Subject: [Rats] Pull request for the charra YANG model

From: "Eric Voit (evoit)" <[email-masked]>
Date: Wed, 10 Jun 2020 16:17:52 +0000

Henk,         Michael,

Shwetha,   Bill,

Frank,        Tom,

Guy,

As authors of the Charra YANG model, I wanted to let you know I have created
a pull request
<https://github.com/ietf-rats-wg/basic-yang-module/pull/8/files> .  I am
proposing some fixes due to a number of concerns
<https://github.com/ietf-rats-wg/basic-yang-module/issues/6>  I had about
the YANG model:

*	PCR numbers should be their own type, not a UINT8. PCRs should be
limited to [0..31]
*	We should use ENUMs instead of strings for TCG and IETF crypto
algorithm types. Strings allow lots of errors to be introduced which we can
protect using a larger, more detailed ENUM construct.
*	Most devices do not have multiple line cards. Because of that, we
should not have nested keys of [node id] [tpm name]. This adds unnecessary
complexity for the vast majority of users. Instead the tpm should have a
mandatory leafref back to node-id when compute-nodes is not null.
*	The YANG doctors will not let us have a TPM-Name of "ALL". Instead
of "ALL" we should be able to assume that an RPC means all hardware based
TPMs if a specific TPM is not named in the RPC. 
*	We should add leaf for a unique 'certificate-name' is used. This
allows for a cleaner certificate migration path, and most RPC users won't
need to track node-ids. 
*	We should have optional YANG features for TPM1.2 and TPM2.0 so that
RPCs are not exposed when there are no such TPMs of that type are supported.
*	We should create new reusable groupings rather than repeat
definitions. 

If your guys have suggestions and improvements for this pull request, that
would be great.   I also think the netequip boot pull request
<https://github.com/ietf-rats-wg/basic-yang-module/pull/5>  can also be
integrated.

Thanks,

Eric

---

From: "Eric Voit (evoit)" <[email-masked]>
Date: Wed, 17 Jun 2020 21:25:22 +0000

I have updated the pull request based on some more thoughts.  The links
below show the full set of proposed deltas.  Main changes are:

*	Align to the drafts currently under WGLC in NETCONF

*	Extracted Crypto-types into a separate YANG file
ietf-crypto-types.yang.  (Note: The proposed structure his matches to the
stated intent of the NETCONF WG.  They almost took iana-crypto-types.yang to
WGLC, but pulled that file to simplify things.)
*	Made certificate leaf-refs to ietf-keystore.yang (this improves the
richness of what can be stored, while making this YANG model smaller.)

*	Made a few uint types into more explicit typing.

Eric

From: Eric Voit (evoit) 
Sent: Wednesday, June 10, 2020 12:18 PM
To: [email-masked]; [email-masked];
Shwetha Bhandari (shwethab) <[email-masked]>; Bill Sulzen (bsulzen)
<[email-masked]>; [email-masked]; [email-masked]; Guy
Fedorkow <[email-masked]>
Cc: [email-masked]
Subject: Pull request for the charra YANG model

Henk,         Michael,

Shwetha,   Bill,

Frank,        Tom,

Guy,

Thanks,

Eric

---

From: "Bill Sulzen (bsulzen)" <[email-masked]>
Date: Mon, 22 Jun 2020 14:33:15 +0000

Eric,

Regarding your issue:

as I read the updated attestation tree, there still is support for multiple
TPMs in a given management plane (i.e. there's still support for multiple
linecards - AKA "composite systems.") But if a given linecard/node within a
management plane entity, then they would have to be differentiated by
tpm-name rather than by node-id. Is that correct?

Thanks,

Bill

From: Eric Voit (evoit) 

Henk,         Michael,

Shwetha,   Bill,

Frank,        Tom,

Guy,

Thanks,

Eric

---

From: "Eric Voit (evoit)" <[email-masked]>
Date: Mon, 22 Jun 2020 14:58:31 +0000

Hi Bill,

From: Bill Sulzen (bsulzen), June 22, 2020 10:33 AM
Subject: RE: Pull request for the charra YANG model

Eric,

Regarding your issue:

as I read the updated attestation tree, there still is support for multiple
TPMs in a given management plane (i.e. there's still support for multiple
linecards - AKA "composite systems.") 

<eric>   Yes your interpretation is correct.  When there are multiple
line-cards, the YANG model requires a leaf-ref to that card. 

But if a given linecard/node within a management plane entity, then they
would have to be differentiated by tpm-name rather than by node-id. Is that
correct?

<eric> The 'tpm-name' object needs to be unique across a composite device,
it could be a random string (in fact this is a common practice for YANG
models).   

Initially I thought about populating that name with the 'tpm-path'.  However
that 'tpm-path' might change across reboots.   Both the 'tpm-path' and
'tpm-name' are unique within a single boot cycle, and can be used as part of
a lookup within the data nodes of 'rats-support-structures'.

Eric

Thanks,

Bill

From: Eric Voit (evoit) 
Sent: Wednesday, June 10, 2020 12:18 PM
To: [email-masked] <mailto:[email-masked]>
; [email-masked] <mailto:[email-masked]> ;
Shwetha Bhandari (shwethab) <[email-masked] <mailto:[email-masked]>
>; Bill Sulzen (bsulzen) <[email-masked] <mailto:[email-masked]> >;
[email-masked] <mailto:[email-masked]> ;
[email-masked] <mailto:[email-masked]> ; Guy Fedorkow
<[email-masked] <mailto:[email-masked]> >
Cc: [email-masked] <mailto:[email-masked]> 
Subject: Pull request for the charra YANG model

Henk,         Michael,

Shwetha,   Bill,

Frank,        Tom,

Guy,

Thanks,

Eric