draft-ietf-anima-bootstrapping-keyinfra-24.txt   draft-ietf-anima-bootstrapping-keyinfra-25.txt 
ANIMA WG M. Pritikin ANIMA WG M. Pritikin
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track M. Richardson Intended status: Standards Track M. Richardson
Expires: January 22, 2020 Sandelman Expires: February 13, 2020 Sandelman
T. Eckert
Futurewei USA
M. Behringer M. Behringer
K. Watsen K. Watsen
Watsen Networks Watsen Networks
July 21, 2019 August 12, 2019
Bootstrapping Remote Secure Key Infrastructures (BRSKI) Bootstrapping Remote Secure Key Infrastructures (BRSKI)
draft-ietf-anima-bootstrapping-keyinfra-24 draft-ietf-anima-bootstrapping-keyinfra-25
Abstract Abstract
This document specifies automated bootstrapping of an Autonomic This document specifies automated bootstrapping of an Autonomic
Control Plane. To do this a remote secure key infrastructure (BRSKI) Control Plane. To do this a Remote Secure Key Infrastructure (BRSKI)
is created using manufacturer installed X.509 certificates, in is created using manufacturer installed X.509 certificates, in
combination with a manufacturer's authorizing service, both online combination with a manufacturer's authorizing service, both online
and offline. Bootstrapping a new device can occur using a routable and offline. Bootstrapping a new device can occur using a routable
address and a cloud service, or using only link-local connectivity, address and a cloud service, or using only link-local connectivity,
or on limited/disconnected networks. Support for lower security or on limited/disconnected networks. Support for lower security
models, including devices with minimal identity, is described for models, including devices with minimal identity, is described for
legacy reasons but not encouraged. Bootstrapping is complete when legacy reasons but not encouraged. Bootstrapping to is complete when
the cryptographic identity of the new key infrastructure is the cryptographic identity of the new key infrastructure is
successfully deployed to the device but the established secure successfully deployed to the device. The established secure
connection can be used to deploy a locally issued certificate to the connection can be used to deploy a locally issued certificate to the
device as well. device as well.
Status of This Memo Status of This Memo
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Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Prior Bootstrapping Approaches . . . . . . . . . . . . . 6 1.1. Prior Bootstrapping Approaches . . . . . . . . . . . . . 6
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
1.3. Scope of solution . . . . . . . . . . . . . . . . . . . . 10 1.3. Scope of solution . . . . . . . . . . . . . . . . . . . . 10
1.3.1. Support environment . . . . . . . . . . . . . . . . . 10 1.3.1. Support environment . . . . . . . . . . . . . . . . . 10
1.3.2. Constrained environments . . . . . . . . . . . . . . 10 1.3.2. Constrained environments . . . . . . . . . . . . . . 11
1.3.3. Network Access Controls . . . . . . . . . . . . . . . 11 1.3.3. Network Access Controls . . . . . . . . . . . . . . . 11
1.3.4. Bootstrapping is not Booting . . . . . . . . . . . . 11 1.3.4. Bootstrapping is not Booting . . . . . . . . . . . . 12
1.4. Leveraging the new key infrastructure / next steps . . . 11 1.4. Leveraging the new key infrastructure / next steps . . . 12
1.5. Requirements for Autonomic Network Infrastructure (ANI) 1.5. Requirements for Autonomic Network Infrastructure (ANI)
devices . . . . . . . . . . . . . . . . . . . . . . . . . 12 devices . . . . . . . . . . . . . . . . . . . . . . . . . 12
2. Architectural Overview . . . . . . . . . . . . . . . . . . . 12 2. Architectural Overview . . . . . . . . . . . . . . . . . . . 13
2.1. Behavior of a Pledge . . . . . . . . . . . . . . . . . . 14 2.1. Behavior of a Pledge . . . . . . . . . . . . . . . . . . 15
2.2. Secure Imprinting using Vouchers . . . . . . . . . . . . 15 2.2. Secure Imprinting using Vouchers . . . . . . . . . . . . 16
2.3. Initial Device Identifier . . . . . . . . . . . . . . . . 16 2.3. Initial Device Identifier . . . . . . . . . . . . . . . . 17
2.3.1. Identification of the Pledge . . . . . . . . . . . . 16 2.3.1. Identification of the Pledge . . . . . . . . . . . . 17
2.3.2. MASA URI extension . . . . . . . . . . . . . . . . . 17 2.3.2. MASA URI extension . . . . . . . . . . . . . . . . . 18
2.4. Protocol Flow . . . . . . . . . . . . . . . . . . . . . . 19 2.4. Protocol Flow . . . . . . . . . . . . . . . . . . . . . . 20
2.5. Architectural Components . . . . . . . . . . . . . . . . 21 2.5. Architectural Components . . . . . . . . . . . . . . . . 23
2.5.1. Pledge . . . . . . . . . . . . . . . . . . . . . . . 21 2.5.1. Pledge . . . . . . . . . . . . . . . . . . . . . . . 23
2.5.2. Join Proxy . . . . . . . . . . . . . . . . . . . . . 21 2.5.2. Join Proxy . . . . . . . . . . . . . . . . . . . . . 23
2.5.3. Domain Registrar . . . . . . . . . . . . . . . . . . 21 2.5.3. Domain Registrar . . . . . . . . . . . . . . . . . . 23
2.5.4. Manufacturer Service . . . . . . . . . . . . . . . . 21 2.5.4. Manufacturer Service . . . . . . . . . . . . . . . . 23
2.5.5. Public Key Infrastructure (PKI) . . . . . . . . . . . 21 2.5.5. Public Key Infrastructure (PKI) . . . . . . . . . . . 23
2.6. Certificate Time Validation . . . . . . . . . . . . . . . 22 2.6. Certificate Time Validation . . . . . . . . . . . . . . . 24
2.6.1. Lack of realtime clock . . . . . . . . . . . . . . . 22 2.6.1. Lack of realtime clock . . . . . . . . . . . . . . . 24
2.6.2. Infinite Lifetime of IDevID . . . . . . . . . . . . . 22 2.6.2. Infinite Lifetime of IDevID . . . . . . . . . . . . . 24
2.7. Cloud Registrar . . . . . . . . . . . . . . . . . . . . . 22 2.7. Cloud Registrar . . . . . . . . . . . . . . . . . . . . . 24
2.8. Determining the MASA to contact . . . . . . . . . . . . . 23 2.8. Determining the MASA to contact . . . . . . . . . . . . . 25
3. Voucher-Request artifact . . . . . . . . . . . . . . . . . . 23 3. Voucher-Request artifact . . . . . . . . . . . . . . . . . . 26
3.1. Nonceless Voucher Requests . . . . . . . . . . . . . . . 24 3.1. Nonceless Voucher Requests . . . . . . . . . . . . . . . 26
3.2. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 24 3.2. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 26
3.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 27
3.4. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 26 3.4. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 28
4. Proxying details (Pledge - Proxy - Registrar) . . . . . . . . 29 4. Proxying details (Pledge - Proxy -
4.1. Pledge discovery of Proxy . . . . . . . . . . . . . . . . 30 Registrar) . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.1.1. Proxy GRASP announcements . . . . . . . . . . . . . . 32 4.1. Pledge discovery of Proxy . . . . . . . . . . . . . . . . 33
4.2. CoAP connection to Registrar . . . . . . . . . . . . . . 33 4.1.1. Proxy GRASP announcements . . . . . . . . . . . . . . 34
4.3. Proxy discovery and communication of Registrar . . . . . 33 4.2. CoAP connection to Registrar . . . . . . . . . . . . . . 35
5. Protocol Details (Pledge - Registrar - MASA) . . . . . . . . 34 4.3. Proxy discovery and communication of Registrar . . . . . 36
5.1. BRSKI-EST TLS establishment details . . . . . . . . . . . 36 5. Protocol Details (Pledge - Registrar - MASA) . . . . . . . . 37
5.2. Pledge Requests Voucher from the Registrar . . . . . . . 37 5.1. BRSKI-EST TLS establishment details . . . . . . . . . . . 39
5.2. Pledge Requests Voucher from the Registrar . . . . . . . 40
5.3. Registrar Authorization of 5.3. Registrar Authorization of
Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 38 Pledge . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.4. BRSKI-MASA TLS establishment details . . . . . . . . . . 38 5.4. BRSKI-MASA TLS establishment details . . . . . . . . . . 42
5.5. Registrar Requests Voucher from MASA . . . . . . . . . . 39 5.4.1. MASA authentication of
5.5.1. MASA renewal of expired vouchers . . . . . . . . . . 41 customer Registrar . . . . . . . . . . . . . . . . . 42
5.5. Registrar Requests Voucher from MASA . . . . . . . . . . 43
5.5.1. MASA renewal of expired vouchers . . . . . . . . . . 45
5.5.2. MASA verification of voucher-request signature 5.5.2. MASA verification of voucher-request signature
consistency . . . . . . . . . . . . . . . . . . . . . 41 consistency . . . . . . . . . . . . . . . . . . . . . 45
5.5.3. MASA authentication of registrar (certificate) . . . 41 5.5.3. MASA authentication of registrar (certificate) . . . 45
5.5.4. MASA revocation checking of registrar (certificate) . 42 5.5.4. MASA revocation checking of registrar (certificate) . 45
5.5.5. MASA verification of pledge prior-signed-voucher- 5.5.5. MASA verification of pledge prior-signed-voucher-
request . . . . . . . . . . . . . . . . . . . . . . . 42 request . . . . . . . . . . . . . . . . . . . . . . . 46
5.5.6. MASA pinning of registrar . . . . . . . . . . . . . . 42 5.5.6. MASA pinning of registrar . . . . . . . . . . . . . . 46
5.5.7. MASA nonce handling . . . . . . . . . . . . . . . . . 42 5.5.7. MASA nonce handling . . . . . . . . . . . . . . . . . 46
5.6. MASA and Registrar Voucher Response . . . . . . . . . . . 43 5.6. MASA and Registrar Voucher Response . . . . . . . . . . . 46
5.6.1. Pledge voucher verification . . . . . . . . . . . . . 45 5.6.1. Pledge voucher verification . . . . . . . . . . . . . 49
5.6.2. Pledge authentication of provisional TLS connection . 46 5.6.2. Pledge authentication of provisional TLS connection . 50
5.7. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 47 5.7. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 51
5.8. Registrar audit log request . . . . . . . . . . . . . . . 48 5.8. Registrar audit log request . . . . . . . . . . . . . . . 52
5.8.1. MASA audit log response . . . . . . . . . . . . . . . 49 5.8.1. MASA audit log response . . . . . . . . . . . . . . . 53
5.8.2. Registrar audit log verification . . . . . . . . . . 50 5.8.2. Registrar audit log verification . . . . . . . . . . 54
5.9. EST Integration for PKI bootstrapping . . . . . . . . . . 51 5.9. EST Integration for PKI bootstrapping . . . . . . . . . . 56
5.9.1. EST Distribution of CA Certificates . . . . . . . . . 52 5.9.1. EST Distribution of CA Certificates . . . . . . . . . 56
5.9.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 52 5.9.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 56
5.9.3. EST Client Certificate Request . . . . . . . . . . . 53 5.9.3. EST Client Certificate Request . . . . . . . . . . . 57
5.9.4. Enrollment Status Telemetry . . . . . . . . . . . . . 53 5.9.4. Enrollment Status Telemetry . . . . . . . . . . . . . 57
5.9.5. Multiple certificates . . . . . . . . . . . . . . . . 54 5.9.5. Multiple certificates . . . . . . . . . . . . . . . . 58
5.9.6. EST over CoAP . . . . . . . . . . . . . . . . . . . . 54 5.9.6. EST over CoAP . . . . . . . . . . . . . . . . . . . . 59
6. Clarification of transfer-encoding . . . . . . . . . . . . . 55 6. Clarification of transfer-encoding . . . . . . . . . . . . . 59
7. Reduced security operational modes . . . . . . . . . . . . . 55 7. Reduced security operational modes . . . . . . . . . . . . . 59
7.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 55 7.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 59
7.2. Pledge security reductions . . . . . . . . . . . . . . . 56 7.2. Pledge security reductions . . . . . . . . . . . . . . . 60
7.3. Registrar security reductions . . . . . . . . . . . . . . 57 7.3. Registrar security reductions . . . . . . . . . . . . . . 61
7.4. MASA security reductions . . . . . . . . . . . . . . . . 58 7.4. MASA security reductions . . . . . . . . . . . . . . . . 62
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59 7.4.1. Issuing Nonceless vouchers . . . . . . . . . . . . . 62
8.1. Well-known EST registration . . . . . . . . . . . . . . . 59 7.4.2. Trusting Owners on First Use . . . . . . . . . . . . 63
8.2. PKIX Registry . . . . . . . . . . . . . . . . . . . . . . 59 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 63
8.3. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 59 8.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 64
8.4. DNS Service Names . . . . . . . . . . . . . . . . . . . . 59 8.2. Well-known EST registration . . . . . . . . . . . . . . . 64
8.5. MUD File Extension for the MASA . . . . . . . . . . . . . 60 8.3. PKIX Registry . . . . . . . . . . . . . . . . . . . . . . 64
8.4. Pledge BRSKI Status Telemetry . . . . . . . . . . . . . . 64
8.5. DNS Service Names . . . . . . . . . . . . . . . . . . . . 65
8.6. MUD File Extension for the MASA . . . . . . . . . . . . . 65
9. Applicability to the Autonomic 9. Applicability to the Autonomic
Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 60 Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 65
10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 61 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 66
10.1. MASA audit log . . . . . . . . . . . . . . . . . . . . . 61 10.1. MASA audit log . . . . . . . . . . . . . . . . . . . . . 66
10.2. What BRSKI-MASA reveals to the manufacturer . . . . . . 62 10.2. What BRSKI-MASA reveals to the manufacturer . . . . . . 67
10.3. Manufacturers and Used or Stolen Equipment . . . . . . . 63 10.3. Manufacturers and Used or Stolen Equipment . . . . . . . 69
10.4. Manufacturers and Grey market equipment . . . . . . . . 64 10.4. Manufacturers and Grey market equipment . . . . . . . . 70
10.5. Some mitigations for meddling by manufacturers . . . . . 65 10.5. Some mitigations for meddling by manufacturers . . . . . 70
11. Security Considerations . . . . . . . . . . . . . . . . . . . 66 11. Security Considerations . . . . . . . . . . . . . . . . . . . 71
11.1. DoS against MASA . . . . . . . . . . . . . . . . . . . . 67 11.1. Denial of Service (DoS) against MASA . . . . . . . . . . 72
11.2. Freshness in Voucher-Requests . . . . . . . . . . . . . 68 11.2. Freshness in Voucher-Requests . . . . . . . . . . . . . 73
11.3. Trusting manufacturers . . . . . . . . . . . . . . . . . 69 11.3. Trusting manufacturers . . . . . . . . . . . . . . . . . 74
11.4. Manufacturer Maintenance of trust anchors . . . . . . . 70 11.4. Manufacturer Maintenance of trust anchors . . . . . . . 75
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 71 11.4.1. Compromise of Manufacturer IDevID signing keys . . . 77
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 71 11.4.2. Compromise of MASA signing keys . . . . . . . . . . 77
13.1. Normative References . . . . . . . . . . . . . . . . . . 72 11.4.3. Compromise of MASA web service . . . . . . . . . . . 79
13.2. Informative References . . . . . . . . . . . . . . . . . 74 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 80
Appendix A. IPv4 and non-ANI operations . . . . . . . . . . . . 77 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 80
A.1. IPv4 Link Local addresses . . . . . . . . . . . . . . . . 78 13.1. Normative References . . . . . . . . . . . . . . . . . . 80
A.2. Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . . 78 13.2. Informative References . . . . . . . . . . . . . . . . . 83
Appendix B. mDNS / DNSSD proxy discovery options . . . . . . . . 78 Appendix A. IPv4 and non-ANI operations . . . . . . . . . . . . 86
Appendix C. MUD Extension . . . . . . . . . . . . . . . . . . . 79 A.1. IPv4 Link Local addresses . . . . . . . . . . . . . . . . 87
Appendix D. Example Vouchers . . . . . . . . . . . . . . . . . . 81 A.2. Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . . 87
D.1. Keys involved . . . . . . . . . . . . . . . . . . . . . . 81 Appendix B. mDNS / DNSSD proxy discovery options . . . . . . . . 87
D.1.1. MASA key pair for voucher signatures . . . . . . . . 81 Appendix C. MUD Extension . . . . . . . . . . . . . . . . . . . 88
D.1.2. Manufacturer key pair for IDevID signatures . . . . . 81 Appendix D. Example Vouchers . . . . . . . . . . . . . . . . . . 90
D.1.3. Registrar key pair . . . . . . . . . . . . . . . . . 82 D.1. Keys involved . . . . . . . . . . . . . . . . . . . . . . 90
D.1.4. Pledge key pair . . . . . . . . . . . . . . . . . . . 84 D.1.1. MASA key pair for voucher signatures . . . . . . . . 90
D.2. Example process . . . . . . . . . . . . . . . . . . . . . 85 D.1.2. Manufacturer key pair for IDevID signatures . . . . . 90
D.2.1. Pledge to Registrar . . . . . . . . . . . . . . . . . 86 D.1.3. Registrar key pair . . . . . . . . . . . . . . . . . 91
D.2.2. Registrar to MASA . . . . . . . . . . . . . . . . . . 89 D.1.4. Pledge key pair . . . . . . . . . . . . . . . . . . . 93
D.2.3. MASA to Registrar . . . . . . . . . . . . . . . . . . 94 D.2. Example process . . . . . . . . . . . . . . . . . . . . . 94
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 98 D.2.1. Pledge to Registrar . . . . . . . . . . . . . . . . . 95
D.2.2. Registrar to MASA . . . . . . . . . . . . . . . . . . 98
D.2.3. MASA to Registrar . . . . . . . . . . . . . . . . . . 103
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 107
1. Introduction 1. Introduction
BRSKI provides a solution for secure zero-touch (automated) bootstrap BRSKI provides a solution for secure zero-touch (automated) bootstrap
of new (unconfigured) devices that are called pledges in this of new (unconfigured) devices that are called pledges in this
document. document.
This document primarily provides for the needs of the ISP and This document primarily provides for the needs of the ISP and
Enterprise focused ANIMA Autonomic Control Plane (ACP) Enterprise focused ANIMA Autonomic Control Plane (ACP)
[I-D.ietf-anima-autonomic-control-plane]. Other users of the BRSKI [I-D.ietf-anima-autonomic-control-plane]. This bootstrap process
protocol will need to provide separate applicability statements that satisfies the [RFC7575] section 3.3 of making all operations secure
include privacy and security considerations appropriate to that by default. Other users of the BRSKI protocol will need to provide
deployment. Section 9 explains the details applicability for this separate applicability statements that include privacy and security
the ACP usage. considerations appropriate to that deployment. Section 9 explains
the details applicability for this the ACP usage.
This document describes how pledges discover (or are discovered by) This document describes how pledges discover (or are discovered by)
an element of the network domain to which the pledge belongs to an element of the network domain to which the pledge belongs that
perform the bootstrap. This element (device) is called the will perform the bootstrap. This element (device) is called the
registrar. Before any other operation, pledge and registrar need to registrar. Before any other operation, pledge and registrar need to
establish mutual trust: establish mutual trust:
1. Registrar authenticating the pledge: "Who is this device? What 1. Registrar authenticating the pledge: "Who is this device? What
is its identity?" is its identity?"
2. Registrar authorizing the pledge: "Is it mine? Do I want it? 2. Registrar authorizing the pledge: "Is it mine? Do I want it?
What are the chances it has been compromised?" What are the chances it has been compromised?"
3. Pledge authenticating the registrar: "What is this registrar's 3. Pledge authenticating the registrar: "What is this registrar's
identity?" identity?"
4. Pledge authorizing the registrar: "Should I join it?" 4. Pledge authorizing the registrar: "Should I join this network?"
This document details protocols and messages to answer the above This document details protocols and messages to answer the above
questions. It uses a TLS connection and an PKIX (X.509v3) questions. It uses a TLS connection and an PKIX-shaped (X.509v3)
certificate (an IEEE 802.1AR [IDevID] LDevID) of the pledge to answer certificate (an IEEE 802.1AR [IDevID] IDevID) of the pledge to answer
points 1 and 2. It uses a new artifact called a "voucher" that the points 1 and 2. It uses a new artifact called a "voucher" that the
registrar receives from a "Manufacturer Authorized Signing Authority" registrar receives from a "Manufacturer Authorized Signing Authority"
(MASA) and passes to the pledge to answer points 3 and 4. (MASA) and passes to the pledge to answer points 3 and 4.
A proxy provides very limited connectivity between the pledge and the A proxy provides very limited connectivity between the pledge and the
registrar. registrar.
The syntactic details of vouchers are described in detail in The syntactic details of vouchers are described in detail in
[RFC8366]. This document details automated protocol mechanisms to [RFC8366]. This document details automated protocol mechanisms to
obtain vouchers, including the definition of a 'voucher-request' obtain vouchers, including the definition of a 'voucher-request'
skipping to change at page 7, line 27 skipping to change at page 7, line 40
1.2. Terminology 1.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The following terms are defined for clarity: The following terms are defined for clarity:
domainID: The domain IDentity is the 160-bit SHA-1 hash of the BIT domainID: The domain IDentity is a unique hash based upon a
STRING of the subjectPublicKey of the pinned-domain-cert leaf, Registrar's certificate. If the certificate includes the
i.e. the Registrars' certificate. This is consistent with the SubjectKeyIdentifier (Section 4.2.1.2 [RFC5280]), then it is to be
subject key identifier (Section 4.2.1.2 [RFC5280]). used as the domainID. If not, then the 160-bit SHA-1 hash as
described in that section is to be used. This value needs to be
calculated by both MASA (to populate the audit log), and by the
Registrar (to recognize itself).
drop-ship: The physical distribution of equipment containing the drop-ship: The physical distribution of equipment containing the
"factory default" configuration to a final destination. In zero- "factory default" configuration to a final destination. In zero-
touch scenarios there is no staging or pre-configuration during touch scenarios there is no staging or pre-configuration during
drop-ship. drop-ship.
imprint: The process where a device obtains the cryptographic key imprint: The process where a device obtains the cryptographic key
material to identify and trust future interactions with a network. material to identify and trust future interactions with a network.
This term is taken from Konrad Lorenz's work in biology with new This term is taken from Konrad Lorenz's work in biology with new
ducklings: during a critical period, the duckling would assume ducklings: during a critical period, the duckling would assume
that anything that looks like a mother duck is in fact their that anything that looks like a mother duck is in fact their
mother. An equivalent for a device is to obtain the fingerprint mother. An equivalent for a device is to obtain the fingerprint
of the network's root certification authority certificate. A of the network's root certification authority certificate. A
device that imprints on an attacker suffers a similar fate to a device that imprints on an attacker suffers a similar fate to a
duckling that imprints on a hungry wolf. Securely imprinting is a duckling that imprints on a hungry wolf. Securely imprinting is a
primary focus of this document [imprinting]. The analogy to primary focus of this document [imprinting]. The analogy to
Lorenz's work was first noted in [Stajano99theresurrecting]. Lorenz's work was first noted in [Stajano99theresurrecting].
enrollment: The process where a device presents key material to a enrollment: The process where a device presents key material to a
network and acquires a network specific identity. For example network and acquires a network-specific identity. For example
when a certificate signing request is presented to a certification when a certificate signing request is presented to a certification
authority and a certificate is obtained in response. authority and a certificate is obtained in response.
Pledge: The prospective device, which has an identity installed at Pledge: The prospective device, which has an identity installed at
the factory. the factory.
Voucher: A signed artifact from the MASA that indicates to a pledge Voucher: A signed artifact from the MASA that indicates to a pledge
the cryptographic identity of the registrar it should trust. the cryptographic identity of the registrar it should trust.
There are different types of vouchers depending on how that trust There are different types of vouchers depending on how that trust
is asserted. Multiple voucher types are defined in [RFC8366] is asserted. Multiple voucher types are defined in [RFC8366]
skipping to change at page 9, line 11 skipping to change at page 9, line 27
the assumed type of proxy. the assumed type of proxy.
IPIP Proxy: A stateless proxy alternative. IPIP Proxy: A stateless proxy alternative.
