Draft: draft-ietf-rats-yang-tpm-charra

Commentary: pending approval of my suggestion on IMA , I am obviously okay with this .
One or more TPMs MUST be embedded in a Composite Device that provides
attestation evidence via the YANG module defined in this document.
The ietf-basic-remote-attestation YANG module enables a composite
device to take on the role of an Attester, in accordance with the
Remote Attestation Procedures (RATS) architecture I-D.ietf-rats-
architecture, and the corresponding challenge-response interaction
model defined in the I-D.ietf-rats-reference-interaction-models
document.  A fresh nonce with an appropriate amount of entropy MUST
be supplied by the YANG client in order to enable a proof-of-
freshness with respect to the attestation Evidence provided by the
Attester running the YANG datastore.  Further, this nonce is used to
prevent replay attacks.  The functions of this YANG module are
restricted to 0-1 TPMs per hardware component.
One or more TPMs MUST be embedded in a Composite Device that provides
attestation evidence via the YANG module defined in this document.
The ietf-basic-remote-attestation YANG module enables a composite
device to take on the role of an Attester, in accordance with the
Remote Attestation Procedures (RATS) architecture I-D.ietf-rats-
architecture, and the corresponding challenge-response interaction
model defined in the I-D.ietf-rats-reference-interaction-models
document.  A fresh nonce with an appropriate amount of entropy
NIST-915121 MUST be supplied by the YANG client in order to enable a
proof-of-freshness with respect to the attestation Evidence provided
by the Attester running the YANG datastore.  Further, this nonce is
used to prevent replay attacks.  The method for communicating the
relationship of each individual TPM to specific measured component
within the Composite Device is out of the scope of this document.
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF RFC6241 or RESTCONF RFC8040.  The lowest NETCONF layer is
the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) RFC6242.  The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
RFC8446.
The YANG module ietf-tpm-remote-attestation.yang specified in this
document defines a schema for data that is designed to be accessed
via network management protocols such as NETCONF RFC6241 or RESTCONF
RFC8040.  The lowest NETCONF layer is the secure transport layer, and
the mandatory-to-implement secure transport is Secure Shell (SSH)
RFC6242.  The lowest RESTCONF layer is HTTPS, and the mandatory-to-
implement secure transport is TLS RFC8446.
It must be verified that the certificate is for an active AIK, i.
e. the certificate provided is able to support Attestation on the
targeted TPM 1.2.
It must be verified that the certificate is for an active AK, i.
e. the certificate provided is able to support Attestation on the
targeted TPM 2.0.
Pulling lots of logs can chew up system resources.
It must be verified that the certificate is for an active AIK,
i.e., the certificate provided is able to support Attestation on
the targeted TPM 1.2.
It must be verified that the certificate is for an active AK,
i.e., the certificate provided is able to support Attestation on
the targeted TPM 2.0.
Requesting a large volume of logs from the attester could require
significant system resources and create a denial of service.
Information collected through the RPCs above could reveal that
specific versions of software and configurations of endpoints that
could identify vulnerabilities on those systems.  Therefore RPCs
should be protected by NACM RFC8341 to limit the extraction of
attestation data by only authorized Verifiers.
For the YANG module ietf-tcg-algs.yang, please use care when
selecting specific algorithms.  The introductory section of TCG-Algos
highlights that some algorithms should be considered legacy, and
recommends implementers and adopters diligently evaluate available
information such as governmental, industrial, and academic research
before selecting an algorithm for use.