draft-ietf-anima-bootstrapping-keyinfra-02.txt   draft-ietf-anima-bootstrapping-keyinfra-03.txt 
ANIMA WG M. Pritikin ANIMA WG M. Pritikin
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Informational M. Richardson Intended status: Informational M. Richardson
Expires: September 18, 2016 SSW Expires: January 1, 2017 SSW
M. Behringer M. Behringer
S. Bjarnason S. Bjarnason
Cisco Cisco
March 17, 2016 June 30, 2016
Bootstrapping Key Infrastructures Bootstrapping Remote Secure Key Infrastructures (BRSKI)
draft-ietf-anima-bootstrapping-keyinfra-02 draft-ietf-anima-bootstrapping-keyinfra-03
Abstract Abstract
This document specifies automated bootstrapping of a key This document specifies automated bootstrapping of a remote secure
infrastructure (BSKI) using vendor installed IEEE 802.1AR key infrastructure (BRSKI) using vendor installed IEEE 802.1AR
manufacturing installed certificates, in combination with a vendor manufacturing installed certificates, in combination with a vendor
based service on the Internet. Before being authenticated, a new based service on the Internet. Before being authenticated, a new
device has only link-local connectivity, and does not require a device has only link-local connectivity, and does not require a
routable address. When a vendor provides an Internet based service, routable address. When a vendor provides an Internet based service
devices can be forced to join only specific domains but in limited/ devices can be redirected to a local service. In limited/
disconnected networks or legacy environments we describe a variety of disconnected networks or legacy environments we describe a variety of
options that allow bootstrapping to proceed. options that allow bootstrapping to proceed. Support for lower
security models, including devices with minimal identity, is
described for legacy reasons but not encouraged.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 18, 2016. This Internet-Draft will expire on January 1, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Scope of solution . . . . . . . . . . . . . . . . . . . . 5 1.2. Scope of solution . . . . . . . . . . . . . . . . . . . . 6
1.3. Trust bootstrap . . . . . . . . . . . . . . . . . . . . . 6 1.3. Trust bootstrap . . . . . . . . . . . . . . . . . . . . . 7
2. Architectural Overview . . . . . . . . . . . . . . . . . . . 6 2. Architectural Overview . . . . . . . . . . . . . . . . . . . 7
3. Functional Overview . . . . . . . . . . . . . . . . . . . . . 9 3. Functional Overview . . . . . . . . . . . . . . . . . . . . . 9
3.1. Behavior of a New Entity . . . . . . . . . . . . . . . . 10 3.1. Behavior of a New Entity . . . . . . . . . . . . . . . . 11
3.1.1. Discovery . . . . . . . . . . . . . . . . . . . . . . 12 3.1.1. Discovery . . . . . . . . . . . . . . . . . . . . . . 13
3.1.2. Identity . . . . . . . . . . . . . . . . . . . . . . 13 3.1.2. Identity . . . . . . . . . . . . . . . . . . . . . . 14
3.1.3. Request Join . . . . . . . . . . . . . . . . . . . . 14 3.1.3. Request Join . . . . . . . . . . . . . . . . . . . . 15
3.1.4. Imprint . . . . . . . . . . . . . . . . . . . . . . . 14 3.1.4. Imprint . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.5. Enrollment . . . . . . . . . . . . . . . . . . . . . 15 3.1.5. Lack of realtime clock . . . . . . . . . . . . . . . 16
3.1.6. Being Managed . . . . . . . . . . . . . . . . . . . . 16 3.1.6. Enrollment . . . . . . . . . . . . . . . . . . . . . 17
3.2. Behavior of a Proxy . . . . . . . . . . . . . . . . . . . 16 3.1.7. Being Managed . . . . . . . . . . . . . . . . . . . . 18
3.2.1. CoAP connection to Registrar . . . . . . . . . . . . 16 3.2. Behavior of a Proxy . . . . . . . . . . . . . . . . . . . 18
3.2.2. HTTPS proxy connection to Registrar . . . . . . . . . 17 3.2.1. CoAP connection to Registrar . . . . . . . . . . . . 19
3.3. Behavior of the Registrar (Bootstrap Server) . . . . . . 18 3.2.2. HTTPS proxy connection to Registrar . . . . . . . . . 19
3.3.1. Entity Authentication . . . . . . . . . . . . . . . . 19 3.3. Behavior of the Registrar (Bootstrap Server) . . . . . . 20
3.3.2. Entity Authorization . . . . . . . . . . . . . . . . 19 3.3.1. Entity Authentication . . . . . . . . . . . . . . . . 21