MASA Service: A third-party Manufacturer Authorized Signing MASA Service: A third-party Manufacturer Authorized Signing
Authority (MASA) service on the global Internet. The MASA signs Authority (MASA) service on the global Internet. The MASA signs
vouchers. It also provides a repository for audit log information vouchers. It also provides a repository for audit log information
of privacy protected bootstrapping events. It does not track of privacy protected bootstrapping events. It does not track
ownership. ownership.
MASA Audit Log: A list of previous owners maintained by the MASA on
a per device (per pledge) basis. Described in Section 5.8.1.
Ownership Tracker: An Ownership Tracker service on the global Ownership Tracker: An Ownership Tracker service on the global
Internet. The Ownership Tracker uses business processes to Internet. The Ownership Tracker uses business processes to
accurately track ownership of all devices shipped against domains accurately track ownership of all devices shipped against domains
that have purchased them. Although optional, this component that have purchased them. Although optional, this component
allows vendors to provide additional value in cases where their allows vendors to provide additional value in cases where their
sales and distribution channels allow for accurately tracking of sales and distribution channels allow for accurately tracking of
such ownership. Ownership tracking information is indicated in such ownership. Ownership tracking information is indicated in
vouchers as described in [RFC8366] vouchers as described in [RFC8366]
IDevID: An Initial Device Identity X.509 certificate installed by IDevID: An Initial Device Identity X.509 certificate installed by
skipping to change at page 12, line 13 skipping to change at page 12, line 34
certificate has optionally been issued from the Domain CA. This certificate has optionally been issued from the Domain CA. This
makes it possible to securely deploy functionalities across the makes it possible to securely deploy functionalities across the
domain, e.g: domain, e.g:
o Device management. o Device management.
o Routing authentication. o Routing authentication.
o Service discovery. o Service discovery.
The major beneficiary is that it possible to use the credentials The major intended beneficiary is that it possible to use the
deployed by this protocol to secure the Autonomic Control Plane (ACP) credentials deployed by this protocol to secure the Autonomic Control
([I-D.ietf-anima-autonomic-control-plane]). Plane (ACP) ([I-D.ietf-anima-autonomic-control-plane]).
1.5. Requirements for Autonomic Network Infrastructure (ANI) devices 1.5. Requirements for Autonomic Network Infrastructure (ANI) devices
The BRSKI protocol can be used in a number of environments. Some of The BRSKI protocol can be used in a number of environments. Some of
the options in this document are the result of requirements that are the options in this document are the result of requirements that are
out of the ANI scope. This section defines the base requirements for out of the ANI scope. This section defines the base requirements for
ANI devices. ANI devices.
For devices that intend to become part of an Autonomic Network For devices that intend to become part of an Autonomic Network
Infrastructure (ANI) ([I-D.ietf-anima-reference-model]) that includes Infrastructure (ANI) ([I-D.ietf-anima-reference-model]) that includes
an Autonomic Control Plane an Autonomic Control Plane
([I-D.ietf-anima-autonomic-control-plane]), the BRSKI protocol MUST ([I-D.ietf-anima-autonomic-control-plane]), the BRSKI protocol MUST
be implemented. be implemented.
The pledge must perform discovery of the proxy as described in The pledge must perform discovery of the proxy as described in
Section 4.1 using GRASP [I-D.ietf-anima-grasp] M_FLOOD announcements. Section 4.1 using GRASP DULL [I-D.ietf-anima-grasp] M_FLOOD
announcements.
Upon successfully validating a voucher artifact, a status telemetry Upon successfully validating a voucher artifact, a status telemetry
MUST be returned. See Section 5.7. MUST be returned. See Section 5.7.
An ANIMA ANI pledge MUST implement the EST automation extensions An ANIMA ANI pledge MUST implement the EST automation extensions
described in Section 5.9. They supplement the [RFC7030] EST to described in Section 5.9. They supplement the [RFC7030] EST to
better support automated devices that do not have an end user. better support automated devices that do not have an end user.
The ANI Join Registrar ASA MUST support all the BRSKI and above The ANI Join Registrar Autonomic Service Agent (ASA) MUST support all
listed EST operations. the BRSKI and above listed EST operations.
All ANI devices SHOULD support the BRSKI proxy function, using All ANI devices SHOULD support the BRSKI proxy function, using
circuit proxies over the ACP. (See Section 4.3) circuit proxies over the ACP. (See Section 4.3)
2. Architectural Overview 2. Architectural Overview
The logical elements of the bootstrapping framework are described in The logical elements of the bootstrapping framework are described in
this section. Figure 1 provides a simplified overview of the this section. Figure 1 provides a simplified overview of the
components. components.
skipping to change at page 13, line 35 skipping to change at page 14, line 35
|IDevID | . +------------+ | e.g. RFC7030 . |IDevID | . +------------+ | e.g. RFC7030 .
| | . +-----------------+----------+ . | | . +-----------------+----------+ .
| | . | Key Infrastructure | . | | . | Key Infrastructure | .
| | . | (e.g., PKI Certificate | . | | . | (e.g., PKI Certificate | .
+-------+ . | Authority) | . +-------+ . | Authority) | .
. +----------------------------+ . . +----------------------------+ .
. . . .
................................................ ................................................
"Domain" components "Domain" components
Figure 1 Figure 1: Architecture Overview
We assume a multi-vendor network. In such an environment there could We assume a multi-vendor network. In such an environment there could
be a Manufacturer Service for each manufacturer that supports devices be a Manufacturer Service for each manufacturer that supports devices
following this document's specification, or an integrator could following this document's specification, or an integrator could
provide a generic service authorized by multiple manufacturers. It provide a generic service authorized by multiple manufacturers. It
is unlikely that an integrator could provide Ownership Tracking is unlikely that an integrator could provide Ownership Tracking
services for multiple manufacturers due to the required sales channel services for multiple manufacturers due to the required sales channel
integrations necessary to track ownership. integrations necessary to track ownership.
The domain is the managed network infrastructure with a Key The domain is the managed network infrastructure with a Key
Infrastructure the pledge is joining. The domain provides initial Infrastructure the pledge is joining. The domain provides initial
device connectivity sufficient for bootstrapping through a proxy. device connectivity sufficient for bootstrapping through a proxy.
The domain registrar authenticates the pledge, makes authorization The domain registrar authenticates the pledge, makes authorization
decisions, and distributes vouchers obtained from the Manufacturer decisions, and distributes vouchers obtained from the Manufacturer
Service. Optionally the registrar also acts as a PKI Registration Service. Optionally the registrar also acts as a PKI Certification
Authority. Authority.
2.1. Behavior of a Pledge 2.1. Behavior of a Pledge
The pledge goes through a series of steps, which are outlined here at The pledge goes through a series of steps, which are outlined here at
a high level. a high level.
------------ ------------
/ Factory \ / Factory \
\ default / \ default /
skipping to change at page 14, line 46 skipping to change at page 15, line 46
| | (5) Enroll |<---+ (non-error HTTP codes ) | | (5) Enroll |<---+ (non-error HTTP codes )
^------------+ |\___/ (e.g. 202 'Retry-After') ^------------+ |\___/ (e.g. 202 'Retry-After')
| Enroll +------+-------+ | Enroll +------+-------+
| Failure | | Failure |
| -----v------ | -----v------
| / Enrolled \ | / Enrolled \
^------------+ | ^------------+ |
Factory \------------/ Factory \------------/
reset reset
Figure 2: pledge state diagram Figure 2: Pledge State Diagram
State descriptions for the pledge are as follows: State descriptions for the pledge are as follows:
1. Discover a communication channel to a registrar. 1. Discover a communication channel to a registrar.
2. Identify itself. This is done by presenting an X.509 IDevID 2. Identify itself. This is done by presenting an X.509 IDevID
credential to the discovered registrar (via the proxy) in a TLS credential to the discovered registrar (via the proxy) in a TLS
handshake. (The registrar credentials are only provisionally handshake. (The registrar credentials are only provisionally
accepted at this time). accepted at this time).
skipping to change at page 15, line 21 skipping to change at page 16, line 21
included ensuring that any responses can be associated with this included ensuring that any responses can be associated with this
particular bootstrapping attempt. particular bootstrapping attempt.
4. Imprint on the registrar. This requires verification of the 4. Imprint on the registrar. This requires verification of the
manufacturer service provided voucher. A voucher contains manufacturer service provided voucher. A voucher contains
sufficient information for the pledge to complete authentication sufficient information for the pledge to complete authentication
of a registrar. This document details this step in depth. of a registrar. This document details this step in depth.
5. Enroll. After imprint an authenticated TLS (HTTPS) connection 5. Enroll. After imprint an authenticated TLS (HTTPS) connection
exists between pledge and registrar. Enrollment over Secure exists between pledge and registrar. Enrollment over Secure
Transport (EST) [RFC7030] is then used to obtain a domain Transport (EST) [RFC7030] can then used to obtain a domain
certificate from a registrar. certificate from a registrar.
The pledge is now a member of, and can be managed by, the domain and The pledge is now a member of, and can be managed by, the domain and
will only repeat the discovery aspects of bootstrapping if it is will only repeat the discovery aspects of bootstrapping if it is
returned to factory default settings. returned to factory default settings.
This specification details integration with EST enrollment so that This specification details integration with EST enrollment so that
pledges can optionally obtain a locally issued certificate, although pledges can optionally obtain a locally issued certificate, although
any REST interface could be integrated in future work. any REST interface could be integrated in future work.
2.2. Secure Imprinting using Vouchers 2.2. Secure Imprinting using Vouchers
A voucher is a cryptographically protected artifact (a digital A voucher is a cryptographically protected artifact (using a digital
signature) to the pledge device authorizing a zero-touch imprint on signature) to the pledge device authorizing a zero-touch imprint on
the registrar domain. the registrar domain.
The format and cryptographic mechanism of vouchers is described in The format and cryptographic mechanism of vouchers is described in
detail in [RFC8366]. detail in [RFC8366].
Vouchers provide a flexible mechanism to secure imprinting: the Vouchers provide a flexible mechanism to secure imprinting: the
pledge device only imprints when a voucher can be validated. At the pledge device only imprints when a voucher can be validated. At the
lowest security levels the MASA can indiscriminately issue vouchers lowest security levels the MASA can indiscriminately issue vouchers
and log claims of ownership by domains. At the highest security and log claims of ownership by domains. At the highest security
skipping to change at page 16, line 9 skipping to change at page 17, line 9
sales channel integration would verify actual (legal) ownership of sales channel integration would verify actual (legal) ownership of
the pledge by the domain. This provides the flexibility for a number the pledge by the domain. This provides the flexibility for a number
of use cases via a single common protocol mechanism on the pledge and of use cases via a single common protocol mechanism on the pledge and
registrar devices that are to be widely deployed in the field. The registrar devices that are to be widely deployed in the field. The
MASA services have the flexibility to leverage either the currently MASA services have the flexibility to leverage either the currently
defined claim mechanisms or to experiment with higher or lower defined claim mechanisms or to experiment with higher or lower
security levels. security levels.
Vouchers provide a signed but non-encrypted communication channel Vouchers provide a signed but non-encrypted communication channel
among the pledge, the MASA, and the registrar. The registrar among the pledge, the MASA, and the registrar. The registrar
maintains control over the transport and policy decisions allowing maintains control over the transport and policy decisions, allowing
the local security policy of the domain network to be enforced. the local security policy of the domain network to be enforced.
2.3. Initial Device Identifier 2.3. Initial Device Identifier
Pledge authentication and pledge voucher-request signing is via a Pledge authentication and pledge voucher-request signing is via a
PKIX certificate installed during the manufacturing process. This is PKIX-shaped certificate installed during the manufacturing process.
the 802.1AR Initial Device Identifier (IDevID), and it provides a This is the 802.1AR Initial Device Identifier (IDevID), and it
basis for authenticating the pledge during the protocol exchanges provides a basis for authenticating the pledge during the protocol
described here. There is no requirement for a common root PKI exchanges described here. There is no requirement for a common root
hierarchy. Each device manufacturer can generate its own root PKI hierarchy. Each device manufacturer can generate its own root
certificate. Specifically, the IDevID enables: certificate. Specifically, the IDevID enables:
1. Uniquely identifying the pledge by the Distinguished Name (DN) 1. Uniquely identifying the pledge by the Distinguished Name (DN)
and subjectAltName (SAN) parameters in the IDevID. The unique and subjectAltName (SAN) parameters in the IDevID. The unique
identification of a pledge in the voucher objects are derived identification of a pledge in the voucher objects are derived
from those parameters as described below. from those parameters as described below. Section 10.2 discussed
privacy implications.
2. Provides a cryptographic authentication of the pledge to the 2. Provides a cryptographic authentication of the pledge to the
Registrar (see Section 5.3). Registrar (see Section 5.3).
3. Secure auto-discovery of the pledge's MASA by the registrar (see 3. Secure auto-discovery of the pledge's MASA by the registrar (see
Section 2.8). Section 2.8).
4. Signing of voucher-request by the pledge's IDevID (see 4. Signing of voucher-request by the pledge's IDevID (see
Section 3). Section 3).
skipping to change at page 17, line 49 skipping to change at page 19, line 5
possible confusion about the source of the serial-number (hwSerialNum possible confusion about the source of the serial-number (hwSerialNum
vs serialNumber). vs serialNumber).
2.3.2. MASA URI extension 2.3.2. MASA URI extension
This document defines a new PKIX non-critical certificate extension This document defines a new PKIX non-critical certificate extension
to carry the MASA URI. This extension is intended to be used in the to carry the MASA URI. This extension is intended to be used in the
IDevID certificate. The URI is represented as described in IDevID certificate. The URI is represented as described in
Section 7.4 of [RFC5280]. Section 7.4 of [RFC5280].
Any Internationalized Resource Identifiers (IRIs) MUST be mapped to The URI provides the authority information. The BRSKI "/.well-known"
URIs as specified in Section 3.1 of [RFC3987] before they are placed tree ([RFC5785]) is described in Section 5.
in the certificate extension. The IRI provides the authority
information. The BRSKI "/.well-known" tree ([RFC5785]) is described
in Section 5.
As explained in [RFC5280] section 7.4, a complete IRI SHOULD be in A complete URI MAY be in this extension, including the 'scheme',
this extension, including the scheme, iauthority, and ipath. As a 'authority', and 'path', The complete URI will typically be used in
consideration to constrained systems, this MAY be reduced to only the diagnostic or experimental situations. Typically, (and in
iauthority, in which case a scheme of "https://" ([RFC7230] section consideration to constrained systems), this SHOULD be reduced to only
2.7.3) and ipath of "/.well-known/est" is to be assumed, as explained the 'authority', in which case a scheme of "https://" ([RFC7230]
in Section 5. section 2.7.3) and 'path' of "/.well-known/est" is to be assumed, as
explained in Section 5.
The registrar can assume that only the iauthority is present in the The registrar can assume that only the 'authority' is present in the
extension, if there are no slash ("/") characters in the extension. extension, if there are no slash ("/") characters in the extension.
Section 7.4 of [RFC5280] calls out various schemes that MUST be Section 7.4 of [RFC5280] calls out various schemes that MUST be
supported, including LDAP, HTTP and FTP. However, the registrar MUST supported, including LDAP, HTTP and FTP. However, the registrar MUST
use HTTPS for the BRSKI-MASA connection. use HTTPS for the BRSKI-MASA connection.
The new extension is identified as follows: The new extension is identified as follows:
<CODE BEGINS> <CODE BEGINS>
skipping to change at page 19, line 18 skipping to change at page 20, line 18
internet(1) security(5) mechanisms(5) pkix(7) internet(1) security(5) mechanisms(5) pkix(7)
id-mod(0) id-mod-MASAURLExtn2016(TBD) } id-mod(0) id-mod-MASAURLExtn2016(TBD) }
DEFINITIONS IMPLICIT TAGS ::= BEGIN DEFINITIONS IMPLICIT TAGS ::= BEGIN
-- EXPORTS ALL -- -- EXPORTS ALL --
IMPORTS IMPORTS
EXTENSION EXTENSION
FROM PKIX-CommonTypes-2009 FROM PKIX-CommonTypes-2009
{ iso(1) identified-organization(3) dod(6) internet(1) { iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkixCommon-02(57) } id-mod-pkixCommon-02(57) }
id-pe FROM PKIX1Explicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-explicit-02(51) } ;
id-pe
FROM PKIX1Explicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-explicit-02(51) } ;
MASACertExtensions EXTENSION ::= { ext-MASAURL, ... } MASACertExtensions EXTENSION ::= { ext-MASAURL, ... }
ext-MASAURL EXTENSION ::= { SYNTAX MASAURLSyntax ext-MASAURL EXTENSION ::= { SYNTAX MASAURLSyntax
IDENTIFIED BY id-pe-masa-url } IDENTIFIED BY id-pe-masa-url }
id-pe-masa-url OBJECT IDENTIFIER ::= { id-pe TBD } id-pe-masa-url OBJECT IDENTIFIER ::= { id-pe TBD }
MASAURLSyntax ::= IA5String MASAURLSyntax ::= IA5String
END END
<CODE ENDS> <CODE ENDS>
Figure 3: MASAURL ASN.1 Module
The choice of id-pe is based on guidance found in Section 4.2.2 of The choice of id-pe is based on guidance found in Section 4.2.2 of
[RFC5280], "These extensions may be used to direct applications to [RFC5280], "These extensions may be used to direct applications to
on-line information about the issuer or the subject". The MASA URL on-line information about the issuer or the subject". The MASA URL
is precisely that: online information about the particular subject. is precisely that: online information about the particular subject.
2.4. Protocol Flow 2.4. Protocol Flow
A representative flow is shown in Figure 3: A representative flow is shown in Figure 4
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| Pledge | | Circuit | | Domain | | Vendor | | Pledge | | Circuit | | Domain | | Vendor |
| | | Join | | Registrar | | Service | | | | Join | | Registrar | | Service |
| | | Proxy | | (JRC) | | (MASA) | | | | Proxy | | (JRC) | | (MASA) |
+--------+ +---------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| | | Internet | | | | Internet |
[discover] | | | [discover] | | |
|<-RFC4862 IPv6 addr | | | |<-RFC4862 IPv6 addr | | |
|<-RFC3927 IPv4 addr | Appendix A | Legend | |<-RFC3927 IPv4 addr | Appendix A | Legend |
|-------------------->| | C - circuit | |-------------------->| | C - circuit |
skipping to change at page 20, line 51 skipping to change at page 21, line 50
|-------voucher status telemetry--------->| | |-------voucher status telemetry--------->| |
| |<-device audit log--| | |<-device audit log--|
| [verify audit log and voucher] | | [verify audit log and voucher] |
|<--------------------------------------->| | |<--------------------------------------->| |
[enroll] | | [enroll] | |
| Continue with RFC7030 enrollment | | | Continue with RFC7030 enrollment | |
| using now bidirectionally authenticated | | | using now bidirectionally authenticated | |
| TLS session. | | | TLS session. | |
[enrolled] | | [enrolled] | |
Figure 3 Figure 4: Protocol Time Sequence Diagram
On initial bootstrap, a new device (the pledge) uses a local service
autodiscovery (GRASP or mDNS) to locate a join proxy. The join proxy
connects the pledge to a local registrar (the JRC).
Having found a candidate registrar, the fledgling pledge sends some
information about itself to the registrar, including its serial
number in the form of a voucher request and its device identity
certificate (IDevID) as part of the TLS session.
The registrar can determine whether it expected such a device to
appear, and locates a MASA. The location of the MASA is usually
found in an extension in the IDevID. Having determined that the MASA
is suitable, the entire information from the initial voucher request
(including device serial number) is transmitted over the internet in
a TLS protected channel to the manufacturer, along with information
about the registrar/owner.
The manufacturer can then apply policy based on the provided
information, as well as other sources of information (such as sales
records), to decide whether to approve the claim by the registrar to
own the device; if the claim is accepted, a voucher is issued that
directs the device to accept its new owner.
The voucher is returned to the registrar, but not immediately to the
device -- the registrar has an opportunity to examine the voucher,
the MASA's audit logs, and other sources of information to determine
whether the device has been tampered with, and whether the bootstrap
should be accepted.
No filtering of information is possible in the signed voucher, so
this is a binary yes-or-no decision. If the registrar accepts the
voucher as a proper one for its device, the voucher is returned to
the pledge for imprinting.
The voucher also includes a trust anchor that the pledge uses as
representing the owner. This is used to successfully bootstrap from
an environment where only the manufacturer has built-in trust by the
device into an environment where the owner now has a PKI footprint on
the device.
When BRSKI is followed with EST this single footprint is further
leveraged into the full owner's PKI and a LDevID for the device.
Subsequent reporting steps provide flows of information to indicate
success/failure of the process.
2.5. Architectural Components 2.5. Architectural Components
2.5.1. Pledge 2.5.1. Pledge
The pledge is the device that is attempting to join. Until the The pledge is the device that is attempting to join. Until the
pledge completes the enrollment process, it has link-local network pledge completes the enrollment process, it has link-local network
connectivity only to the proxy. connectivity only to the proxy.
2.5.2. Join Proxy 2.5.2. Join Proxy
skipping to change at page 21, line 46 skipping to change at page 23, line 46
2.5.4. Manufacturer Service 2.5.4. Manufacturer Service
The Manufacturer Service provides two logically separate functions: The Manufacturer Service provides two logically separate functions:
the Manufacturer Authorized Signing Authority (MASA) described in the Manufacturer Authorized Signing Authority (MASA) described in
Section 5.5 and Section 5.6, and an ownership tracking/auditing Section 5.5 and Section 5.6, and an ownership tracking/auditing
function described in Section 5.7 and Section 5.8. function described in Section 5.7 and Section 5.8.
2.5.5. Public Key Infrastructure (PKI) 2.5.5. Public Key Infrastructure (PKI)
The Public Key Infrastructure (PKI) administers certificates for the The Public Key Infrastructure (PKI) administers certificates for the
domain of concerns, providing the trust anchor(s) for it and allowing domain of concern, providing the trust anchor(s) for it and allowing
enrollment of pledges with domain certificates. enrollment of pledges with domain certificates.
The voucher provides a method for the distribution of a single PKI The voucher provides a method for the distribution of a single PKI
trust anchor (as the "pinned-domain-cert"). A distribution of the trust anchor (as the "pinned-domain-cert"). A distribution of the
full set of current trust anchors is possible using the optional EST full set of current trust anchors is possible using the optional EST
integration. integration.
The domain's registrar acts as an [RFC5272] Registration Authority, The domain's registrar acts as an [RFC5272] Registration Authority,
requesting certificates for pledges from the Key Infrastructure. requesting certificates for pledges from the Key Infrastructure.
skipping to change at page 22, line 19 skipping to change at page 24, line 19
document does not place any additional architectural requirements on document does not place any additional architectural requirements on
the Public Key Infrastructure. the Public Key Infrastructure.
2.6. Certificate Time Validation 2.6. Certificate Time Validation
2.6.1. Lack of realtime clock 2.6.1. Lack of realtime clock
Many devices when bootstrapping do not have knowledge of the current Many devices when bootstrapping do not have knowledge of the current
time. Mechanisms such as Network Time Protocols cannot be secured time. Mechanisms such as Network Time Protocols cannot be secured
until bootstrapping is complete. Therefore bootstrapping is defined until bootstrapping is complete. Therefore bootstrapping is defined
in a method that does not require knowledge of the current time. A with a framework that does not require knowledge of the current time.
pledge MAY ignore all time stamps in the voucher and in the A pledge MAY ignore all time stamps in the voucher and in the
certificate validity periods if it does not know the current time. certificate validity periods if it does not know the current time.
The pledge is exposed to dates in the following five places: The pledge is exposed to dates in the following five places:
registrar certificate notBefore, registrar certificate notAfter, registrar certificate notBefore, registrar certificate notAfter,
voucher created-on, and voucher expires-on. Additionally, CMS voucher created-on, and voucher expires-on. Additionally, CMS
signatures contain a signingTime. signatures contain a signingTime.
A pledge with a real time clock in which it has confidence in, MUST
check the above time fields in all certificates and signatures that
ir processes.
If the voucher contains a nonce then the pledge MUST confirm the If the voucher contains a nonce then the pledge MUST confirm the
nonce matches the original pledge voucher-request. This ensures the nonce matches the original pledge voucher-request. This ensures the
voucher is fresh. See Section 5.2. voucher is fresh. See Section 5.2.
