A YANG Data Model for Challenge-Response-based Remote Attestation Procedures using TPMs
draft-ietf-rats-yang-tpm-charra-06
The information below is for an old version of the document.
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| Authors | Henk Birkholz , Michael Eckel , Shwetha Bhandari , Eric Voit , Bill Sulzen , Liang Xia , Tom Laffey , Guy Fedorkow | ||
| Last updated | 2021-04-01 (Latest revision 2021-01-14) | ||
| Replaces | draft-birkholz-rats-basic-yang-module | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-rats-yang-tpm-charra-06
RATS Working Group H. Birkholz
Internet-Draft M. Eckel
Intended status: Standards Track Fraunhofer SIT
Expires: 3 October 2021 S. Bhandari
ThoughtSpot
E. Voit
B. Sulzen
Cisco
L. Xia
Huawei
T. Laffey
HPE
G. Fedorkow
Juniper
1 April 2021
A YANG Data Model for Challenge-Response-based Remote Attestation
Procedures using TPMs
draft-ietf-rats-yang-tpm-charra-06
Abstract
This document defines a YANG RPC and a small number of configuration
node required to retrieve attestation evidence about integrity
measurements from a device following the operational context defined
in TPM-based Network Device Remote Integrity Verification.
Complementary measurement logs are also provided by the YANG RPC
originating from one or more roots of trust of measurement. The
module defined requires at least one TPM 1.2 or TPM 2.0 and
corresponding Trusted Software Stack included in the device
components of the composite device the YANG server is running on.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on 3 October 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. The YANG Module for Basic Remote Attestation Procedures . . . 3
2.1. YANG Modules . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1. ietf-tpm-remote-attestation . . . . . . . . . . . . . 3
2.1.2. ietf-tcg-algs . . . . . . . . . . . . . . . . . . . . 31
3. IANA considerations . . . . . . . . . . . . . . . . . . . . . 47
4. Security Considerations . . . . . . . . . . . . . . . . . . . 47
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 48
6. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 48
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 49
7.1. Normative References . . . . . . . . . . . . . . . . . . 49
7.2. Informative References . . . . . . . . . . . . . . . . . 50
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 51
1. Introduction
This document is based on the terminology defined in the
[I-D.ietf-rats-architecture] and uses the operational context defined
in [I-D.ietf-rats-tpm-based-network-device-attest] as well as the
interaction model and information elements defined in
[I-D.ietf-rats-reference-interaction-models]. The currently
supported hardware security modules (HWM) are the Trusted Platform
Module (TPM) [TPM1.2] and [TPM2.0] specified by the Trusted Computing
Group (TCG). One ore more TPMs embedded in the components of a
composite device - sometimes also referred to as an aggregate device
- are required in order to use the YANG module defined in this
document. A TPM is used as a root of trust for reporting (RTR) in
order to retrieve attestation evidence from a composite device (quote
primitive operation). Additionally, it is used as a root of trust
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for storage (RTS) in order to retain shielded secrets and store
system measurements using a folding hash function (extend primitive
operation).
1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. The YANG Module for Basic Remote Attestation Procedures
One or more TPMs MUST be embedded in the composite device that is
providing 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 Claimant and 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. The functions of this YANG module are restricted to 0-1
TPMs per hardware component.
2.1. YANG Modules
2.1.1. ietf-tpm-remote-attestation
This YANG module imports modules from [RFC6991], [RFC8348],
[I-D.ietf-netconf-keystore], ietf-tcg-algs.yang Section 2.1.2.3.
2.1.1.1. Features
This module supports the following features:
<TPMs> - Indicates that multiple TPMs on the device can support
remote attestation, This feature is applicable in cases where
multiple line cards, each with its own TPM.
<bios> - Indicates the device supports the retrieval of bios event
logs.
<ima> - Indicates the device supports the retrieval of Integrity
Measurement Architecture event logs.
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<netequip_boot> - Indicates the device supports the retrieval of
netequip boot event logs.
2.1.1.2. Identities
This module supports the following types of attestation event logs:
<ima>, <bios>, and <netequip_boot>.
2.1.1.3. RPCs
2.1.1.3.1. <tpm20-challenge-response-attestation>
This RPC allows a Verifier to request a quote of PCRs from a TPM2.0
compliant cryptoprocessor. Where the feature <TPMs> is active, and
one or more <certificate-name> is not provided, all TPM2.0 compliant
cryptoprocessors will respond. A YANG tree diagram of this RPC is as
follows:
+---x tpm20-challenge-response-attestation {taa:TPM20}?
+---w input
| +---w tpm20-attestation-challenge
| +---w nonce-value binary
| +---w tpm20-pcr-selection* []
| | +---w TPM20-hash-algo? identityref
| | +---w pcr-index* tpm:pcr
| +---w certificate-name* certificate-name-ref {tpm:TPMs}?
+--ro output
+--ro tpm20-attestation-response* []
+--ro certificate-name certificate-name-ref
+--ro TPMS_QUOTE_INFO binary
+--ro quote-signature? binary
+--ro up-time? uint32
+--ro unsigned-pcr-values* []
+--ro TPM20-hash-algo? identityref
+--ro pcr-values* [pcr-index]
+--ro pcr-index pcr
+--ro pcr-value? binary
An example of an RPC challenge requesting PCRs 0-7 from a SHA256 bank
could look like the following:
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<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<tpm20-challenge-response-attestation>
xmlns="urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation">
<nonce>110101010110011011111001010010100</nonce>
<tpm20-pcr-selection>
<TPM20-hash-algo
xmlns:taa="urn:ietf:params:xml:ns:yang:ietf-tcg-algs">
taa:TPM_ALG_SHA256
</TPM20-hash-algo>
<pcr-index>0</pcr-index>
<pcr-index>1</pcr-index>
<pcr-index>2</pcr-index>
<pcr-index>3</pcr-index>
<pcr-index>4</pcr-index>
<pcr-index>5</pcr-index>
<pcr-index>6</pcr-index>
<pcr-index>7</pcr-index>
</tpm20-pcr-selection>
</tpm20-challenge-response-attestation>
</rpc>
and a successful response might be formated as follows:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<tpm12-attestation-response
xmlns="urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation">
<certificate-name
xmlns:ks=urn:ietf:params:xml:ns:yang:ietf-keystore>
ks:(instance of Certificate name in the Keystore)
</certificate-name>
<TPMS_QUOTE_INFO>
(raw information from the TPM Quote, this includes a digest
across the requested PCRs, the nonce, TPM2 time counters.)
</TPMS_QUOTE_INFO>
<quote-signature>
(signature across TPMS_QUOTE_INFO)
</quote-signature>
</tpm12-attestation-response>
</rpc-reply>
2.1.1.4. <tpm12-challenge-response-attestation>
This RPC allows a Verifier to request a quote of PCRs from a TPM1.2
compliant cryptoprocessor. Where the feature <TPMs> is active, and
one or more <certificate-name> is not provided, all TPM1.2 compliant
cryptoprocessors will respond. A YANG tree diagram of this RPC is as
follows:
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+---x tpm12-challenge-response-attestation {taa:TPM12}?
