HTTP Transport for Trusted Execution Environment Provisioning: Agent Initiated Communication
draft-ietf-teep-otrp-over-http-15

[Ballot comment]
Thanks to Carsten Bormann for the ARTART review.

The shepherd writeup confirms that Proposed Standard is the requested status, but doesn't indicate why that was chosen.  (It's fairly clear that this is a protocol or even an applicability statement, but a sentence or two about that would be great to include.)  The shepherd writeup is also substantially dated; it's from mid-2021, and mentions a sponsoring AD who is no longer on the IESG.

Section 1 is "Introduction" yet makes a normative ("SHOULD") assertion, which is peculiar.  If this is a new assertion, it should be in its own later section; if it's imported from another TEEP document, I suggest expressing it some other way ("generally required" or suchlike) so that this document isn't seen as the normative one on this point.

The SHOULD near the top of Section 3 is bare, in the sense that it presents a choice to implementers but no guidance about when it might be legitimate to deviate from the recommended behavior.  I suggest adding at last a brief discussion of this.  (At least I presume this is a new SHOULD; at first I read this as if it's importing a SHOULD from Section 4.13 of RFC 9205, but there's no SHOULD in that section.)

I have similar comments about the SHOULD in Section 6.2.  What if I use some other response code?

I have the same question as Erik about timeouts.

[Ballot comment]
Thanks for this document. There was one thing in the introduction which rubbed me the wrong way. I acknowledge that this is probably due to a defect in my personality, but I thought I'd flag it and you can address it or disregard it as you please.

The sentence in question is,

  There are two topological scenarios in which TEEP could be deployed:

The quoted sentence implies that the list (Agent behind NAT/firewall, TAM behind NAT/firewall) is exhaustive. But surely both TAM and Agent on the open Internet would work too?

For that matter, there's a large body of work (in which I am not at all expert) that aims to accommodate both client and server being behind a NAT or firewall. I assume you don't want to go to the additional labor to cater for this scenario, and therefore it really is one in which TEEP could *not* be deployed.

[Ballot comment]
Thanks for this document. There was one thing in the introduction which rubbed me the wrong way. I acknowledge that this is probably due to a defect in my personality, but I thought I'd flag it and you can address it or disregard it as you please.

The sentence in question is,

  There are two topological scenarios in which TEEP could be deployed:

The quoted sentence implies that the list, viz. (Agent behind NAT/firewall, TAM behind NAT/firewall being the two) is exhaustive. But surely both TAM and Agent on the open Internet would work too?

For that matter, there's a large body of work (in which I am not at all expert) that aims to accommodate both client and server being behind a NAT or firewall. I assume you don't want to go to the additional labor to cater for this scenario, and therefore it really is one in which TEEP could *not* be deployed.

[Ballot comment]
# AD Review of draft-ietf-teep-otrp-over-http-14
cc @fpalombini

Thank you for the work on this document.

Many thanks to Carsten Bormann for his ART ART review: https://mailarchive.ietf.org/arch/msg/art/XCL1Bpk7GLkeoJ4NM2jzbhw2aJA/. I note that a few of Carsten's comments have made it to v-14, although I didn't find any reply to his email. In particular, I agree with Carsten on the SHOULD in section 6.2, see my third point below.

## Comments

### Reference to 9205 4.4.2 for security considerations

Section 4:
> See Sections 4.4.2 and 6 of [RFC9205] for more discussion of additional security considerations that apply in this case.

Which part of 4.4.2 of 9205 is relevant here?

### Update BCP195 reference

Section 4:
> See [BCP195] for additional TLS recommendations and [RFC7925] for TLS recommendations related to IoT devices.

The BCP195 reference should be updated to point to 9325, which obsoletes 7525

### SHOULD be 204

Section 6.2:
> If the TAM passes back an empty buffer, the TEEP/HTTP Server sends a successful (2xx) response with no body. It SHOULD be status 204 (No Content).

As Carsten asks, what alternative to 204 is there? What would be the reason to deviate from the SHOULD?

## Notes

This review is in the ["IETF Comments" Markdown format][ICMF], You can use the
[`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues.

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments

[Ballot comment]
Thanks for working on this specification. I haven't find any TSV related issues in this specification in my review.

I have comments/questions that I believe would improve the document if addressed -

# it says -

  and a "Trusted Application Manager (TAM)" on the server side) SHOULD themselves run inside a TEE

  why is it necessary to use normative language here? is this something this spec describing first for the TEEP architecture? It is however not the intention of this specification to define TAM placement, or?