2.6.2. Infinite Lifetime of IDevID 2.6.2. Infinite Lifetime of IDevID
[RFC5280] explains that long lived pledge certificates "SHOULD be [RFC5280] explains that long lived pledge certificates "SHOULD be
assigned the GeneralizedTime value of 99991231235959Z". Registrars assigned the GeneralizedTime value of 99991231235959Z". Registrars
MUST support such lifetimes and SHOULD support ignoring pledge MUST support such lifetimes and SHOULD support ignoring pledge
lifetimes if they did not follow the RFC5280 recommendations. lifetimes if they did not follow the RFC5280 recommendations.
For example, IDevID may have incorrect lifetime of N <= 3 years, For example, IDevID may have incorrect lifetime of N <= 3 years,
rendering replacement pledges from storage useless after N years rendering replacement pledges from storage useless after N years
unless registrars support ignoring such a lifetime. unless registrars support ignoring such a lifetime.
2.7. Cloud Registrar 2.7. Cloud Registrar
There exist operationally open network wherein devices gain There exist operationally open networks wherein devices gain
unauthenticated access to the Internet at large. In these use cases unauthenticated access to the Internet at large. In these use cases
the management domain for the device needs to be discovered within the management domain for the device needs to be discovered within
the larger Internet. These are less likely within the anima scope the larger Internet. The case where a device can boot and get access
but may be more important in the future. to larger Internet are less likely within the ANIMA ACP scope but may
be more important in the future. In the ANIMA ACP scope, new devices
will be quarantined behind a Join Proxy.
There are additionally some greenfield situations involving an There are additionally some greenfield situations involving an
entirely new installation where a device may have some kind of entirely new installation where a device may have some kind of
management uplink that it can use (such as via 3G network for management uplink that it can use (such as via 3G network for
instance). In such a future situation, the device might use this instance). In such a future situation, the device might use this
management interface to learn that it should configure itself to management interface to learn that it should configure itself to
become the local registrar. become the local registrar.
In order to support these scenarios, the pledge MAY contact a well In order to support these scenarios, the pledge MAY contact a well
known URI of a cloud registrar if a local registrar cannot be known URI of a cloud registrar if a local registrar cannot be
discovered or if the pledge's target use cases do not include a local discovered or if the pledge's target use cases do not include a local
registrar. registrar.
If the pledge uses a well known URI for contacting a cloud registrar If the pledge uses a well known URI for contacting a cloud registrar
an Implicit Trust Anchor database (see [RFC7030]) MUST be used to an Implicit Trust Anchor database (see [RFC7030]) MUST be used to
authenticate service as described in [RFC6125]. This is consistent authenticate that service as described in [RFC6125]. This is
with the human user configuration of an EST server URI in [RFC7030] consistent with the human user configuration of an EST server URI in
which also depends on RFC6125. [RFC7030] which also depends on RFC6125.
2.8. Determining the MASA to contact 2.8. Determining the MASA to contact
The registrar needs to be able to contact a MASA that is trusted by The registrar needs to be able to contact a MASA that is trusted by
the pledge in order to obtain vouchers. There are three mechanisms the pledge in order to obtain vouchers. There are three mechanisms
described: described:
The device's Initial Device Identifier (IDevID) will normally contain The device's Initial Device Identifier (IDevID) will normally contain
the MASA URL as detailed in Section 2.3. This is the RECOMMENDED the MASA URL as detailed in Section 2.3. This is the RECOMMENDED
mechanism. mechanism.
If the registrar is integrated with [I-D.ietf-opsawg-mud] and the If the registrar is integrated with [RFC8520] and the pledge IDevID
pledge IDevID contains the id-pe-mud-url then the registrar MAY contains the id-pe-mud-url then the registrar MAY attempt to obtain
attempt to obtain the MASA URL from the MUD file. The MUD file the MASA URL from the MUD file. The MUD file extension for the MASA
extension for the MASA URL is defined in Appendix C. URL is defined in Appendix C.
It can be operationally difficult to ensure the necessary X.509 It can be operationally difficult to ensure the necessary X.509
extensions are in the pledge's IDevID due to the difficulty of extensions are in the pledge's IDevID due to the difficulty of
aligning current pledge manufacturing with software releases and aligning current pledge manufacturing with software releases and
development. As a final fallback the registrar MAY be manually development. As a final fallback the registrar MAY be manually
configured or distributed with a MASA URL for each manufacturer. configured or distributed with a MASA URL for each manufacturer.
Note that the registrar can only select the configured MASA URL based Note that the registrar can only select the configured MASA URL based
on the trust anchor -- so manufacturers can only leverage this on the trust anchor -- so manufacturers can only leverage this
approach if they ensure a single MASA URL works for all pledge's approach if they ensure a single MASA URL works for all pledge's
associated with each trust anchor. associated with each trust anchor.
3. Voucher-Request artifact 3. Voucher-Request artifact
Voucher-requests are how vouchers are requested. The semantics of Voucher-requests are how vouchers are requested. The semantics of
the vouchers are described below, in the YANG model. the vouchers are described below, in the YANG model.
A pledge forms the "pledge voucher-request" and submits it to the A pledge forms the "pledge voucher-request", signs it with it's
registrar. IDevID and submits it to the registrar.
The registrar in turn forms the "registrar voucher-request", and The registrar in turn forms the "registrar voucher-request", signs it
submits it to the MASA. with it's Registrar keypair and submits it to the MASA.
The "proximity-registrar-cert" leaf is used in the pledge voucher- The "proximity-registrar-cert" leaf is used in the pledge voucher-
requests. This provides a method for the pledge to assert the requests. This provides a method for the pledge to assert the
registrar's proximity. registrar's proximity.
The "prior-signed-voucher-request" leaf is used in registrar voucher- The "prior-signed-voucher-request" leaf is used in registrar voucher-
requests. If present, it is the signed pledge voucher-request. This requests. If present, it is the signed pledge voucher-request
provides a method for the registrar to forward the pledge's signed artifact. This provides a method for the registrar to forward the
request to the MASA. This completes transmission of the signed pledge's signed request to the MASA. This completes transmission of
"proximity-registrar-cert" leaf. the signed "proximity-registrar-cert" leaf.
Unless otherwise signaled (outside the voucher-request artifact), the Unless otherwise signaled (outside the voucher-request artifact), the
signing structure is as defined for vouchers, see [RFC8366]. signing structure is as defined for vouchers, see [RFC8366].
3.1. Nonceless Voucher Requests 3.1. Nonceless Voucher Requests
A registrar MAY also retrieve nonceless vouchers by sending nonceless A registrar MAY also retrieve nonceless vouchers by sending nonceless
voucher-requests to the MASA in order to obtain vouchers for use when voucher-requests to the MASA in order to obtain vouchers for use when
the registrar does not have connectivity to the MASA. No "prior- the registrar does not have connectivity to the MASA. No "prior-
signed-voucher-request" leaf would be included. The registrar will signed-voucher-request" leaf would be included. The registrar will
skipping to change at page 25, line 8 skipping to change at page 27, line 8
The following tree diagram illustrates a high-level view of a The following tree diagram illustrates a high-level view of a
voucher-request document. The voucher-request builds upon the voucher-request document. The voucher-request builds upon the
voucher artifact described in [RFC8366]. The tree diagram is voucher artifact described in [RFC8366]. The tree diagram is
described in [RFC8340]. Each node in the diagram is fully described described in [RFC8340]. Each node in the diagram is fully described
by the YANG module in Section 3.4. Please review the YANG module for by the YANG module in Section 3.4. Please review the YANG module for
a detailed description of the voucher-request format. a detailed description of the voucher-request format.
module: ietf-voucher-request module: ietf-voucher-request
grouping voucher-request-grouping grouping voucher-request-grouping
+-- voucher +---- voucher
+-- created-on? yang:date-and-time +---- created-on? yang:date-and-time
+-- expires-on? yang:date-and-time +---- expires-on? yang:date-and-time
+-- assertion? enumeration +---- assertion? enumeration
+-- serial-number string +---- serial-number string
+-- idevid-issuer? binary +---- idevid-issuer? binary
+-- pinned-domain-cert? binary +---- pinned-domain-cert? binary
+-- domain-cert-revocation-checks? boolean +---- domain-cert-revocation-checks? boolean
+-- nonce? binary +---- nonce? binary
+-- last-renewal-date? yang:date-and-time +---- last-renewal-date? yang:date-and-time
+-- prior-signed-voucher-request? binary +---- prior-signed-voucher-request? binary
+-- proximity-registrar-cert? binary +---- proximity-registrar-cert? binary
Figure 5: YANG Tree diagram for Voucher-Request
3.3. Examples 3.3. Examples
This section provides voucher-request examples for illustration This section provides voucher-request examples for illustration
purposes. The contents of the certificate have been elided to save purposes. The contents of the certificate have been elided to save
space. For detailed examples, see Appendix D.2. These examples space. For detailed examples, see Appendix D.2. These examples
conform to the encoding rules defined in [RFC7951]. conform to the encoding rules defined in [RFC7951].
Example (1) The following example illustrates a pledge voucher- Example (1) The following example illustrates a pledge voucher-
request. The assertion leaf is indicated as 'proximity' request. The assertion leaf is indicated as 'proximity'
and the registrar's TLS server certificate is included and the registrar's TLS server certificate is included
in the 'proximity-registrar-cert' leaf. See in the 'proximity-registrar-cert' leaf. See
Section 5.2. Section 5.2.
{ {
"ietf-voucher-request:voucher": { "ietf-voucher-request:voucher": {
"assertion": "proximity",
"nonce": "62a2e7693d82fcda2624de58fb6722e5", "nonce": "62a2e7693d82fcda2624de58fb6722e5",
"serial-number" : "JADA123456789", "serial-number" : "JADA123456789",
"created-on": "2017-01-01T00:00:00.000Z", "created-on": "2017-01-01T00:00:00.000Z",
"proximity-registrar-cert": "base64encodedvalue==" "proximity-registrar-cert": "base64encodedvalue=="
} }
} }
Figure 6: JSON representation of example Voucher-Request
Example (2) The following example illustrates a registrar voucher- Example (2) The following example illustrates a registrar voucher-
request. The 'prior-signed-voucher-request' leaf is request. The 'prior-signed-voucher-request' leaf is
populated with the pledge's voucher-request (such as the populated with the pledge's voucher-request (such as the
prior example). The pledge's voucher-request is a prior example). The pledge's voucher-request is a
binary object. In the JSON encoding used here it must binary CMS signed object. In the JSON encoding used
be base64 encoded. The nonce, created-on and assertion here it must be base64 encoded. The nonce, created-on
is carried forward. The serial-number is extracted from and assertion is carried forward. The serial-number is
the pledge's Client Certificate from the TLS connection. extracted from the pledge's Client Certificate from the
See Section 5.5. TLS connection. See Section 5.5.
{ {
"ietf-voucher-request:voucher": { "ietf-voucher-request:voucher": {
"assertion" : "proximity",
"nonce": "62a2e7693d82fcda2624de58fb6722e5", "nonce": "62a2e7693d82fcda2624de58fb6722e5",
"created-on": "2017-01-01T00:00:02.000Z", "created-on": "2017-01-01T00:00:02.000Z",
"idevid-issuer": "base64encodedvalue==" "idevid-issuer": "base64encodedvalue=="
"serial-number": "JADA123456789" "serial-number": "JADA123456789"
"prior-signed-voucher-request": "base64encodedvalue==" "prior-signed-voucher-request": "base64encodedvalue=="
} }
} }
Figure 7: JSON representation of example Prior-Signed Voucher-Request
Example (3) The following example illustrates a registrar voucher- Example (3) The following example illustrates a registrar voucher-
request. The 'prior-signed-voucher-request' leaf is not request. The 'prior-signed-voucher-request' leaf is not
populated with the pledge's voucher-request nor is the populated with the pledge's voucher-request nor is the
nonce leaf. This form might be used by a registrar nonce leaf. This form might be used by a registrar
requesting a voucher when the pledge can not communicate requesting a voucher when the pledge can not communicate
with the registrar (such as when it is powered down, or with the registrar (such as when it is powered down, or
still in packaging), and therefore could not submit a still in packaging), and therefore could not submit a
nonce. This scenario is most useful when the registrar nonce. This scenario is most useful when the registrar
is aware that it will not be able to reach the MASA is aware that it will not be able to reach the MASA
during deployment. See Section 5.5. during deployment. See Section 5.5.
{ {
"ietf-voucher-request:voucher": { "ietf-voucher-request:voucher": {
"created-on": "2017-01-01T00:00:02.000Z", "created-on": "2017-01-01T00:00:02.000Z",
"idevid-issuer": "base64encodedvalue==" "idevid-issuer": "base64encodedvalue=="
"serial-number": "JADA123456789" "serial-number": "JADA123456789"
} }
} }
Figure 8: JSON representation of Offline Voucher-Request
3.4. YANG Module 3.4. YANG Module
Following is a YANG [RFC7950] module formally extending the [RFC8366] Following is a YANG [RFC7950] module formally extending the [RFC8366]
voucher into a voucher-request. voucher into a voucher-request.
<CODE BEGINS> file "ietf-voucher-request@2018-02-14.yang" <CODE BEGINS> file "ietf-voucher-request@2018-02-14.yang"
module ietf-voucher-request { module ietf-voucher-request {
yang-version 1.1; yang-version 1.1;
namespace namespace
"urn:ietf:params:xml:ns:yang:ietf-voucher-request"; "urn:ietf:params:xml:ns:yang:ietf-voucher-request";
prefix "vch"; prefix "vch";
import ietf-restconf { import ietf-restconf {
prefix rc; prefix rc;
description "This import statement is only present to access description "This import statement is only present to access
the yang-data extension defined in RFC 8040."; the yang-data extension defined in RFC 8040.";
reference "RFC 8040: RESTCONF Protocol"; reference "RFC 8040: RESTCONF Protocol";
} }
skipping to change at page 27, line 25 skipping to change at page 29, line 36
organization organization
"IETF ANIMA Working Group"; "IETF ANIMA Working Group";
contact contact
"WG Web: <http://tools.ietf.org/wg/anima/> "WG Web: <http://tools.ietf.org/wg/anima/>
WG List: <mailto:anima@ietf.org> WG List: <mailto:anima@ietf.org>
Author: Kent Watsen Author: Kent Watsen
<mailto:kwatsen@juniper.net> <mailto:kwatsen@juniper.net>
Author: Michael H. Behringer Author: Michael H. Behringer
<mailto:Michael.H.Behringer@gmail.com> <mailto:Michael.H.Behringer@gmail.com>
Author: Steinthor Bjarnason Author: Toerless Eckert
<mailto:sbjarnason@arbor.net> <mailto:ttef@cs.fau.de>
Author: Max Pritikin Author: Max Pritikin
<mailto:pritikin@cisco.com> <mailto:pritikin@cisco.com>
Author: Michael Richardson Author: Michael Richardson
<mailto:mcr+ietf@sandelman.ca>"; <mailto:mcr+ietf@sandelman.ca>";
description description
"This module defines the format for a voucher request. "This module defines the format for a voucher request.
It is a superset of the voucher itself. It is a superset of the voucher itself.
It provides content to the MASA for consideration It provides content to the MASA for consideration
during a voucher request. during a voucher request.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', '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 RFC2119 RFC8174 when, and only when, they described in BCP 14 RFC2119 RFC8174 when, and only when, they
appear in all capitals, as shown here. appear in all capitals, as shown here.
Copyright (c) 2017 IETF Trust and the persons identified as Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or without Redistribution and use in source and binary forms, with or without
modification, is permitted pursuant to, and subject to the license modification, is permitted pursuant to, and subject to the license
terms contained in, the Simplified BSD License set forth in Section terms contained in, the Simplified BSD License set forth in Section
4.c of the IETF Trust's Legal Provisions Relating to IETF Documents 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see the RFC This version of this YANG module is part of RFC XXXX; see the RFC
itself for full legal notices."; itself for full legal notices.";
revision "2018-02-14" { revision "2018-02-14" {
description description
"Initial version"; "Initial version";
reference reference
"RFC XXXX: Voucher Profile for Bootstrapping Protocols"; "RFC XXXX: Voucher Profile for Bootstrapping Protocols";
} }
skipping to change at page 29, line 11 skipping to change at page 31, line 23
leaf prior-signed-voucher-request { leaf prior-signed-voucher-request {
type binary; type binary;
description description
"If it is necessary to change a voucher, or re-sign and "If it is necessary to change a voucher, or re-sign and
forward a voucher that was previously provided along a forward a voucher that was previously provided along a
protocol path, then the previously signed voucher SHOULD be protocol path, then the previously signed voucher SHOULD be
included in this field. included in this field.
For example, a pledge might sign a voucher request For example, a pledge might sign a voucher request
with a proximity-registrar-cert, and the registrar with a proximity-registrar-cert, and the registrar
then includes it in the prior-signed-voucher-request field. then includes it as the prior-signed-voucher-request field.
This is a simple mechanism for a chain of trusted This is a simple mechanism for a chain of trusted
parties to change a voucher request, while parties to change a voucher request, while
maintaining the prior signature information. maintaining the prior signature information.
The Registrar and MASA MAY examine the prior signed The Registrar and MASA MAY examine the prior signed
voucher information for the voucher information for the
purposes of policy decisions. For example this information purposes of policy decisions. For example this information
could be useful to a MASA to determine that both pledge and could be useful to a MASA to determine that both pledge and
registrar agree on proximity assertions. The MASA SHOULD registrar agree on proximity assertions. The MASA SHOULD
remove all prior-signed-voucher-request information when remove all prior-signed-voucher-request information when
skipping to change at page 29, line 34 skipping to change at page 31, line 46
} }
leaf proximity-registrar-cert { leaf proximity-registrar-cert {
type binary; type binary;
description description
"An X.509 v3 certificate structure as specified by RFC 5280, "An X.509 v3 certificate structure as specified by RFC 5280,
Section 4 encoded using the ASN.1 distinguished encoding Section 4 encoded using the ASN.1 distinguished encoding
rules (DER), as specified in ITU-T X.690. rules (DER), as specified in ITU-T X.690.
The first certificate in the Registrar TLS server The first certificate in the Registrar TLS server
certificate_list sequence (see [RFC5246]) presented by certificate_list sequence (the end-entity TLS certificate,
the Registrar to the Pledge. This MUST be populated in a see [RFC8446]) presented by the Registrar to the Pledge.
Pledge's voucher request if a proximity assertion is This MUST be populated in a Pledge's voucher request when a
requested."; proximity assertion is requested.";
} }
} }
} }
} }
} }
<CODE ENDS> <CODE ENDS>
Figure 9: YANG module for Voucher-Request
4. Proxying details (Pledge - Proxy - Registrar) 4. Proxying details (Pledge - Proxy - Registrar)
This section applies is normative for uses with an ANIMA ACP. The
use of GRASP mechanism part of the ACP. Other users of BRSKI will
need to define an equivalent proxy mechanism, and an equivalent
mechanism to configure the proxy.
The role of the proxy is to facilitate communications. The proxy The role of the proxy is to facilitate communications. The proxy
forwards packets between the pledge and a registrar that has been forwards packets between the pledge and a registrar that has been
provisioned to the proxy via GRASP discovery. provisioned to the proxy via full GRASP ACP discovery.
This section defines a stateful proxy mechanism which is referred to This section defines a stateful proxy mechanism which is referred to
as a "circuit" proxy. as a "circuit" proxy. This is a form of Application Level Gateway
([RFC2663] section 2.9).
The proxy does not terminate the TLS handshake: it passes streams of The proxy does not terminate the TLS handshake: it passes streams of
bytes onward without examination. A proxy MUST NOT assume any bytes onward without examination. A proxy MUST NOT assume any
specific TLS version. specific TLS version. Please see {{RFC8446}} section 9.3 for details
on TLS invariants.
A Registrar can directly provide the proxy announcements described A Registrar can directly provide the proxy announcements described
below, in which case the announced port can point directly to the below, in which case the announced port can point directly to the
Registrar itself. In this scenario the pledge is unaware that there Registrar itself. In this scenario the pledge is unaware that there
is no proxing occurring. This is useful for Registrars servicing is no proxing occurring. This is useful for Registrars which are
pledges on directly connected networks. servicing pledges on directly connected networks.
As a result of the proxy Discovery process in Section 4.1.1, the port As a result of the proxy Discovery process in Section 4.1.1, the port
number exposed by the proxy does not need to be well known, or number exposed by the proxy does not need to be well known, or
require an IANA allocation. require an IANA allocation.
During the discovery of the Registrar by the Join Proxy, the Join During the discovery of the Registrar by the Join Proxy, the Join
Proxy will also learn which kinds of proxy mechanisms are available. Proxy will also learn which kinds of proxy mechanisms are available.
This will allow the Join Proxy to use the lowest impact mechanism This will allow the Join Proxy to use the lowest impact mechanism
which the Join Proxy and Registrar have in common. which the Join Proxy and Registrar have in common.
skipping to change at page 30, line 43 skipping to change at page 33, line 16
to many class 2 IoT devices. to many class 2 IoT devices.
The document [I-D.richardson-anima-state-for-joinrouter] provides a The document [I-D.richardson-anima-state-for-joinrouter] provides a
more extensive analysis and background of the alternative proxy more extensive analysis and background of the alternative proxy
methods. methods.
4.1. Pledge discovery of Proxy 4.1. Pledge discovery of Proxy
The result of discovery is a logical communication with a registrar, The result of discovery is a logical communication with a registrar,
through a proxy. The proxy is transparent to the pledge. The through a proxy. The proxy is transparent to the pledge. The
communication between the pledge is over IPv6 Link-Local addresses. communication between the pledge and Join Proxy is over IPv6 Link-
Local addresses.
To discover the proxy the pledge performs the following actions: To discover the proxy the pledge performs the following actions:
1. MUST: Obtains a local address using IPv6 methods as described in 1. MUST: Obtains a local address using IPv6 methods as described in
[RFC4862] IPv6 Stateless Address AutoConfiguration. Use of [RFC4862] IPv6 Stateless Address AutoConfiguration. Use of
[RFC4941] temporary addresses is encouraged. To limit pervasive [RFC4941] temporary addresses is encouraged. To limit pervasive
monitoring ( [RFC7258]), a new temporary address MAY use a short monitoring ( [RFC7258]), a new temporary address MAY use a short
lifetime (that is, set TEMP_PREFERRED_LIFETIME to be short). lifetime (that is, set TEMP_PREFERRED_LIFETIME to be short).
Pledges will generally prefer use of IPv6 Link-Local addresses, Pledges will generally prefer use of IPv6 Link-Local addresses,
and discovery of proxy will be by Link-Local mechanisms. IPv4 and discovery of proxy will be by Link-Local mechanisms. IPv4
skipping to change at page 31, line 20 skipping to change at page 33, line 43
listen concurrently for other sources of information, see listen concurrently for other sources of information, see
Appendix B. Appendix B.
Once a proxy is discovered the pledge communicates with a registrar Once a proxy is discovered the pledge communicates with a registrar
through the proxy using the bootstrapping protocol defined in through the proxy using the bootstrapping protocol defined in
Section 5. Section 5.
While the GRASP M_FLOOD mechanism is passive for the pledge, the While the GRASP M_FLOOD mechanism is passive for the pledge, the
optional other methods (mDNS, and IPv4 methods) are active. The optional other methods (mDNS, and IPv4 methods) are active. The
pledge SHOULD run those methods in parallel with listening to for the pledge SHOULD run those methods in parallel with listening to for the
M_FLOOD. The active methods SHOULD exponentially back-off to a M_FLOOD. The active methods SHOULD back-off by doubling to a maximum
maximum of one hour to avoid overloading the network with discovery of one hour to avoid overloading the network with discovery attempts.
attempts. Detection of change of physical link status (Ethernet Detection of change of physical link status (Ethernet carrier for
carrier for instance) SHOULD reset the exponential back off. instance) SHOULD reset the back off timers.
The pledge could discover more than one proxy on a given physical The pledge could discover more than one proxy on a given physical
interface. The pledge can have a multitude of physical interfaces as interface. The pledge can have a multitude of physical interfaces as
well: a layer-2/3 Ethernet switch may have hundreds of physical well: a layer-2/3 Ethernet switch may have hundreds of physical
ports. ports.