+---w input
| +---w tpm12-attestation-challenge
| +---w pcr-index* pcr
| +---w nonce-value binary
| +---w certificate-name* certificate-name-ref {tpm:TPMs}?
+--ro output
+--ro tpm12-attestation-response* []
+--ro certificate-name certificate-name-ref
+--ro up-time? uint32
+--ro TPM_QUOTE2? binary
2.1.1.5. <log-retrieval>
This RPC allows a Verifier to acquire the evidence which was extended
into specific PCRs. A YANG tree diagram of this RPC is as follows:
+---x log-retrieval
+---w input
| +---w log-selector* []
| | +---w tpm-name* string
| | +---w (index-type)?
| | | +--:(last-entry)
| | | | +---w last-entry-value? binary
| | | +--:(index)
| | | | +---w last-index-number? uint64
| | | +--:(timestamp)
| | | +---w timestamp? yang:date-and-time
| | +---w log-entry-quantity? uint16
| +---w log-type identityref
+--ro output
+--ro system-event-logs
+--ro node-data* []
+--ro tpm-name? string
+--ro up-time? uint32
+--ro log-result
+--ro (attested_event_log_type)
+--:(bios)
| +--ro bios-event-logs
| +--ro bios-event-entry* [event-number]
| +--ro event-number uint32
| +--ro event-type? uint32
| +--ro pcr-index? pcr
| +--ro digest-list* []
| | +--ro hash-algo? identityref
| | +--ro digest* binary
| +--ro event-size? uint32
| +--ro event-data* uint8
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+--:(ima)
| +--ro ima-event-logs
| +--ro ima-event-entry* [event-number]
| +--ro event-number uint64
| +--ro ima-template? string
| +--ro filename-hint? string
| +--ro filedata-hash? binary
| +--ro filedata-hash-algorithm? string
| +--ro template-hash-algorithm? string
| +--ro template-hash? binary
| +--ro pcr-index? pcr
| +--ro signature? binary
+--:(netequip_boot)
+--ro boot-event-logs
+--ro boot-event-entry* [event-number]
+--ro event-number uint64
+--ro filename-hint? string
+--ro filedata-hash? binary
+--ro filedata-hash-algorithm? string
+--ro file-version? string
+--ro file-type? string
+--ro pcr-index? pcr
2.1.1.6. Data Nodes
This section provides a high level description of the data nodes
containing the configuration and operational objects with the YANG
model. For more details, please see the YANG model itself in
Section 2.1.1.7.
container <rats-support-structures> - This houses the set of
information relating to a device's TPM(s).
container <tpms> - Provides configuration and operational details for
each supported TPM, including the tpm-firmware-version, PCRs which
may be quoted, certificates which are associated with that TPM, and
the current operational status. Of note is the certificates which
are associated with that TPM. As a certificate is associated with a
single Attestation key, knowledge of the certificate allows a
specific TPM to be identified.
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+--rw tpms
+--rw tpm* [tpm-name]
+--rw tpm-name string
+--ro hardware-based? boolean
+--ro tpm-physical-index? int32 {ietfhw:entity-mib}?
+--ro tpm-path? string
+--ro compute-node compute-node-ref {tpm:TPMs}?
+--ro tpm-manufacturer? string
+--rw tpm-firmware-version identityref
+--rw TPM12-hash-algo? identityref
+--rw TPM12-pcrs* pcr
+--rw tpm20-pcr-bank* [TPM20-hash-algo]
| +--rw TPM20-hash-algo identityref
| +--rw pcr-index* tpm:pcr
+--ro tpm-status enumeration
+--rw certificates
+--rw certificate* [certificate-name]
+--rw certificate-name string
+--rw certificate-keystore-ref? -> /ks:keystore/asymmetric-keys/asymmetric-key/certificates/certificate/name
+--rw certificate-type? enumeration
container <attester-supported-algos> - Identifies which TCG
algorithms are available for use the Attesting platform. This allows
an operator to limit algorithms available for use by RPCs to just a
desired set from the universe of all allowed by TCG.
+--rw attester-supported-algos
+--rw tpm12-asymmetric-signing* identityref {taa:TPM12}?
+--rw tpm12-hash* identityref {taa:TPM12}?
+--rw tpm20-asymmetric-signing* identityref {taa:TPM20}?
+--rw tpm20-hash* identityref {taa:TPM20}?
container <compute-nodes> - When there is more than one TPM
supported, this container maintains the set of information related to
the compute associated with a specific TPM. This allows each
specific TPM to identify on which <compute-node> it belongs.
+--rw compute-nodes {tpm:TPMs}?
+--ro compute-node* [node-id]
+--ro node-id string
+--ro node-physical-index? int32 {ietfhw:entity-mib}?
+--ro node-name? string
+--ro node-location? string
2.1.1.7. YANG Module
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<CODE BEGINS> file ietf-tpm-remote-attestation@2020-12-17.yang
module ietf-tpm-remote-attestation {
namespace "urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation";
prefix "tpm";
import ietf-yang-types {
prefix yang;
}
import ietf-hardware {
prefix ietfhw;
}
import ietf-keystore {
prefix ks;
}
import ietf-tcg-algs {
prefix taa;
}
organization
"IETF RATS (Remote ATtestation procedureS) Working Group";
contact
"WG Web : <http://datatracker.ietf.org/wg/rats/>
WG List : <mailto:rats@ietf.org>
Author : Eric Voit <evoit@cisco.com>
Author : Henk Birkholz <henk.birkholz@sit.fraunhofer.de>
Author : Michael Eckel <michael.eckel@sit.fraunhofer.de>
Author : Shwetha Bhandari <shwetha.bhandari@thoughtspot.com>
Author : Bill Sulzen <bsulzen@cisco.com>
Author : Liang Xia (Frank) <frank.xialiang@huawei.com>
Author : Tom Laffey <tom.laffey@hpe.com>
Author : Guy Fedorkow <gfedorkow@juniper.net>";
description
"A YANG module to enable a TPM 1.2 and TPM 2.0 based
remote attestation procedure using a challenge-response
interaction model and the TPM 1.2 and TPM 2.0 Quote
primitive operations.
Copyright (c) 2020 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Simplified
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
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This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices."