3.3.3. Claiming the New Entity . . . . . . . . . . . . . . . 20 3.3.2. Entity Authorization . . . . . . . . . . . . . . . . 21
3.3.4. Log Verification . . . . . . . . . . . . . . . . . . 20 3.3.3. Claiming the New Entity . . . . . . . . . . . . . . . 22
3.3.5. Forwarding Audit Token plus Configuration . . . . . . 21 3.3.4. Log Verification . . . . . . . . . . . . . . . . . . 23
3.4. Behavior of the MASA Service . . . . . . . . . . . . . . 21 3.4. Behavior of the MASA Service . . . . . . . . . . . . . . 24
3.4.1. Issue Authorization Token and Log the event . . . . . 21 3.4.1. Issue Authorization Token and Log the event . . . . . 24
3.4.2. Retrieve Audit Entries from Log . . . . . . . . . . . 22 3.4.2. Retrieve Audit Entries from Log . . . . . . . . . . . 24
3.5. Leveraging the new key infrastructure / next steps . . . 22 3.5. Leveraging the new key infrastructure / next steps . . . 24
3.5.1. Network boundaries . . . . . . . . . . . . . . . . . 22 3.5.1. Network boundaries . . . . . . . . . . . . . . . . . 25
3.6. Interactions with Network Access Control . . . . . . . . 22 3.6. Interactions with Network Access Control . . . . . . . . 25
4. Domain Operator Activities . . . . . . . . . . . . . . . . . 23 4. Domain Operator Activities . . . . . . . . . . . . . . . . . 25
4.1. Instantiating the Domain Certification Authority . . . . 23 4.1. Instantiating the Domain Certification Authority . . . . 25
4.2. Instantiating the Registrar . . . . . . . . . . . . . . . 23 4.2. Instantiating the Registrar . . . . . . . . . . . . . . . 25
4.3. Accepting New Entities . . . . . . . . . . . . . . . . . 23 4.3. Accepting New Entities . . . . . . . . . . . . . . . . . 26
4.4. Automatic Enrollment of Devices . . . . . . . . . . . . . 24 4.4. Automatic Enrollment of Devices . . . . . . . . . . . . . 27
4.5. Secure Network Operations . . . . . . . . . . . . . . . . 24 4.5. Secure Network Operations . . . . . . . . . . . . . . . . 27
5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 25 5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 27
5.1. IEEE 802.1AR as client identity . . . . . . . . . . . . . 27 5.1. Request Audit Token from the Registrar . . . . . . . . . 30
5.2. EST over CoAP . . . . . . . . . . . . . . . . . . . . . . 28 5.2. Request Audit Token from MASA . . . . . . . . . . . . . . 32
5.3. Request Audit Token . . . . . . . . . . . . . . . . . . . 28 5.3. Audit Token Response . . . . . . . . . . . . . . . . . . 33
5.4. Request Audit Token from MASA . . . . . . . . . . . . . . 29 5.3.1. Completing authentication of Provisional TLS
5.5. Basic Configuration Information Package . . . . . . . . . 30 connection . . . . . . . . . . . . . . . . . . . . . 34
5.6. Request MASA authorization log . . . . . . . . . . . . . 31 5.4. Audit Token Status Telemetry . . . . . . . . . . . . . . 35
6. Reduced security operational modes . . . . . . . . . . . . . 32 5.5. MASA authorization log Request . . . . . . . . . . . . . 36
6.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 32 5.6. MASA authorization log Response . . . . . . . . . . . . . 36
6.2. New Entity security reductions . . . . . . . . . . . . . 33 5.7. EST Integration for PKI bootstrapping . . . . . . . . . . 37
6.3. Registrar security reductions . . . . . . . . . . . . . . 33 5.7.1. EST Distribution of CA Certificates . . . . . . . . . 37
6.4. MASA security reductions . . . . . . . . . . . . . . . . 34 5.7.2. EST CSR Attributes . . . . . . . . . . . . . . . . . 38
7. Security Considerations . . . . . . . . . . . . . . . . . . . 34 5.7.3. EST Client Certificate Request . . . . . . . . . . . 38
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36 5.7.4. Enrollment Status Telemetry . . . . . . . . . . . . . 38
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.7.5. EST over CoAP . . . . . . . . . . . . . . . . . . . . 39
9.1. Normative References . . . . . . . . . . . . . . . . . . 36 6. Reduced security operational modes . . . . . . . . . . . . . 40
9.2. Informative References . . . . . . . . . . . . . . . . . 37 6.1. Trust Model . . . . . . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 6.2. New Entity security reductions . . . . . . . . . . . . . 41
