I agree with all the proposed resolutions. For context, there was some prior 
discussion of this errata here: 
https://mailarchive.ietf.org/arch/msg/emu/K_XWBMevKNdxdWskK8RkBt1ZpSQ/

Jorge Vergara

From: Joseph Salowey <j...@salowey.net>
Sent: Wednesday, October 21, 2020 5:13 PM
To: EMU WG <emu@ietf.org>; Jouni Malinen <j...@w1.fi>; Jorge Vergara 
<jover...@microsoft.com>; Oleg Pekar <oleg.pekar.2...@gmail.com>
Subject: Resolution of TEAP Errata 5767

Errata 5767: 
https://www.rfc-editor.org/errata/eid5767<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.rfc-editor.org%2Ferrata%2Feid5767&data=04%7C01%7Cjovergar%40microsoft.com%7C50b56afadcf34732d50708d8761f45d5%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637389223977410444%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=24y%2BkrsBw1mdGuNMMgqmqiRz%2BqeFt9jVX4qUHtlUJwY%3D&reserved=0>
Status: Verified
Revision:

Section 3.3.1 says:

   EAP method messages are carried within EAP-Payload TLVs defined in
   Section 4.2.10.  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.

It should say:

   EAP method messages are carried within EAP-Payload TLVs defined in
   Section 4.2.10.  Upon completion of each EAP authentication method in
   the tunnel, the server MUST send an Intermediate-Result TLV
   indicating the result.

Section 3.3.3 says:

  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.

It should say:

  The Crypto-Binding TLV and Intermediate-Result TLV MUST be included
  to perform cryptographic binding after each successful EAP authentication
  method in a sequence of one or more EAP methods.

Section 3.8.3 says:

   Upon successful completion of the EAP method in Phase 2, the peer and
   server exchange a Crypto-Binding TLV to bind the inner method with
   the outer tunnel and ensure that a man-in-the-middle attack has not
   been attempted.

It should say:

   Upon successful completion of the EAP authentication method in Phase 2,
   the peer and server exchange a Crypto-Binding TLV to bind the inner
   method with the outer tunnel and ensure that a man-in-the-middle attack
   has not been attempted.

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 after each inner EAP
  authentication method.

Section 4.2.13 says:

 It MUST be included with the Intermediate-Result TLV to perform
 cryptographic binding after each successful EAP method in a
 sequence of EAP methods, before proceeding with another inner
 EAP method.

It should say:

 It MUST be included with the Intermediate-Result TLV to perform
 cryptographic binding after each successful EAP authentication
 method in a sequence of EAP methods, before proceeding with
 another inner EAP method.

Notes:

TEAP description is somewhat vague in discussion about "EAP methods" vs. "EAP 
authentication methods" as it comes to the EAP methods performed in Phase 2 
within the TLS tunnel. RFC 3748 defines Identity request/response as an EAP 
method. However, this method is not an "authentication method" which is a 
special case of an method where the Type is 4 or greater.

RFC 7170 uses correct terminology in the first paragraph of Section 3.3.1 when 
talking about multiple authentication methods not being allowed by RFC 3748 in 
a single EAP conversation. However, many, but not all, of the following "[EAP] 
method" instances are actually referring to "[EAP] authentication method". This 
results in incorrect claims on when the Intermediate-Result TLV and 
Crypto-Binding TLV are used. They are not used after an EAP non-authentication 
method like Identity (e.g., see the example in C.3); they are used after each 
EAP authentication method like EAP-pwd.

Furthermore, the comment about "more than one method is going to be executed in 
the tunnel" does not sound accurate. This applies even if only a single EAP 
authentication method is executed in the tunnel (Identity method is not 
required to be executed). The proposed text in this errata entry addresses 
these two issues in Section 3.3.1. The following additional changes would be 
needed to make rest of the specification use the terms more accurately:

3.3.3: "after each successful EAP method" --> "after each successful EAP 
authentication method"
3.8.3: "completion of the EAP method" --> "completion of the EAP authentication 
method"
4.2.11: "between multiple inner EAP methods within EAP" --> "after each inner 
EAP authentication method"
4.2.13: "after each successful EAP method" --> "after each successful EAP 
authentication method"
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