draft-ietf-rats-yang-tpm-charra-17.txt   draft-ietf-rats-yang-tpm-charra-18.txt 
RATS Working Group H. Birkholz RATS Working Group H. Birkholz
Internet-Draft M. Eckel Internet-Draft M. Eckel
Intended status: Standards Track Fraunhofer SIT Intended status: Standards Track Fraunhofer SIT
Expires: 17 September 2022 S. Bhandari Expires: 21 September 2022 S. Bhandari
ThoughtSpot ThoughtSpot
E. Voit E. Voit
B. Sulzen B. Sulzen
Cisco Cisco
L. Xia L. Xia
Huawei Huawei
T. Laffey T. Laffey
HPE HPE
G. Fedorkow G. Fedorkow
Juniper Juniper
16 March 2022 20 March 2022
A YANG Data Model for Challenge-Response-based Remote Attestation A YANG Data Model for Challenge-Response-based Remote Attestation
Procedures using TPMs Procedures using TPMs
draft-ietf-rats-yang-tpm-charra-17 draft-ietf-rats-yang-tpm-charra-18
Abstract Abstract
This document defines YANG RPCs and a few configuration nodes This document defines YANG RPCs and a few configuration nodes
required to retrieve attestation evidence about integrity required to retrieve attestation evidence about integrity
measurements from a device, following the operational context defined measurements from a device, following the operational context defined
in TPM-based Network Device Remote Integrity Verification. in TPM-based Network Device Remote Integrity Verification.
Complementary measurement logs are also provided by the YANG RPCs, Complementary measurement logs are also provided by the YANG RPCs,
originating from one or more roots of trust for measurement (RTMs). originating from one or more roots of trust for measurement (RTMs).
The module defined requires at least one TPM 1.2 or TPM 2.0 as well The module defined requires at least one TPM 1.2 or TPM 2.0 as well
skipping to change at page 2, line 10 skipping to change at page 2, line 10
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 17 September 2022. This Internet-Draft will expire on 21 September 2022.
Copyright Notice Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text extracted from this document must include Revised BSD License text as
as described in Section 4.e of the Trust Legal Provisions and are described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License. provided without warranty as described in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. The YANG Module for Basic Remote Attestation Procedures . . . 3 2. The YANG Module for Basic Remote Attestation Procedures . . . 3
2.1. YANG Modules . . . . . . . . . . . . . . . . . . . . . . 3 2.1. YANG Modules . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1. 'ietf-tpm-remote-attestation' . . . . . . . . . . . . 4 2.1.1. 'ietf-tpm-remote-attestation' . . . . . . . . . . . . 4
2.1.2. 'ietf-tcg-algs' . . . . . . . . . . . . . . . . . . . 33 2.1.2. 'ietf-tcg-algs' . . . . . . . . . . . . . . . . . . . 33
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48
skipping to change at page 3, line 9 skipping to change at page 3, line 9
interaction model and information elements defined in interaction model and information elements defined in
[I-D.ietf-rats-reference-interaction-models]. The currently [I-D.ietf-rats-reference-interaction-models]. The currently
supported hardware security modules (HSMs) are the Trusted Platform supported hardware security modules (HSMs) are the Trusted Platform
Modules (TPMs) [TPM1.2] and [TPM2.0] as specified by the Trusted Modules (TPMs) [TPM1.2] and [TPM2.0] as specified by the Trusted
Computing Group (TCG). One TPM, or multiple TPMs in the case of a Computing Group (TCG). One TPM, or multiple TPMs in the case of a
Composite Device, are required in order to use the YANG module Composite Device, are required in order to use the YANG module
defined in this document. Each TPM is used as a root of trust for defined in this document. Each TPM is used as a root of trust for
storage (RTS) in order to store system security measurement Evidence. storage (RTS) in order to store system security measurement Evidence.
And each TPM is used as a root of trust for reporting (RTR) in order And each TPM is used as a root of trust for reporting (RTR) in order
to retrieve attestation Evidence. This is done by using a YANG RPC to retrieve attestation Evidence. This is done by using a YANG RPC
to request a quote which exposes a rolling hash the security to request a quote which exposes a rolling hash of the security
measurements held internally within the TPM. measurements held internally within the TPM.
Specific terms imported from [I-D.ietf-rats-architecture] and used in Specific terms imported from [I-D.ietf-rats-architecture] and used in
this document include: Attester, Composite Device, Evidence. this document include: Attester, Composite Device, Evidence.
Specific terms imported from [TPM2.0-Key] and used in this document Specific terms imported from [TPM2.0-Key] and used in this document
include: Endorsement Key (EK), Initial Attestation Key (IAK), include: Endorsement Key (EK), Initial Attestation Key (IAK),
Attestation Identity Key (AIK), Local Attestation Key (LAK). Attestation Identity Key (AIK), Local Attestation Key (LAK).
1.1. Requirements notation 1.1. Requirements notation
skipping to change at page 4, line 12 skipping to change at page 4, line 12
In this section the several YANG modules are defined. In this section the several YANG modules are defined.