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
are to be interpreted as described in BCP 14 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision "2021-03-16" {
description
"Initial version";
reference
"draft-ietf-rats-yang-tpm-charra";
}
/*****************/
/* Features */
/*****************/
feature TPMs {
description
"The device supports the remote attestation of multiple
TPM based cryptoprocessors.";
}
feature bios {
description
"The device supports the bios logs.";
reference
"https://trustedcomputinggroup.org/wp-content/uploads/
PC-ClientSpecific_Platform_Profile_for_TPM_2p0_Systems_v51.pdf
Section 9.4.5.2";
}
feature ima {
description
"The device supports Integrity Measurement Architecture logs.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TCG_IWG_CEL_v1_r0p30_13feb2021.pdf Section 4.3";
}
feature netequip_boot {
description
"The device supports the netequip_boot logs.";
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}
/*****************/
/* Typedefs */
/*****************/
typedef pcr {
type uint8 {
range "0..31";
}
description
"Valid index number for a PCR. At this point 0-31 is viable.";
}
typedef compute-node-ref {
type leafref {
path "/tpm:rats-support-structures/tpm:compute-nodes" +
"/tpm:compute-node/tpm:node-name";
}
description
"This type is used to reference a hardware node. It is quite
possible this leafref will eventually point to another YANG
module's node.";
}
typedef certificate-name-ref {
type leafref {
path "/tpm:rats-support-structures/tpm:tpms/tpm:tpm" +
"/tpm:certificates/tpm:certificate/tpm:certificate-name";
}
description
"A type which allows identification of a TPM based certificate.";
}
/******************/
/* Identities */
/******************/
identity attested_event_log_type {
description
"Base identity allowing categorization of the reasons why and
attested measurement has been taken on an Attester.";
}
identity ima {
base attested_event_log_type;
description
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"An event type recorded in IMA.";
}
identity bios {
base attested_event_log_type;
description
"An event type associated with BIOS/UEFI.";
}
identity netequip_boot {
base attested_event_log_type;
description
"An event type associated with Network Equipment Boot.";
}
/*****************/
/* Groupings */
/*****************/
grouping TPM20-hash-algo {
description
"The cryptographic algorithm used to hash the TPM2 PCRs. This
must be from the list of platform supported options.";
leaf TPM20-hash-algo {
type identityref {
base taa:hash;
}
must "/tpm:rats-support-structures/tpm:attester-supported-algos"
+ "/tpm:tpm20-hash" {
error-message "Not a platform supported TPM20-hash-algo";
}
default taa:TPM_ALG_SHA256;
description
"The hash scheme that is used to hash a TPM1.2 PCR. This
must be one of those supported by a platform.";
}
}
grouping TPM12-hash-algo {
description
"The cryptographic algorithm used to hash the TPM1.2 PCRs.";
leaf TPM12-hash-algo {
type identityref {
base taa:hash;
}
must "/tpm:rats-support-structures/tpm:attester-supported-algos"
+ "/tpm:tpm12-hash" {
error-message "Not a platform supported TPM12-hash-algo";
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}
default taa:TPM_ALG_SHA1;
description
"The hash scheme that is used to hash a TPM1.2 PCR. This
MUST be one of those supported by a platform. This assumes
that an algorithm other than SHA1 can be supported on some
TPM1.2 cryptoprocessor variant.";
}
}
grouping nonce {
description
"A random number intended to be used once to show freshness
and to allow the detection of replay attacks.";
leaf nonce-value {
type binary;
mandatory true;
description
"This nonce SHOULD be generated via a registered
cryptographic-strength algorithm. In consequence,
the length of the nonce depends on the hash algorithm
used. The algorithm used in this case is independent
from the hash algorithm used to create the hash-value
in the response of the attestor.";
}
}
grouping tpm12-pcr-selection {
description
"A Verifier can request one or more PCR values using its
individually created Attestation Key Certificate (AC).
The corresponding selection filter is represented in this
grouping.
Requesting a PCR value that is not in scope of the AC used,
detailed exposure via error msg should be avoided.";
leaf-list pcr-index {
/* the following XPATH must be updated to ensure that only
selectable PCRs are allowed in the RPC
must "/tpm:rats-support-structures/tpm:tpms" +
"/tpm:tpm[tpm-name = current()]" +
"/tpm:tpm[TPM12-pcrs = current()]" {
error-message "Acquiring this PCR index is not supported";
}
*/
type pcr;
description
"The numbers/indexes of the PCRs. At the moment this is limited
to 32.";
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}
}
grouping tpm20-pcr-selection {
description
"A Verifier can acquire one or more PCR values, which are hashed
together in a TPM2B_DIGEST coming from the TPM2. The selection
list of desired PCRs and the Hash Algorithm is represented in
this grouping.";
list tpm20-pcr-selection {
unique "TPM20-hash-algo";
description
"Specifies the list of PCRs and Hash Algorithms that can be
returned within a TPM2B_DIGEST.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7";
uses TPM20-hash-algo;
leaf-list pcr-index {
/* the following XPATH must be updated to ensure that only
selectable PCRs are allowed in the RPC
must "/tpm:rats-support-structures/tpm:tpms" +
"/tpm:tpm[tpm-name = current()]" +
"/tpm:tpm20-pcr-bank[pcr-index = current()]" {
error-message "Acquiring this PCR index is not supported";
}
*/
type tpm:pcr;
description
"The numbers of the PCRs that which are being tracked
with a hash based on the TPM20-hash-algo.";
}
}
}
grouping certificate-name-ref {
description
"Identifies a certificate in a keystore.";
leaf certificate-name {
type certificate-name-ref;
mandatory true;
description
"Identifies a certificate in a keystore.";
}
}
grouping tpm-name {
description
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"A unique TPM on a device.";
leaf tpm-name {
type string;
description
"Unique system generated name for a TPM on a device.";
}
}
grouping tpm-name-selector {
description
"One or more TPM on a device.";
leaf-list tpm-name {
type string;
config false;
description
"Name of one or more unique TPMs on a device. If this object
exists, a selection should pull only the objects related to
these TPM(s). If it does not exist, all qualifying TPMs that
are 'hardware-based' equals true on the device are selected.";
}
}
grouping node-uptime {
description
"Uptime in seconds of the node.";
leaf up-time {
type uint32;
description
"Uptime in seconds of this node reporting its data";
}
}
grouping tpm12-attestation {
description
"Contains an instance of TPM1.2 style signed cryptoprocessor
measurements. It is supplemented by unsigned Attester
information.";
uses node-uptime;
leaf TPM_QUOTE2 {
type binary;
description
"Result of a TPM1.2 Quote2 operation. This includes PCRs,
signatures, locality, the provided nonce and other data which
can be further parsed to appraise the Attester.";
reference
"TPM1.2 commands rev116 July 2007, Section 16.5";
}
}
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grouping tpm20-attestation {
description
"Contains an instance of TPM2 style signed cryptoprocessor
measurements. It is supplemented by unsigned Attester
information.";
leaf TPMS_QUOTE_INFO {
type binary;
mandatory true;
description
"A hash of the latest PCR values (and the hash algorithm used)
which have been returned from a Verifier for the selected PCRs
and Hash Algorithms.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.12.1";
}
leaf quote-signature {
type binary;
description
"Quote signature returned by TPM Quote. The signature was
generated using the key associated with the
certificate-name.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 11.2.1";
}
uses node-uptime;
list unsigned-pcr-values {
description
"PCR values in each PCR bank. This might appear redundant with
the TPM2B_DIGEST, but that digest is calculated across multiple
PCRs. Having to verify across multiple PCRs does not
necessarily make it easy for a Verifier to appraise just the
minimum set of PCR information which has changed since the last
received TPM2B_DIGEST. Put another way, why should a Verifier
reconstruct the proper value of all PCR Quotes when only a
single PCR has changed?