6.3. Registrar security reductions . . . . . . . . . . . . . . 41
6.4. MASA security reductions . . . . . . . . . . . . . . . . 42
7. Security Considerations . . . . . . . . . . . . . . . . . . . 42
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 44
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.1. Normative References . . . . . . . . . . . . . . . . . . 44
9.2. Informative References . . . . . . . . . . . . . . . . . 45
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 46
1. Introduction 1. Introduction
To literally "pull yourself up by the bootstraps" is an impossible To literally "pull yourself up by the bootstraps" is an impossible
action. Similarly the secure establishment of a key infrastructure action. Similarly the secure establishment of a key infrastructure
without external help is also an impossibility. Today it is accepted without external help is also an impossibility. Today it is accepted
that the initial connections between nodes are insecure, until key that the initial connections between nodes are insecure, until key
distribution is complete, or that domain-specific keying material is distribution is complete, or that domain-specific keying material is
pre-provisioned on each new device in a costly and non-scalable pre-provisioned on each new device in a costly and non-scalable
manner. This document describes a zero-touch approach to manner. This document describes a zero-touch approach to
skipping to change at page 6, line 17 skipping to change at page 6, line 30
access data centers. But this solution is not exclusive to the access data centers. But this solution is not exclusive to the
large, it is intended to scale to thousands of devices located in large, it is intended to scale to thousands of devices located in
hostile environments, such as ISP provided CPE devices which are hostile environments, such as ISP provided CPE devices which are
drop-shipped to the end user. The situation where an order is drop-shipped to the end user. The situation where an order is
fulfilled from distributed warehouse from a common stock and shipped fulfilled from distributed warehouse from a common stock and shipped
directly to the target location at the request of the domain owner is directly to the target location at the request of the domain owner is
explicitly supported. That stock ("SKU") could be provided to a explicitly supported. That stock ("SKU") could be provided to a
number of potential domain owners, and the eventual domain owner will number of potential domain owners, and the eventual domain owner will
not know a-priori which device will go to which location. not know a-priori which device will go to which location.
The bootstraping process can take minutes to complete depending on
the network infrastructure and device processing speed. The network
communication itself is not "chatty" but there can be delays for
privacy reasons. This protocol is not intended for low latency
handoffs.
Specifically, there are protocol aspects described here which might Specifically, there are protocol aspects described here which might
result in congestion collapse or energy-exhaustion of intermediate result in congestion collapse or energy-exhaustion of intermediate
battery powered routers in an LLN. Those types of networks SHOULD battery powered routers in an LLN. Those types of networks SHOULD
NOT use this solution. These limitations are predominately related NOT use this solution. These limitations are predominately related
to the large credential and key sizes required for device to the large credential and key sizes required for device
authentication. Defining symmetric key techniques that meet the authentication. Defining symmetric key techniques that meet the
operational requirements is out-of-scope but the underlying protocol operational requirements is out-of-scope but the underlying protocol
operations (TLS handshake and signing structures) have sufficient operations (TLS handshake and signing structures) have sufficient
algorithm agility to support such techniques when defined. algorithm agility to support such techniques when defined.
