorge

From: Emu <emu-boun...@ietf.org> On Behalf Of Oleg Pekar
Sent: Sunday, May 3, 2020 10:02 AM
To: Jouni Malinen <j...@w1.fi>; EMU WG <emu@ietf.org>
Subject: [Emu] TEAP - RFC 7170 - Errata

Hi Jouni,
You filed Errata ID: 5767, 5844, 5845 regarding sending of Intermediate-Result 
TLV. Can we clarify a general scheme of sending Intermediate-Result TLV and 
Crypto-Binding TLV in all cases? It is not exactly clear what is "EAP 
authentication method" and what is its different from "EAP method" (you 
referred to appendix C.3 as an example of "EAP Method" but it is not clear why 
it is not an "EAP authentication method" - could you please clarify).

Here's the list of cases with the current RFC instructions (please add if 
something is missing):

1. A single inner EAP method is executed inside the tunnel.
*** RFC says ***
Section 4.2.11 "An Intermediate-Result TLV indicating success MUST be 
accompanied by a Crypto-Binding TLV". Section 3.3 "Phase 2 MUST always end with 
a Crypto-Binding TLV exchange"

2. Multiple inner EAP methods are executed inside the tunnel.
*** RFC says ***
Send Intermediate-Result TLV if more than one method is going to be executed in 
the tunnel. Send Crypto-Binding TLV if Intermediate-Result TLV indicates 
success.
Section 3.3.1 "If more than one method is going to be executed in the tunnel, 
then upon method completion, the server MUST send an Intermediate-Result TLV 
indicating the result" - wrong
Section 3.3.3 "The Crypto-Binding TLV and Intermediate-Result TLV MUST be 
included to perform cryptographic binding after each successful EAP method in a 
sequence of one or more EAP methods" - correct

3. Basic Password Authentication (using Basic-Password-Auth-Req/Response) is 
executed inside the tunnel
*** RFC says ***
Send Intermediate-Result TLV.
Section 3.3.2 "Upon receiving the response, the server indicates the success or 
failure of the exchange using an Intermediate-Result TLV" - thus Crypto-Binding 
TLV MUST be also sent as quoted in #1.

4. No inner EAP method is executed inside the tunnel.
*** RFC says ***
Section 3.3.3 "A successful TEAP Phase 2 conversation MUST always end in a 
successful Crypto-Binding TLV and Result TLV exchange.  A TEAP server may 
initiate the Crypto-Binding TLV and Result TLV exchange without initiating any 
EAP conversation in TEAP Phase 2"
Section 4.2.13 "The Crypto-Binding TLV MUST be exchanged and verified before 
the final Result TLV exchange, regardless of whether there is an inner EAP 
method authentication or not"

******
Jouni, you provided multiple suggestions for fixing this. Incorporating you 
suggestions, the bottomline could be:
* Send Intermediate-Result TLV after each inner EAP method but not after Basic 
Password Authentication TLV exchange
* Send Crypto-Binding TLV based on inner method MSK/EMSK after each inner EAP 
method that exports MSK/EMSK and send Crypto-Binding TLV based on Zero-MSK in 
case of no inner method was executed

And then it should be declared explicitly and all the places where these TLV 
are mentioned can be fixed accordingly.

Please share your opinion.
~ Oleg



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