To help this happen, if the Attester does know specific PCR
values, the Attester can provide these individual values via
'unsigned-pcr-values'. By comparing this information to the
what has previously been validated, it is possible for a
Verifier to confirm the Attester's signature while eliminating
significant processing.";
uses TPM20-hash-algo;
list pcr-values {
key pcr-index;
description
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"List of one PCR bank.";
leaf pcr-index {
type pcr;
description
"PCR index number.";
}
leaf pcr-value {
type binary;
description
"PCR value.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7";
}
}
}
}
grouping log-identifier {
description
"Identifier for type of log to be retrieved.";
leaf log-type {
type identityref {
base attested_event_log_type;
}
mandatory true;
description
"The corresponding measurement log type identity.";
}
}
grouping boot-event-log {
description
"Defines an event log corresponding to the event that extended
the PCR";
leaf event-number {
type uint32;
description
"Unique event number of this event";
}
leaf event-type {
type uint32;
description
"log event type";
}
leaf pcr-index {
type pcr;
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description
"Defines the PCR index that this event extended";
}
list digest-list {
description
"Hash of event data";
leaf hash-algo {
type identityref {
base taa:hash;
}
description
"The hash scheme that is used to compress the event data in
each of the leaf-list digest items.";
}
leaf-list digest {
type binary;
description
"The hash of the event data using the algorithm of the
'hash-algo' against 'event data'.";
}
}
leaf event-size {
type uint32;
description
"Size of the event data";
}
leaf-list event-data {
type uint8;
description
"The event data size determined by event-size";
}
}
grouping bios-event-log {
description
"Measurement log created by the BIOS/UEFI.";
list bios-event-entry {
key event-number;
description
"Ordered list of TCG described event log
that extended the PCRs in the order they
were logged";
uses boot-event-log;
}
}
grouping ima-event {
description
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"Defines an hash log extend event for IMA measurements";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TCG_IWG_CEL_v1_r0p30_13feb2021.pdf Section 4.3";
leaf event-number {
type uint64;
description
"Unique number for this event for sequencing";
}
leaf ima-template {
type string;
description
"Name of the template used for event logs
for e.g. ima, ima-ng, ima-sig";
}
leaf filename-hint {
type string;
description
"File that was measured";
}
leaf filedata-hash {
type binary;
description
"Hash of filedata";
}
leaf filedata-hash-algorithm {
type string;
description
"Algorithm used for filedata-hash";
}
leaf template-hash-algorithm {
type string;
description
"Algorithm used for template-hash";
}
leaf template-hash {
type binary;
description
"hash(filedata-hash, filename-hint)";
}
leaf pcr-index {
type pcr;
description
"Defines the PCR index that this event extended";
}
leaf signature {
type binary;
description
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"The file signature";
}
}
grouping ima-event-log {
description
"Measurement log created by IMA.";
list ima-event-entry {
key event-number;
description
"Ordered list of ima event logs by event-number";
uses ima-event;
}
}
grouping netequip-boot-event {
description
"Defines an hash log extend event for Network Equipment Boot.";
leaf event-number {
type uint64;
description
"Unique number for this event for sequencing";
}
leaf filename-hint {
type string;
description
"File that was measured";
}
leaf filedata-hash {
type binary;
description
"Hash of filedata";
}
leaf filedata-hash-algorithm {
type string;
description
"Algorithm used for filedata-hash.";
}
leaf file-version {
type string;
description
"File version information.";
}
leaf file-type {
type string;
description
"Indicating at which boot stage the file is loaded,
such as BIOS, BootLoader, etc.";
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}
leaf pcr-index {
type pcr;
description
"Defines the PCR index that this event extended";
}
}
grouping network-equipment-boot-event-log {
description
"Measurement log created by Network Equipment Boot.";
list boot-event-entry {
key event-number;
description
"Ordered list of Network Equipment Boot event logs
by event-number.";
uses netequip-boot-event;
}
}
grouping event-logs {
description
"A selector for the log and its type.";
choice attested_event_log_type {
mandatory true;
description
"Event log type determines the event logs content.";
case bios {
if-feature "bios";
description
"BIOS/UEFI event logs";
container bios-event-logs {
description
"BIOS/UEFI event logs";
uses bios-event-log;
}
}
case ima {
if-feature "ima";
description
"IMA event logs.";
container ima-event-logs {
description
"IMA event logs.";
uses ima-event-log;
}
}
case netequip_boot {
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if-feature "netequip_boot";
description
"Network Equipment Boot event logs";
container boot-event-logs {
description
"Network equipment boot event logs.";
uses network-equipment-boot-event-log;
}
}
}
}
/**********************/
/* RPC operations */
/**********************/
rpc tpm12-challenge-response-attestation {
if-feature "taa:TPM12";
description
"This RPC accepts the input for TSS TPM 1.2 commands made to the
attesting device.";
input {
container tpm12-attestation-challenge {
description
"This container includes every information element defined
in the reference challenge-response interaction model for
remote attestation. Corresponding values are based on
TPM 1.2 structure definitions";
uses tpm12-pcr-selection;
uses nonce;
leaf-list certificate-name {
if-feature "tpm:TPMs";
type certificate-name-ref;
must "/tpm:rats-support-structures/tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm12']" +
"/tpm:certificates/" +
"/tpm:certificate[certificate-name-ref=current()]" {
error-message "Not an available TPM1.2 AIK certificate.";
}
description
"When populated, the RPC will only get a Quote for the
TPMs associated with these certificate(s).";
}
}
}
output {
list tpm12-attestation-response {
unique "certificate-name";
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description
"The binary output of TPM 1.2 TPM_Quote/TPM_Quote2, including
the PCR selection and other associated attestation evidence
metadata";
uses certificate-name-ref {
description
"Certificate associated with this tpm12-attestation.";
}
uses tpm12-attestation;
}
}
}
rpc tpm20-challenge-response-attestation {
if-feature "taa:TPM20";
description
"This RPC accepts the input for TSS TPM 2.0 commands of the
managed device. ComponentIndex from the hardware manager YANG
module to refer to dedicated TPM in composite devices,
e.g. smart NICs, is still a TODO.";
input {
container tpm20-attestation-challenge {
description
"This container includes every information element defined
in the reference challenge-response interaction model for
remote attestation. Corresponding values are based on
TPM 2.0 structure definitions";
uses nonce;
uses tpm20-pcr-selection;
leaf-list certificate-name {
if-feature "tpm:TPMs";
type certificate-name-ref;
must "/tpm:rats-support-structures/tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm20']" +
"/tpm:certificates/" +
"/tpm:certificate[certificate-name-ref=current()]" {
error-message "Not an available TPM2.0 AIK certificate.";
}
description
"When populated, the RPC will only get a Quote for the
TPMs associated with the certificates.";
}
}
}
output {
list tpm20-attestation-response {
unique "certificate-name";
description
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"The binary output of TPM2b_Quote in one TPM chip of the
node which identified by node-id. An TPMS_ATTEST structure
including a length, encapsulated in a signature";
uses certificate-name-ref {
description
"Certificate associated with this tpm20-attestation.";
}
uses tpm20-attestation;
}
}
}
rpc log-retrieval {
description
"Logs Entries are either identified via indices or via providing
the last line received. The number of lines returned can be
limited. The type of log is a choice that can be augmented.";
input {
list log-selector {
description
"Selection of log entries to be reported.";
uses tpm-name-selector;
choice index-type {
description
"Last log entry received, log index number, or timestamp.";
case last-entry {
description
"The last entry of the log already retrieved.";
leaf last-entry-value {
type binary;
description
"Content of an log event which matches 1:1 with a
unique event record contained within the log. Log
entries subsequent to this will be passed to the
requester. Note: if log entry values are not unique,
this MUST return an error.";
}
}
case index {
description
"Numeric index of the last log entry retrieved, or
zero.";
leaf last-index-number {
type uint64;
description
"The last numeric index number of a log entry.