Each possible proxy offer SHOULD be attempted up to the point where a Each possible proxy offer SHOULD be attempted up to the point where a
voucher is received: while there are many ways in which the attempt voucher is received: while there are many ways in which the attempt
may fail, it does not succeed until the voucher has been validated. may fail, it does not succeed until the voucher has been validated.
skipping to change at page 32, line 4 skipping to change at page 34, line 27
to different proxies SHOULD be sent with an interval of 3 to 5s. The to different proxies SHOULD be sent with an interval of 3 to 5s. The
pledge SHOULD continue to listen to for additional GRASP M_FLOOD pledge SHOULD continue to listen to for additional GRASP M_FLOOD
messages during the connection attempts. messages during the connection attempts.
Once a connection to a registrar is established (e.g. establishment Once a connection to a registrar is established (e.g. establishment
of a TLS session key) there are expectations of more timely of a TLS session key) there are expectations of more timely
responses, see Section 5.2. responses, see Section 5.2.
Once all discovered services are attempted (assuming that none Once all discovered services are attempted (assuming that none
succeeded) the device MUST return to listening for GRASP M_FLOOD. It succeeded) the device MUST return to listening for GRASP M_FLOOD. It
SHOULD periodically retry the manufacturer specific mechanisms. The SHOULD periodically retry any manufacturer-specific mechanisms. The
pledge MAY prioritize selection order as appropriate for the pledge MAY prioritize selection order as appropriate for the
anticipated environment. anticipated environment.
4.1.1. Proxy GRASP announcements 4.1.1. Proxy GRASP announcements
A proxy uses the DULL GRASP M_FLOOD mechanism to announce itself. A proxy uses the DULL GRASP M_FLOOD mechanism to announce itself.
This announcement can be within the same message as the ACP This announcement can be within the same message as the ACP
announcement detailed in [I-D.ietf-anima-autonomic-control-plane]. announcement detailed in [I-D.ietf-anima-autonomic-control-plane].
The M_FLOOD is formatted as follows:
[M_FLOOD, 12340815, h'fe800000000000000000000000000001', 180000,
["AN_Proxy", 4, 1, ""],
[O_IPv6_LOCATOR,
h'fe800000000000000000000000000001', IPPROTO_TCP, 4443]]
Figure 6b: Proxy Discovery The formal CDDL [RFC8610] definition is:
The formal CDDL [I-D.ietf-cbor-cddl] definition is:
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
+[objective, (locator-option / [])]] +[objective, (locator-option / [])]]
objective = ["AN_Proxy", objective-flags, loop-count, objective = ["AN_Proxy", objective-flags, loop-count,
objective-value] objective-value]
ttl = 180000 ; 180,000 ms (3 minutes) ttl = 180000 ; 180,000 ms (3 minutes)
initiator = ACP address to contact Registrar initiator = ACP address to contact Registrar
objective-flags = sync-only ; as in GRASP spec objective-flags = sync-only ; as in GRASP spec
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objective-value = any ; none objective-value = any ; none
locator-option = [ O_IPv6_LOCATOR, ipv6-address, locator-option = [ O_IPv6_LOCATOR, ipv6-address,
transport-proto, port-number ] transport-proto, port-number ]
ipv6-address = the v6 LL of the Proxy ipv6-address = the v6 LL of the Proxy
$transport-proto /= IPPROTO_TCP ; note this can be any value from the $transport-proto /= IPPROTO_TCP ; note this can be any value from the
; IANA protocol registry, as per ; IANA protocol registry, as per
; [GRASP] section 2.9.5.1, note 3. ; [GRASP] section 2.9.5.1, note 3.
port-number = selected by Proxy port-number = selected by Proxy
Figure 6c: AN_Proxy CDDL Figure 10: CDDL definition of Proxy Discovery message
Here is an example M_FLOOD announcing a proxy at fe80::1, on TCP port
4443.
[M_FLOOD, 12340815, h'fe800000000000000000000000000001', 180000,
["AN_Proxy", 4, 1, ""],
[O_IPv6_LOCATOR,
h'fe800000000000000000000000000001', IPPROTO_TCP, 4443]]
Figure 11: Example of Proxy Discovery message
On a small network the Registrar MAY include the GRASP M_FLOOD On a small network the Registrar MAY include the GRASP M_FLOOD
announcements to locally connected networks. announcements to locally connected networks.
The $transport-proto above indicates the method that the pledge- The $transport-proto above indicates the method that the pledge-
proxy-registrar will use. The TCP method described here is proxy-registrar will use. The TCP method described here is
mandatory, and other proxy methods, such as CoAP methods not defined mandatory, and other proxy methods, such as CoAP methods not defined
in this document are optional. Other methods MUST NOT be enabled in this document are optional. Other methods MUST NOT be enabled
unless the Join Registrar ASA indicates support for them in it's own unless the Join Registrar ASA indicates support for them in it's own
announcement. announcement.
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number, including using a stock port 443. ANI proxies MUST support number, including using a stock port 443. ANI proxies MUST support
GRASP discovery of registrars. GRASP discovery of registrars.
The M_FLOOD is formatted as follows: The M_FLOOD is formatted as follows:
[M_FLOOD, 12340815, h'fda379a6f6ee00000200000064000001', 180000, [M_FLOOD, 12340815, h'fda379a6f6ee00000200000064000001', 180000,
["AN_join_registrar", 4, 255, "EST-TLS"], ["AN_join_registrar", 4, 255, "EST-TLS"],
[O_IPv6_LOCATOR, [O_IPv6_LOCATOR,
h'fda379a6f6ee00000200000064000001', IPPROTO_TCP, 8443]] h'fda379a6f6ee00000200000064000001', IPPROTO_TCP, 8443]]
Figure 7a: Registrar Discovery Figure 12: An example of a Registrar announcement message
The formal CDDL definition is: The formal CDDL definition is:
flood-message = [M_FLOOD, session-id, initiator, ttl, flood-message = [M_FLOOD, session-id, initiator, ttl,
+[objective, (locator-option / [])]] +[objective, (locator-option / [])]]
objective = ["AN_join_registrar", objective-flags, loop-count, objective = ["AN_join_registrar", objective-flags, loop-count,
objective-value] objective-value]
initiator = ACP address to contact Registrar initiator = ACP address to contact Registrar
objective-flags = sync-only ; as in GRASP spec objective-flags = sync-only ; as in GRASP spec
sync-only = 4 ; M_FLOOD only requires synchronization sync-only = 4 ; M_FLOOD only requires synchronization
loop-count = 255 ; mandatory maximum loop-count = 255 ; mandatory maximum
objective-value = text ; name of the (list of) of supported objective-value = text ; name of the (list of) of supported
; protocols: "EST-TLS" for RFC7030. ; protocols: "EST-TLS" for RFC7030.
Figure 7: AN_join_registrar CDDL Figure 13: CDDL definition for Registrar announcement message
The M_FLOOD message MUST be sent periodically. The default SHOULD be The M_FLOOD message MUST be sent periodically. The default SHOULD be
60 seconds, the value SHOULD be operator configurable but SHOULD be 60 seconds, the value SHOULD be operator configurable but SHOULD be
not smaller than 60 seconds. The frequency of sending MUST be such not smaller than 60 seconds. The frequency of sending MUST be such
that the aggregate amount of periodic M_FLOODs from all flooding that the aggregate amount of periodic M_FLOODs from all flooding
sources cause only negligible traffic across the ACP. sources cause only negligible traffic across the ACP.
Here are some examples of locators for illustrative purposes. Only Here are some examples of locators for illustrative purposes. Only
the first one ($transport-protocol = 6, TCP) is defined in this the first one ($transport-protocol = 6, TCP) is defined in this
document and is mandatory to implement. document and is mandatory to implement.
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BRSKI is described as extensions to EST [RFC7030]. The goal of these BRSKI is described as extensions to EST [RFC7030]. The goal of these
extensions is to reduce the number of TLS connections and crypto extensions is to reduce the number of TLS connections and crypto
operations required on the pledge. The registrar implements the operations required on the pledge. The registrar implements the
BRSKI REST interface within the same "/.well-known" URI tree as the BRSKI REST interface within the same "/.well-known" URI tree as the
existing EST URIs as described in EST [RFC7030] section 3.2.2. The existing EST URIs as described in EST [RFC7030] section 3.2.2. The
communication channel between the pledge and the registrar is communication channel between the pledge and the registrar is
referred to as "BRSKI-EST" (see Figure 1). referred to as "BRSKI-EST" (see Figure 1).
The communication channel between the registrar and MASA is similarly The communication channel between the registrar and MASA is similarly
described as extensions to EST within the same "/.well-known" tree. described as extensions to EST within the same "/.well-known" tree.
For clarity this channel is referred to as "BRSKI-MASA". (See For clarity this channel is referred to as "BRSKI-MASA". (See
Figure 1). Figure 1).
MASA URI is "https://" iauthority "/.well-known/est". The MASA URI is "https://" authority "/.well-known/est".
BRSKI uses existing CMS message formats for existing EST operations. BRSKI uses existing CMS message formats for existing EST operations.
BRSKI uses JSON [RFC8259] for all new operations defined here, and BRSKI uses JSON [RFC8259] for all new operations defined here, and
voucher formats. voucher formats.
While EST section 3.2 does not insist upon use of HTTP 1.1 persistent While EST section 3.2 does not insist upon use of HTTP 1.1 persistent
connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD use connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD use
persistent connections. The intention of this guidance is to ensure persistent connections. The intention of this guidance is to ensure
the provisional TLS state occurs only once, and that the subsequent the provisional TLS state occurs only once, and that the subsequent
resolution of the provision state is not subject to a MITM attack resolution of the provision state is not subject to a MITM attack
during a critical phase. during a critical phase.
If non-persistent connections are used, then both the pledge and the
registrar MUST remember the certificates seen, and also sent for the
first connection. They MUST check each subsequent connections for
the same certificates, and each end MUST use the same certificates as
well. This places a difficult restriction on rolling certificates on
the Registrar.
Summarized automation extensions for the BRSKI-EST flow are: Summarized automation extensions for the BRSKI-EST flow are:
o The pledge either attempts concurrent connections via each o The pledge either attempts concurrent connections via each
discovered proxy, or it times out quickly and tries connections in discovered proxy, or it times out quickly and tries connections in
series, as explained at the end of Section 5.1. series, as explained at the end of Section 5.1.
o The pledge provisionally accepts the registrar certificate during o The pledge provisionally accepts the registrar certificate during
the TLS handshake as detailed in Section 5.1. the TLS handshake as detailed in Section 5.1.
o The pledge requests and validates a voucher using the new REST o The pledge requests and validates a voucher using the new REST
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o Mandatory bootstrap steps conclude with voucher status telemetry o Mandatory bootstrap steps conclude with voucher status telemetry
(see Section 5.7). (see Section 5.7).
The BRSKI-EST TLS connection can now be used for EST enrollment. The BRSKI-EST TLS connection can now be used for EST enrollment.
The extensions for a registrar (equivalent to EST server) are: The extensions for a registrar (equivalent to EST server) are:
o Client authentication is automated using Initial Device Identity o Client authentication is automated using Initial Device Identity
(IDevID) as per the EST certificate based client authentication. (IDevID) as per the EST certificate based client authentication.
The subject field's DN encoding MUST include the "serialNumber" The subject field's DN encoding MUST include the "serialNumber"
attribute with the device's unique serial number. attribute with the device's unique serial number as explained in
Section 2.3.1
o This extends the informal set of "identifer type" values defined
in [RFC6125] to include a SERIALNUM-ID category of identifier that
can be included in a certificate and therefore that can also be
used for matching purposes. As noted in that document this is not
a formal definition as the underlying types have been previously
defined elsewhere. The SERIALNUM-ID whitelist is collated
according to manufacturer trust anchor since serial numbers are
not globally unique.
o The registrar requests and validates the voucher from the MASA. o The registrar requests and validates the voucher from the MASA.
o The registrar forwards the voucher to the pledge when requested. o The registrar forwards the voucher to the pledge when requested.
o The registrar performs log verifications in addition to local o The registrar performs log verifications in addition to local
authorization checks before accepting optional pledge device authorization checks before accepting optional pledge device
enrollment requests. enrollment requests.
5.1. BRSKI-EST TLS establishment details 5.1. BRSKI-EST TLS establishment details
skipping to change at page 36, line 32 skipping to change at page 39, line 20
registrar is the TLS server. All security associations established registrar is the TLS server. All security associations established
are between the pledge and the registrar regardless of proxy are between the pledge and the registrar regardless of proxy
operations. operations.
Establishment of the BRSKI-EST TLS connection is as specified in EST Establishment of the BRSKI-EST TLS connection is as specified in EST
[RFC7030] section 4.1.1 "Bootstrap Distribution of CA Certificates" [RFC7030] section 4.1.1 "Bootstrap Distribution of CA Certificates"
[RFC7030] wherein the client is authenticated with the IDevID [RFC7030] wherein the client is authenticated with the IDevID
certificate, and the EST server (the registrar) is provisionally certificate, and the EST server (the registrar) is provisionally
authenticated with an unverified server certificate. authenticated with an unverified server certificate.
The signatures in the certificate MUST be validated even if a signing
key can not (yet) be validated. The certificate (or chain) MUST be
retained for later validation.
A self-signed certificate for the Registrar is acceptable as the
voucher will validate it.
[RFC5280] section 4.2.1.2 does not mandate that the
SubjectKeyIdentifier extension be present in non-CA certificates. It
is RECOMMENDED that Registrar certificates (even if self-signed),
always include the SubjectKeyIdentifier to be used as a DomainID, and
that a hash stronger than SHA-1 be used.
The pledge performs input validation of all data received until a The pledge performs input validation of all data received until a
voucher is verified as specified in Section 5.6.1 and the TLS voucher is verified as specified in Section 5.6.1 and the TLS
connection leaves the provisional state. Until these operations are connection leaves the provisional state. Until these operations are
complete the pledge could be communicating with an attacker. complete the pledge could be communicating with an attacker.
The pledge code needs to be written with the assumption that all data
is being transmitted at this point to an unauthenticated peer, and
that received data, while inside a TLS connection, MUST be considered
untrusted. This particularly applies to HTTP headers and CMS
structures that make up the voucher.
A pledge that can connect to multiple registries concurrently SHOULD A pledge that can connect to multiple registries concurrently SHOULD
do so. Some devices may be unable to do so for lack of threading, or do so. Some devices may be unable to do so for lack of threading, or
resource issues. Concurrent connections defeat attempts by a resource issues. Concurrent connections defeat attempts by a
malicious proxy from causing a TCP Slowloris-like attack (see malicious proxy from causing a TCP Slowloris-like attack (see
[slowloris]). [slowloris]).
A pledge that can not maintain as many connections as there are A pledge that can not maintain as many connections as there are
eligible proxies will need to rotate among the various choices, eligible proxies will need to rotate among the various choices,
terminating connections that do not appear to be making progress. If terminating connections that do not appear to be making progress. If
no connection is making progess after 5 seconds then the pledge no connection is making progess after 5 seconds then the pledge
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5.2. Pledge Requests Voucher from the Registrar 5.2. Pledge Requests Voucher from the Registrar
When the pledge bootstraps it makes a request for a voucher from a When the pledge bootstraps it makes a request for a voucher from a
registrar. registrar.
This is done with an HTTPS POST using the operation path value of This is done with an HTTPS POST using the operation path value of
"/.well-known/est/requestvoucher". "/.well-known/est/requestvoucher".
The pledge voucher-request Content-Type is: The pledge voucher-request Content-Type is:
application/voucher-cms+json The request is a "YANG-defined JSON application/voucher-cms+json [RFC8366] defines a "YANG-defined JSON
document that has been signed using a CMS structure" as described document that has been signed using a CMS structure", and the
in Section 3 using the JSON encoding described in [RFC7951]. This voucher-request described in Section 3 is created in the same way.
voucher media type is defined in [RFC8366] and is also used for The media type is the same as defined in [RFC8366]. and is also
the pledge voucher-request. The pledge SHOULD sign the request used for the pledge voucher-request. The pledge MUST sign the
using the Section 2.3 credential. request using the Section 2.3 credential.
Registrar implementations SHOULD anticipate future media types but of Registrar implementations SHOULD anticipate future media types but of
course will simply fail the request if those types are not yet known. course will simply fail the request if those types are not yet known.
The pledge SHOULD include an [RFC7231] section 5.3.2 "Accept" header The pledge SHOULD include an [RFC7231] section 5.3.2 "Accept" header
field indicating the acceptable media type for the voucher response. field indicating the acceptable media type for the voucher response.
The "application/voucher-cms+json" media type is defined in [RFC8366] The "application/voucher-cms+json" media type is defined in [RFC8366]
but constrained voucher formats are expected in the future. but constrained voucher formats are expected in the future.
Registrar's and MASA's are expected to be flexible in what they Registrars and MASA are expected to be flexible in what they accept.
accept.
The pledge populates the voucher-request fields as follows: The pledge populates the voucher-request fields as follows:
created-on: Pledges that have a realtime clock are RECOMMENDED to created-on: Pledges that have a realtime clock are RECOMMENDED to
populate this field with the current date and time in yang:date- populate this field with the current date and time in yang:date-
and-time format. This provides additional information to the and-time format. This provides additional information to the
MASA. Pledges that have no real-time clocks MAY omit this field. MASA. Pledges that have no real-time clocks MAY omit this field.
nonce: The pledge voucher-request MUST contain a cryptographically nonce: The pledge voucher-request MUST contain a cryptographically
strong random or pseudo-random number nonce. (see [RFC4086]) Doing strong random or pseudo-random number nonce. (see [RFC4086]) Doing
so ensures Section 2.6.1 functionality. The nonce MUST NOT be so ensures Section 2.6.1 functionality. The nonce MUST NOT be
reused for multiple bootstrapping attempts. (The registrar reused for multiple bootstrapping attempts. (The registrar
voucher-request MAY omit the nonce as per Section 3.1) voucher-request MAY omit the nonce as per Section 3.1)
proximity-registrar-cert: In a pledge voucher-request this is the proximity-registrar-cert: In a pledge voucher-request this is the
first certificate in the TLS server 'certificate_list' sequence first certificate in the TLS server 'certificate_list' sequence
(see [RFC5246]) presented by the registrar to the pledge. This (see [RFC5246]) presented by the registrar to the pledge. That
MUST be populated in a pledge voucher-request if the "proximity" is, it is the end-entity certificate. This MUST be populated in a
assertion is populated. pledge voucher-request if the "proximity" assertion is populated.
All other fields MAY be omitted in the pledge voucher-request. All other fields MAY be omitted in the pledge voucher-request.
An example JSON payload of a pledge voucher-request is in Section 3.3 An example JSON payload of a pledge voucher-request is in Section 3.3
Example 1. Example 1.
The registrar validates the client identity as described in EST The registrar validates the client identity as described in EST
[RFC7030] section 3.3.2. The registrar confirms that the 'proximity' [RFC7030] section 3.3.2.
assertion and associated 'proximity-registrar-cert' are correct.
The registrar confirms that the assertion is 'proximity' and that
pinned 'proximity-registrar-cert' is the Registrar's certificate. If
this validation fails, then there a On-Path Attacker (MITM), and the
connection MUST be closed after the returning an HTTP 401 error code.
5.3. Registrar Authorization of Pledge 5.3. Registrar Authorization of Pledge
In a fully automated network all devices must be securely identified In a fully automated network all devices must be securely identified
and authorized to join the domain. and authorized to join the domain.
A Registrar accepts or declines a request to join the domain, based A Registrar accepts or declines a request to join the domain, based
on the authenticated identity presented. Automated acceptance on the authenticated identity presented. For different networks,
criteria include: examples of Automated acceptance may include:
o allow any device of a specific type (as determined by the X.509 o allow any device of a specific type (as determined by the X.509
IDevID), IDevID),
o allow any device from a specific vendor (as determined by the o allow any device from a specific vendor (as determined by the
X.509 IDevID), X.509 IDevID),
o allow a specific device from a vendor (as determined by the X.509 o allow a specific device from a vendor (as determined by the X.509
IDevID) against a domain white list. (The mechanism for checking IDevID) against a domain white list. (The mechanism for checking
a shared white list potentially used by multiple Registrars is out a shared white list potentially used by multiple Registrars is out
of scope). of scope).
If these validations fail the registrar SHOULD respond with the HTTP If validation fails the registrar SHOULD respond with the HTTP 404
404 error code. If the voucher-request is in an unknown format, then error code. If the voucher-request is in an unknown format, then an
an HTTP 406 error code is more appropriate. A situation that could HTTP 406 error code is more appropriate. A situation that could be
be resolved with administrative action (such as adding a vendor to a resolved with administrative action (such as adding a vendor to a
whitelist) MAY be responded with an 403 HTTP error code. whitelist) MAY be responded with an 403 HTTP error code.
If authorization is successful the registrar obtains a voucher from If authorization is successful the registrar obtains a voucher from
the MASA service (see Section 5.5) and returns that MASA signed the MASA service (see Section 5.5) and returns that MASA signed
voucher to the pledge as described in Section 5.6. voucher to the pledge as described in Section 5.6.
5.4. BRSKI-MASA TLS establishment details 5.4. BRSKI-MASA TLS establishment details
The BRSKI-MASA TLS connection is a 'normal' TLS connection The BRSKI-MASA TLS connection is a 'normal' TLS connection
appropriate for HTTPS REST interfaces. The registrar initiates the appropriate for HTTPS REST interfaces. The registrar initiates the
connection and uses the MASA URL obtained as described in connection and uses the MASA URL obtained as described in
Section 2.8. The mechanisms in [RFC6125] SHOULD be used Section 2.8. The mechanisms in [RFC6125] SHOULD be used
authentication of the MASA. Some vendors will establish explicit (or authentication of the MASA. Some vendors will establish explicit (or
private) trust anchors for validating their MASA; this will typically private) trust anchors for validating their MASA; this will typically
done as part of a sales channel integration. Registars SHOULD permit done as part of a sales channel integration.
trust anchors to be pre-configured on a per-vendor basis.
The primary method of registrar "authentication" by the MASA is As described in [RFC7030], the MASA and the registrars SHOULD be
detailed in Section 5.5. As detailed in Section 11 the MASA might prepared to support TLS client certificate authentication and/or HTTP
find it necessary to request additional registrar authentication. Basic or Digest authentication. This connection MAY also have no
client authentication at all.
The MASA and the registrars SHOULD be prepared to support TLS client Registars SHOULD permit trust anchors to be pre-configured on a per-
certificate authentication and/or HTTP Basic or Digest authentication vendor(MASA) basis. Registrars SHOULD include the ability to
as described in [RFC7030] for EST clients. This connection MAY also configure a TLS ClientCertificate on a per-MASA basis, or to use no
have no client authentication at all (Section 7.4) client certificate. Registrars SHOULD also permit an HTTP Basic and
Digest authentication to be configured.
The authentication of the BRSKI-MASA connection does not affect the The authentication of the BRSKI-MASA connection does not change the
voucher-request process, as voucher-requests are already signed by voucher-request process, as voucher-requests are already signed by
the registrar. Instead, this authentication provides access control the registrar. Instead, this authentication provides access control
to the audit log. to the audit log.
Implementors are advised that contacting the MASA is to establish a Implementors are advised that contacting the MASA is to establish a
secured REST connection with a web service and that there are a secured REST connection with a web service and that there are a
number of authentication models being explored within the industry. number of authentication models being explored within the industry.
Registrars are RECOMMENDED to fail gracefully and generate useful Registrars are RECOMMENDED to fail gracefully and generate useful
administrative notifications or logs in the advent of unexpected HTTP administrative notifications or logs in the advent of unexpected HTTP
401 (Unauthorized) responses from the MASA. 401 (Unauthorized) responses from the MASA.
5.4.1. MASA authentication of customer Registrar
Providing per-customer options requires that the customer's registrar
be uniquely identified. This can be done by any stateless method
that HTTPS supports: such as with HTTP Basic or Digest authentication
(that is using a password), but the use of TLS Client Certificate
authentication is RECOMMENDED.
Stateful methods involving API tokens, or HTTP Cookies are not
recommended.
It is expected that the setup and configuration of per-customer
Client Certificates is done as part of a sales ordering process.
The use of public PKI (i.e. WebPKI) End-Entity Certificates to
identify the Registrar is reasonable, and if done universally this
would permit a MASA to identify a customers' Registrar simply by a
FQDN.