2.1.1. 'ietf-tpm-remote-attestation' 2.1.1. 'ietf-tpm-remote-attestation'
This YANG module imports modules from [RFC6991] with prefix 'yang', This YANG module imports modules from [RFC6991] with prefix 'yang',
[RFC8348] with prefix 'hw', [I-D.ietf-netconf-keystore] with prefix [RFC8348] with prefix 'hw', [I-D.ietf-netconf-keystore] with prefix
'ks', and 'ietf-tcg-algs.yang' Section 2.1.2.3 with prefix 'taa'. 'ks', and 'ietf-tcg-algs.yang' Section 2.1.2.3 with prefix 'taa'.
Additionally, references are made to [RFC8032], [RFC8017], [RFC6933], Additionally, references are made to [RFC8032], [RFC8017], [RFC6933],
[TPM1.2-Commands], [TPM2.0-Arch], [TPM2.0-Structures], [TPM2.0-Key], [TPM1.2-Commands], [TPM2.0-Arch], [TPM2.0-Structures], [TPM2.0-Key],
[TPM1.2-Structures], [bios-log], [ima-log], [BIOS-Log-Event-Type], as [TPM1.2-Structures], [bios-log], [BIOS-Log-Event-Type], as well as
well as Appendix A and Appendix B. Appendix A and Appendix B.
2.1.1.1. Features 2.1.1.1. Features
This module supports the following features: This module supports the following features:
* 'mtpm': Indicates that multiple TPMs on the device can support * 'mtpm': Indicates that multiple TPMs on the device can support
remote attestation. For example, this feature could be used in remote attestation. For example, this feature could be used in
cases where multiple line cards are present, each with its own cases where multiple line cards are present, each with its own
TPM. TPM.
* 'bios': Indicates that the device supports the retrieval of BIOS/ * 'bios': Indicates that the device supports the retrieval of BIOS/
UEFI event logs. [bios-log] UEFI event logs. [bios-log]
* 'ima': Indicates that the device supports the retrieval of event * 'ima': Indicates that the device supports the retrieval of event
logs from the Linux Integrity Measurement Architecture (IMA logs from the Linux Integrity Measurement Architecture (IMA, see
[ima-log]). Also see Appendix A. Appendix A).
* 'netequip_boot': Indicates that the device supports the retrieval * 'netequip_boot': Indicates that the device supports the retrieval
of netequip boot event logs. See Appendix A and Appendix B. of netequip boot event logs. See Appendix A and Appendix B.
2.1.1.2. Identities 2.1.1.2. Identities
This module supports the following types of attestation event logs: This module supports the following types of attestation event logs:
'bios', 'ima', and 'netequip_boot'. 'bios', 'ima', and 'netequip_boot'.
2.1.1.3. Remote Procedure Calls (RPCs) 2.1.1.3. Remote Procedure Calls (RPCs)
skipping to change at page 9, line 27 skipping to change at page 9, line 27
| +--rw tpm20-hash-algo identityref | +--rw tpm20-hash-algo identityref
| +--rw pcr-index* tpm:pcr | +--rw pcr-index* tpm:pcr
+--ro status enumeration +--ro status enumeration
+--rw certificates +--rw certificates
+--rw certificate* [name] +--rw certificate* [name]
+--rw name string +--rw name string
+--rw keystore-ref? leafref {ks:asymmetric-keys}? +--rw keystore-ref? leafref {ks:asymmetric-keys}?
+--rw type? enumeration +--rw type? enumeration
container 'attester-supported-algos' - Identifies which TCG hash container 'attester-supported-algos' - Identifies which TCG hash
algorithms are available for use on the Attesting platform. This algorithms are available for use on the Attesting platform. An
allows an operator to limit algorithms available for use by RPCs to operator will use this information to limit algorithms available for
just a desired set from the universe of all allowed hash algorithms use by RPCs to just a desired set from the universe of all allowed
by the TCG. hash algorithms by the TCG.
+--rw attester-supported-algos +--rw attester-supported-algos
+--rw tpm12-asymmetric-signing* identityref +--rw tpm12-asymmetric-signing* identityref
+--rw tpm12-hash* identityref +--rw tpm12-hash* identityref
+--rw tpm20-asymmetric-signing* identityref +--rw tpm20-asymmetric-signing* identityref
+--rw tpm20-hash* identityref +--rw tpm20-hash* identityref
container 'compute-nodes' - When there is more than one TPM container 'compute-nodes' - When there is more than one TPM
supported, this container maintains the set of information related to supported, this container maintains the set of information related to
the compute node associated with a specific TPM. This allows each the compute node associated with a specific TPM. This allows each
skipping to change at page 10, line 6 skipping to change at page 10, line 6
+--rw compute-nodes {tpm:mtpm}? +--rw compute-nodes {tpm:mtpm}?