Zero means to start at the beginning of the log.
Entries subsequent to this will be passed to the
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requester.";
}
}
case timestamp {
leaf timestamp {
type yang:date-and-time;
description
"Timestamp from which to start the extraction. The
next log entry subsequent to this timestamp is to
be sent.";
}
description
"Timestamp from which to start the extraction.";
}
}
leaf log-entry-quantity {
type uint16;
description
"The number of log entries to be returned. If omitted, it
means all of them.";
}
}
uses log-identifier;
}
output {
container system-event-logs {
description
"The requested data of the measurement event logs";
list node-data {
unique "tpm-name";
description
"Event logs of a node in a distributed system
identified by the node name";
uses tpm-name;
uses node-uptime;
container log-result {
description
"The requested entries of the corresponding log.";
uses event-logs;
}
}
}
}
}
/**************************************/
/* Config & Oper accessible nodes */
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/**************************************/
container rats-support-structures {
description
"The datastore definition enabling verifiers or relying
parties to discover the information necessary to use the
remote attestation RPCs appropriately.";
container compute-nodes {
if-feature "tpm:TPMs";
description
"Holds the set device subsystems/components in this composite
device that support TPM operations.";
list compute-node {
key node-id;
config false;
min-elements 2;
description
"A component within this composite device which
supports TPM operations.";
leaf node-id {
type string;
description
"ID of the compute node, such as Board Serial Number.";
}
leaf node-physical-index {
if-feature ietfhw:entity-mib;
type int32 {
range "1..2147483647";
}
config false;
description
"The entPhysicalIndex for the compute node.";
reference
"RFC 6933: Entity MIB (Version 4) - entPhysicalIndex";
}
leaf node-name {
type string;
description
"Name of the compute node.";
}
leaf node-location {
type string;
description
"Location of the compute node, such as slot number.";
}
}
}
container tpms {
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description
"Holds the set of TPMs within an Attester.";
list tpm {
key tpm-name;
unique "tpm-path";
description
"A list of TPMs in this composite device that RATS
can be conducted with.";
uses tpm-name;
leaf hardware-based {
type boolean;
config false;
description
"Answers the question: is this TPM is a hardware based
TPM?";
}
leaf tpm-physical-index {
if-feature ietfhw:entity-mib;
type int32 {
range "1..2147483647";
}
config false;
description
"The entPhysicalIndex for the TPM.";
reference
"RFC 6933: Entity MIB (Version 4) - entPhysicalIndex";
}
leaf tpm-path {
type string;
config false;
description
"Path to a unique TPM on a device. This can change across
reboots.";
}
leaf compute-node {
if-feature "tpm:TPMs";
type compute-node-ref;
config false;
mandatory true;
description
"Indicates the compute node measured by this TPM.";
}
leaf tpm-manufacturer {
type string;
config false;
description
"TPM manufacturer name.";
}
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leaf tpm-firmware-version {
type identityref {
base taa:cryptoprocessor;
}
mandatory true;
description
"Identifies the cryptoprocessor API set supported. This
is automatically configured by the device and should not
be changed.";
}
uses TPM12-hash-algo {
when "tpm-firmware-version = 'taa:tpm12'";
refine TPM12-hash-algo {
description
"The hash algorithm overwrites the default used for PCRs
on this TPM1.2 compliant cryptoprocessor.";
}
}
leaf-list TPM12-pcrs {
when "../tpm-firmware-version = 'taa:tpm12'";
type pcr;
description
"The PCRs which may be extracted from this TPM1.2
compliant cryptoprocessor.";
}
list tpm20-pcr-bank {
when "../tpm-firmware-version = 'taa:tpm20'";
key "TPM20-hash-algo";
description
"Specifies the list of PCRs that may be extracted for
a specific Hash Algorithm on this TPM2 compliant
cryptoprocessor. A bank is a set of PCRs which are
extended using a particular hash algorithm.";
reference
"https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7";
leaf TPM20-hash-algo {
type identityref {
base taa:hash;
}
must "/tpm:rats-support-structures"
+ "/tpm:attester-supported-algos"
+ "/tpm:tpm20-hash" {
error-message "Not a platform supported TPM20-hash-algo";
}
description
"The hash scheme actively being used to hash a
one or more TPM2.0 PCRs.";
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}
leaf-list pcr-index {
type tpm:pcr;
description
"Defines what TPM2 PCRs are available to be extracted.";
}
}
leaf tpm-status {
type enumeration {
enum operational {
value 0;
description
"The TPM currently is currently running normally and
is ready to accept and process TPM quotes.";
reference
"TPM-Rev-2.0-Part-1-Architecture-01.07-2014-03-13.pdf
Section 12";
}
enum non-operational {
value 1;
description
"TPM is in a state such as startup or shutdown which
precludes the processing of TPM quotes.";
}
}
config false;
mandatory true;
description
"TPM chip self-test status.";
}
container certificates {
description
"The TPM's certificates, including EK certificates
and AK certificates.";
list certificate {
key "certificate-name";
description
"Three types of certificates can be accessed via
this statement, including Initial Attestation
Key Cert, Local Attestation Key Cert or
Endorsement Key Cert.";
leaf certificate-name {
type string;
description
"An arbitrary name uniquely identifying a certificate
associated within key within a TPM.";
}
leaf certificate-keystore-ref {
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type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "/ks:certificates/ks:certificate/ks:name";
}
description
"A reference to a specific certificate of an
asymmetric key in the Keystore.";
/* Note: It is also possible to import a grouping which
allows local definition via an imported keystore
schema. */
}
leaf certificate-type {
type enumeration {
enum endorsement-cert {
value 0;
description
"Endorsement Key (EK) Certificate type.";
}
enum initial-attestation-cert {
value 1;
description
"Initial Attestation key (IAK) Certificate type.";
}
enum local-attestation-cert {
value 2;
description
"Local Attestation Key (LAK) Certificate type.";
}
}
description
"Type of this certificate";
}
}
}
}
}
container attester-supported-algos {
description
"Identifies which TPM algorithms are available for use on an
attesting platform.";
leaf-list tpm12-asymmetric-signing {
when "../../tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm12']";
if-feature "taa:TPM12";
type identityref {
base taa:asymmetric;
}
description
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"Platform Supported TPM12 asymmetric algorithms.";
}
leaf-list tpm12-hash {
when "../../tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm12']";
if-feature "taa:TPM12";
type identityref {
base taa:hash;
}
description
"Platform supported TPM12 hash algorithms.";
}
leaf-list tpm20-asymmetric-signing {
when "../../tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm20']";
if-feature "taa:TPM20";
type identityref {
base taa:asymmetric;
}
description
"Platform Supported TPM20 asymmetric algorithms.";
}
leaf-list tpm20-hash {
when "../../tpm:tpms" +
"/tpm:tpm[tpm:tpm-firmware-version='taa:tpm20']";
if-feature "taa:TPM20";
type identityref {
base taa:hash;
}
description
"Platform supported TPM20 hash algorithms.";
}
}
}
}
<CODE ENDS>
2.1.2. ietf-tcg-algs
Cryptographic algorithm types were initially included within -v14
NETCONF's iana-crypto-types.yang. Unfortunately all this content
including the algorithms needed here failed to make the -v15 used
WGLC. As a result this document has encoded the TCG Algorithm
definitions of [TCG-Algos], revision 1.32. By including this full
table as a separate YANG file within this document, it is possible
for other YANG models to leverage the contents of this model.