# it says -

    Since POST responses without explicit freshness information are uncacheable (see Section 9.3.3 of [RFC9110]), no Cache-Control header is needed.

  Should this not say -

    Since POST responses without explicit freshness information are uncacheable (see Section 9.3.3 of [RFC9110]), hence Cache-Control header MUST NOT be used.

  I.e. use normative language to avoid the use of that particular header? also explains if a Cache-Control header would generate error.

[Ballot comment]
Thank you to Stefan Santesson for the SECDIR review.

** Section 5.  Starting in this section there is the introduction of the concept of “message buffers” being exchanged.  Is there some more formal description of that idea in this context.  I didn’t find that term defined in draft-ietf-teep-protocol or draft-ietf-teep-architecture.

** Section 8.  The protocol interaction model has URI being exchanged and followed.  Consider providing a reference to Section 7 of RFC 3986 to provide generic guidance about de-referencing URIs.

[Ballot comment]
# Internet AD comments for draft-ietf-teep-otrp-over-http-14
CC @ekline

## Comments

### S5.6, S6.4

* Is there any discussion that can be referenced for how to set "reasonable"
  timeouts?  Even though the HTTP transport layer may be up and functioning,
  how long is too long to wait for message processing before an error should
  be declared by one of the layers?

  I'm sure the timeout needs might vary according to many different factors,
  but does the desired timeout need to be conveyed by some mechanism to the
  TEEP/HTTP {Client,Server} layer?

## Nits

### S7

* Item 1: s/cient/client/

(Via drafts-lastcall-comment@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has reviewed draft-ietf-teep-otrp-over-http-13, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

Thank you,

Michelle Thangtamsatid
IANA Services Specialist

The following Last Call announcement was sent out (ends 2022-04-07):

From: The IESG
To: IETF-Announce
CC: draft-ietf-teep-otrp-over-http@ietf.org, kaduk@mit.edu, kondtir@gmail.com, teep-chairs@ietf.org, teep@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (HTTP Transport for Trusted Execution Environment Provisioning: Agent Initiated Communication) to Proposed Standard


The IESG has received a request from the Trusted Execution Environment
Provisioning WG (teep) to consider the following document: - 'HTTP Transport
for Trusted Execution Environment Provisioning: Agent
  Initiated Communication'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2022-04-07. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  The Trusted Execution Environment Provisioning (TEEP) Protocol is
  used to manage code and configuration data in a Trusted Execution
  Environment (TEE).  This document specifies the HTTP transport for
  TEEP communication where a Trusted Application Manager (TAM) service
  is used to manage code and data in TEEs on devices that can initiate
  communication to the TAM.  An implementation of this document can (if
  desired) run outside of any TEE, but interacts with a TEEP
  implementation that runs inside a TEE.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-teep-otrp-over-http/



No IPR declarations have been submitted directly on this I-D.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Proposed Standard as indicated on the title page header and in the datatracker.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

  This document specifies the HTTP transport for
  TEEP communication where a Trusted Application Manager (TAM) service
  is used to manage code and data in TEEs on devices that can initiate
  communication to the TAM. The TEEP-over-HTTP implementation can be implemented
  either outside a TEE (i.e., in a TEEP "Broker") or inside a TEE.


Working Group Summary:

The draft was adopted in Jan 2020 with good WG support for adoption.  The draft has been widely discussed and reviewed. The author of this document has extensive experience with the TEE technologies and implementations, he is also the co-author of the TEEP Protocol WG draft.

Further, there has been active participation in IETF hackathon activities from WG members to implement and test TEEP protocol with HTTP transport.

Document Quality:

The draft is mature enough after several revisions and there is strong consensus in the WG to pass the WGLC and go to next stage.

Personnel:

  K Tirumaleswar Reddy (shepherd)
  Benjamin Kaduk (AD)

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I reviewed the document and found it is ready.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No, the document was a subject of several reviews in the WG and presentations in IETF meetings.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

Mark Nottingham did multiple reviews on behalf of the httpbis WG, especially for conformance to bcp56bis, at the request of the WG.

I personally don't think that more reviews are needed.

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

None.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

All authors and contributors confirmed that they are not aware of any IPR related to this draft.