+--ro compute-node* [node-id] +--ro compute-node* [node-id]
+--ro node-id string +--ro node-id string
+--ro node-physical-index? int32 {hw:entity-mib}? +--ro node-physical-index? int32 {hw:entity-mib}?
+--ro node-name? string +--ro node-name? string
+--ro node-location? string +--ro node-location? string
2.1.1.6. YANG Module 2.1.1.6. YANG Module
<CODE BEGINS> file "ietf-tpm-remote-attestation@2022-03-15.yang" <CODE BEGINS> file "ietf-tpm-remote-attestation@2022-03-15.yang"
module ietf-tpm-remote-attestation { module ietf-tpm-remote-attestation {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation"; namespace "urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation";
prefix tpm; prefix tpm;
import ietf-yang-types { import ietf-yang-types {
prefix yang; prefix yang;
} }
import ietf-hardware { import ietf-hardware {
prefix hw; prefix hw;
} }
import ietf-keystore { import ietf-keystore {
skipping to change at page 11, line 12 skipping to change at page 11, line 13
This version of this YANG module is part of RFC XXXX This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC (https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices. itself for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as 'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here."; they appear in all capitals, as shown here.";
revision 2022-03-15 { revision 2022-03-18 {
description description
"Initial version"; "Initial version";
reference reference
"RFC XXXX: A YANG Data Model for Challenge-Response-based Remote "RFC XXXX: A YANG Data Model for Challenge-Response-based Remote
Attestation Procedures using TPMs"; Attestation Procedures using TPMs";
} }
/*****************/ /*****************/
/* Features */ /* Features */
/*****************/ /*****************/
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feature ima { feature ima {
description description
"The device supports Integrity Measurement Architecture logs. "The device supports Integrity Measurement Architecture logs.
Many variants of IMA logs exist in the deployment. Each encodes Many variants of IMA logs exist in the deployment. Each encodes
the log entry contents as the specific measurements which get the log entry contents as the specific measurements which get
hashed into a PCRs as Evidence. See the reference below for hashed into a PCRs as Evidence. See the reference below for
one example of such an encoding."; one example of such an encoding.";
reference reference
"ima-log: "ima-log:
https://www.trustedcomputinggroup.org/wp-content/uploads/ https://www.trustedcomputinggroup.org/wp-content/uploads/
TCG_IWG_CEL_v1_r0p41_pub.pdf Section 4.3"; TCG_IWG_CEL_v1_r0p41_pub.pdf Section 5.1.6";
} }
feature netequip_boot { feature netequip_boot {
description description
"The device supports the netequip_boot logs."; "The device supports the netequip_boot logs.";
reference reference
"netequip-boot-log: "netequip-boot-log:
https://www.kernel.org/doc/Documentation/ABI/testing/ima_policy"; RFC AAAA Appendix B";
} }
/*****************/ /*****************/
/* Typedefs */ /* Typedefs */
/*****************/ /*****************/
typedef pcr { typedef pcr {
type uint8 { type uint8 {
range "0..31"; range "0..31";
} }
description description
"Valid index number for a PCR. A {{TPM2.0}} compliant PCR index "Valid index number for a PCR. A {{TPM2.0}} compliant PCR index
extends from 0-31. At this time a typical TPM would have no extends from 0-31. At this time a typical TPM would have no
more than 32 PCRS."; more than 32 PCRS.";
} }
typedef compute-node-ref { typedef compute-node-ref {
type leafref { type leafref {
path "/tpm:rats-support-structures/tpm:compute-nodes" path "/tpm:rats-support-structures/tpm:compute-nodes"
+ "/tpm:compute-node/tpm:node-name"; + "/tpm:compute-node/tpm:node-id";
} }
description description
"This type is used to reference a hardware node. Note that an "This type is used to reference a hardware node. Note that an
implementer might include an alternative leafref pointing to a implementer might include an alternative leafref pointing to a
different YANG module node specifying hardware structures."; different YANG module node specifying hardware structures.";
} }
typedef certificate-name-ref { typedef certificate-name-ref {
type leafref { type leafref {
path "/tpm:rats-support-structures/tpm:tpms/tpm:tpm" path "/tpm:rats-support-structures/tpm:tpms/tpm:tpm"
skipping to change at page 13, line 38 skipping to change at page 13, line 40
/*****************/ /*****************/
grouping tpm20-hash-algo { grouping tpm20-hash-algo {
description description
"The cryptographic algorithm used to hash the TPM2 PCRs. This "The cryptographic algorithm used to hash the TPM2 PCRs. This
must be from the list of platform supported options."; must be from the list of platform supported options.";
leaf tpm20-hash-algo { leaf tpm20-hash-algo {
type identityref { type identityref {
base taa:hash; base taa:hash;
} }
must '/tpm:rats-support-structures/tpm:attester-supported-algos' must '. = /tpm:rats-support-structures'
+ '/tpm:tpm20-hash' { + '/tpm:attester-supported-algos/tpm:tpm20-hash' {