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2.1.2.1. Features
There are two types of features supported <TPM12> and <TPM20>.
Support for either of these features indicates that a cryptoprocessor
supporting the corresponding type of TCG API is present on an
Attester. Most commonly, only one type of cryptoprocessor will be
available on an Attester.
2.1.2.2. Identities
There are three types of identities in this model.
The first are the cryptographic functions supportable by a TPM
algorithm, these include: <asymmetric>, <symmetric>, <hash>,
<signing>, <anonymous_signing>, <encryption_mode>, <method>, and
<object_type>. The definitions of each of these are in Table 2 of
[TCG-Algos].
The second are API specifications for tpms: <tpm12> and <tpm2>.
The third are specific algorithm types. Each algorithm type defines
what cryptographic functions may be supported, and on which type of
API specification. It is not required that an implementation of a
specific TPM will support all algorithm types. The contents of each
specific algorithm mirrors what is in Table 3 of [TCG-Algos].
2.1.2.3. YANG Module
<CODE BEGINS> ietf-tcg-algs@2020-09-18.yang
module ietf-tcg-algs {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-tcg-algs";
prefix taa;
organization
"IETF RATS Working Group";
contact
"WG Web: <http://datatracker.ietf.org/wg/rats/>
WG List: <mailto:rats@ietf.org>
Author: Eric Voit <mailto:evoit@cisco.com>";
description
"This module defines a identities for asymmetric algorithms.
Copyright (c) 2020 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
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or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Simplified
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
are to be interpreted as described in BCP 14 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision 2020-09-18 {
description
"Initial version";
reference
"RFC XXXX: tbd";
}
/*****************/
/* Features */
/*****************/
feature TPM12 {
description
"This feature indicates algorithm support for the TPM 1.2 API
as per TPM-main-1.2-Rev94-part-2, Section 4.8.";
}
feature TPM20 {
description
"This feature indicates algorithm support for the TPM 2.0 API
as per TPM-Rev-2.0-Part-1-Architecture-01.38 Section 11.4.";
}
/*****************/
/* Identities */
/*****************/
/* There needs to be collasping/verification of some of the identity
types between the various algorithm types listed below */
identity asymmetric {
description
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"A TCG recognized asymmetric algorithm with a public and
private key.";
reference
"http://trustedcomputinggroup.org/resource/tcg-algorithm-registry/
TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity symmetric {
description
"A TCG recognized symmetric algorithm with only a private key.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity hash {
description
"A TCG recognized hash algorithm that compresses input data to
a digest value or indicates a method that uses a hash.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity signing {
description
"A TCG recognized signing algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity anonymous_signing {
description
"A TCG recognized anonymous signing algorithm.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity encryption_mode {
description
"A TCG recognized encryption mode.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity method {
description
"A TCG recognized method such as a mask generation function.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
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}
identity object_type {
description
"A TCG recognized object type.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 2";
}
identity cryptoprocessor {
description
"Base identity identifying a crytoprocessor.";
}
identity tpm12 {
if-feature "TPM12";
base cryptoprocessor;
description
"Supportable by a TPM1.2.";
reference
"TPM-Main-Part-2-TPM-Structures_v1.2_rev116_01032011.pdf
TPM_ALGORITHM_ID values, page 18";
}
identity tpm20 {
if-feature "TPM12";
base cryptoprocessor;
description
"Supportable by a TPM2.";
reference
"TPM-Rev-2.0-Part-2-Structures-01.38.pdf
The TCG Algorithm Registry. Table 9";
}
identity TPM_ALG_RSA {
if-feature "TPM12 or TPM20";
base tpm12;
base tpm20;
base asymmetric;
base object_type;
description
"RSA algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
RFC 8017. ALG_ID: 0x0001";
}
identity TPM_ALG_TDES {
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if-feature "TPM12";
base tpm12;
base symmetric;
description
"Block cipher with various key sizes (Triple Data Encryption
Algorithm, commonly called Triple Data Encryption Standard)
Note: was banned in TPM1.2 v94";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 18033-3. ALG_ID: 0x0003";
}
identity TPM_ALG_SHA1 {
if-feature "TPM12 or TPM20";
base hash;
base tpm12;
base tpm20;
description
"SHA1 algorithm - Deprecated due to insufficient cryptographic
protection. However it is still useful for hash algorithms
where protection is not required.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10118-3. ALG_ID: 0x0004";
}
identity TPM_ALG_HMAC {
if-feature "TPM12 or TPM20";
base tpm12;
base tpm20;
base hash;
base signing;
description
"Hash Message Authentication Code (HMAC) algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3,
ISO/IEC 9797-2 and RFC2014. ALG_ID: 0x0005";
}
identity TPM_ALG_AES {
if-feature "TPM12";
base tpm12;
base symmetric;
description
"The AES algorithm with various key sizes";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 18033-3. ALG_ID: 0x0006";
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}
identity TPM_ALG_MGF1 {
if-feature "TPM20";
base tpm20;
base hash;
base method;
description
"hash-based mask-generation function";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3,
IEEE Std 1363-2000 and IEEE Std 1363a -2004.