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that is not yet part of the domain. that is not yet part of the domain.
Proxy: A domain entity that helps the New Entity join the domain. A Proxy: A domain entity that helps the New Entity join the domain. A
Proxy facilitates communication for devices that find themselves Proxy facilitates communication for devices that find themselves
in an environment where they are not provided connectivity until in an environment where they are not provided connectivity until
after they are validated as members of the domain. The New Entity after they are validated as members of the domain. The New Entity
is unaware that they are communicating with a proxy rather than is unaware that they are communicating with a proxy rather than
directly with the Registrar. directly with the Registrar.
MASA Service: A Manufacturer Authorized Signing Authority (MASA) MASA Service: A Manufacturer Authorized Signing Authority (MASA)
service on the global Internet. The MASA provides a trusted service on the global Internet. The MASA provides a repository
repository for audit log information concerning privacy protected for audit log information concerning privacy protected
bootstrapping events. bootstrapping events.
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 allows that have purchased them. Although optional this component allows
vendors to provide additional value in cases where their sales and vendors to provide additional value in cases where their sales and
distribution channels allow for accurately tracking of such distribution channels allow for accurately tracking of such
ownership. ownership.
skipping to change at page 9, line 18 skipping to change at page 10, line 11
and autonomically bootstrap into a key infrastructure delineating the and autonomically bootstrap into a key infrastructure delineating the
autonomic domain. See [I-D.irtf-nmrg-autonomic-network-definitions] autonomic domain. See [I-D.irtf-nmrg-autonomic-network-definitions]
for more information. for more information.
This section details the state machine and operational flow for each This section details the state machine and operational flow for each
of the main three entities. The New Entity, the Domain (primarily of the main three entities. The New Entity, the Domain (primarily
the Registrar) and the MASA service. the Registrar) and the MASA service.
A representative flow is shown in Figure 2: A representative flow is shown in Figure 2:
+--------+ +-------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| New | | Proxy | | Domain | | Vendor | | New | | Circuit | | Domain | | Vendor |
| Entity | | | | Registrar | | Service | | Entity | | Proxy | | Registrar | | Service |
| | | | | | | (Internet | | | | | | | | (Internet |
+--------+ +-------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| | | | | | | |
|<-RFC3927 IPv4 adr | | | |<-RFC3927 IPv4 adr | | |
or|<-RFC4862 IPv6 adr | | | or|<-RFC4862 IPv6 adr | | |
| | | | | | | |
|-------------------->| | | |-------------------->| | |
| optional: mDNS query| | | | optional: mDNS query| | |
| RFC6763/RFC6762 | | | | RFC6763/RFC6762 | | |
| | | | | | | |
|<--------------------| | | |<--------------------| | |
| mDNS broadcast | | | | mDNS broadcast | | |
| response or periodic| | | | response or periodic| | |
| | | | | | | |
|<------------------->|<----------------->| | |<------------------->C<----------------->| |
| (d)TLS via the Proxy | | | TLS via the Circuit Proxy | |
|<--Registrar TLS server authentication---| | |<--Registrar TLS server authentication---| |
[PROVISIONAL accept of server cert] | | [PROVISIONAL accept of server cert] | |
P---IEEE 802.1AR client authentication--->| | P---IEEE 802.1AR client authentication--->| |
P | | | P | | |
P---Request Audit Token (include nonce)-->| | P---Request Audit Token (include nonce)-->| |
P | | | P | | |
P | /---> | | P | /---> | |
P | | [accept device?] | P | | [accept device?] |
P | | [contact Vendor] | P | | [contact Vendor] |
P | | |--New Entity ID---->| P | | |--New Entity ID---->|
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P | | |--optional:nonce--->| P | | |--optional:nonce--->|
P | | | [extract DomainID] P | | | [extract DomainID]
P | | | | P | | | |
P | optional: | [update audit log] P | optional: | [update audit log]
P | |can | | P | |can | |
P | |occur | optional: is | P | |occur | optional: is |
P | |in | an ownership | P | |in | an ownership |
P | |advance | voucher available? P | |advance | voucher available?