error-message "This platform does not support tpm20-hash-algo"; error-message "This platform does not support tpm20-hash-algo";
} }
default "taa:TPM_ALG_SHA256"; default "taa:TPM_ALG_SHA256";
description description
"The hash scheme that is used to hash a TPM2.0 PCR. This "The hash scheme that is used to hash a TPM2.0 PCR. This
must be one of those supported by a platform."; must be one of those supported by a platform.";
} }
} }
grouping tpm12-hash-algo { grouping tpm12-hash-algo {
skipping to change at page 14, line 4 skipping to change at page 14, line 6
default "taa:TPM_ALG_SHA256"; default "taa:TPM_ALG_SHA256";
description description
"The hash scheme that is used to hash a TPM2.0 PCR. This "The hash scheme that is used to hash a TPM2.0 PCR. This
must be one of those supported by a platform."; must be one of those supported by a platform.";
} }
} }
grouping tpm12-hash-algo { grouping tpm12-hash-algo {
description description
"The cryptographic algorithm used to hash the TPM1.2 PCRs."; "The cryptographic algorithm used to hash the TPM1.2 PCRs.";
leaf tpm12-hash-algo { leaf tpm12-hash-algo {
type identityref { type identityref {
base taa:hash; base taa:hash;
} }
must '/tpm:rats-support-structures/tpm:attester-supported-algos' must '. = /tpm:rats-support-structures'
+ '/tpm:tpm12-hash' { + '/tpm:attester-supported-algos/tpm:tpm12-hash' {
error-message "This platform does not support tpm12-hash-algo"; error-message "This platform does not support tpm12-hash-algo";
} }
default "taa:TPM_ALG_SHA1"; default "taa:TPM_ALG_SHA1";
description description
"The hash scheme that is used to hash a TPM1.2 PCR. This "The hash scheme that is used to hash a TPM1.2 PCR. This
MUST be one of those supported by a platform."; MUST be one of those supported by a platform.";
} }
} }
grouping nonce { grouping nonce {
skipping to change at page 15, line 29 skipping to change at page 15, line 31
"Specifies the list of PCRs and Hash Algorithms that can be "Specifies the list of PCRs and Hash Algorithms that can be
returned within a TPM2B_DIGEST."; returned within a TPM2B_DIGEST.";
reference reference
"TPM2.0-Structures: "TPM2.0-Structures:
https://www.trustedcomputinggroup.org/wp-content/uploads/ https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7"; TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7";
uses tpm20-hash-algo; uses tpm20-hash-algo;
leaf-list pcr-index { leaf-list pcr-index {
type pcr; type pcr;
must '/tpm:rats-support-structures/tpm:tpms' must '/tpm:rats-support-structures/tpm:tpms'
+ '/tpm:tpm[name = current()] and ' + '/tpm:tpm[name = current()]'
+ '/tpm:rats-support-structures/tpm:tpms/tpm:tpm'
+ '/tpm:tpm20-pcr-bank[pcr-index = current()]' { + '/tpm:tpm20-pcr-bank[pcr-index = current()]' {
error-message "Acquiring this PCR index is not supported"; error-message "Acquiring this PCR index is not supported";
} }
description description
"The numbers of the PCRs that which are being tracked "The numbers of the PCRs that which are being tracked
with a hash based on the tpm20-hash-algo. In addition, with a hash based on the tpm20-hash-algo. In addition,
any selection of PCRs MUST verify that the set of PCRs any selection of PCRs MUST verify that the set of PCRs
requested are a subset the set of PCR indexes exposed requested are a subset the set of PCR indexes exposed
within /tpm:rats-support-structures/tpm:tpms within /tpm:rats-support-structures/tpm:tpms
/tpm:tpm[name=current()]/tpm:tpm20-pcr-bank /tpm:tpm[name=current()]/tpm:tpm20-pcr-bank
skipping to change at page 18, line 48 skipping to change at page 18, line 50
grouping boot-event-log { grouping boot-event-log {
description description
"Defines a specific instance of an event log entry "Defines a specific instance of an event log entry
and corresponding to the information used to and corresponding to the information used to
extend the PCR"; extend the PCR";
leaf event-number { leaf event-number {
type uint32; type uint32;
description description
"Unique event number of this event which monotonically "Unique event number of this event which monotonically
increases. The maximum event number should not be increases within a given event log. The maximum event
reached, nor is wrapping back to an earlier number number should not be reached, nor is wrapping back to
supported."; an earlier number supported.";
} }
leaf event-type { leaf event-type {
type uint32; type uint32;
description description
"BIOS Log Event Type: "BIOS Log Event Type:
https://trustedcomputinggroup.org/wp-content/uploads/ https://trustedcomputinggroup.org/wp-content/uploads/
TCG_PCClient_PFP_r1p05_v23_pub.pdf Section 10.4.1"; TCG_PCClient_PFP_r1p05_v23_pub.pdf Section 10.4.1";
} }
leaf pcr-index { leaf pcr-index {
type pcr; type pcr;
skipping to change at page 25, line 5 skipping to change at page 25, line 7
rpc log-retrieval { rpc log-retrieval {
description description
"Logs Entries are either identified via indices or via providing "Logs Entries are either identified via indices or via providing
the last line received. The number of lines returned can be the last line received. The number of lines returned can be