The use of DANE records in DNSSEC signed zones would also permit use
of a FQDN to identify customer Registrars.
A third (and simplest, but least flexible) mechanism would be for the
MASA to simply store the Registrar's certificate pinned in a
database.
A MASA without any supply chain integration can simply accept
Registrars without any authentication, or can accept them on a blind
Trust-on-First-Use basis as described in Section 7.4.2.
This document does not make a specific recommendation as there is
likely different trade offs in different environments and product
values. Even within the ANIMA ACP applicability, there is a
significant difference between supply chain logistics for $100 CPE
devices and $100,000 core routers.
5.5. Registrar Requests Voucher from MASA 5.5. Registrar Requests Voucher from MASA
When a registrar receives a pledge voucher-request it in turn submits When a registrar receives a pledge voucher-request it in turn submits
a registrar voucher-request to the MASA service via an HTTPS RESTful a registrar voucher-request to the MASA service via an HTTPS
interface ([RFC7231]). interface ([RFC7231]).
This is done with an HTTP POST using the operation path value of This is done with an HTTP POST using the operation path value of
"/.well-known/est/requestvoucher". "/.well-known/est/requestvoucher".
The voucher media type "application/voucher-cms+json" is defined in The voucher media type "application/voucher-cms+json" is defined in
[RFC8366] and is also used for the registrar voucher-request. It is [RFC8366] and is also used for the registrar voucher-request. It is
a JSON document that has been signed using a CMS structure. The a JSON document that has been signed using a CMS structure. The
registrar MUST sign the registrar voucher-request. The entire registrar MUST sign the registrar voucher-request. The entire
registrar certificate chain, up to and including the Domain CA, MUST registrar certificate chain, up to and including the Domain CA, MUST
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This list SHOULD be the entire list presented to the Registrar in the This list SHOULD be the entire list presented to the Registrar in the
Pledge's original request (see Section 5.2) but MAY be a subset. Pledge's original request (see Section 5.2) but MAY be a subset.
MASA's are expected to be flexible in what they accept. MASA's are expected to be flexible in what they accept.
The registrar populates the voucher-request fields as follows: The registrar populates the voucher-request fields as follows:
created-on: The Registrars SHOULD populate this field with the created-on: The Registrars SHOULD populate this field with the
current date and time when the Registrar formed this voucher current date and time when the Registrar formed this voucher
request. This field provides additional information to the MASA. request. This field provides additional information to the MASA.
nonce: This is the value from the pledge voucher-request. The nonce: This value, if present, is copied from the pledge voucher-
registrar voucher-request MAY omit the nonce as per Section 3.1) request. The registrar voucher-request MAY omit the nonce as per
Section 3.1.
serial-number: The serial number of the pledge the registrar would serial-number: The serial number of the pledge the registrar would
like a voucher for. The registrar determines this value by like a voucher for. The registrar determines this value by
parsing the authenticated pledge IDevID certificate. See parsing the authenticated pledge IDevID certificate. See
Section 2.3. The registrar MUST verify that the serial number Section 2.3. The registrar MUST verify that the serial number
field it parsed matches the serial number field the pledge field it parsed matches the serial number field the pledge
provided in its voucher-request. This provides a sanity check provided in its voucher-request. This provides a sanity check
useful for detecting error conditions and logging. The registrar useful for detecting error conditions and logging. The registrar
MUST NOT simply copy the serial number field from a pledge voucher MUST NOT simply copy the serial number field from a pledge voucher
request as that field is claimed but not certified. request as that field is claimed but not certified.
idevid-issuer: The idevid-issuer value from the pledge certificate idevid-issuer: The Issuer value from the value from the pledge
is included to ensure a unique identity. IDevID certificate is included to ensure a uniqueness of the
serial-number. In the case of nonceless (offline) voucher-
request, then an appropriate value needs to be configured from the
same out-of-band source as the serial-number.
prior-signed-voucher-request: The signed pledge voucher-request prior-signed-voucher-request: The signed pledge voucher-request
SHOULD be included in the registrar voucher-request. (NOTE: what SHOULD be included in the registrar voucher-request. The entire
is included is the complete pledge voucher-request, inclusive of CMS signed structure is to be included, base64 encoded for
the 'assertion', 'proximity-registrar-cert', etc wrapped by the transport in the JSON structure.
pledge's original signature). If a signed voucher-request was not
received from the pledge then this leaf is omitted from the
registrar voucher request.
A nonceless registrar voucher-request MAY be submitted to the MASA. A nonceless registrar voucher-request MAY be submitted to the MASA.
Doing so allows the registrar to request a voucher when the pledge is Doing so allows the registrar to request a voucher when the pledge is
offline, or when the registrar anticipates not being able to connect offline, or when the registrar anticipates not being able to connect
to the MASA while the pledge is being deployed. Some use cases to the MASA while the pledge is being deployed. Some use cases
require the registrar to learn the appropriate IDevID SerialNumber require the registrar to learn the appropriate IDevID SerialNumber
field and appropriate 'Accept header field' values from the physical field and appropriate 'Accept header field' values from the physical
device labeling or from the sales channel (out-of-scope for this device labeling or from the sales channel (out-of-scope for this
document). document).
skipping to change at page 41, line 34 skipping to change at page 45, line 34
a registrar. This is confirmed by verifying that the id-kp-cmcRA a registrar. This is confirmed by verifying that the id-kp-cmcRA
extended key usage extension field (as detailed in EST RFC7030 extended key usage extension field (as detailed in EST RFC7030
section 3.6.1) exists in the certificate of the entity that signed section 3.6.1) exists in the certificate of the entity that signed
the registrar voucher-request. This verification is only a the registrar voucher-request. This verification is only a
consistency check that the unauthenticated domain CA intended the consistency check that the unauthenticated domain CA intended the
voucher-request signer to be a registrar. Performing this check voucher-request signer to be a registrar. Performing this check
provides value to the domain PKI by assuring the domain administrator provides value to the domain PKI by assuring the domain administrator
that the MASA service will only respect claims from authorized that the MASA service will only respect claims from authorized
Registration Authorities of the domain. Registration Authorities of the domain.
The MASA verifies that the domain CA certificate is included in the
CMS structure as detailed in Section 5.5.
5.5.3. MASA authentication of registrar (certificate) 5.5.3. MASA authentication of registrar (certificate)
If a nonceless voucher-request is submitted the MASA MUST If a nonceless voucher-request is submitted the MASA MUST
authenticate the registrar as described in either EST [RFC7030] authenticate the registrar as described in either EST [RFC7030]
section 3.2, section 3.3, or by validating the registrar's section 3.2.3, section 3.3.2, or by validating the registrar's
certificate used to sign the registrar voucher-request. Any of these certificate used to sign the registrar voucher-request. Any of these
methods reduce the risk of DDoS attacks and provide an authenticated methods reduce the risk of DDoS attacks and provide an authenticated
identity as an input to sales channel integration and authorizations identity as an input to sales channel integration and authorizations
(details are out-of-scope of this document). (details are out-of-scope of this document).
In the nonced case, validation of the registrar MAY be omitted if the In the nonced case, validation of the Registrar's identity (via TLS
Client Certificate or HTTP authentication) MAY be omitted if the
device policy is to accept audit-only vouchers. device policy is to accept audit-only vouchers.
5.5.4. MASA revocation checking of registrar (certificate) 5.5.4. MASA revocation checking of registrar (certificate)
As noted in Section 5.5.3 the MASA performs registrar authentication As noted in Section 5.5.3 the MASA performs registrar authentication
in a subset of situations (e.g. nonceless voucher requests). Normal in a subset of situations (e.g. nonceless voucher requests). Normal
PKIX revocation checking is assumed during either EST client PKIX revocation checking is assumed during either EST client
authentication or voucher-request signature validation. Similarly, authentication or voucher-request signature validation. Similarly,
as noted in Section 5.5.2, the MASA performs normal PKIX revocation as noted in Section 5.5.2, the MASA performs normal PKIX revocation
checking during signature consistency checks (a signature by a checking during signature consistency checks (a signature by a
registrar certificate that has been revoked is an inconsistency). registrar certificate that has been revoked is an inconsistency).
5.5.5. MASA verification of pledge prior-signed-voucher-request 5.5.5. MASA verification of pledge prior-signed-voucher-request
The MASA MAY verify that the registrar voucher-request includes the The MASA MAY verify that the registrar voucher-request includes the
'prior-signed-voucher-request' field. If so the prior-signed- 'prior-signed-voucher-request' field. If so the prior-signed-
voucher-request MUST include a 'proximity-registrar-cert' that is voucher-request MUST include a 'proximity-registrar-cert' that is
consistent with the certificate used to sign the registrar voucher- consistent with the certificate used to sign the registrar voucher-
request. Additionally the voucher-request serial-number leaf MUST request. Additionally the voucher-request serial-number leaf MUST
match the pledge serial-number that the MASA extracts from the match the pledge serial-number that the MASA extracts from the
signing certificate of the prior-signed-voucher-request. The MASA is signing certificate of the prior-signed-voucher-request.
aware of which pledges support signing of their voucher requests and
can use this information to confirm proximity of the pledge with the
registrar, thus ensuring that the BRSKI-EST TLS connection has no
man-in-the-middle.
If these checks succeed the MASA updates the voucher and audit log If these checks succeed the MASA updates the voucher and audit log
assertion leafs with the "proximity" assertion. assertion leafs with the "proximity" assertion.
5.5.6. MASA pinning of registrar 5.5.6. MASA pinning of registrar
The registrar's certificate chain is extracted from the signature The registrar's certificate chain is extracted from the signature
method. The chain includes the domain CA certificate as specified in method. The chain includes the domain CA certificate as specified in
Section 5.5. This certificate is used to populate the "pinned- Section 5.5.2. This certificate is used to populate the "pinned-
domain-cert" of the voucher being issued. The domainID (e.g., hash domain-cert" of the voucher being issued. The domainID (e.g., hash
of the root public key) is determined from the pinned-domain-cert and of the root public key) is determined from the pinned-domain-cert and
is used to update the audit log. is used to update the audit log.
5.5.7. MASA nonce handling 5.5.7. MASA nonce handling
The MASA does not verify the nonce itself. If the registrar voucher- The MASA does not verify the nonce itself. If the registrar voucher-
request contains a nonce, and the prior-signed-voucher-request request contains a nonce, and the prior-signed-voucher-request
exists, then the MASA MUST verify that the nonce is consistent. exists, then the MASA MUST verify that the nonce is consistent.
(Recall from above that the voucher-request might not contain a (Recall from above that the voucher-request might not contain a
nonce, see Section 5.5 and Section 5.5.3). nonce, see Section 5.5 and Section 5.5.3).
The MASA MUST use the nonce from the registrar voucher-request for The MASA populates the audit-log with the nonce that was verified.
the resulting voucher and audit log. The prior-signed-voucher- If a nonceless voucher is issued, then the audit log is to be
request nonce is ignored during this operation. populated with the JSON value "null".
5.6. MASA and Registrar Voucher Response 5.6. MASA and Registrar Voucher Response
The MASA voucher response to the registrar is forwarded without The MASA voucher response to the registrar is forwarded without
changes to the pledge; therefore this section applies to both the changes to the pledge; therefore this section applies to both the
MASA and the registrar. The HTTP signaling described applies to both MASA and the registrar. The HTTP signaling described applies to both
the MASA and registrar responses. A registrar either caches prior the MASA and registrar responses.
MASA responses or dynamically requests a new voucher based on local
policy (it does not generate or sign a voucher). Registrar When a voucher request arrives at the registrar, if it has a cached
evaluation of the voucher itself is purely for transparency and audit response from the MASA for the corresponding registrar voucher-
purposes to further inform log verification (see Section 5.8.2) and request, that cached response can be used according to local policy;
therefore a registrar could accept future voucher formats that are otherwise the registrar constructs a new registrar voucher-request
opaque to the registrar. and sends it to the MASA.
Registrar evaluation of the voucher itself is purely for transparency
and audit purposes to further inform log verification (see
Section 5.8.2) and therefore a registrar could accept future voucher
formats that are opaque to the registrar.
If the voucher-request is successful, the server (MASA responding to If the voucher-request is successful, the server (MASA responding to
registrar or registrar responding to pledge) response MUST contain an registrar or registrar responding to pledge) response MUST contain an
HTTP 200 response code. The server MUST answer with a suitable 4xx HTTP 200 response code. The server MUST answer with a suitable 4xx
or 5xx HTTP [RFC7230] error code when a problem occurs. In this or 5xx HTTP [RFC7230] error code when a problem occurs. In this
case, the response data from the MASA MUST be a plaintext human- case, the response data from the MASA MUST be a plaintext human-
readable (ASCII, English) error message containing explanatory readable (ASCII, English) error message containing explanatory
information describing why the request was rejected. information describing why the request was rejected.
The registrar MAY respond with an HTTP 202 ("the request has been The registrar MAY respond with an HTTP 202 ("the request has been
skipping to change at page 43, line 45 skipping to change at page 47, line 40
pledge would keep track of the appropriate Retry-After header field pledge would keep track of the appropriate Retry-After header field
values for any number of outstanding registrars but this would values for any number of outstanding registrars but this would
involve a state table on the pledge. Instead the pledge MAY ignore involve a state table on the pledge. Instead the pledge MAY ignore
the exact Retry-After value in favor of a single hard coded value (a the exact Retry-After value in favor of a single hard coded value (a
registrar that is unable to complete the transaction after the first registrar that is unable to complete the transaction after the first
60 seconds has another chance a minute later). A pledge SHOULD only 60 seconds has another chance a minute later). A pledge SHOULD only
maintain a 202 retry-state for up to 4 days, which is longer than a maintain a 202 retry-state for up to 4 days, which is longer than a
long weekend, after which time the enrollment attempt fails and the long weekend, after which time the enrollment attempt fails and the
pledge returns to discovery state. pledge returns to discovery state.
A pledge that retries a request after receiving a 202 message MUST
resend the same voucher-request. It MUST NOT sign a new voucher-
request each time, and in particular, it MUST NOT change the nonce
value.
In order to avoid infinite redirect loops, which a malicious In order to avoid infinite redirect loops, which a malicious
registrar might do in order to keep the pledge from discovering the registrar might do in order to keep the pledge from discovering the
correct registrar, the pledge MUST NOT follow more than one correct registrar, the pledge MUST NOT follow more than one
redirection (3xx code) to another web origins. EST supports redirection (3xx code) to another web origins. EST supports
redirection but requires user input; this change allows the pledge to redirection but requires user input; this change allows the pledge to
follow a single redirection without a user interaction. follow a single redirection without a user interaction.
A 403 (Forbidden) response is appropriate if the voucher-request is A 403 (Forbidden) response is appropriate if the voucher-request is
not signed correctly, stale, or if the pledge has another outstanding not signed correctly, stale, or if the pledge has another outstanding
voucher that cannot be overridden. voucher that cannot be overridden.
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A 406 (Not Acceptable) response is appropriate if a voucher of the A 406 (Not Acceptable) response is appropriate if a voucher of the
desired type or using the desired algorithms (as indicated by the desired type or using the desired algorithms (as indicated by the
Accept: header fields, and algorithms used in the signature) cannot Accept: header fields, and algorithms used in the signature) cannot
be issued such as because the MASA knows the pledge cannot process be issued such as because the MASA knows the pledge cannot process
that type. The registrar SHOULD use this response if it determines that type. The registrar SHOULD use this response if it determines
the pledge is unacceptable due to inventory control, MASA audit logs, the pledge is unacceptable due to inventory control, MASA audit logs,
or any other reason. or any other reason.
A 415 (Unsupported Media Type) response is appropriate for a request A 415 (Unsupported Media Type) response is appropriate for a request
that has a voucher-request or accept encoding that is not understood. that has a voucher-request or Accept: value that is not understood.
The voucher response format is as indicated in the submitted Accept The voucher response format is as indicated in the submitted Accept
header fields or based on the MASA's prior understanding of proper header fields or based on the MASA's prior understanding of proper
format for this Pledge. Only the [RFC8366] "application/voucher- format for this Pledge. Only the [RFC8366] "application/voucher-
cms+json" media type is defined at this time. The syntactic details cms+json" media type is defined at this time. The syntactic details
of vouchers are described in detail in [RFC8366]. Figure 8 shows a of vouchers are described in detail in [RFC8366]. Figure 14 shows a
sample of the contents of a voucher. sample of the contents of a voucher.
{ {
"ietf-voucher:voucher": { "ietf-voucher:voucher": {
"nonce": "62a2e7693d82fcda2624de58fb6722e5", "nonce": "62a2e7693d82fcda2624de58fb6722e5",
"assertion": "logging", "assertion": "logging",
"pinned-domain-cert": "base64encodedvalue==", "pinned-domain-cert": "base64encodedvalue==",
"serial-number": "JADA123456789" "serial-number": "JADA123456789"
} }
} }
Figure 8: An example voucher Figure 14: An example voucher
Figure 1: An example voucher
The MASA populates the voucher fields as follows: The MASA populates the voucher fields as follows:
nonce: The nonce from the pledge if available. See Section 5.5.7. nonce: The nonce from the pledge if available. See Section 5.5.7.
assertion: The method used to verify assertion. See Section 5.5.5. assertion: The method used to verify the relationship between pledge
and registrar. See Section 5.5.5.
pinned-domain-cert: The domain CA cert. See Section 5.5.6. This pinned-domain-cert: The domain CA cert. See Section 5.5.6. This
figure is illustrative, for an example, see Appendix D.2 figure is illustrative, for an example, see Appendix D.2
serial-number: The serial-number as provided in the voucher-request. serial-number: The serial-number as provided in the voucher-request.
Also see Section 5.5.5. Also see Section 5.5.5.
domain-cert-revocation-checks: Set as appropriate for the pledge's domain-cert-revocation-checks: Set as appropriate for the pledge's
capabilities and as documented in [RFC8366]. The MASA MAY set capabilities and as documented in [RFC8366]. The MASA MAY set
this field to 'false' since setting it to 'true' would require this field to 'false' since setting it to 'true' would require
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The pledge MUST verify the serial-number field of the signed voucher The pledge MUST verify the serial-number field of the signed voucher
matches the pledge's own serial-number. matches the pledge's own serial-number.
The pledge MUST verify that the voucher nonce field is accurate and The pledge MUST verify that the voucher nonce field is accurate and
matches the nonce the pledge submitted to this registrar, or that the matches the nonce the pledge submitted to this registrar, or that the
voucher is nonceless (see Section 7.2). voucher is nonceless (see Section 7.2).
The pledge MUST be prepared to parse and fail gracefully from a The pledge MUST be prepared to parse and fail gracefully from a
voucher response that does not contain a 'pinned-domain-cert' field. voucher response that does not contain a 'pinned-domain-cert' field.
Such a thing indicates a failure to enroll in this domain, and the
pledge MUST attempt joining with other available Join Proxy.
The pledge MUST be prepared to ignore additional fields that it does The pledge MUST be prepared to ignore additional fields that it does
not recognize. not recognize.
5.6.2. Pledge authentication of provisional TLS connection 5.6.2. Pledge authentication of provisional TLS connection
The 'pinned-domain-cert' element of the voucher contains the domain The 'pinned-domain-cert' element of the voucher contains the domain
CA's public key. The pledge MUST use the 'pinned-domain-cert' trust CA's public key. The pledge MUST use the 'pinned-domain-cert' trust
anchor to immediately complete authentication of the provisional TLS anchor to immediately complete authentication of the provisional TLS
connection. connection.
If a registrar's credentials cannot be verified using the pinned- If a registrar's credentials cannot be verified using the pinned-
domain-cert trust anchor from the voucher then the TLS connection is domain-cert trust anchor from the voucher then the TLS connection is
immediately discarded and the pledge abandons attempts to bootstrap immediately discarded and the pledge abandons attempts to bootstrap
with this discovered registrar. The pledge SHOULD send voucher with this discovered registrar. The pledge SHOULD send voucher
status telemetry (described below) before closing the TLS connection. status telemetry (described below) before closing the TLS connection.
The pledge MUST attempt to enroll using any other proxies it has The pledge MUST attempt to enroll using any other proxies it has
found. It SHOULD return to the same proxy again after attempting found. It SHOULD return to the same proxy again after unsuccessful
with other proxies. Attempts should be attempted in the exponential attempts with other proxies. Attempts should be made repeated at
backoff described earlier. Attempts SHOULD be repeated as failure intervals according to the backoff timer described earlier. Attempts
may be the result of a temporary inconsistently (an inconsistently SHOULD be repeated as failure may be the result of a temporary
rolled registrar key, or some other mis-configuration). The inconsistently (an inconsistently rolled registrar key, or some other
inconsistently could also be the result an active MITM attack on the mis-configuration). The inconsistently could also be the result an
EST connection. active MITM attack on the EST connection.
The registrar MUST use a certificate that chains to the pinned- The registrar MUST use a certificate that chains to the pinned-
domain-cert as its TLS server certificate. domain-cert as its TLS server certificate.
The pledge's PKIX path validation of a registrar certificate's The pledge's PKIX path validation of a registrar certificate's
validity period information is as described in Section 2.6.1. Once validity period information is as described in Section 2.6.1. Once
the PKIX path validation is successful the TLS connection is no the PKIX path validation is successful the TLS connection is no
longer provisional. longer provisional.
The pinned-domain-cert MAY be installed as an trust anchor for future The pinned-domain-cert MAY be installed as an trust anchor for future
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The domain is expected to provide indications to the system The domain is expected to provide indications to the system
administrators concerning device lifecycle status. To facilitate administrators concerning device lifecycle status. To facilitate
this it needs telemetry information concerning the device's status. this it needs telemetry information concerning the device's status.
To indicate pledge status regarding the voucher, the pledge MUST post To indicate pledge status regarding the voucher, the pledge MUST post
a status message to the Registrar. a status message to the Registrar.
The posted data media type: application/json The posted data media type: application/json
The client HTTP POSTs the following to the server at the EST well The client HTTP POSTs the following to the server at the URI ".well-
known URI "/voucher_status". known/est/voucher_status".
The format and semantics described below are for version 1. A The format and semantics described below are for version 1. A
version field is included to permit significant changes to this version field is included to permit significant changes to this
feedback in the future. A Registrar that receives a status message feedback in the future. A Registrar that receives a status message
with a version larger than it knows about SHOULD log the contents and with a version larger than it knows about SHOULD log the contents and
alert a human. alert a human.
The Status field indicates if the voucher was acceptable. Boolean The Status field indicates if the voucher was acceptable. Boolean
values are acceptable. values are acceptable.
skipping to change at page 47, line 45 skipping to change at page 51, line 47
The reason-context attribute is an arbitrary JSON object (literal The reason-context attribute is an arbitrary JSON object (literal
value or hash of values) which provides additional information value or hash of values) which provides additional information
specific to this pledge. The contents of this field are not subject specific to this pledge. The contents of this field are not subject
to standardization. to standardization.
The version, and status fields MUST be present. The Reason field The version, and status fields MUST be present. The Reason field
SHOULD be present whenever the status field is negative. The Reason- SHOULD be present whenever the status field is negative. The Reason-
Context field is optional. Context field is optional.
The keys to this JSON hash are case-insensitive. Figure 2 shows an The keys to this JSON hash are case-insensitive. Figure 15 shows an
example JSON. example JSON.
{ {
"version":"1", "version":"1",
"status":false, "status":false,
"reason":"Informative human readable message", "reason":"Informative human readable message",
"reason-context": { "additional" : "JSON" } "reason-context": { "additional" : "JSON" }
} }
Figure 2: Example Status Telemetry Figure 15: Example Status Telemetry
The server SHOULD respond with an HTTP 200 but MAY simply fail with The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. The client ignores any response. Within the an HTTP 404 error. The client ignores any response. Within the
server logs the server SHOULD capture this telemetry information. server logs the server SHOULD capture this telemetry information.
Additional standard JSON fields in this POST MAY be added, see Additional standard JSON fields in this POST MAY be added, see
Section 8.3. A server that sees unknown fields should log them, but Section 8.4. A server that sees unknown fields should log them, but
otherwise ignore them. otherwise ignore them.