P | | | | P | | | |
P | | |<-device audit log--| P | | |<-device audit log--|
P | | |<-audit token-------|
P | | | | P | | | |
P | | |<-optional: --------| P | | | choice: |
P | \----> | ownership voucher | P | | |<-audit token-------|
P | | |<-or: ownership-----|
P | \----> | voucher |
P | | | P | | |
P | [verify audit log or voucher] | P | [verify audit log or voucher] |
P | | | P | | |
P<--Audit token and/or ownership voucher--| | P<--Audit token and/or ownership voucher--| |
[verify response ]| | | [verify response ]| | |
[verify provisional cert ]| | | [verify provisional cert ]| | |
| | | | | | | |
|---------------------------------------->| | |---------------------------------------->| |
| Continue with RFC7030 enrollment | | | Continue with RFC7030 enrollment | |
| using now bidirectionally authenticated | | | using now bidirectionally authenticated | |
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Factory +--------------+ Factory +--------------+
reset reset
Figure 3 Figure 3
State descriptions for the New Entity are as follows: State descriptions for the New Entity are as follows:
1. Discover a communication channel to the "closest" Registrar. 1. Discover a communication channel to the "closest" Registrar.
2. Identify itself. This is done by presenting an IEEE 802.1AR 2. Identify itself. This is done by presenting an IEEE 802.1AR
credentials to the discovered Registrar (via the Proxy) in a credentials to the discovered Registrar (via the Proxy) in a TLS
(d)TLS handshake. (Although the Registrar is also authenticated handshake. (Although the Registrar is also authenticated these
these credentials are only provisionally accepted at this time). credentials are only provisionally accepted at this time).
3. Requests to Join the discovered Registrar. The acceptable 3. Requests to Join the discovered Registrar. A unique nonce is
imprint methods are indicated along with a nonce ensuring that included ensuring that any responses can be associated with this
any responses can be associated with this particular particular bootstrapping attempt.
bootstrapping attempt.
4. Imprint on the Registrar. This requires verification of the 4. Imprint on the Registrar. This requires verification of the
vendor service "Audit Token" or the validation of the vendor vendor service "Audit Token" or the validation of the vendor
service "Ownership Voucher". Either of these responses contains service "Ownership Voucher". Either of these responses contains
sufficient information for the New Entity to complete sufficient information for the New Entity to complete
authentication of the Registrar. (The New Entity can now finish authentication of the Registrar. (The New Entity can now finish
authentication of the Registrar (d)TLS server certificate) authentication of the Registrar TLS server certificate)
5. Enroll by accepting the domain specific information from the 5. Enroll by accepting the domain specific information from the
Registrar, and by obtaining a domain certificate from the Registrar, and by obtaining a domain certificate from the
Registrar using a standard enrollment protocol, e.g. Enrollment Registrar using a standard enrollment protocol, e.g. Enrollment
over Secure Transport (EST) [RFC7030]. over Secure Transport (EST) [RFC7030].
6. The New Entity is now a member of, and can be managed by, the 6. The New Entity is now a member of, and can be managed by, the
domain and will only repeat the discovery aspects of domain and will only repeat the discovery aspects of
bootstrapping if it is returned to factory default settings. bootstrapping if it is returned to factory default settings.
skipping to change at page 12, line 37 skipping to change at page 13, line 36
3.1.1. Discovery 3.1.1. Discovery
The result of discovery is logically communication with a Proxy The result of discovery is logically communication with a Proxy
instead of a Domain Registrar but in such a case the proxy instead of a Domain Registrar but in such a case the proxy
facilitates communication with the actual Domain Registrar in a facilitates communication with the actual Domain Registrar in a
manner that is transparent to the New Entity. Therefore or clarity a manner that is transparent to the New Entity. Therefore or clarity a
Proxy is always assumed. Proxy is always assumed.