limited. The type of log is a choice that can be augmented."; limited. The type of log is a choice that can be augmented.";
input { input {
uses log-identifier; uses log-identifier;
list log-selector { list log-selector {
description description
"Only log entries which meet all the selection criteria provided "Only log entries which meet all the selection criteria
are to be returned by the RPC output."; provided are to be returned by the RPC output.";
leaf-list name { leaf-list name {
type string; type string;
description description
"Name of one or more unique TPMs on a device. If this object "Name of one or more unique TPMs on a device. If this
exists, a selection should pull only the objects related to object exists, a selection should pull only the objects
these TPM(s). If it does not exist, all qualifying TPMs that related to these TPM(s). If it does not exist, all
are 'hardware-based' equals true on the device are selected."; qualifying TPMs that are 'hardware-based' equals true
on the device are selected. When this selection
criteria is provided, it will be considered as a logical
AND with any other selection criteria provided.";
} }
choice index-type { choice index-type {
description description
"Last log entry received, log index number, or timestamp."; "Last log entry received, log index number, or timestamp.";
case last-entry { case last-entry {
description description
"The last entry of the log already retrieved."; "The last entry of the log already retrieved.";
leaf last-entry-value { leaf last-entry-value {
type binary; type binary;
description description
skipping to change at page 29, line 4 skipping to change at page 29, line 9
type identityref { type identityref {
base taa:cryptoprocessor; base taa:cryptoprocessor;
} }
mandatory true; mandatory true;
description description
"Identifies the cryptoprocessor API set supported. This "Identifies the cryptoprocessor API set supported. This
is automatically configured by the device and should not is automatically configured by the device and should not
be changed."; be changed.";
} }
uses tpm12-hash-algo { uses tpm12-hash-algo {
when "firmware-version = 'taa:tpm12'"; when "derived-from-or-self(firmware-version, 'taa:tpm12')";
refine "tpm12-hash-algo" { refine "tpm12-hash-algo" {
description description
"The hash algorithm overwrites the default used for PCRs "The hash algorithm overwrites the default used for PCRs
on this TPM1.2 compliant cryptoprocessor."; on this TPM1.2 compliant cryptoprocessor.";
} }
} }
leaf-list tpm12-pcrs { leaf-list tpm12-pcrs {
when "../firmware-version = 'taa:tpm12'"; when
"derived-from-or-self(../firmware-version, 'taa:tpm12')";
type pcr; type pcr;
description description
"The PCRs which may be extracted from this TPM1.2 "The PCRs which may be extracted from this TPM1.2
compliant cryptoprocessor."; compliant cryptoprocessor.";
} }
list tpm20-pcr-bank { list tpm20-pcr-bank {
when "../firmware-version = 'taa:tpm20'"; when
"derived-from-or-self(../firmware-version, 'taa:tpm20')";
key "tpm20-hash-algo"; key "tpm20-hash-algo";
description description
"Specifies the list of PCRs that may be extracted for "Specifies the list of PCRs that may be extracted for
a specific Hash Algorithm on this TPM2 compliant a specific Hash Algorithm on this TPM2 compliant
cryptoprocessor. A bank is a set of PCRs which are cryptoprocessor. A bank is a set of PCRs which are
extended using a particular hash algorithm."; extended using a particular hash algorithm.";
reference reference
"TPM2.0-Structures: "TPM2.0-Structures:
https://www.trustedcomputinggroup.org/wp-content/uploads/ https://www.trustedcomputinggroup.org/wp-content/uploads/
TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7"; TPM-Rev-2.0-Part-2-Structures-01.38.pdf Section 10.9.7";
skipping to change at page 33, line 16 skipping to change at page 33, line 17
This document has encoded the TCG Algorithm definitions of This document has encoded the TCG Algorithm definitions of
[TCG-Algos], revision 1.32. By including this full table as a [TCG-Algos], revision 1.32. By including this full table as a
separate YANG file within this document, it is possible for other separate YANG file within this document, it is possible for other
YANG models to leverage the contents of this model. Specific YANG models to leverage the contents of this model. Specific
references to [RFC2104], [RFC8017], [ISO-IEC-9797-1], references to [RFC2104], [RFC8017], [ISO-IEC-9797-1],
[ISO-IEC-9797-2], [ISO-IEC-10116], [ISO-IEC-10118-3], [ISO-IEC-9797-2], [ISO-IEC-10116], [ISO-IEC-10118-3],
[ISO-IEC-14888-3], [ISO-IEC-15946-1], [ISO-IEC-18033-3], [ISO-IEC-14888-3], [ISO-IEC-15946-1], [ISO-IEC-18033-3],
[IEEE-Std-1363-2000], [IEEE-Std-1363a-2004], [NIST-PUB-FIPS-202], [IEEE-Std-1363-2000], [IEEE-Std-1363a-2004], [NIST-PUB-FIPS-202],
[NIST-SP800-38C], [NIST-SP800-38D], [NIST-SP800-38F], [NIST-SP800-38C], [NIST-SP800-38D], [NIST-SP800-38F],
[NIST-SP800-56A], [NIST-SP800-108], [bios-log], [ima-log], as well as [NIST-SP800-56A], [NIST-SP800-108], [bios-log], as well as Appendix A
Appendix A and Appendix B exist within the YANG Model. and Appendix B exist within the YANG Model.