ALG_ID: 0x0007";
}
identity TPM_ALG_KEYEDHASH {
if-feature "TPM20";
base tpm20;
base hash;
base object_type;
description
"An encryption or signing algorithm using a keyed hash. These
may use XOR for encryption or an HMAC for signing and may
also refer to a data object that is neither signing nor
encrypting.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. . ALG_ID: 0x0008";
}
identity TPM_ALG_XOR {
if-feature "TPM12 or TPM20";
base tpm12;
base tpm20;
base hash;
base symmetric;
description
"The XOR encryption algorithm.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. ALG_ID: 0x000A";
}
identity TPM_ALG_SHA256 {
if-feature "TPM20";
base tpm20;
base hash;
description
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"The SHA 256 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10118-3. ALG_ID: 0x000B";
}
identity TPM_ALG_SHA384 {
if-feature "TPM20";
base tpm20;
base hash;
description
"The SHA 384 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10118-3. ALG_ID: 0x000C";
}
identity TPM_ALG_SHA512 {
if-feature "TPM20";
base tpm20;
base hash;
description
"The SHA 512 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10118-3. ALG_ID: 0x000D";
}
identity TPM_ALG_NULL {
if-feature "TPM20";
base tpm20;
description
"NULL algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. ALG_ID: 0x0010";
}
identity TPM_ALG_SM3_256 {
if-feature "TPM20";
base tpm20;
base hash;
description
"The SM3 hash algorithm.";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
GM/T 0004-2012 - SM3_256. ALG_ID: 0x0012";
}
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identity TPM_ALG_SM4 {
if-feature "TPM20";
base tpm20;
base symmetric;
description
"SM4 symmetric block cipher";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
GB/T 32907-2016. ALG_ID: 0x0013";
}
identity TPM_ALG_RSASSA {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
description
"Signature algorithm defined in section 8.2 (RSASSAPKCS1-v1_5)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and RFC 8017.
ALG_ID: 0x0014";
}
identity TPM_ALG_RSAES {
if-feature "TPM20";
base tpm20;
base asymmetric;
base encryption_mode;
description
"Signature algorithm defined in section 7.2 (RSAES-PKCS1-v1_5)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and RFC 8017
ALG_ID: 0x0015";
}
identity TPM_ALG_RSAPSS {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
description
"Padding algorithm defined in section 8.1 (RSASSA PSS)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and RFC 8017.
ALG_ID: 0x0016";
}
identity TPM_ALG_OAEP {
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if-feature "TPM20";
base tpm20;
base asymmetric;
base encryption_mode;
description
"Padding algorithm defined in section 7.1 (RSASSA OAEP)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and RFC 8017.
ALG_ID: 0x0017";
}
identity TPM_ALG_ECDSA {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
description
"Signature algorithm using elliptic curve cryptography (ECC)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 14888-3. ALG_ID: 0x0018";
}
identity TPM_ALG_ECDH {
if-feature "TPM20";
base tpm20;
base asymmetric;
base method;
description
"Secret sharing using ECC";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-56A and RFC 7748. ALG_ID: 0x0019";
}
identity TPM_ALG_ECDAA {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
base anonymous_signing;
description
"Elliptic-curve based anonymous signing scheme";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. ALG_ID: 0x001A";
}
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identity TPM_ALG_SM2 {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
base encryption_mode;
base method;
description
"SM2 - depending on context, either an elliptic-curve based,
signature algorithm, an encryption scheme, or a key exchange
protocol";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
A GM/T 0003.1-2012, GM/T 0003.2-2012, GM/T 0003.3-2012,
GM/T 0003.5-2012 SM2. ALG_ID: 0x001B";
}
identity TPM_ALG_ECSCHNORR {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
description
"Elliptic-curve based Schnorr signature";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. ALG_ID: 0x001C";
}
identity TPM_ALG_ECMQV {
if-feature "TPM20";
base tpm20;
base asymmetric;
base method;
description
"Two-phase elliptic-curve key";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-56A. ALG_ID: 0x001D";
}
identity TPM_ALG_KDF1_SP800_56A {
if-feature "TPM20";
base tpm20;
base hash;
base method;
description
"Concatenation key derivation function";
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reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-56A (approved alternative1) section 5.8.1.
ALG_ID: 0x0020";
}
identity TPM_ALG_KDF2 {
if-feature "TPM20";
base tpm20;
base hash;
base method;
description
"Key derivation function";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
IEEE 1363a-2004 KDF2 section 13.2. ALG_ID: 0x0021";
}
identity TPM_ALG_KDF1_SP800_108 {
base TPM_ALG_KDF2;
description
"A key derivation method";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-108 - Section 5.1 KDF. ALG_ID: 0x0022";
}
identity TPM_ALG_ECC {
if-feature "TPM20";
base tpm20;
base asymmetric;
base object_type;
description
"Prime field ECC";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 15946-1. ALG_ID: 0x0023";
}
identity TPM_ALG_SYMCIPHER {
if-feature "TPM20";
base tpm20;
description
"Object type for a symmetric block cipher";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
TCG TPM 2.0 library specification. ALG_ID: 0x0025";
}
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identity TPM_ALG_CAMELLIA {
if-feature "TPM20";
base tpm20;
base symmetric;
description
"The Camellia algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 18033-3. ALG_ID: 0x0026";
}
identity TPM_ALG_SHA3_256 {
if-feature "TPM20";
base tpm20;
base hash;
description
"ISO/IEC 10118-3 - the SHA 256 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST PUB FIPS 202. ALG_ID: 0x0027";
}
identity TPM_ALG_SHA3_384 {
if-feature "TPM20";
base tpm20;
base hash;
description
"The SHA 384 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST PUB FIPS 202. ALG_ID: 0x0028";
}
identity TPM_ALG_SHA3_512 {
if-feature "TPM20";
base tpm20;
base hash;
description
"The SHA 512 algorithm";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST PUB FIPS 202. ALG_ID: 0x0029";
}
identity TPM_ALG_CMAC {
if-feature "TPM20";
base tpm20;
base symmetric;
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base signing;
description
"block Cipher-based Message Authentication Code (CMAC)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 9797-1:2011 Algorithm 5. ALG_ID: 0x003F";
}
identity TPM_ALG_CTR {
if-feature "TPM20";
base tpm20;
base symmetric;
base encryption_mode;
description
"Counter mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10116. ALG_ID: 0x0040";
}
identity TPM_ALG_OFB {
base tpm20;
base symmetric;
base encryption_mode;
description
"Output Feedback mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10116. ALG_ID: 0x0041";
}
identity TPM_ALG_CBC {
if-feature "TPM20";
base tpm20;
base symmetric;
base encryption_mode;
description
"Cipher Block Chaining mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10116. ALG_ID: 0x0042";
}
identity TPM_ALG_CFB {
if-feature "TPM20";
base tpm20;
base symmetric;
base encryption_mode;
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description
"Cipher Feedback mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10116. ALG_ID: 0x0043";
}
identity TPM_ALG_ECB {
if-feature "TPM20";
base tpm20;
base symmetric;
base encryption_mode;
description
"Electronic Codebook mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
ISO/IEC 10116. ALG_ID: 0x0044";
}
identity TPM_ALG_CCM {
if-feature "TPM20";
base tpm20;
base symmetric;
base signing;
base encryption_mode;
description
"Counter with Cipher Block Chaining-Message Authentication
Code (CCM)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-38C. ALG_ID: 0x0050";
}
identity TPM_ALG_GCM {
if-feature "TPM20";
base tpm20;
base symmetric;
base signing;
base encryption_mode;
description
"Galois/Counter Mode (GCM)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-38D. ALG_ID: 0x0051";
}
identity TPM_ALG_KW {
if-feature "TPM20";
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base tpm20;
base symmetric;
base signing;
base encryption_mode;
description
"AES Key Wrap (KW)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-38F. ALG_ID: 0x0052";
}
identity TPM_ALG_KWP {
if-feature "TPM20";
base tpm20;
base symmetric;
base signing;
base encryption_mode;
description
"AES Key Wrap with Padding (KWP)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-38F. ALG_ID: 0x0053";
}
identity TPM_ALG_EAX {
if-feature "TPM20";
base tpm20;
base symmetric;
base signing;
base encryption_mode;
description
"Authenticated-Encryption Mode";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
NIST SP800-38F. ALG_ID: 0x0054";
}
identity TPM_ALG_EDDSA {
if-feature "TPM20";
base tpm20;
base asymmetric;
base signing;
description
"Edwards-curve Digital Signature Algorithm (PureEdDSA)";
reference
"TCG_Algorithm_Registry_r1p32_pub Table 3 and
RFC 8032. ALG_ID: 0x0060";
}
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}
<CODE ENDS>
Note that not all cryptographic functions are required for use by
ietf-tpm-remote-attestation.yang. However the full definition of
Table 3 of [TCG-Algos] will allow use by additional YANG
specifications.