  ** Dave Thaler – https://mailarchive.ietf.org/arch/msg/teep/yZJzKpxkJmsnw2zjpgD9sZlN2lI/

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosure has been filed that reference this document.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The WG consensus is solid.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

IDnits reported no issues.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

The draft contains no YANG or XML modules to validate.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

No.

(15) Are there downward normative references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No, publication of this document will not change the status of any existing RFCs.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

No new IANA registries are defined by this document.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

The draft has no IANA actions.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, YANG modules, etc.

The draft does not define any YANG module.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

The draft contains no YANG or XML modules to validate.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Proposed Standard as indicated on the title page header and in the datatracker.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

  This document specifies the HTTP transport for
  TEEP communication where a Trusted Application Manager (TAM) service
  is used to manage code and data in TEEs on devices that can initiate
  communication to the TAM. The TEEP-over-HTTP implementation can be implemented
  either outside a TEE (i.e., in a TEEP "Broker") or inside a TEE.


Working Group Summary:

The draft was adopted in Jan 2020 with good WG support for adoption.  The draft has been widely discussed and reviewed. The author of this document has extensive experience with the TEE technologies and implementations, he is also the co-author of the TEEP Protocol WG draft.

Further, there has been active participation in IETF hackathon activities from WG members to implement and test TEEP protocol with HTTP transport.

Document Quality:

The draft is mature enough after several revisions and there is strong consensus in the WG to pass the WGLC and go to next stage.

Personnel:

  K Tirumaleswar Reddy (shepherd)
  Benjamin Kaduk (AD)

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I reviewed the document and found it is ready.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No, the document was a subject of several reviews in the WG and presentations in IETF meetings.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

Mark Nottingham did multiple reviews on behalf of the httpbis WG, especially for conformance to bcp56bis, at the request of the WG.

I personally don't think that more reviews are needed.

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

None.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

All authors and contributors confirmed that they are not aware of any IPR related to this draft.

  ** Dave Thaler – https://mailarchive.ietf.org/arch/msg/teep/yZJzKpxkJmsnw2zjpgD9sZlN2lI/

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosure has been filed that reference this document.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The WG consensus is solid.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

IDnits reported no issues.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

The draft contains no YANG or XML modules to validate.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

No.

(15) Are there downward normative references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No, publication of this document will not change the status of any existing RFCs.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

No new IANA registries are defined by this document.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

The draft has no IANA actions.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, YANG modules, etc.

The draft does not define any YANG module.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

The draft contains no YANG or XML modules to validate.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

Proposed Standard as indicated on the title page header and in the datatracker.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

  This document specifies the HTTP transport for
  TEEP communication where a Trusted Application Manager (TAM) service
  is used to manage code and data in TEEs on devices that can initiate
  communication to the TAM. The TEEP-over-HTTP implementation can be implemented
  either outside a TEE (i.e., in a TEEP "Broker") or inside a TEE.


Working Group Summary:

The draft was adopted in Jan 2020 with good WG support for adoption.  The draft has been widely discussed and reviewed. The author of this document has extensive experience with the TEE technologies and implementations, he is also the co-author of the TEEP Protocol WG draft.

Futher, active participation in IETF hackathon activities from WG members to implement and test TEEP protocol with HTTP transport.

Document Quality:

The draft is mature enough after several revisions and there is strong consensus in the WG to pass the WGLC and go to next stage.

Personnel:

  K Tirumaleswar Reddy (shepherd)
  Benjamin Kaduk (AD)

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

I reviewed the document and found it is ready.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

No, the document was a subject of several reviews in the WG and presentations in IETF meetings.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

I personally don't think that more reviews are needed.

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

None.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

All authors and contributors confirmed that they are not aware of any IPR related to this draft.

  ** Dave Thaler – https://mailarchive.ietf.org/arch/msg/teep/yZJzKpxkJmsnw2zjpgD9sZlN2lI/

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosure has been filed that reference this document.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

The WG consensus is solid.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

No.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

IDnits reported no issues.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

The draft contains no YANG or XML modules to validate.

(13) Have all references within this document been identified as either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

No.

(15) Are there downward normative references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

No.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

No, publication of this document will not change the status of any existing RFCs.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126).

No new IANA registries are defined by this document.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

The draft has no IANA actions.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, YANG modules, etc.

The draft does not define any YANG module.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools (https://trac.ietf.org/trac/ops/wiki/yang-review-tools) for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

The draft contains no YANG or XML modules to validate.