2.1.2.1. Features 2.1.2.1. Features
There are two types of features supported: 'TPM12' and 'TPM20'. There are two types of features supported: 'TPM12' and 'TPM20'.
Support for either of these features indicates that a cryptoprocessor Support for either of these features indicates that a cryptoprocessor
supporting the corresponding type of TCG TPM API is present on an supporting the corresponding type of TCG TPM API is present on an
Attester. Most commonly, only one type of cryptoprocessor will be Attester. Most commonly, only one type of cryptoprocessor will be
available on an Attester. available on an Attester.
2.1.2.2. Identities 2.1.2.2. Identities
skipping to change at page 48, line 36 skipping to change at page 48, line 36
description description
"Edwards-curve Digital Signature Algorithm (PureEdDSA)"; "Edwards-curve Digital Signature Algorithm (PureEdDSA)";
reference reference
"TCG-Algos:TCG Algorithm Registry Rev1.32 Table 3 and "TCG-Algos:TCG Algorithm Registry Rev1.32 Table 3 and
RFC 8032. ALG_ID: 0x0060"; RFC 8032. ALG_ID: 0x0060";
} }
} }
<CODE ENDS> <CODE ENDS>
Note that not all cryptographic functions are required for use by Note that not all cryptographic functions are required for use by
"ietf-tpm-remote-attestation.yang". However the full definition of ietf-tpm-remote-attestation.yang. However the full definition of
Table 3 of [TCG-Algos] will allow use by additional YANG Table 3 of [TCG-Algos] will allow use by additional YANG
specifications. specifications.
3. IANA Considerations 3. IANA Considerations
This document registers the following namespace URIs in the This document registers the following namespace URIs in the
[xml-registry] as per [RFC3688]: [xml-registry] as per [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation URI: urn:ietf:params:xml:ns:yang:ietf-tpm-remote-attestation
skipping to change at page 51, line 17 skipping to change at page 51, line 17
Section 9.4.5.2", n.d., Section 9.4.5.2", n.d.,
<https://trustedcomputinggroup.org/wp-content/uploads/PC-C <https://trustedcomputinggroup.org/wp-content/uploads/PC-C
lientSpecific_Platform_Profile_for_TPM_2p0_Systems_v51.pdf lientSpecific_Platform_Profile_for_TPM_2p0_Systems_v51.pdf
>. >.
[BIOS-Log-Event-Type] [BIOS-Log-Event-Type]
"TCG PC Client Platform Firmware Profile Specification", "TCG PC Client Platform Firmware Profile Specification",
n.d., <https://trustedcomputinggroup.org/wp- n.d., <https://trustedcomputinggroup.org/wp-
content/uploads/TCG_PCClient_PFP_r1p05_v23_pub.pdf>. content/uploads/TCG_PCClient_PFP_r1p05_v23_pub.pdf>.
[cel] "Canonical Event Log Format, Section 4.3", n.d.,
<https://trustedcomputinggroup.org/wp-content/uploads/
TCG_IWG_CEL_v1_r0p41_pub.pdf>.
[I-D.ietf-netconf-keystore] [I-D.ietf-netconf-keystore]
Watsen, K., "A YANG Data Model for a Keystore", Work in Watsen, K., "A YANG Data Model for a Keystore", Work in
Progress, Internet-Draft, draft-ietf-netconf-keystore-24, Progress, Internet-Draft, draft-ietf-netconf-keystore-24,
7 March 2022, <https://www.ietf.org/archive/id/draft-ietf- 7 March 2022, <https://www.ietf.org/archive/id/draft-ietf-
netconf-keystore-24.txt>. netconf-keystore-24.txt>.
[I-D.ietf-rats-architecture] [I-D.ietf-rats-architecture]
Birkholz, H., Thaler, D., Richardson, M., Smith, N., and Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote Attestation Procedures Architecture", Work W. Pan, "Remote Attestation Procedures Architecture", Work
in Progress, Internet-Draft, draft-ietf-rats-architecture- in Progress, Internet-Draft, draft-ietf-rats-architecture-
skipping to change at page 51, line 48 skipping to change at page 52, line 5
[IEEE-Std-1363-2000] [IEEE-Std-1363-2000]
"IEEE 1363-2000 - IEEE Standard Specifications for Public- "IEEE 1363-2000 - IEEE Standard Specifications for Public-
Key Cryptography", n.d., Key Cryptography", n.d.,
<https://standards.ieee.org/standard/1363-2000.html>. <https://standards.ieee.org/standard/1363-2000.html>.