3. IANA considerations
This document will include requests to IANA:
To be defined yet. But keeping up with changes to ietf-tcg-algs.yang
will be necessary.
4. Security Considerations
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].
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., config true, which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
Container: </rats-support-structures/attester-supported-algos>
* <tpm12-asymmetric-signing>, <tpm12-hash>, <tpm20-asymmetric-
signing>, and <tpm20-hash> all could be populated with algorithms
which are not supported by the underlying physical TPM installed
by the equipment vendor.
Container: </rats-support-structures/tpms>
* <tpm-name> - Although shown as 'rw', it is system generated
* <tpm20-pcr-bank> - It is possible to configure PCRs for extraction
which are not being extended by system software. This could
unnecessarily use TPM resources.
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* <certificates> - It is possible to provision a certificate which
does not correspond to a Attestation Identity Key (AIK) within the
TPM.
RPC: <tpm12-challenge-response-attestation> - Need to verify that the
certificate is for an active AIK.
RPC: <tpm20-challenge-response-attestation> - Need to verify that the
certificate is for an active AIK.
RPC: <log-retrieval> - Pulling lots of logs can chew up system
resources.
5. Acknowledgements
Not yet.
6. Change Log
Changes from version 04 to version 05:
* YANG Dr comments covered
Changes from version 03 to version 04:
* TPM1.2 Quote1 eliminated
* YANG model simplifications so redundant info isn't exposed
Changes from version 02 to version 03:
* moved to tcg-algs
* cleaned up model to eliminate sources of errors
* removed key establishment RPC
* added lots of XPATH which must all be scrubbed still
* Descriptive text added on model contents.
Changes from version 01 to version 02:
* Extracted Crypto-types into a separate YANG file
* Mades the algorithms explicit, not strings
* Hash Algo as key the selected TPM2 PCRs
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* PCR numbers are their own type
* Eliminated nested keys for node-id plus tpm-name
* Eliminated TPM-Name of "ALL"
* Added TPM-Path
Changes from version 00 to version 01:
* Addressed author's comments
* Extended complementary details about attestation-certificates
* Relabeled chunk-size to log-entry-quantity
* Relabeled location with compute-node or tpm-name where appropriate
* Added a valid entity-mib physical-index to compute-node and tpm-
name to map it back to hardware inventory
* Relabeled name to tpm_name
* Removed event-string in last-entry
7. References
7.1. Normative References
[I-D.ietf-netconf-keystore]
Watsen, K., "A YANG Data Model for a Keystore", Work in
Progress, Internet-Draft, draft-ietf-netconf-keystore-21,
10 February 2021, <https://www.ietf.org/archive/id/draft-
ietf-netconf-keystore-21.txt>.
[I-D.ietf-rats-architecture]
Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote Attestation Procedures Architecture", Work
in Progress, Internet-Draft, draft-ietf-rats-architecture-
11, 30 March 2021, <https://www.ietf.org/archive/id/draft-
ietf-rats-architecture-11.txt>.
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[I-D.ietf-rats-reference-interaction-models]
Birkholz, H., Eckel, M., Newton, C., and L. Chen,
"Reference Interaction Models for Remote Attestation
Procedures", Work in Progress, Internet-Draft, draft-ietf-
rats-reference-interaction-models-01, 23 October 2020,
<https://www.ietf.org/archive/id/draft-ietf-rats-
reference-interaction-models-01.txt>.
[I-D.ietf-rats-tpm-based-network-device-attest]
Fedorkow, G., Voit, E., and J. Fitzgerald-McKay, "TPM-
based Network Device Remote Integrity Verification", Work
in Progress, Internet-Draft, draft-ietf-rats-tpm-based-
network-device-attest-06, 7 December 2020,
<https://www.ietf.org/archive/id/draft-ietf-rats-tpm-
based-network-device-attest-06.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8348] Bierman, A., Bjorklund, M., Dong, J., and D. Romascanu, "A
YANG Data Model for Hardware Management", RFC 8348,
DOI 10.17487/RFC8348, March 2018,
<https://www.rfc-editor.org/info/rfc8348>.
[TCG-Algos]
"TCG_Algorithm_Registry_r1p32_pub", n.d.,
<hhttp://trustedcomputinggroup.org/resource/tcg-algorithm-
registry/>.
[TPM1.2] TCG, ., "TPM 1.2 Main Specification", 2 October 2003,
<https://trustedcomputinggroup.org/resource/tpm-main-
specification/>.
[TPM2.0] TCG, ., "TPM 2.0 Library Specification", 15 March 2013,
<https://trustedcomputinggroup.org/resource/tpm-library-
specification/>.
7.2. Informative References
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[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Authors' Addresses
Henk Birkholz
Fraunhofer SIT
Rheinstrasse 75
64295 Darmstadt
Germany
Email: henk.birkholz@sit.fraunhofer.de
Michael Eckel
Fraunhofer SIT
Rheinstrasse 75
64295 Darmstadt
Germany
Email: michael.eckel@sit.fraunhofer.de
Shwetha Bhandari
ThoughtSpot
Email: shwetha.bhandari@thoughtspot.com
Eric Voit
Cisco Systems
Email: evoit@cisco.com
Birkholz, et al. Expires 3 October 2021 [Page 51]
Internet-Draft YANG-CHARRA for TPMs April 2021
Bill Sulzen
Cisco Systems
Email: bsulzen@cisco.com
Liang Xia (Frank)
Huawei Technologies
101 Software Avenue, Yuhuatai District
Nanjing
Jiangsu, 210012
China
Email: Frank.Xialiang@huawei.com
Tom Laffey
Hewlett Packard Enterprise
Email: tom.laffey@hpe.com
Guy C. Fedorkow
Juniper Networks
10 Technology Park Drive
Westford
Email: gfedorkow@juniper.net
Birkholz, et al. Expires 3 October 2021 [Page 52]