Subject: [Teep] Artart last call review of draft-ietf-teep-architecture-16

From: Russ Housley via Datatracker <[email-masked]>
Date: Mon, 28 Mar 2022 15:07:44 -0700

Reviewer: Russ Housley
Review result: Almost Ready

I am the assigned ARTART reviewer for this Internet-Draft.

Document: draft-ietf-teep-architecture-16
Reviewer: Russ Housley
Review Date: 2022-03-28
IETF LC End Date: 2022-04-07
IESG Telechat date: unknown

Summary: Almost Ready

Major Concerns: None.

Minor Concerns:

Section 3.3 says:

   Weak security in Internet of Things (IoT) devices has been posing
   threats to critical infrastructure that relies upon such devices.

I'm a bit confused by this opening sentence.  IoT devices usually depend
upon an infrastructure.  This seems to be talking about an infrastructure
that depends upon a collection of IoT devices.  I suggest a minor edits
to help the reader understand that this sentence is not talking about
network infrastructure.

Section 9.3 says that a compromised REE "might drop or delay messages".
This discussion should be expanded to include the replay of messages.

Section 9.4 says:

   A root CA for TAM certificates might get compromised or its
   certificate might expire, or a Trust Anchor other than a root CA
   certificate may also expire or be compromised.

I do not understand the difference between a Root CA and a Trust Anchor.
These are usually used a synonyms.  Please explain the difference that
in intended here.

Nits:

Section 1 says:

   ... The problems in the bullets above, on the
   other hand, require a new protocol, i.e., the TEEP protocol, for TEEs
   that can install and enumerate TAs in a TEE-secured location and
   where another domain-specific protocol standard (e.g., [GSMA],
   [OTRP]) that meets the needs is not already in use.

Recommend breaking this long sentence up into at least two sentences.
There are two points.  First, the need for a protocol to address the
items listed earlier.  Second, where an existing domain-specific
protocol does not already exist, a new more general protocol is needed.

Section 4.4 says:

   ... Implementations must support encryption of
   such Personalization Data to preserve the confidentiality of
   potentially sensitive data contained within it, and must support
   integrity protection of the Personalization Data.

Why not say that implementation must support mechanisms for the
confidentiality and integrity protection of such Personalization Data?
Also, it seems like draft-ietf-suit-firmware-encryption offers one
mechanism for such protection.  Should it be referenced here?

Section 4: Is an "App Store" a place where apps are stored, or is it a
place where apps a purchased?  The term seems to be used both ways, and
in one place, the document is very general by saying, "an app store
or other app repository".  Elsewhere, the term "Trust Anchor Store" is
clearly a place for storage of trust anchors.

Section 9.7: Please consider changing the section title to be something
like: "TEE Certificate Expiry and Renewal".  There is an earlier section
that talks about expiration of Root CA certificates.

---

From: Hannes Tschofenig <[email-masked]>
Date: Tue, 29 Mar 2022 06:06:32 +0000

Hi Russ,

Thanks for the review.

I have created a few PR based on your comments:
https://github.com/ietf-teep/architecture/pull/234

I have added a few remarks below (mainly agreeing with your observations).

Ciao
Hannes

-----Original Message-----
From: Russ Housley via Datatracker <[email-masked]>
Sent: Tuesday, March 29, 2022 12:08 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Artart last call review of draft-ietf-teep-architecture-16

Reviewer: Russ Housley

Summary: Almost Ready

Major Concerns: None.

Minor Concerns:

Section 3.3 says:

I'm a bit confused by this opening sentence.  IoT devices usually depend upon an infrastructure.  This seems to be talking about an infrastructure that depends upon a collection of IoT devices.  I suggest a minor edits to help the reader understand that this sentence is not talking about network infrastructure.

[Hannes] I have changed the sentence to improve the wording.

[Hannes] Agree.

Section 9.4 says:

I do not understand the difference between a Root CA and a Trust Anchor.
These are usually used a synonyms.  Please explain the difference that in intended here.

[Hannes] Good point. I removed part of the sentence.

Nits:

Section 1 says:

Recommend breaking this long sentence up into at least two sentences.
There are two points.  First, the need for a protocol to address the items listed earlier.  Second, where an existing domain-specific protocol does not already exist, a new more general protocol is needed.

[Hannes] Splitting the sentence improves readability.

Section 4.4 says:

Why not say that implementation must support mechanisms for the confidentiality and integrity protection of such Personalization Data?
Also, it seems like draft-ietf-suit-firmware-encryption offers one mechanism for such protection.  Should it be referenced here?

[Hannes] Agree that the sentence should be simplified. You are also right by saying that a solution is available. I am not sure we should reference the solution in this document or in the protocol spec.

Section 4: Is an "App Store" a place where apps are stored, or is it a place where apps a purchased?  The term seems to be used both ways, and in one place, the document is very general by saying, "an app store or other app repository".  Elsewhere, the term "Trust Anchor Store" is clearly a place for storage of trust anchors.

[Hannes] I am not entirely sure what do about this one. I hope for input from my co-authors.

Section 9.7: Please consider changing the section title to be something
like: "TEE Certificate Expiry and Renewal".  There is an earlier section that talks about expiration of Root CA certificates.

[Hannes] Makes sense.

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