To discover the Domain Bootstrap Server the New Entity performs the To discover the Domain Bootstrap Server the New Entity performs the
following actions in this order: following actions:
a. MUST: Obtains a local address using either IPv4 or IPv6 methods a. MUST: Obtains a local address using either IPv4 or IPv6 methods
as described in [RFC4862] IPv6 Stateless Address as described in [RFC4862] IPv6 Stateless Address
AutoConfiguration or [RFC3927] Dynamic Configuration of IPv4 AutoConfiguration or [RFC3927] Dynamic Configuration of IPv4
Link-Local Addresses. Link-Local Addresses.
b. MAY: Performs DNS-based Service Discovery [RFC6763] over b. MUST: Performs DNS-based Service Discovery [RFC6763] over
Multicast DNS [RFC6762] searching for the service Multicast DNS [RFC6762] searching for the service
"_bootstrapks._tcp.local." "_bootstrapks._tcp.local.". To prevent unaccceptable levels of
network traffic the congestion avoidance mechanisms specified in
c. SHOULD: Listen for an unsolicited broadcast response as described [RFC6762] section 7 MUST be followed. The New Entity SHOULD
in [RFC6762]. This allows devices to avoid announcing their listen for an unsolicited broadcast response as described in
[RFC6762]. This allows devices to avoid announcing their
presence via mDNS broadcasts and instead silently join a network presence via mDNS broadcasts and instead silently join a network
by watching for periodic unsolicited broadcast responses. by watching for periodic unsolicited broadcast responses.
d. MAY: Performs DNS-based Service Discovery [RFC6763] over normal c. MAY: Performs DNS-based Service Discovery [RFC6763] over normal
DNS operations. In this case the domain is known so the service DNS operations. The service searched for is
searched for is "_bootstrapks._tcp.example.com". "_bootstrapks._tcp.example.net". In this case the domain
"example.net" is discovered as described in [RFC6763] section 11.
e. MAY: If no local bootstrapks service is located using the DNS- d. MAY: If no local bootstrapks service is located using the DNS-
based Service Discovery methods the New Entity contacts a well based Service Discovery methods the New Entity contacts a well
known vendor provided bootstrapping server by performing a DNS known vendor provided bootstrapping server by performing a DNS
lookup using a well known URI such as "bootstrapks.vendor- lookup using a well known URI such as "bootstrapks.vendor-
example.com". example.com". The details of the URI are vendor specific.
Vendors that leverage this method SHOULD provision appropriately.
Once a Registrar is discovered (technically a communication channel DNS-based service discovery communicates the local proxy IPv4 or IPv6
through a Proxy) the New Entity communicates with the Registrar using address and port to the New Entity. Once a proxy is discovered the
New Entity communicates with the Registrar through the proxy using
the bootstrapping protocol defined in Section 5. The current DNS the bootstrapping protocol defined in Section 5. The current DNS
services returned during each query is maintained until bootstrapping services returned during each query is maintained until bootstrapping
is completed. If bootstrapping fails and the New Entity returns to is completed. If bootstrapping fails and the New Entity returns to
the Discovery state it picks up where it left off and continues the Discovery state it picks up where it left off and continues
attempting bootstrapping. For example if the first Multicast DNS attempting bootstrapping. For example if the first Multicast DNS
_bootstrapks._tcp.local response doesn't work then the second and _bootstrapks._tcp.local response doesn't work then the second and
third responses are tried. If these fail the New Entity moves on to third responses are tried. If these fail the New Entity moves on to
normal DNS-based Service Discovery. normal DNS-based Service Discovery.