5.8. Registrar audit log request 5.8. Registrar audit log request
After receiving the pledge status telemetry Section 5.7, the After receiving the pledge status telemetry Section 5.7, the
registrar SHOULD request the MASA audit log from the MASA service. registrar SHOULD request the MASA audit log from the MASA service.
This is done with an HTTP POST using the operation path value of This is done with an HTTP POST using the operation path value of
"/.well-known/est/requestauditlog". "/.well-known/est/requestauditlog".
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A registrar MAY request logs at future times. If the registrar A registrar MAY request logs at future times. If the registrar
generates a new request then the MASA is forced to perform the generates a new request then the MASA is forced to perform the
additional cryptographic operations to verify the new request. additional cryptographic operations to verify the new request.
A MASA that receives a request for a device that does not exist, or A MASA that receives a request for a device that does not exist, or
for which the requesting owner was never an owner returns an HTTP 404 for which the requesting owner was never an owner returns an HTTP 404
("Not found") code. ("Not found") code.
Rather than returning the audit log as a response to the POST (with a Rather than returning the audit log as a response to the POST (with a
return code 200), the MASA MAY instead return a 201 ("Created") return code 200), the MASA MAY instead return a 201 ("Created")
RESTful response ([RFC7231] sections 6.3.2 and 7.1) containing a URL response ([RFC7231] sections 6.3.2 and 7.1) containing a URL to the
to the prepared (and easily cachable) audit response. prepared (and idempotent, therefore cachable) audit response.
In order to avoid enumeration of device audit logs, MASA that return In order to avoid enumeration of device audit logs, MASA that return
URLs SHOULD take care to make the returned URL unguessable. For URLs SHOULD take care to make the returned URL unguessable.
instance, rather than returning URLs containing a database number [W3C.WD-capability-urls-20140218] provides very good additional
such as https://example.com/auditlog/1234 or the EUI of the device guidance. For instance, rather than returning URLs containing a
such https://example.com/auditlog/10-00-00-11-22-33, the MASA SHOULD database number such as https://example.com/auditlog/1234 or the EUI
return a randomly generated value (a "slug" in web parlance). The of the device such https://example.com/auditlog/10-00-00-11-22-33,
value is used to find the relevant database entry. the MASA SHOULD return a randomly generated value (a "slug" in web
parlance). The value is used to find the relevant database entry.
A MASA that returns a code 200 MAY also include a Location: header A MASA that returns a code 200 MAY also include a Location: header
for future reference by the registrar. for future reference by the registrar.
5.8.1. MASA audit log response 5.8.1. MASA audit log response
A log data file is returned consisting of all log entries associated A log data file is returned consisting of all log entries associated
with the device selected by the IDevID presented in the request. The with the device selected by the IDevID presented in the request. The
audit log may be abridged by removal of old or repeated values as audit log may be abridged by removal of old or repeated values as
explained below. The returned data is in JSON format ([RFC7951]), explained below. The returned data is in JSON format ([RFC7159]),
and the Content-Type SHOULD be "application/json". For example: and the Content-Type SHOULD be "application/json". For example:
{ {
"version":"1", "version":"1",
"events":[ "events":[
{ {
"date":"<date/time of the entry>", "date":"<date/time of the entry>",
"domainID":"<domainID extracted from voucher-request>", "domainID":"<domainID extracted from voucher-request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>", "nonce":"<any nonce if supplied (or NULL)>",
"assertion":"<the value from the voucher assertion leaf>", "assertion":"<the value from the voucher assertion leaf>",
"truncated":"<the number of domainID entries truncated>" "truncated":"<the number of domainID entries truncated>"
}, },
{ {
"date":"<date/time of the entry>", "date":"<date/time of the entry>",
"domainID":"<anotherDomainID extracted from voucher-request>", "domainID":"<anotherDomainID extracted from voucher-request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>", "nonce":"<any nonce if supplied (or NULL)>",
"assertion":"<the value from the voucher assertion leaf>" "assertion":"<the value from the voucher assertion leaf>"
}
],
"truncation": {
"nonced duplicates": "<total number of entries truncated>",
"nonceless duplicates": "<total number of entries truncated>",
"arbitrary": "<number of domainID entries removed entirely>"
} }
} ],
"truncation": {
"nonced duplicates": "<total number of entries truncated>",
"nonceless duplicates": "<total number of entries truncated>",
"arbitrary": "<number of domainID entries removed entirely>"
}
}
Figure 3: Example of audit-log response Figure 16: Example of audit-log response
Distribution of a large log is less than ideal. This structure can Distribution of a large log is less than ideal. This structure can
be optimized as follows: Nonced or Nonceless entries for the same be optimized as follows: Nonced or Nonceless entries for the same
domainID MAY be abridged from the log leaving only the single most domainID MAY be abridged from the log leaving only the single most
recent nonced or nonceless entry for that domainID. In the case of recent nonced or nonceless entry for that domainID. In the case of
truncation the 'event' truncation value SHOULD contain a count of the truncation the 'event' truncation value SHOULD contain a count of the
number of events for this domainID that were omitted. The log SHOULD number of events for this domainID that were omitted. The log SHOULD
NOT be further reduced but there could exist operational situation NOT be further reduced but there could exist operational situation
where maintaining the full log is not possible. In such situations where maintaining the full log is not possible. In such situations
the log MAY be arbitrarily abridged for length, with the number of the log MAY be arbitrarily abridged for length, with the number of
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If the truncation count exceeds 1024 then the MASA MAY use this value If the truncation count exceeds 1024 then the MASA MAY use this value
without further incrementing it. without further incrementing it.
A log where duplicate entries for the same domain have been omitted A log where duplicate entries for the same domain have been omitted
("nonced duplicates" and/or "nonceless duplicates) could still be ("nonced duplicates" and/or "nonceless duplicates) could still be
acceptable for informed decisions. A log that has had "arbitrary" acceptable for informed decisions. A log that has had "arbitrary"
truncations is less acceptable but manufacturer transparency is truncations is less acceptable but manufacturer transparency is
better than hidden truncations. better than hidden truncations.
A registrar that sees a version value greater than 1 indicates an
audit log format that has been enhanced with additional information.
No information will be removed in future versions; should an
incompatible change be desired in the future, then a new HTTP end
point will be used.
This document specifies a simple log format as provided by the MASA This document specifies a simple log format as provided by the MASA
service to the registrar. This format could be improved by service to the registrar. This format could be improved by
distributed consensus technologies that integrate vouchers with distributed consensus technologies that integrate vouchers with
technologies such as block-chain or hash trees or optimized logging technologies such as block-chain or hash trees or optimized logging
approaches. Doing so is out of the scope of this document but is an approaches. Doing so is out of the scope of this document but is an
anticipated improvement for future work. As such, the registrar anticipated improvement for future work. As such, the registrar
client SHOULD anticipate new kinds of responses, and SHOULD provide SHOULD anticipate new kinds of responses, and SHOULD provide operator
operator controls to indicate how to process unknown responses. controls to indicate how to process unknown responses.
5.8.2. Registrar audit log verification 5.8.2. Registrar audit log verification
Each time the Manufacturer Authorized Signing Authority (MASA) issues Each time the Manufacturer Authorized Signing Authority (MASA) issues
a voucher, it appends details of the assignment to an internal audit a voucher, it appends details of the assignment to an internal audit
log for that device. The internal audit log is processed when log for that device. The internal audit log is processed when
responding to requests for details as described in Section 5.8. The responding to requests for details as described in Section 5.8. The
contents of the audit log can express a variety of trust levels, and contents of the audit log can express a variety of trust levels, and
this section explains what kind of trust a registrar can derive from this section explains what kind of trust a registrar can derive from
the entries. the entries.
skipping to change at page 51, line 39 skipping to change at page 55, line 47
the MASA issued the associated voucher as a result of positive the MASA issued the associated voucher as a result of positive
verification of ownership but this can still be problematic for verification of ownership but this can still be problematic for
registrar's that expected only new (not pre-owned) pledges. A registrar's that expected only new (not pre-owned) pledges. A
"logged" assertion informs the registrar that the prior vouchers "logged" assertion informs the registrar that the prior vouchers
were issued with minimal verification. A "proximity" assertion were issued with minimal verification. A "proximity" assertion
assures the registrar that the pledge was truly communicating with assures the registrar that the pledge was truly communicating with
the prior domain and thus provides assurance that the prior domain the prior domain and thus provides assurance that the prior domain
really has deployed the pledge. really has deployed the pledge.
A relatively simple policy is to white list known (internal or A relatively simple policy is to white list known (internal or
external) domainIDs and to require all vouchers to have a nonce and/ external) domainIDs. To require all vouchers to have a nonce.
or require that all nonceless vouchers be from a subset (e.g. only Alternatively to require that all nonceless vouchers be from a subset
internal) domainIDs. A simple action is to revoke any locally issued (e.g. only internal) domainIDs. If the policy is violated a simple
credentials for the pledge in question or to refuse to forward the action is to revoke any locally issued credentials for the pledge in
voucher. A registrar MAY be configured to ignore the history of the question or to refuse to forward the voucher. The Registrar MUST
device but it is RECOMMENDED that this only be configured if hardware then refuse any EST actions, and SHOULD inform a human via a log. A
assisted NEA [RFC5209] is supported. registrar MAY be configured to ignore (i.e. override the above
policy) the history of the device but it is RECOMMENDED that this
only be configured if hardware assisted (i.e. TPM anchored) Network
Endpoint Assessment (NEA) [RFC5209] is supported.
5.9. EST Integration for PKI bootstrapping 5.9. EST Integration for PKI bootstrapping
The pledge SHOULD follow the BRSKI operations with EST enrollment The pledge SHOULD follow the BRSKI operations with EST enrollment
operations including "CA Certificates Request", "CSR Attributes" and operations including "CA Certificates Request", "CSR Attributes" and
"Client Certificate Request" or "Server-Side Key Generation", etc. "Client Certificate Request" or "Server-Side Key Generation", etc.
This is a relatively seamless integration since BRSKI REST calls This is a relatively seamless integration since BRSKI REST calls
provide an automated alternative to the manual bootstrapping method provide an automated alternative to the manual bootstrapping method
described in [RFC7030]. As noted above, use of HTTP 1.1 persistent described in [RFC7030]. As noted above, use of HTTP 1.1 persistent
connections simplifies the pledge state machine. connections simplifies the pledge state machine.
Although EST allows clients to obtain multiple certificates by Although EST allows clients to obtain multiple certificates by
sending multiple CSR requests BRSKI mandates use of the CSR sending multiple CSR requests; BRSKI does not support this mechanism
Attributes request and mandates that the registrar validate the CSR directly. This is because BRSKI pledges MUST use the CSR Attributes
request ([RFC7030] section 4.5). The registrar MUST validate the CSR
against the expected attributes. This implies that client requests against the expected attributes. This implies that client requests
will "look the same" and therefore result in a single logical will "look the same" and therefore result in a single logical
certificate being issued even if the client were to make multiple certificate being issued even if the client were to make multiple
requests. Registrars MAY contain more complex logic but doing so is requests. Registrars MAY contain more complex logic but doing so is
out-of-scope of this specification. BRSKI does not signal any out-of-scope of this specification. BRSKI does not signal any
enhancement or restriction to this capability. enhancement or restriction to this capability.
5.9.1. EST Distribution of CA Certificates 5.9.1. EST Distribution of CA Certificates
The pledge SHOULD request the full EST Distribution of CA The pledge SHOULD request the full EST Distribution of CA
Certificates message. See RFC7030, section 4.1. Certificates message. See RFC7030, section 4.1.
This ensures that the pledge has the complete set of current CA This ensures that the pledge has the complete set of current CA
certificates beyond the pinned-domain-cert (see Section 5.6.1 for a certificates beyond the pinned-domain-cert (see Section 5.6.2 for a
discussion of the limitations inherent in having a single certificate discussion of the limitations inherent in having a single certificate
instead of a full CA Certificates response.) Although these instead of a full CA Certificates response.) Although these
limitations are acceptable during initial bootstrapping, they are not limitations are acceptable during initial bootstrapping, they are not
appropriate for ongoing PKIX end entity certificate validation. appropriate for ongoing PKIX end entity certificate validation.
5.9.2. EST CSR Attributes 5.9.2. EST CSR Attributes
Automated bootstrapping occurs without local administrative Automated bootstrapping occurs without local administrative
configuration of the pledge. In some deployments it is plausible configuration of the pledge. In some deployments it is plausible
that the pledge generates a certificate request containing only that the pledge generates a certificate request containing only
skipping to change at page 53, line 15 skipping to change at page 57, line 27
server) informs the pledge of the proper fields to include in the server) informs the pledge of the proper fields to include in the
generated CSR. This approach is beneficial to automated generated CSR. This approach is beneficial to automated
bootstrapping in the widest number of environments. bootstrapping in the widest number of environments.
If the hardwareModuleName in the X.509 IDevID is populated then it If the hardwareModuleName in the X.509 IDevID is populated then it
SHOULD by default be propagated to the LDevID along with the SHOULD by default be propagated to the LDevID along with the
hwSerialNum. The EST server SHOULD support local policy concerning hwSerialNum. The EST server SHOULD support local policy concerning
this functionality. this functionality.
In networks using the BRSKI enrolled certificate to authenticate the In networks using the BRSKI enrolled certificate to authenticate the
ACP (Autonomic Control Plane), the EST attributes MUST include the ACP (Autonomic Control Plane), the EST CSR attributes MUST include
"ACP information" field. See the ACP Domain Information Fields defined in
[I-D.ietf-anima-autonomic-control-plane] for more details. [I-D.ietf-anima-autonomic-control-plane] section 6.1.2.
The registrar MUST also confirm that the resulting CSR is formatted The registrar MUST also confirm that the resulting CSR is formatted
as indicated before forwarding the request to a CA. If the registrar as indicated before forwarding the request to a CA. If the registrar
is communicating with the CA using a protocol such as full CMC, which is communicating with the CA using a protocol such as full CMC, which
provides mechanisms to override the CSR attributes, then these provides mechanisms to override the CSR attributes, then these
mechanisms MAY be used even if the client ignores CSR Attribute mechanisms MAY be used even if the client ignores CSR Attribute
guidance. guidance.
5.9.3. EST Client Certificate Request 5.9.3. EST Client Certificate Request
The pledge MUST request a new client certificate. See RFC7030, The pledge MUST request a new client certificate. See RFC7030,
section 4.2. section 4.2.
5.9.4. Enrollment Status Telemetry 5.9.4. Enrollment Status Telemetry
For automated bootstrapping of devices, the administrative elements For automated bootstrapping of devices, the administrative elements
providing bootstrapping also provide indications to the system providing bootstrapping also provide indications to the system
administrators concerning device lifecycle status. This might administrators concerning device lifecycle status. This might
include information concerning attempted bootstrapping messages seen include information concerning attempted bootstrapping messages seen
by the client, MASA provides logs and status of credential by the client. The MASA provides logs and status of credential
enrollment. [RFC7030] assumes an end user and therefore does not enrollment. [RFC7030] assumes an end user and therefore does not
include a final success indication back to the server. This is include a final success indication back to the server. This is
insufficient for automated use cases. insufficient for automated use cases.
To indicate successful enrollment the client SHOULD re-negotiate the In order to communicate this indicator, the client HTTP POSTs the
EST TLS session using the newly obtained credentials. This occurs by following to the server at the new EST endpoint at "/.well-known/est/
the client initiating a new TLS ClientHello message on the existing enrollstatus".
TLS connection. The client MAY simply close the old TLS session and
start a new one. The server MUST support either model. To indicate successful enrollment the client SHOULD first re-
negotiate the EST TLS session using the newly obtained credentials.
TLS 1.2 supports doing this in-band, but TLS 1.3 does not. The
client SHOULD therefore close the existing TLS connection, and start
a new one.
In the case of a FAIL, the Reason string indicates why the most In the case of a FAIL, the Reason string indicates why the most
recent enrollment failed. The SubjectKeyIdentifier field MUST be recent enrollment failed. The SubjectKeyIdentifier field MUST be
included if the enrollment attempt was for a keypair that is locally included if the enrollment attempt was for a keypair that is locally
known to the client. If EST /serverkeygen was used and failed then known to the client. If EST /serverkeygen was used and failed then
the field is omitted from the status telemetry. the field is omitted from the status telemetry.
In the case of a SUCCESS the Reason string is omitted. The In the case of a SUCCESS the Reason string is omitted. The
SubjectKeyIdentifier is included so that the server can record the SubjectKeyIdentifier is included so that the server can record the
successful certificate distribution. successful certificate distribution.
Status media type: application/json An example status report can be seen below. It is sent with with the
media type: application/json
The client HTTP POSTs the following to the server at the new EST well
known URI /enrollstatus.
{ {
"version":"1", "version":"1",
"Status":true, "Status":true,
"Reason":"Informative human readable message", "Reason":"Informative human readable message",
"reason-context": "Additional information" "reason-context": "Additional information"
} }
Figure 4: Example of enrollment status POST Figure 17: Example of enrollment status POST
The server SHOULD respond with an HTTP 200 but MAY simply fail with The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. an HTTP 404 error.
Within the server logs the server MUST capture if this message was Within the server logs the server MUST capture if this message was
received over an TLS session with a matching client certificate. received over an TLS session with a matching client certificate.
This allows for clients that wish to minimize their crypto operations
to simply POST this response without renegotiating the TLS session -
at the cost of the server not being able to accurately verify that
enrollment was truly successful.
5.9.5. Multiple certificates 5.9.5. Multiple certificates
Pledges that require multiple certificates could establish direct EST Pledges that require multiple certificates could establish direct EST
connections to the registrar. connections to the registrar.
5.9.6. EST over CoAP 5.9.6. EST over CoAP
This document describes extensions to EST for the purposes of This document describes extensions to EST for the purposes of
bootstrapping of remote key infrastructures. Bootstrapping is bootstrapping of remote key infrastructures. Bootstrapping is
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Encoding" heading, and the payloads to be [RFC4648] Base64 encoded Encoding" heading, and the payloads to be [RFC4648] Base64 encoded
DER. DER.
When used within BRSKI, the original RFC7030 EST endpoints remain When used within BRSKI, the original RFC7030 EST endpoints remain
Base64 encoded, but the new BRSKI end points which send and receive Base64 encoded, but the new BRSKI end points which send and receive
binary artifacts (specifically, /requestvoucher) are binary. That binary artifacts (specifically, /requestvoucher) are binary. That
is, no encoding is used. is, no encoding is used.
In the BRSKI context, the EST "Content-Transfer-Encoding" header In the BRSKI context, the EST "Content-Transfer-Encoding" header
field if present, SHOULD be ignored. This header field does not need field if present, SHOULD be ignored. This header field does not need
to included. to be included.
7. Reduced security operational modes 7. Reduced security operational modes
A common requirement of bootstrapping is to support less secure A common requirement of bootstrapping is to support less secure
operational modes for support specific use cases. The following operational modes for support specific use cases. The following
sections detail specific ways that the pledge, registrar and MASA can sections detail specific ways that the pledge, registrar and MASA can
be configured to run in a less secure mode for the indicated reasons. be configured to run in a less secure mode for the indicated reasons.
This section is considered non-normative in the generality of the This section is considered non-normative in the generality of the
protocol. Use of the suggested mechanism here MUST be detailed in protocol. Use of the suggested mechanism here MUST be detailed in
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Registrar: When interacting with a MASA a registrar makes all Registrar: When interacting with a MASA a registrar makes all
decisions. For Ownership Audit Vouchers (see [RFC8366]) the decisions. For Ownership Audit Vouchers (see [RFC8366]) the
registrar is provided an opportunity to accept MASA decisions. registrar is provided an opportunity to accept MASA decisions.
Vendor Service, MASA: This form of manufacturer service is trusted Vendor Service, MASA: This form of manufacturer service is trusted
to accurately log all claim attempts and to provide authoritative to accurately log all claim attempts and to provide authoritative
log information to registrars. The MASA does not know which log information to registrars. The MASA does not know which
devices are associated with which domains. These claims could be devices are associated with which domains. These claims could be
strengthened by using cryptographic log techniques to provide strengthened by using cryptographic log techniques to provide
append only, cryptographic assured, publicly auditable logs. append only, cryptographic assured, publicly auditable logs.
Current text provides only for a trusted manufacturer.
Vendor Service, Ownership Validation: This form of manufacturer Vendor Service, Ownership Validation: This form of manufacturer
service is trusted to accurately know which device is owned by service is trusted to accurately know which device is owned by
which domain. which domain.
7.2. Pledge security reductions 7.2. Pledge security reductions
The pledge can choose to accept vouchers using less secure methods. The pledge can choose to accept vouchers using less secure methods.
These methods enable offline and emergency (touch based) deployment These methods enable offline and emergency (touch based) deployment
use cases: use cases:
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3. The pledge MAY have an operational mode where it skips voucher 3. The pledge MAY have an operational mode where it skips voucher
validation one time. For example if a physical button is validation one time. For example if a physical button is
depressed during the bootstrapping operation. This can be useful depressed during the bootstrapping operation. This can be useful
if the manufacturer service is unavailable. This behavior SHOULD if the manufacturer service is unavailable. This behavior SHOULD
be available via local configuration or physical presence methods be available via local configuration or physical presence methods
(such as use of a serial/craft console) to ensure new entities (such as use of a serial/craft console) to ensure new entities
can always be deployed even when autonomic methods fail. This can always be deployed even when autonomic methods fail. This
allows for unsecured imprint. allows for unsecured imprint.
4. A craft/serial console COULD include a command such as "est- 4. A craft/serial console could include a command such as "est-
enroll [2001:db8:0:1]:443" that begins the EST process from the enroll [2001:db8:0:1]:443" that begins the EST process from the
point after the voucher is validated. This process SHOULD point after the voucher is validated. This process SHOULD
include server certificate verification using an on-screen include server certificate verification using an on-screen
fingerprint. fingerprint.
It is RECOMMENDED that "trust on first use" or any method of skipping It is RECOMMENDED that "trust on first use" or any method of skipping
voucher validation (including use of craft serial console) only be voucher validation (including use of craft serial console) only be
available if hardware assisted Network Endpoint Assessment [RFC5209] available if hardware assisted Network Endpoint Assessment [RFC5209]
is supported. This recommendation ensures that domain network is supported. This recommendation ensures that domain network
monitoring can detect inappropriate use of offline or emergency monitoring can detect inappropriate use of offline or emergency
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vouchers. vouchers.
5. A registrar MAY accept voucher formats of future types that can 5. A registrar MAY accept voucher formats of future types that can
not be parsed by the Registrar. This reduces the Registrar's not be parsed by the Registrar. This reduces the Registrar's
visibility into the exact voucher contents but does not change visibility into the exact voucher contents but does not change
the protocol operations. the protocol operations.
7.4. MASA security reductions 7.4. MASA security reductions
Lower security modes chosen by the MASA service affect all device Lower security modes chosen by the MASA service affect all device
deployments unless bound to the specific device identities. In which deployments unless the lower-security behavior is tied to specific
case these modes can be provided as additional features for specific device identities. The modes described below can be applied to
customers. The MASA service can choose to run in less secure modes specific devices via knowledge of what devices were sold. They can
by: also be bound to specific customers (independent of the device
identity) by authenticating the customer's Registrar.
1. Not enforcing that a nonce is in the voucher. This results in 7.4.1. Issuing Nonceless vouchers
distribution of a voucher that never expires and in effect makes
the Domain an always trusted entity to the pledge during any
subsequent bootstrapping attempts. That this occurred is
captured in the log information so that the registrar can make
appropriate security decisions when a pledge joins the Domain.
This is useful to support use cases where registrars might not be
online during actual device deployment. Because this results in
a long lived voucher and does not require the proof that the
device is online, this is only accepted when the registrar is
authenticated by the MASA and authorized to provide this
functionality. The MASA is RECOMMENDED to use this functionality
only in concert with an enhanced level of ownership tracking
(out-of-scope.) If the pledge device is known to have a real-
time-clock that is set from the factory, use of a voucher
validity period is RECOMMENDED.