[IEEE-Std-1363a-2004] [IEEE-Std-1363a-2004]
"1363a-2004 - IEEE Standard Specifications for Public-Key "1363a-2004 - IEEE Standard Specifications for Public-Key
Cryptography - Amendment 1: Additional Techniques", n.d., Cryptography - Amendment 1: Additional Techniques", n.d.,
<https://ieeexplore.ieee.org/document/1335427>. <https://ieeexplore.ieee.org/document/1335427>.
[ima-log] "Canonical Event Log Format, Section 4.3", n.d.,
<https://trustedcomputinggroup.org/wp-content/uploads/
TCG_IWG_CEL_v1_r0p41_pub.pdf>.
[ISO-IEC-10116] [ISO-IEC-10116]
"ISO/IEC 10116:2017 - Information technology", n.d., "ISO/IEC 10116:2017 - Information technology", n.d.,
<https://www.iso.org/standard/64575.html>. <https://www.iso.org/standard/64575.html>.
[ISO-IEC-10118-3] [ISO-IEC-10118-3]
"Dedicated hash-functions - ISO/IEC 10118-3:2018", n.d., "Dedicated hash-functions - ISO/IEC 10118-3:2018", n.d.,
<https://www.iso.org/standard/67116.html>. <https://www.iso.org/standard/67116.html>.
[ISO-IEC-14888-3] [ISO-IEC-14888-3]
"ISO/IEC 14888-3:2018 - Digital signatures with appendix", "ISO/IEC 14888-3:2018 - Digital signatures with appendix",
skipping to change at page 57, line 8 skipping to change at page 57, line 8
extended file attributes. extended file attributes.
In support of the appraisal of Evidence, IMA maintains an ordered In support of the appraisal of Evidence, IMA maintains an ordered
list of measurements in kernel-space, the Stored Measurement Log list of measurements in kernel-space, the Stored Measurement Log
(SML), for all files that have been measured before execution since (SML), for all files that have been measured before execution since
the operating system was started. Although IMA can be used without a the operating system was started. Although IMA can be used without a
TPM, it is typically used in conjunction with a TPM to anchor the TPM, it is typically used in conjunction with a TPM to anchor the
integrity of the SML in a hardware-protected secure storage location, integrity of the SML in a hardware-protected secure storage location,
i.e., Platform Configuration Registers (PCRs) provided by TPMs. IMA i.e., Platform Configuration Registers (PCRs) provided by TPMs. IMA
provides the SML in both binary and ASCII representations in the provides the SML in both binary and ASCII representations in the
Linux security file system _securityfs_ ("/sys/kernel/security/ Linux security file system _securityfs_ (/sys/kernel/security/ima/).
ima/").
IMA templates define the format of the SML, i.e., which fields are IMA templates define the format of the SML, i.e., which fields are
included in a log record. Examples are file path, file hash, user included in a log record. Examples are file path, file hash, user
ID, group ID, file signature, and extended file attributes. IMA ID, group ID, file signature, and extended file attributes. IMA
comes with a set of predefined template formats and also allows a comes with a set of predefined template formats and also allows a
custom format, i.e., a format consisting of template fields supported custom format, i.e., a format consisting of template fields supported
by IMA. Template usage is typically determined by boot arguments by IMA. Template usage is typically determined by boot arguments
passed to the kernel. Alternatively, the format can also be hard- passed to the kernel. Alternatively, the format can also be hard-
compiled into custom kernels. IMA templates and fields are coded into custom kernels. IMA templates and fields are extensible
extensible in the kernel source code. As a result, more template in the kernel source code. As a result, more template fields can be
fields can be added in the future. added in the future.
IMA policies define which files are measured using the IMA policy IMA policies define which files are measured using the IMA policy
language. Built-in policies can be passed as boot arguments to the language. Built-in policies can be passed as boot arguments to the
kernel. Custom IMA policies can be defined once during runtime or be kernel. Custom IMA policies can be defined once during runtime or be
hard-compiled into a custom kernel. If no policy is defined, no hard-coded into a custom kernel. If no policy is defined, no
measurements are taken and IMA is effectively disabled. measurements are taken and IMA is effectively disabled.
A comprehensive description of the content fields ins in native Linux
IMA TLV format can be found in Table 16 of the Canonical Event Log
(CEL) specification [cel]. The CEL specification also illustrates
the use of templates to enable extended or customized IMA TLV formats
in Section 5.1.6.
