Subject: [Emu] Proposed Resolution to TEAP Errata 5844

From: Joseph Salowey <[email-masked]>
Date: Sun, 25 Oct 2020 12:10:41 -0700

Errata 5844: https://www.rfc-editor.org/errata/eid5844
Status: Verified
Revision:

Section 3.3.2 says:

Upon receiving the response, the server
   indicates the success or failure of the exchange using an
   Intermediate-Result TLV.

It Should say:

Upon receiving the response, the server MUST
   indicate the success or failure of the exchange using an
   Intermediate-Result TLV.

Section 3.6 says:

3. The Intermediate-Result TLVs carry success or failure indications of the
individual EAP methods in TEAP Phase 2.

It Should say:

3. The Intermediate-Result TLVs carry success or failure indications of the
individual EAP methods and basic password authentication in TEAP Phase 2.

Section 4.2.11 says:

The Intermediate-Result TLV provides support for acknowledged intermediate
Success and Failure messages between multiple inner EAP methods within EAP.

It Should say:

The Intermediate-Result TLV provides support for acknowledged intermediate
Success and Failure messages between multiple inner EAP methods or basic
password authentication within EAP.

Section C.1 says:

                            <- Crypto-Binding TLV (Request),
                                Result TLV (Success),
                                (Optional PAC TLV)

       Crypto-Binding TLV(Response),
       Result TLV (Success),
       (PAC-Acknowledgement TLV) ->

It should say:

                            <- Intermediate-Result-TLV (Success),
                                Crypto-Binding TLV (Request),
                                Result TLV (Success),
                                (Optional PAC TLV)

       Intermediate-Result-TLV (Success),
       Crypto-Binding TLV(Response),
       Result TLV (Success),
       (PAC-Acknowledgement TLV) ->

Section C.2 Says:
                <- Result TLV (Failure)

            Result TLV (Failure) ->

It Should Say:

                <- Intermediate-Result-TLV (Failure),
                     Result TLV (Failure)

            Intermediate-Result-TLV (Failure),
       Result TLV (Failure) ->

Notes:

Section 3.3.2 implies that Intermediate-Result TLV is used after each round
of Basic-Password-Auth-Req/Resp TLVs. However, the example sequence in C.1
does not show this. The proposed change in this errata adds the
Intermediate-Result TLV indication here. Similar change should be done in
C.2 (i.e., add Intermediate-Result TLV (Failure) to the messages that
include Result TLV) since the language in 3.3.2 describe the indication to
be used for both success and failure cases.

In addition to this change in C.1, it would be good to clarify the
specification globally to avoid confusion about this case since almost all
discussion regarding Intermediate-Result TLV currently is in the context of
inner EAP authentication. 3.3.2 should have a MUST statement similar to
3.3.1. 3.6 should cover success or failure indications of basic password
auth like it does EAP methods. 4.2.11 should note Intermediate-Result TLV
is used with both inner EAP and basic password auth.

---

From: Oleg Pekar <[email-masked]>
Date: Mon, 26 Oct 2020 10:27:33 +0200

Few comments:
1) It seems that the server MUST send Crypto-Binding TLV after a single EAP
authentication method, after each of EAP authentications methods in a
sequence, after no inner method but not after
Basic-Password-Authentication. Shouldn't we close this gap for the sake of
simplicity and structure? (Only Zero-MSK Crypto-Binding TLV is possible in
this case, the same as in no inner method case). Is
Basic-Password-Authentication treated as a case of no inner method?
Technically it is already correct but still may not be clear enough.

This also affects section "4.2.13. Crypto-Binding TLV":

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.

Shouldn't we mention "inner EAP method or basic password authentication"?

2) [Minor] It is written both "EAP methods **and** basic password
authentication" and "EAP methods **or**basic password authentication" in
different sections above. Shouldn't we use the same all the time?

On Sun, Oct 25, 2020 at 9:10 PM Joseph Salowey <[email-masked]> wrote:

> 3. The Intermediate-Result TLVs carry success or failure indications of
> the individual EAP methods in TEAP Phase 2.
>
> It Should say:
>
> 3. The Intermediate-Result TLVs carry success or failure indications of
> the individual EAP methods and basic password authentication in TEAP Phase
> 2.
>
> Section 4.2.11 says:
>
> Section 3.3.2 implies that Intermediate-Result TLV is used after each
> round of Basic-Password-Auth-Req/Resp TLVs. However, the example sequence
> in C.1 does not show this. The proposed change in this errata adds the

---

From: Joseph Salowey <[email-masked]>
Date: Mon, 26 Oct 2020 20:39:08 -0700

On Mon, Oct 26, 2020 at 1:27 AM Oleg Pekar <[email-masked]>
wrote:

> Few comments:
> 1) It seems that the server MUST send Crypto-Binding TLV after a single
> EAP authentication method, after each of EAP authentications methods in a

[Joe] There are two cases where CryptoBinding is used, after completion of
an EAP authentication exchange and with the Result-TLV exchange.   Since
password based authentication does not generate a key there is no need for
crypto binding.  It is just treated as a TLV.

> [Joe] It should be consistent. Re-worded slightly:

3. The Intermediate-Result TLVs carry success or failure indications of
each individual EAP authentication method or basic password authentication
in TEAP Phase 2.

And

The Intermediate-Result TLV provides support for acknowledged intermediate
Success and Failure messages for inner EAP authentication methods or basic
password authentication.

>> The Intermediate-Result TLV provides support for acknowledged
>> intermediate Success and Failure messages between multiple inner EAP
>> methods within EAP.
>>
>> It Should say:
>>
>> The Intermediate-Result TLV provides support for acknowledged
>> intermediate Success and Failure messages between multiple inner EAP
>> methods or basic password authentication within EAP.
>>
>> Section C.1 says:
>>

---

From: Joseph Salowey <[email-masked]>
Date: Mon, 26 Oct 2020 20:44:20 -0700

> crypto binding.  It is just treated as a TLV.

[Joe] Section 4.2.11 contradicts this - "An Intermediate-Result TLV
indicating success MUST be accompanied by a Crypto-Binding TLV."  I think
we need to use the 0 MSK with the basic password authentication.