2. Not verifying ownership before responding with a voucher. This A MASA has the option of not including a nonce is in the voucher,
is expected to be a common operational model because doing so and/or not requiring one to be present in the voucher-request. This
relieves the manufacturer providing MASA services from having to results in distribution of a voucher that never expires and in effect
track ownership during shipping and supply chain and allows for a makes the Domain an always trusted entity to the pledge during any
very low overhead MASA service. A registrar uses the audit log subsequent bootstrapping attempts. That a nonceless voucher was
information as a defense in depth strategy to ensure that this issued is captured in the log information so that the registrar can
does not occur unexpectedly (for example when purchasing new make appropriate security decisions when a pledge joins the Domain.
equipment the registrar would throw an error if any audit log This is useful to support use cases where registrars might not be
information is reported.) The MASA SHOULD verify the 'prior- online during actual device deployment.
signed-voucher-request' information for pledges that support that
functionality. This provides a proof-of-proximity check that While a nonceless voucher may include an expiry date, a typical use
reduces the need for ownership verification. for a nonceless voucher is for it to be long-lived. If the device
can be trusted to have an accurate clock (the MASA will know), then a
nonceless voucher CAN be issued with a limited lifetime.
A more typical case for a nonceless voucher is for use with offline
onboarding scenarios where it is not possible to pass a fresh
voucher-request to the MASA. The use of a long-lived voucher also
eliminates concern about the availability of the MASA many years in
the future. Thus many nonceless vouchers will have no expiry dates.
Thus, the long lived nonceless voucher does not require the proof
that the device is online. Issuing such a thing is only accepted
when the registrar is authenticated by the MASA and the MASA is
authorized to provide this functionality to this customer. The MASA
is RECOMMENDED to use this functionality only in concert with an
enhanced level of ownership tracking (out-of-scope.)
If the pledge device is known to have a real-time-clock that is set
from the factory, use of a voucher validity period is RECOMMENDED.
7.4.2. Trusting Owners on First Use
A MASA has the option of not verifying ownership before responding
with a voucher. This is expected to be a common operational model
because doing so relieves the manufacturer providing MASA services
from having to track ownership during shipping and supply chain and
allows for a very low overhead MASA service. A registrar uses the
audit log information as a defense in depth strategy to ensure that
this does not occur unexpectedly (for example when purchasing new
equipment the registrar would throw an error if any audit log
information is reported.) The MASA SHOULD verify the 'prior-signed-
voucher-request' information for pledges that support that
functionality. This provides a proof-of-proximity check that reduces
the need for ownership verification.
A MASA that practices Trust-on-First-Use (TOFU) for Registrar
identity may wish to annotate the origin of the connection by IP
address or netblock, and restrict future use of that identity from
other locations. A MASA that does this SHOULD take care to not
create nuissance situations for itself when a customer has multiple
registrars, or uses outgoing IPv6 NAT44 connections that change
frequently.
8. IANA Considerations 8. IANA Considerations
This document requires the following IANA actions: This document requires the following IANA actions:
8.1. Well-known EST registration 8.1. The IETF XML Registry
This document registers a URI in the "IETF XML Registry" [RFC3688].
IANA has registered the following:
URI: urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa
Registrant Contact: The ANIMA WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
8.2. Well-known EST registration
This document extends the definitions of "est" (so far defined via This document extends the definitions of "est" (so far defined via
RFC7030) in the "https://www.iana.org/assignments/well-known-uris/ RFC7030) in the "https://www.iana.org/assignments/well-known-uris/
well-known-uris.xhtml" registry. IANA is asked to change the well-known-uris.xhtml" registry. IANA is asked to change the
registration of "est" to include RFC7030 and this document. registration of "est" to include RFC7030 and this document.
8.2. PKIX Registry 8.3. PKIX Registry
IANA is requested to register the following: IANA is requested to register the following:
This document requests a number for id-mod-MASAURLExtn2016(TBD) from This document requests a number for id-mod-MASAURLExtn2016(TBD) from
the pkix(7) id-mod(0) Registry. the pkix(7) id-mod(0) Registry.
This document has received an early allocation from the id-pe This document has received an early allocation from the id-pe
registry (SMI Security for PKIX Certificate Extension) for id-pe- registry (SMI Security for PKIX Certificate Extension) for id-pe-
masa-url with the value 32, resulting in an OID of masa-url with the value 32, resulting in an OID of
1.3.6.1.5.5.7.1.32. 1.3.6.1.5.5.7.1.32.
8.3. Pledge BRSKI Status Telemetry 8.4. Pledge BRSKI Status Telemetry
IANA is requested to create a new Registry entitled: "BRSKI IANA is requested to create a new Registry entitled: "BRSKI
Parameters", and within that Registry to create a table called: Parameters", and within that Registry to create a table called:
"Pledge BRSKI Status Telemetry Attributes". New items can be added "Pledge BRSKI Status Telemetry Attributes". New items can be added
using the Specification Required. The following items are to be in using the Specification Required. The following items are to be in
the initial registration, with this document (Section 5.7) as the the initial registration, with this document (Section 5.7) as the
reference: reference:
o version o version
o Status o Status
o Reason o Reason
o reason-context o reason-context
8.4. DNS Service Names 8.5. DNS Service Names
IANA is requested to register the following Service Names: IANA is requested to register the following Service Names:
Service Name: brski-proxy Service Name: brski-proxy
Transport Protocol(s): tcp Transport Protocol(s): tcp
Assignee: IESG <iesg@ietf.org>. Assignee: IESG <iesg@ietf.org>.
Contact: IESG <iesg@ietf.org> Contact: IESG <iesg@ietf.org>
Description: The Bootstrapping Remote Secure Key Description: The Bootstrapping Remote Secure Key
Infrastructures Proxy Infrastructures Proxy
Reference: [This document] Reference: [This document]
Service Name: brski-registrar Service Name: brski-registrar
Transport Protocol(s): tcp Transport Protocol(s): tcp
Assignee: IESG <iesg@ietf.org>. Assignee: IESG <iesg@ietf.org>.
Contact: IESG <iesg@ietf.org> Contact: IESG <iesg@ietf.org>
Description: The Bootstrapping Remote Secure Key Description: The Bootstrapping Remote Secure Key
Infrastructures Registrar Infrastructures Registrar
Reference: [This document] Reference: [This document]
8.5. MUD File Extension for the MASA 8.6. MUD File Extension for the MASA
The IANA is requested to list the name "masa" in the MUD extensions The IANA is requested to list the name "masa" in the MUD extensions
registry defined in [I-D.ietf-opsawg-mud]. Its use is documented in registry defined in [RFC8520]. Its use is documented in Appendix C.
Appendix C.
9. Applicability to the Autonomic Control Plane 9. Applicability to the Autonomic Control Plane
This document provides a solution to the requirements for secure This document provides a solution to the requirements for secure
bootstrap set out in Using an Autonomic Control Plane for Stable bootstrap set out in Using an Autonomic Control Plane for Stable
Connectivity of Network Operations, Administration, and Maintenance Connectivity of Network Operations, Administration, and Maintenance
[RFC8368], A Reference Model for Autonomic Networking [RFC8368], A Reference Model for Autonomic Networking
[I-D.ietf-anima-reference-model] and specifically the An Autonomic [I-D.ietf-anima-reference-model] and specifically the An Autonomic
Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section
3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and 3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and
Network). Network).
The protocol described in this document has appeal in a number of The protocol described in this document has appeal in a number of
other non-ANIMA use cases. Such uses of the protocol will be other non-ANIMA use cases. Such uses of the protocol will be
deploying into other environments with different tradeoffs of deploying into other environments with different tradeoffs of
privacy, security, reliability and autonomy from manufacturers. As privacy, security, reliability and autonomy from manufacturers. As
such those use cases will need to provide their own applicability such those use cases will need to provide their own applicability
statements, and will need to address unique privacy and security statements, and will need to address unique privacy and security
considerations for the environments in which they are used. considerations for the environments in which they are used.
The autonomic control plane that this document provides bootstrap for The autonomic control plane (ACP) that is bootstrapped by the BRSKI
is typically a medium to large Internet Service Provider protocol is typically used by medium to large Internet Service
organization, or an equivalent Enterprise that has significant Provider organizations. Equivalent enterprises that has significant
layer-3 router connectivity. (A network consisting of primarily layer-3 router connectivity also will find significant benefit,
layer-2 is not excluded, but the adjacencies that the ACP will create particularly if the Enterprise has many sites. (A network consisting
and maintain will not reflect the topology until all devices of primarily layer-2 is not excluded, but the adjacencies that the
participate in the ACP). ACP will create and maintain will not reflect the topology until all
devices participate in the ACP).
As specified in the ANIMA charter, this work "..focuses on As specified in the ANIMA charter, this work "..focuses on
professionally-managed networks." Such a network has an operator and professionally-managed networks." Such a network has an operator and
can do things like install, configure and operate the Registrar can do things like install, configure and operate the Registrar
function. The operator makes purchasing decisions and is aware of function. The operator makes purchasing decisions and is aware of
what manufacturers it expects to see on it's network. what manufacturers it expects to see on its network.
Such an operator is also capable of performing bootstrapping of a Such an operator is also capable of performing bootstrapping of a
device using a serial-console (craft console). The zero-touch device using a serial-console (craft console). The zero-touch
mechanism presented in this and the ACP document represents a mechanism presented in this and the ACP document
significiant efficiency: in particular it reduces the need to put [I-D.ietf-anima-autonomic-control-plane] represents a significiant
senior experts on airplanes to configure devices in person. efficiency: in particular it reduces the need to put senior experts
on airplanes to configure devices in person.
There is a recognition as the technology evolves that not every There is a recognition as the technology evolves that not every
situation may work out, and occasionally a human may still have to situation may work out, and occasionally a human may still have to
visit. In recognition of this, some mechanisms are presented in visit. In recognition of this, some mechanisms are presented in
Section 7.2. The manufacturer MUST provide at least one of the one- Section 7.2. The manufacturer MUST provide at least one of the one-
touch mechanisms described that permit enrollment to be proceed touch mechanisms described that permit enrollment to be proceed
without availability of any manufacturer server (such as the MASA). without availability of any manufacturer server (such as the MASA).
The BRSKI protocol is going into environments where there have The BRSKI protocol is going into environments where there have
already been quite a number of vendor proprietary management systems. already been quite a number of vendor proprietary management systems.
Those are not expected to go away quickly, but rather to leverage the Those are not expected to go away quickly, but rather to leverage the
secure credentials that are provisioned by BRSKI. The connectivity secure credentials that are provisioned by BRSKI. The connectivity
requirements of said management systems are provided by the ACP. requirements of said management systems are provided by the ACP.
10. Privacy Considerations 10. Privacy Considerations
10.1. MASA audit log 10.1. MASA audit log
The MASA audit log includes a hash of the domainID for each Registrar The MASA audit log includes a hash of the domainID for each Registrar
a voucher has been issued to. This information is closely related to a voucher has been issued to. This information is closely related to
the actual domain identity, especially when paired with the anti-DDoS the actual domain identity. A MASA may need additional defenses
authentication information the MASA might collect. This could against Denial of Service attacks (Section 11.1), and this may
provide sufficient information for the MASA service to build a involve collecting additional (unspecified here) information. This
could provide sufficient information for the MASA service to build a
detailed understanding the devices that have been provisioned within detailed understanding the devices that have been provisioned within
a domain. a domain.
There are a number of design choices that mitigate this risk. The There are a number of design choices that mitigate this risk. The
domain can maintain some privacy since it has not necessarily been domain can maintain some privacy since it has not necessarily been
authenticated and is not authoritatively bound to the supply chain. authenticated and is not authoritatively bound to the supply chain.
Additionally the domainID captures only the unauthenticated subject Additionally the domainID captures only the unauthenticated subject
key identifier of the domain. A privacy sensitive domain could key identifier of the domain. A privacy sensitive domain could
theoretically generate a new domainID for each device being deployed. theoretically generate a new domainID for each device being deployed.
skipping to change at page 62, line 36 skipping to change at page 67, line 43
which enrollment would have be repeated. which enrollment would have be repeated.
The BRSKI call-home mechanism is mediated via the owner's Registrar, The BRSKI call-home mechanism is mediated via the owner's Registrar,
and the information that is transmitted is directly auditable by the and the information that is transmitted is directly auditable by the
device owner. This is in stark contrast to many "call-home" device owner. This is in stark contrast to many "call-home"
protocols where the device autonomously calls home and uses an protocols where the device autonomously calls home and uses an
undocumented protocol. undocumented protocol.
While the contents of the signed part of the pledge voucher request While the contents of the signed part of the pledge voucher request
can not be changed, they are not encrypted at the registrar. The can not be changed, they are not encrypted at the registrar. The
ability to audit the messages by the owner of the network prevents ability to audit the messages by the owner of the network a mechanism
exfiltration of data by a nefarious pledge. The contents of an to defend against exfiltration of data by a nefarious pledge. Both
unsigned voucher request are, however, completely changeable by the are, to re-iterate, encrypted by TLS while in transit.
Registrar. Both are, to re-iterate, encrypted by TLS while in
transit.
The BRSKI-MASA exchange reveals the following information to the The BRSKI-MASA exchange reveals the following information to the
manufacturer: manufacturer:
o the identity of the device being enrolled (down to the serial- o the identity of the device being enrolled (down to the serial-
number!). number!).
o an identity of the domain owner in the form of the domain trust o an identity of the domain owner in the form of the domain trust
anchor. However, this is not a global PKI anchored name within anchor. However, this is not a global PKI anchored name within
the WebPKI, so this identity could be pseudonymous. If there is the WebPKI, so this identity could be pseudonymous. If there is
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This document details a protocol for bootstrapping that balances This document details a protocol for bootstrapping that balances
operational concerns against security concerns. As detailed in the operational concerns against security concerns. As detailed in the
introduction, and touched on again in Section 7, the protocol allows introduction, and touched on again in Section 7, the protocol allows
for reduced security modes. These attempt to deliver additional for reduced security modes. These attempt to deliver additional
control to the local administrator and owner in cases where less control to the local administrator and owner in cases where less
security provides operational benefits. This section goes into more security provides operational benefits. This section goes into more
detail about a variety of specific considerations. detail about a variety of specific considerations.
To facilitate logging and administrative oversight, in addition to To facilitate logging and administrative oversight, in addition to
triggering Registration verification of MASA logs, the pledge reports triggering Registrar verification of MASA logs, the pledge reports on
on voucher parsing status to the registrar. In the case of a voucher parsing status to the registrar. In the case of a failure,
failure, this information is informative to a potentially malicious this information is informative to a potentially malicious registrar.
registrar. This is mandated anyway because of the operational This is mandated anyway because of the operational benefits of an
benefits of an informed administrator in cases where the failure is informed administrator in cases where the failure is indicative of a
indicative of a problem. The registrar is RECOMMENDED to verify MASA problem. The registrar is RECOMMENDED to verify MASA logs if voucher
logs if voucher status telemetry is not received. status telemetry is not received.
To facilitate truly limited clients EST RFC7030 section 3.3.2 To facilitate truly limited clients EST RFC7030 section 3.3.2
requirements that the client MUST support a client authentication requirements that the client MUST support a client authentication
model have been reduced in Section 7 to a statement that the model have been reduced in Section 7 to a statement that the
registrar "MAY" choose to accept devices that fail cryptographic registrar "MAY" choose to accept devices that fail cryptographic
authentication. This reflects current (poor) practices in shipping authentication. This reflects current (poor) practices in shipping
devices without a cryptographic identity that are NOT RECOMMENDED. devices without a cryptographic identity that are NOT RECOMMENDED.
During the provisional period of the connection the pledge MUST treat During the provisional period of the connection the pledge MUST treat
all HTTP header and content data as untrusted data. HTTP libraries all HTTP header and content data as untrusted data. HTTP libraries
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Pledges might chose to engage in protocol operations with multiple Pledges might chose to engage in protocol operations with multiple
discovered registrars in parallel. As noted above they will only do discovered registrars in parallel. As noted above they will only do
so with distinct nonce values, but the end result could be multiple so with distinct nonce values, but the end result could be multiple
vouchers issued from the MASA if all registrars attempt to claim the vouchers issued from the MASA if all registrars attempt to claim the
device. This is not a failure and the pledge choses whichever device. This is not a failure and the pledge choses whichever
voucher to accept based on internal logic. The registrars verifying voucher to accept based on internal logic. The registrars verifying
log information will see multiple entries and take this into account log information will see multiple entries and take this into account
for their analytics purposes. for their analytics purposes.
11.1. DoS against MASA 11.1. Denial of Service (DoS) against MASA
There are uses cases where the MASA could be unavailable or There are uses cases where the MASA could be unavailable or
uncooperative to the Registrar. They include active DoS attacks, uncooperative to the Registrar. They include active DoS attacks,
planned and unplanned network partitions, changes to MASA policy, or planned and unplanned network partitions, changes to MASA policy, or
other instances where MASA policy rejects a claim. These introduce other instances where MASA policy rejects a claim. These introduce
an operational risk to the Registrar owner in that MASA behavior an operational risk to the Registrar owner in that MASA behavior
might limit the ability to bootstrap a pledge device. For example might limit the ability to bootstrap a pledge device. For example
this might be an issue during disaster recovery. This risk can be this might be an issue during disaster recovery. This risk can be
mitigated by Registrars that request and maintain long term copies of mitigated by Registrars that request and maintain long term copies of
"nonceless" vouchers. In that way they are guaranteed to be able to "nonceless" vouchers. In that way they are guaranteed to be able to
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balance. balance.
The MASA is exposed to DoS attacks wherein attackers claim an The MASA is exposed to DoS attacks wherein attackers claim an
unbounded number of devices. Ensuring a registrar is representative unbounded number of devices. Ensuring a registrar is representative
of a valid manufacturer customer, even without validating ownership of a valid manufacturer customer, even without validating ownership
of specific pledge devices, helps to mitigate this. Pledge of specific pledge devices, helps to mitigate this. Pledge
signatures on the pledge voucher-request, as forwarded by the signatures on the pledge voucher-request, as forwarded by the
registrar in the prior-signed-voucher-request field of the registrar registrar in the prior-signed-voucher-request field of the registrar
voucher-request, significantly reduce this risk by ensuring the MASA voucher-request, significantly reduce this risk by ensuring the MASA
can confirm proximity between the pledge and the registrar making the can confirm proximity between the pledge and the registrar making the
request. This mechanism is optional to allow for constrained request. Supply chain integration ("know your customer") is an
devices. Supply chain integration ("know your customer") is an
additional step that MASA providers and device vendors can explore. additional step that MASA providers and device vendors can explore.
11.2. Freshness in Voucher-Requests 11.2. Freshness in Voucher-Requests
A concern has been raised that the pledge voucher-request should A concern has been raised that the pledge voucher-request should
contain some content (a nonce) provided by the registrar and/or MASA contain some content (a nonce) provided by the registrar and/or MASA
in order for those actors to verify that the pledge voucher-request in order for those actors to verify that the pledge voucher-request
is fresh. is fresh.
There are a number of operational problems with getting a nonce from There are a number of operational problems with getting a nonce from
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Establishing this trust between domain and manufacturer is outside Establishing this trust between domain and manufacturer is outside
the scope of BRSKI. There are a number of mechanisms that can the scope of BRSKI. There are a number of mechanisms that can
adopted including: adopted including:
o Manually configuring each manufacturer's trust anchor. o Manually configuring each manufacturer's trust anchor.
o A Trust-On-First-Use (TOFU) mechanism. A human would be queried o A Trust-On-First-Use (TOFU) mechanism. A human would be queried
upon seeing a manufacturer's trust anchor for the first time, and upon seeing a manufacturer's trust anchor for the first time, and
then the trust anchor would be installed to the trusted store. then the trust anchor would be installed to the trusted store.
There are risks with this; even if the key to name is validated There are risks with this; even if the key to name mapping is
using something like the WebPKI, there remains the possibility validated using something like the WebPKI, there remains the
that the name is a look alike: e.g, dem0.example. vs demO.example. possibility that the name is a look alike: e.g, dem0.example. vs
demO.example.
o scanning the trust anchor from a QR code that came with the o scanning the trust anchor from a QR code that came with the
packaging (this is really a manual TOFU mechanism) packaging (this is really a manual TOFU mechanism)
o some sales integration process where trust anchors are provided as o some sales integration process where trust anchors are provided as
part of the sales process, probably included in a digital packing part of the sales process, probably included in a digital packing
"slip", or a sales invoice. "slip", or a sales invoice.
o consortium membership, where all manufacturers of a particular o consortium membership, where all manufacturers of a particular
device category (e.g, a light bulb, or a cable-modem) are signed device category (e.g, a light bulb, or a cable-modem) are signed
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2019 will have hardware and software capable of validating algorithms 2019 will have hardware and software capable of validating algorithms
common in 2019, and will have no defense against attacks (both common in 2019, and will have no defense against attacks (both
quantum and von-neuman brute force attacks) which have not yet been quantum and von-neuman brute force attacks) which have not yet been
invented. This concern is orthogonal to the concern about access to invented. This concern is orthogonal to the concern about access to
private keys, but this concern likely dominates and limits the private keys, but this concern likely dominates and limits the
lifespan of a device in a warehouse. If any update to firmware to lifespan of a device in a warehouse. If any update to firmware to
support new cryptographic mechanism were possible (while the device support new cryptographic mechanism were possible (while the device
was in a warehouse), updates to trust anchors would also be done at was in a warehouse), updates to trust anchors would also be done at
the same time. the same time.
The set of standard operating proceedures for maintaining high value
private keys is well documented. For instance, the WebPKI provides a
number of options for audits at {{cabforumaudit}}, and the DNSSEC
root operations are well documented at {{dnssecroot}}.
It is not clear if Manufacturers will take this level of precaution,
or how strong the economic incentives are to maintain an appropriate
level of security.
This next section examines the risk due to a compromised MASA key.
This is followed by examination of the risk of a compromised
manufacturer IDevID signing key. The third section sections below
examines the situation where MASA web server itself is under attacker
control, but that the MASA signing key itself is safe in a not-
directly connected hardware module.
11.4.1. Compromise of Manufacturer IDevID signing keys
An attacker that has access to the key that the manufacturer uses to
sign IDevID certificates can create counterfeit devices. Such
devices can claim to be from a particular manufacturer, but be
entirely different devices: Trojan horses in effect.
As the attacker controls the MASA URL in the certificate, the
registrar can be convinced to talk to the attackers' MASA. The
Registrar does not need to be in any kind of promiscuous mode to be
vulnerable.
In addition to creating fake devices, the attacker may also be able
to issue revocations for existing certificates if the IDevID
certificate process relies upon CRL lists that are distributed.
There does not otherwise seem to be any risk from this compromise to
devices which are already deployed, or which are sitting locally in
boxes waiting for deployment (local spares). The issue is that
operators will be unable to trust devices which have been in an
uncontrolled warehouse as they do not know if those are real devices.
11.4.2. Compromise of MASA signing keys
There are two periods of time in which to consider: when the MASA key
has fallen into the hands of an attacker, and after the MASA
recognizes that the key has been compromised.
11.4.2.1. Attacker opportunties with compromised MASA key
An attacker that has access to the MASA signing key could create
vouchers. These vouchers could be for existing deployed devices, or
for devices which are still in a warehouse. In order to exploit
these vouchers two things need to occur: the device has to go through
a factory default boot cycle, and the registrar has to be convinced
to contact the attacker's MASA.
If the attacker controls a Registrar which is visible to the device,
then there is no difficulty in delivery of the false voucher. A
possible practical example of an attack like this would be in a data
center, at an ISP peering point (whether a public IX, or a private
peering point). In such a situation, there are already cables
attached to the equipment that lead to other devices (the peers at
the IX), and through those links, the false voucher could be
delivered. The difficult part would be get the device put through a
factory reset. This might be accomplished through social engineering
of data center staff. Most locked cages have ventilation holes, and
possibly a long "paperclip" could reach through to depress a factory
reset button. Once such a piece of ISP equipment has been
compromised, it could be used to compromise equipment that was
connected to (through long haul links even), assuming that those
pieces of equipment could also be forced through a factory reset.
The above scenario seems rather unlikely as it requires some element
of physical access; but were there a remote exploit that did not
cause a direct breach, but rather a fault that resulted in a factory
reset, this could provide a reasonable path.
The above deals with ANI uses of BRSKI. For cases where 802.11 or
802.15.4 is involved, the need to connect directly to the device is
eliminated, but the need to do a factory reset is not. Physical
possession of the device is not required as above, provided that
there is some way to force a factory reset. With some consumers
devices with low overall implementation quality, the end users might
be familiar with needing to reset the device regularly.