Appendix B. IMA for Network Equipment Boot Logs Appendix B. IMA for Network Equipment Boot Logs
Network equipment can generally implement similar IMA-protected Network equipment can generally implement similar IMA-protected
functions to generate measurements (Claims) about the boot process of functions to generate measurements (Claims) about the boot process of
a device and enable corresponding remote attestation. Network a device and enable corresponding remote attestation. Network
Equipment Boot Logs combine the measurement and logging of boot Equipment Boot Logs combine the measurement and logging of boot
components and operating system components (executables and files) components and operating system components (executables and files)
into a single log file in identical IMA format. into a single log file in a format identical to the IMA format. Note
that the format used for logging measurement of boot components in
this scheme differs from the boot logging strategy described
elsewhere in this document.
During the boot process of the network device, i.e., from BIOS to the During the boot process of the network device, i.e., from BIOS to the
end of the operating system and user-space, all files executed during end of the operating system and user-space, all files executed can be
this process can be measured and logged in the order of their measured and logged in the order of their execution. When the
execution. When the Verifier initiates a remote attestation process Verifier initiates a remote attestation process (e.g., challenge-
(e.g., challenge-response remote attestation as defined in this response remote attestation as defined in this document), the network
document), the network equipment takes on the role of an Attester and equipment takes on the role of an Attester and can convey to the
can convey to the Verifier Claims that comprise the measurement log Verifier Claims that comprise the measurement log as well as the
as well as the corresponding PCR values (Evidence) of a TPM. corresponding PCR values (Evidence) of a TPM.
The verifier can appraise the integrity (compliance with the The verifier can appraise the integrity (compliance with the
Reference Values) of each executed file by comparing its measured Reference Values) of each executed file by comparing its measured
value with the Reference Value. Based on the execution order, the value with the Reference Value. Based on the execution order, the
Verifier can compute a PCR reference value (by replaying the log) and Verifier can compute a PCR reference value (by replaying the log) and
compare it to the Measurement Log Claims obtained in conjunction with compare it to the Measurement Log Claims obtained in conjunction with
the PCR Evidence to assess their trustworthiness with respect to an the PCR Evidence to assess their trustworthiness with respect to an
intended operational state. intended operational state.
Not only during the operating system loading phase, even during the Network equipment usually executes multiple components in parallel.
BIOS boot phase, network equipment usually executes multiple This holds not only during the operating system loading phase, but
components. With this measurement log mechanism, network equipment also even during the BIOS boot phase. With this measurement log
can take on the role of an Attester, proving to the Verifier the mechanism, network equipment can take on the role of an Attester,
trustworthiness of its boot process. Using the measurement log, proving to the Verifier the trustworthiness of its boot process.
Verifiers can precisely identify mismatching log entries to infer Using the measurement log, Verifiers can precisely identify
potentially tampered components. mismatching log entries to infer potentially tampered components.
This mechanism also supports scenarios that modify files on the This mechanism also supports scenarios that modify files on the
Attester and are executed during the boot phase (e.g., updating/ Attester that are subsequently executed during the boot phase (e.g.,
patching) by simply updating the appropriate Reference Values in updating/patching) by simply updating the appropriate Reference
Reference Integrity Manifests that inform Verifiers about how an Values in Reference Integrity Manifests that inform Verifiers about
Attester is composed. how an Attester is composed.
Authors' Addresses Authors' Addresses
Henk Birkholz Henk Birkholz
Fraunhofer SIT Fraunhofer SIT
Rheinstrasse 75 Rheinstrasse 75
64295 Darmstadt 64295 Darmstadt
Germany Germany
Email: henk.birkholz@sit.fraunhofer.de Email: henk.birkholz@sit.fraunhofer.de
Michael Eckel Michael Eckel
Fraunhofer SIT Fraunhofer SIT
Rheinstrasse 75 Rheinstrasse 75
64295 Darmstadt 64295 Darmstadt
Germany Germany
Email: michael.eckel@sit.fraunhofer.de Email: michael.eckel@sit.fraunhofer.de
Shwetha Bhandari Shwetha Bhandari
ThoughtSpot ThoughtSpot
Email: shwetha.bhandari@thoughtspot.com Email: shwetha.bhandari@thoughtspot.com
Eric Voit Eric Voit
Cisco Systems Cisco Systems
Email: evoit@cisco.com Email: evoit@cisco.com
Bill Sulzen Bill Sulzen
Cisco Systems Cisco Systems
Email: bsulzen@cisco.com Email: bsulzen@cisco.com
Liang Xia (Frank) Liang Xia (Frank)
Huawei Technologies Huawei Technologies
101 Software Avenue, Yuhuatai District 101 Software Avenue, Yuhuatai District
Nanjing Nanjing
Jiangsu, 210012 Jiangsu, 210012
China China
Email: Frank.Xialiang@huawei.com Email: Frank.Xialiang@huawei.com
Tom Laffey Tom Laffey
Hewlett Packard Enterprise Hewlett Packard Enterprise
Email: tom.laffey@hpe.com Email: tom.laffey@hpe.com
Guy C. Fedorkow Guy C. Fedorkow
Juniper Networks Juniper Networks
10 Technology Park Drive 10 Technology Park Drive
Westford Westford
Email: gfedorkow@juniper.net Email: gfedorkow@juniper.net
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