Re: [Teep] [Last-Call] Artart last call review of draft-ietf-teep-architecture-16

[Mingliang Pei <[e-mail]>]

See PR: https://github.com/ietf-teep/architecture/pull/236, thanks, Ming

On Thu, Apr 7, 2022 at 1:52 PM Mingliang Pei <[e-mail]>
wrote:

> Hi Russ,
>
> Great, thank you. Please see inline. I will update RFC with the two points
> agreed.
>
> Best,
>
> Ming
>
>
> On Thu, Apr 7, 2022 at 12:31 PM Russ Housley <[e-mail]> wrote:
>
>> Please see below.
>>
>> On Apr 6, 2022, at 8:54 PM, Mingliang Pei <
>> mingliang.pei=[e-mail]> wrote:
>>
>> Thanks Russ for your comments. Thanks Hannes for the PR. I made a minor
>> comment on the PR. The changes look good overall.
>>
>> Please see my comments inline about "trust anchor" and "app store".
>>
>> Best,
>>
>> Ming
>>
>> On Mon, Mar 28, 2022 at 11:06 PM Hannes Tschofenig <
>> [e-mail]> wrote:
>>
>>> 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 <[e-mail]>
>>> Sent: Tuesday, March 29, 2022 12:08 AM
>>> To: [e-mail]
>>> Cc: [e-mail]; [e-mail];
>>> [e-mail]
>>> Subject: Artart last call review of draft-ietf-teep-architecture-16
>>>
>>> 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.
>>>
>>> [Hannes] I have changed the sentence to improve the wording.
>>>
>>> Section 9.3 says that a compromised REE "might drop or delay messages".
>>> This discussion should be expanded to include the replay of messages.
>>>
>>> [Hannes] Agree.
>>>
>>> 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.
>>>
>>> [Hannes] Good point. I removed part of the sentence.
>>>
>>>
>> [Ming] Trust Anchor definition says "The Trust Anchor may be a
>> certificate or it may be a raw public key.". When it is a certificate,
>> it doesn't have to be the root certificate. It could be an issuing CA while
>> it isn't a common practice. Do we limit it to a self-signed root CA? I am
>> fine with this, and update accordingly.
>>
>>
>> I think the point about not a "Root Certificate" in all situations is
>> very helpful.  Please add that to the document.
>>
>>
> Ming: will add a clarification line in the definition of "Trust Anchor"
> that a "A Trust Anchor can be a non-root certificate when it is a
> certificate.", and keep the original statement above.
>
>>
>>
>>> 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.
>>>
>>> [Hannes] Splitting the sentence improves readability.
>>>
>>> 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?
>>>
>>> [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.
>>>
>>>
>> [Ming] "app store" intends to mean "where apps are stored and can be
>> acquired (such as Apple App Store / Google Play)". "Trust Anchor Store"
>> means some storage within a device to keep a list of Trust Anchors. How
>> about add a definition of "App Store" that was depicted in the diagram
>> under Section "Entity Relations" to say the following?
>>
>>
>> Definitions would resolve this comment.
>>
>>
> Ming: thanks
>
>>
>> App Store: a service provider where an Untrusted Application may be
>> downloaded.
>>
>>
>> Suggestion: App Store: an online location from which Untrusted
>> Applications can be downloaded.
>>
>
> Ming: looks better. I will use your version.
>
>
>>
>> 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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