The authors are unable to come up with an attack scenario where a
compromised voucher signature enables an attacker to introduce a
compromised pledge into an existing operator's network. This is the
case because the operator controls the communication between
Registrar and MASA, and there is no opportunity to introduce the fake
voucher through that conduit.
11.4.2.2. Risks after key compromise is known
Once the operator of the MASA realizes that the voucher signing key
has been compromised it has to do a few things.
First, it MUST issue a firmware update to all devices that had that
key as a trust anchor, such that they will no longer trust vouchers
from that key. This will affect devices in the field which are
operating, but those devices, being in operation, are not performing
onboarding operations, so this is not a critical patch.
Devices in boxes (in warehouses) are vulnerable, and remain
vulnerable until patched. An operator would be prudent to unbox the
devices, onboard them in a safe environment, and then perform
firmware updates. This does not have to be done by the end-operator;
it could be done by a distributor that stores the spares. A
recommended practice for high value devices (which typically have a
<4hr service window) may be to validate the device operation on a
regular basis anyway.
If the onboarding process includes attestations about firmware
versions, then through that process the operator would be advised to
upgrade the firmware before going into production. Unfortunately,
this does not help against situations where the attacker operates
their own Registrar (as listed above).
[RFC8366] section 6.1 explains the need for short-lived vouchers.
The nonce guarantees freshness, and the short-lived nature of the
voucher means that the window to deliver a fake voucher is very
short. A nonceless, long-lived voucher would be the only option for
the attacker, and devices in the warehouse would be vulnerable to
such a thing.
A key operational recommendation is for manufacturers to sign
nonceless, long-lived vouchers with a different key that they sign
short-lived vouchers. That key needs significantly better
protection. If both keys come from a common trust-anchor (the
manufacturer's CA), then a compromise of the manufacturer's CA would
be a bigger problem.
11.4.3. Compromise of MASA web service
An attacker that takes over the MASA web service has a number of
attacks. The most obvious one is simply to take the database listing
customers and devices and to sell this data to other attackers who
will now know where to find potentially vulnerable devices.
The second most obvious thing that the attacker can do is to kill the
service, or make it operate unreliably, making customers frustrated.
This could have a serious affect on ability to deploy new services by
customers, and would be a significant issue during disaster recovery.
While the compromise of the MASA web service may lead to the
compromise of the MASA voucher signing key, if the signing occurs
offboard (such as in a hardware signing module, HSM), then the key
may well be safe, but control over it resides with the attacker.
Such an attacker can issue vouchers for any device presently in
service. Said device still needs to be convinced to do through a
factory reset process before an attack.
If the attacker has access to a key that is trusted for long-lived
nonceless vouchers, then they could issue vouchers for devices which
are not yet in service. This attack may be very hard to verify and
as it would involve doing firmware updates on every device in
warehouses (a potentially ruinously expensive process), a
manufacturer might be reluctant to admit this possibility.
12. Acknowledgements 12. Acknowledgements
We would like to thank the various reviewers for their input, in We would like to thank the various reviewers for their input, in
particular William Atwood, Brian Carpenter, Toerless Eckert, Fuyu particular William Atwood, Brian Carpenter, Fuyu Eleven, Eliot Lear,
Eleven, Eliot Lear, Sergey Kasatkin, Anoop Kumar, Markus Stenberg, Sergey Kasatkin, Anoop Kumar, Markus Stenberg, Peter van der Stok,
Peter van der Stok, and Thomas Werner and Thomas Werner
Significant reviews were done by Jari Arko, Christian Huitema and Significant reviews were done by Jari Arko, Christian Huitema and
Russ Housley. Russ Housley.
This document started it's life as a two-page idea from Steinthor This document started it's life as a two-page idea from Steinthor
Bjarnason. Bjarnason.
In addition, significant review comments were receives by many IESG
members, including Adam Roach, Alexey Melnikov, Alissa Cooper,
Benjamin Kaduk, Eric Vyncke, Roman Danyliw, and Magnus Westerlund.
13. References 13. References
13.1. Normative References 13.1. Normative References
[cabforumaudit]
"Information for Auditors and Assessors", August 2019,
<https://cabforum.org/
information-for-auditors-and-assessors/>.
[dnssecroot]
"DNSSEC Practice Statement for the Root Zone ZSK
Operator", December 2017,
<https://www.iana.org/dnssec/dps/zsk-operator/
dps-zsk-operator-v2.0.pdf>.
[I-D.ietf-anima-autonomic-control-plane] [I-D.ietf-anima-autonomic-control-plane]
Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic
Control Plane (ACP)", draft-ietf-anima-autonomic-control- Control Plane (ACP)", draft-ietf-anima-autonomic-control-
plane-19 (work in progress), March 2019. plane-20 (work in progress), July 2019.
[I-D.ietf-anima-grasp] [I-D.ietf-anima-grasp]
Bormann, C., Carpenter, B., and B. Liu, "A Generic Bormann, C., Carpenter, B., and B. Liu, "A Generic
Autonomic Signaling Protocol (GRASP)", draft-ietf-anima- Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
grasp-15 (work in progress), July 2017. grasp-15 (work in progress), July 2017.
[IDevID] "IEEE 802.1AR Secure Device Identifier", December 2009, [IDevID] "IEEE 802.1AR Secure Device Identifier", December 2009,
<http://standards.ieee.org/findstds/ <http://standards.ieee.org/findstds/
standard/802.1AR-2009.html>. standard/802.1AR-2009.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, Ed., "Extensible Authentication Protocol Levkowetz, Ed., "Extensible Authentication Protocol
(EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004, (EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
<https://www.rfc-editor.org/info/rfc3748>. <https://www.rfc-editor.org/info/rfc3748>.
[RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic [RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
Configuration of IPv4 Link-Local Addresses", RFC 3927, Configuration of IPv4 Link-Local Addresses", RFC 3927,
DOI 10.17487/RFC3927, May 2005, DOI 10.17487/RFC3927, May 2005,
<https://www.rfc-editor.org/info/rfc3927>. <https://www.rfc-editor.org/info/rfc3927>.
skipping to change at page 73, line 15 skipping to change at page 81, line 48
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
<https://www.rfc-editor.org/info/rfc4941>. <https://www.rfc-editor.org/info/rfc4941>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS [RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008, (CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
<https://www.rfc-editor.org/info/rfc5272>. <https://www.rfc-editor.org/info/rfc5272>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
skipping to change at page 74, line 14 skipping to change at page 82, line 44
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>. <https://www.rfc-editor.org/info/rfc6763>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030, "Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013, DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>. <https://www.rfc-editor.org/info/rfc7030>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing", Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014, RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>. <https://www.rfc-editor.org/info/rfc7230>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>. <https://www.rfc-editor.org/info/rfc7950>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG", [RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016, RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>. <https://www.rfc-editor.org/info/rfc7951>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
skipping to change at page 74, line 47 skipping to change at page 83, line 38
"A Voucher Artifact for Bootstrapping Protocols", "A Voucher Artifact for Bootstrapping Protocols",
RFC 8366, DOI 10.17487/RFC8366, May 2018, RFC 8366, DOI 10.17487/RFC8366, May 2018,
<https://www.rfc-editor.org/info/rfc8366>. <https://www.rfc-editor.org/info/rfc8366>.
[RFC8368] Eckert, T., Ed. and M. Behringer, "Using an Autonomic [RFC8368] Eckert, T., Ed. and M. Behringer, "Using an Autonomic
Control Plane for Stable Connectivity of Network Control Plane for Stable Connectivity of Network
Operations, Administration, and Maintenance (OAM)", Operations, Administration, and Maintenance (OAM)",
RFC 8368, DOI 10.17487/RFC8368, May 2018, RFC 8368, DOI 10.17487/RFC8368, May 2018,
<https://www.rfc-editor.org/info/rfc8368>. <https://www.rfc-editor.org/info/rfc8368>.
[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>.
[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/info/rfc8610>.
13.2. Informative References 13.2. Informative References
[Dingledine2004] [Dingledine2004]
Dingledine, R., Mathewson, N., and P. Syverson, "Tor: the Dingledine, R., Mathewson, N., and P. Syverson, "Tor: the
second-generation onion router", 2004, second-generation onion router", 2004,
<https://spec.torproject.org/tor-spec>. <https://spec.torproject.org/tor-spec>.
[docsisroot] [docsisroot]
"CableLabs Digital Certificate Issuance Service", February "CableLabs Digital Certificate Issuance Service", February
2018, <https://www.cablelabs.com/resources/ 2018, <https://www.cablelabs.com/resources/
skipping to change at page 75, line 33 skipping to change at page 84, line 38
and J. Nobre, "A Reference Model for Autonomic and J. Nobre, "A Reference Model for Autonomic
Networking", draft-ietf-anima-reference-model-10 (work in Networking", draft-ietf-anima-reference-model-10 (work in
progress), November 2018. progress), November 2018.
[I-D.ietf-anima-stable-connectivity] [I-D.ietf-anima-stable-connectivity]
Eckert, T. and M. Behringer, "Using Autonomic Control Eckert, T. and M. Behringer, "Using Autonomic Control
Plane for Stable Connectivity of Network OAM", draft-ietf- Plane for Stable Connectivity of Network OAM", draft-ietf-
anima-stable-connectivity-10 (work in progress), February anima-stable-connectivity-10 (work in progress), February
2018. 2018.
[I-D.ietf-cbor-cddl]
Birkholz, H., Vigano, C., and C. Bormann, "Concise data
definition language (CDDL): a notational convention to
express CBOR and JSON data structures", draft-ietf-cbor-
cddl-08 (work in progress), March 2019.
[I-D.ietf-netconf-zerotouch]
Watsen, K., Abrahamsson, M., and I. Farrer, "Secure Zero
Touch Provisioning (SZTP)", draft-ietf-netconf-
zerotouch-29 (work in progress), January 2019.
[I-D.ietf-opsawg-mud]
Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
Description Specification", draft-ietf-opsawg-mud-25 (work
in progress), June 2018.
[I-D.richardson-anima-state-for-joinrouter] [I-D.richardson-anima-state-for-joinrouter]
Richardson, M., "Considerations for stateful vs stateless Richardson, M., "Considerations for stateful vs stateless
join router in ANIMA bootstrap", draft-richardson-anima- join router in ANIMA bootstrap", draft-richardson-anima-
state-for-joinrouter-02 (work in progress), January 2018. state-for-joinrouter-02 (work in progress), January 2018.
[imprinting] [imprinting]
"Wikipedia article: Imprinting", July 2015, "Wikipedia article: Imprinting", July 2015,
<https://en.wikipedia.org/wiki/Imprinting_(psychology)>. <https://en.wikipedia.org/wiki/Imprinting_(psychology)>.
[IoTstrangeThings] [IoTstrangeThings]
skipping to change at page 76, line 21 skipping to change at page 85, line 11
privacy update (accessed 2018-12-02)", March 2017, privacy update (accessed 2018-12-02)", March 2017,
<https://www.welivesecurity.com/2017/03/03/ <https://www.welivesecurity.com/2017/03/03/
internet-of-things-security-privacy-iot-update/>. internet-of-things-security-privacy-iot-update/>.
[livingwithIoT] [livingwithIoT]
"What is it actually like to live in a house filled with "What is it actually like to live in a house filled with
IoT devices? (accessed 2018-12-02)", February 2018, IoT devices? (accessed 2018-12-02)", February 2018,
<https://www.siliconrepublic.com/machines/ <https://www.siliconrepublic.com/machines/
iot-smart-devices-reality>. iot-smart-devices-reality>.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <https://www.rfc-editor.org/info/rfc2473>.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations", Translator (NAT) Terminology and Considerations",
RFC 2663, DOI 10.17487/RFC2663, August 1999, RFC 2663, DOI 10.17487/RFC2663, August 1999,
<https://www.rfc-editor.org/info/rfc2663>. <https://www.rfc-editor.org/info/rfc2663>.
[RFC5209] Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J.
Tardo, "Network Endpoint Assessment (NEA): Overview and
Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008,
<https://www.rfc-editor.org/info/rfc5209>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010, DOI 10.17487/RFC5785, April 2010,
<https://www.rfc-editor.org/info/rfc5785>. <https://www.rfc-editor.org/info/rfc5785>.
[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
Galperin, S., and C. Adams, "X.509 Internet Public Key Galperin, S., and C. Adams, "X.509 Internet Public Key
Infrastructure Online Certificate Status Protocol - OCSP", Infrastructure Online Certificate Status Protocol - OCSP",
RFC 6960, DOI 10.17487/RFC6960, June 2013, RFC 6960, DOI 10.17487/RFC6960, June 2013,
<https://www.rfc-editor.org/info/rfc6960>. <https://www.rfc-editor.org/info/rfc6960>.
[RFC6961] Pettersen, Y., "The Transport Layer Security (TLS) [RFC6961] Pettersen, Y., "The Transport Layer Security (TLS)
Multiple Certificate Status Request Extension", RFC 6961, Multiple Certificate Status Request Extension", RFC 6961,
DOI 10.17487/RFC6961, June 2013, DOI 10.17487/RFC6961, June 2013,
<https://www.rfc-editor.org/info/rfc6961>. <https://www.rfc-editor.org/info/rfc6961>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for [RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228, Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014, DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>. <https://www.rfc-editor.org/info/rfc7228>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>. 2014, <https://www.rfc-editor.org/info/rfc7258>.
[RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection [RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection
Most of the Time", RFC 7435, DOI 10.17487/RFC7435, Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
December 2014, <https://www.rfc-editor.org/info/rfc7435>. December 2014, <https://www.rfc-editor.org/info/rfc7435>.
[RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A., [RFC7575] Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking: Definitions and Design Goals", RFC 7575, Networking: Definitions and Design Goals", RFC 7575,
DOI 10.17487/RFC7575, June 2015, DOI 10.17487/RFC7575, June 2015,
<https://www.rfc-editor.org/info/rfc7575>. <https://www.rfc-editor.org/info/rfc7575>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>. <https://www.rfc-editor.org/info/rfc8340>.
[RFC8520] Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
Description Specification", RFC 8520,
DOI 10.17487/RFC8520, March 2019,
<https://www.rfc-editor.org/info/rfc8520>.
[RFC8572] Watsen, K., Farrer, I., and M. Abrahamsson, "Secure Zero
Touch Provisioning (SZTP)", RFC 8572,
DOI 10.17487/RFC8572, April 2019,
<https://www.rfc-editor.org/info/rfc8572>.
[slowloris] [slowloris]
"Slowloris (computer security)", February 2019, "Slowloris (computer security)", February 2019,
<https://en.wikipedia.org/wiki/ <https://en.wikipedia.org/wiki/
Slowloris_(computer_security)/>. Slowloris_(computer_security)/>.
[Stajano99theresurrecting] [Stajano99theresurrecting]
Stajano, F. and R. Anderson, "The resurrecting duckling: Stajano, F. and R. Anderson, "The resurrecting duckling:
security issues for ad-hoc wireless networks", 1999, security issues for ad-hoc wireless networks", 1999,
<https://www.cl.cam.ac.uk/~fms27/ <https://www.cl.cam.ac.uk/~fms27/
papers/1999-StajanoAnd-duckling.pdf>. papers/1999-StajanoAnd-duckling.pdf>.
[TR069] "TR-69: CPE WAN Management Protocol", February 2018, [TR069] "TR-69: CPE WAN Management Protocol", February 2018,
<https://www.broadband-forum.org/standards-and-software/ <https://www.broadband-forum.org/standards-and-software/
technical-specifications/tr-069-files-tools>. technical-specifications/tr-069-files-tools>.
[W3C.WD-capability-urls-20140218]
Tennison, J., "Good Practices for Capability URLs", World
Wide Web Consortium WD WD-capability-urls-20140218,
February 2014,
<http://www.w3.org/TR/2014/WD-capability-urls-20140218>.
Appendix A. IPv4 and non-ANI operations Appendix A. IPv4 and non-ANI operations
The secification of BRSKI in Section 4 intentionally only covers the The secification of BRSKI in Section 4 intentionally only covers the
mechanisms for an IPv6 pledge using Link-Local addresses. This mechanisms for an IPv6 pledge using Link-Local addresses. This
section describes non-normative extensions that can be used in other section describes non-normative extensions that can be used in other
environments. environments.
A.1. IPv4 Link Local addresses A.1. IPv4 Link Local addresses
Instead of an IPv6 link-local address, an IPv4 address may be Instead of an IPv6 link-local address, an IPv4 address may be
skipping to change at page 78, line 43 skipping to change at page 87, line 41
To prevent unaccceptable levels of network traffic, when using mDNS, To prevent unaccceptable levels of network traffic, when using mDNS,
the congestion avoidance mechanisms specified in [RFC6762] section 7 the congestion avoidance mechanisms specified in [RFC6762] section 7
MUST be followed. The pledge SHOULD listen for an unsolicited MUST be followed. The pledge SHOULD listen for an unsolicited
broadcast response as described in [RFC6762]. This allows devices to broadcast response as described in [RFC6762]. This allows devices to
avoid announcing their presence via mDNS broadcasts and instead avoid announcing their presence via mDNS broadcasts and instead
silently join a network by watching for periodic unsolicited silently join a network by watching for periodic unsolicited
broadcast responses. broadcast responses.
Discovery of registrar MAY also be performed with DNS-based service Discovery of registrar MAY also be performed with DNS-based service
discovery by searching for the service "_brski- discovery by searching for the service "_brski-
registrar._tcp.example.com". In this case the domain "example.com" registrar._tcp.<domain>". In this case the domain "example.com" is
is discovered as described in [RFC6763] section 11 (Appendix A.2 discovered as described in [RFC6763] section 11 (Appendix A.2
suggests the use of DHCP parameters). suggests the use of DHCP parameters).
If no local proxy or registrar service is located using the GRASP If no local proxy or registrar service is located using the GRASP
mechanisms or the above mentioned DNS-based Service Discovery methods mechanisms or the above mentioned DNS-based Service Discovery
the pledge MAY contact a well known manufacturer provided methods, the pledge MAY contact a well known manufacturer provided
bootstrapping server by performing a DNS lookup using a well known bootstrapping server by performing a DNS lookup using a well known
URI such as "brski-registrar.manufacturer.example.com". The details URI such as "brski-registrar.manufacturer.example.com". The details
of the URI are manufacturer specific. Manufacturers that leverage of the URI are manufacturer specific. Manufacturers that leverage
this method on the pledge are responsible for providing the registrar this method on the pledge are responsible for providing the registrar
service. Also see Section 2.7. service. Also see Section 2.7.
The current DNS services returned during each query are maintained The current DNS services returned during each query are maintained
until bootstrapping is completed. If bootstrapping fails and the until bootstrapping is completed. If bootstrapping fails and the
pledge returns to the Discovery state, it picks up where it left off pledge returns to the Discovery state, it picks up where it left off
and continues attempting bootstrapping. For example, if the first and continues attempting bootstrapping. For example, if the first
Multicast DNS _bootstrapks._tcp.local response doesn't work then the Multicast DNS _bootstrapks._tcp.local response doesn't work then the
second and third responses are tried. If these fail the pledge moves second and third responses are tried. If these fail the pledge moves
on to normal DNS-based Service Discovery. on to normal DNS-based Service Discovery.
Appendix C. MUD Extension Appendix C. MUD Extension
The following extension augments the MUD model to include a single The following extension augments the MUD model to include a single
node, as described in [I-D.ietf-opsawg-mud] section 3.6, using the node, as described in [RFC8520] section 3.6, using the following
following sample module that has the following tree structure: sample module that has the following tree structure:
module: ietf-mud-brski-masa module: ietf-mud-brski-masa
augment /ietf-mud:mud: augment /ietf-mud:mud:
+--rw masa-server? inet:uri +--rw masa-server? inet:uri
The model is defined as follows: The model is defined as follows:
<CODE BEGINS> file "ietf-mud-extension@2018-02-14.yang" <CODE BEGINS> file "ietf-mud-brski-masaurl-extension@2018-02-14.yang"
module ietf-mud-brski-masa { module ietf-mud-brski-masa {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa"; namespace "urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa";
prefix ietf-mud-brski-masa; prefix ietf-mud-brski-masa;
import ietf-mud { import ietf-mud {
prefix ietf-mud; prefix ietf-mud;
} }
import ietf-inet-types { import ietf-inet-types {
prefix inet; prefix inet;
} }
skipping to change at page 83, line 12 skipping to change at page 92, line 12
c3o= c3o=
-----END CERTIFICATE----- -----END CERTIFICATE-----
The registrar public certificate as decoded by openssl's x509 The registrar public certificate as decoded by openssl's x509
utility. Note that the registrar certificate is marked with the utility. Note that the registrar certificate is marked with the
cmcRA extension. cmcRA extension.
Certificate: Certificate:
Data: Data:
Version: 3 (0x2) Version: 3 (0x2)
Serial Number: 3 (0x3) Serial Number: 3 (0x3)
Signature Algorithm: ecdsa-with-SHA384 Signature Algorithm: ecdsa-with-SHA384
Issuer: DC = ca, DC = sandelman, CN = Unstrung Fount Issuer: DC=ca, DC=sandelman, CN=Unstrung Fountain CA
ain CA
Validity Validity
Not Before: Sep 5 01:12:45 2017 GMT Not Before: Sep 5 01:12:45 2017 GMT
Not After : Sep 5 01:12:45 2019 GMT Not After : Sep 5 01:12:45 2019 GMT
Subject: DC = ca, DC = sandelman, CN = localhost Subject: DC=ca, DC=sandelman, CN=localhost
Subject Public Key Info: Subject Public Key Info:
Public Key Algorithm: id-ecPublicKey Public Key Algorithm: id-ecPublicKey
Public-Key: (256 bit) Public-Key: (256 bit)
pub: pub:
04:35:64:0e:cd:c3:4c:52:33:f4:36:bb:5f:7 04:35:64:0e:cd:c3:4c:52:33:f4:36:bb:5f:7
8:17: 8:17:
34:0c:92:d6:7d:e3:06:80:21:5d:22:fe:85:5 34:0c:92:d6:7d:e3:06:80:21:5d:22:fe:85:5
3:3e: 3:3e:
03:89:f3:35:ba:33:01:79:cf:e0:e9:6f:cf:e 03:89:f3:35:ba:33:01:79:cf:e0:e9:6f:cf:e
9:ba: 9:ba:
13:9b:24:c6:74:53:a1:ff:c1:f0:29:47:ab:2 13:9b:24:c6:74:53:a1:ff:c1:f0:29:47:ab:2
f:96: f:96:
e9:9d:e2:bc:b2 e9:9d:e2:bc:b2
ASN1 OID: prime256v1 ASN1 OID: prime256v1
NIST CURVE: P-256
X509v3 extensions: X509v3 extensions:
X509v3 Basic Constraints: X509v3 Basic Constraints:
CA:FALSE CA:FALSE
Signature Algorithm: ecdsa-with-SHA384 Signature Algorithm: ecdsa-with-SHA384
30:66:02:31:00:b7:fe:24:d0:27:77:af:61:87:20:6d:78: 30:66:02:31:00:b7:fe:24:d0:27:77:af:61:87:20:6d:78:
5b: 5b:
9b:3a:e9:eb:8b:77:40:2e:aa:8c:87:98:da:39:03:c7:4e: 9b:3a:e9:eb:8b:77:40:2e:aa:8c:87:98:da:39:03:c7:4e:
b6: b6:
9e:e3:62:7d:52:ad:c9:a6:ab:6b:71:77:d0:02:24:29:21: 9e:e3:62:7d:52:ad:c9:a6:ab:6b:71:77:d0:02:24:29:21:
02: 02:
skipping to change at page 98, line 20 skipping to change at page 107, line 20
Cisco Cisco
Email: pritikin@cisco.com Email: pritikin@cisco.com
Michael C. Richardson Michael C. Richardson
Sandelman Software Works Sandelman Software Works
Email: mcr+ietf@sandelman.ca Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/ URI: http://www.sandelman.ca/
Toerless Eckert
Futurewei Technologies Inc. USA
2330 Central Expy
Santa Clara 95050
USA
Email: ttef@cs.fau.de
Michael H. Behringer Michael H. Behringer
Email: Michael.H.Behringer@gmail.com Email: Michael.H.Behringer@gmail.com
Kent Watsen Kent Watsen
Watsen Networks Watsen Networks
Email: kent+ietf@watsen.net Email: kent+ietf@watsen.net
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