Once all discovered services are attempted the device SHOULD return Each discovery method attempted SHOULD exponentially back-off
to Multicast DNS and keep trying. The New Entity may prioritize attempts (to a maximum of one hour) to avoid overloading that
selection order as appropriate for the anticipated environment. discovery methods network infrastructure. The back-off timer for
each method MUST be independent of other methods. Methods SHOULD be
run in parallel to avoid head of queue problems. Once a connection
to a Registrar is established (e.g. establishment of a TLS session
key) there are expectations of more timely responses, see
Section 5.1.
[[EDNOTE: An appropriate backoff or rate limiting strategy should be Once all discovered services are attempted the device SHOULD return
defined here such that the device doesn't flood the local network to Multicast DNS. It should periodically retry the vendor specific
with queries. If the device were to eventually give up -- or at mechanisms. The New Entity may prioritize selection order as
least have too long between attempts -- a power cycle would restart appropriate for the anticipated environment.
the backoff mechanism.]]
3.1.2. Identity 3.1.2. Identity
The New Entity identifies itself during the communication protocol The New Entity identifies itself during the communication protocol
handshake. If the client identity is rejected the New Entity repeats handshake. If the client identity is rejected the New Entity repeats
the Discovery process using the next proxy or discovery method the Discovery process using the next proxy or discovery method
available. available.
The bootstrapping protocol server is not authenticated. Thus this The bootstrapping protocol server is not initially authenticated.
connection is provisional and all data received is untrusted until Thus the connection is provisional and all data received is untrusted
sufficiently validated even though it is over a (D)TLS connection. until sufficiently validated even though it is over a TLS connection.
This is aligned with the existing provisional mode of EST [RFC7030] This is aligned with the existing provisional mode of EST [RFC7030]
during s4.1.1 "Bootstrap Distribution of CA Certificates". during s4.1.1 "Bootstrap Distribution of CA Certificates". See
Section 5.3 for more information about when the TLS connection
authenticated is completed.
All security associations established are between the new device and All security associations established are between the new device and
the Bootstrapping server regardless of proxy operations. the Bootstrapping server regardless of proxy operations.
3.1.3. Request Join 3.1.3. Request Join
The New Entity POSTs a request to join the domain to the The New Entity POSTs a request to join the domain to the
Bootstrapping server. This request contains a New Entity generated Bootstrapping server. This request contains a New Entity generated
nonce and informs the Bootstrapping server which imprint methods the nonce and informs the Bootstrapping server which imprint methods the
New Entity will accept. New Entity will accept.
skipping to change at page 14, line 32 skipping to change at page 15, line 40
The nonce ensures the New Entity can verify that responses are The nonce ensures the New Entity can verify that responses are
specific to this bootstrapping attempt. This minimizes the use of specific to this bootstrapping attempt. This minimizes the use of
global time and provides a substantial benefit for devices without a global time and provides a substantial benefit for devices without a
valid clock. valid clock.
3.1.4. Imprint 3.1.4. Imprint
The domain trust anchor is received by the New Entity during the The domain trust anchor is received by the New Entity during the
bootstrapping protocol methods in the form of either an Audit Token bootstrapping protocol methods in the form of either an Audit Token
containing the domainID or an explicit ownership voucher. The goal containing the domain CA cert or an explicit ownership voucher. The
of the imprint state is to securely obtain a copy of this trust goal of the imprint state is to securely obtain a copy of this trust
anchor without involving human interaction. anchor without involving human interaction.
The enrollment protocol EST [RFC7030] details a set of non-autonomic The enrollment protocol EST [RFC7030] details a set of non-autonomic
bootstrapping methods such as: bootstrapping methods such as:
o using the Implicit Trust Anchor database (not an autonomic o using the Implicit Trust Anchor database (not an autonomic
solution because the URL must be securely distributed), solution because the URL must be securely distributed),
o engaging a human user to authorize the CA certificate using out- o engaging a human user to authorize the CA certificate using out-
of-band data (not an autonomic solution because the human user is of-band data (not an autonomic solution because the human user is
skipping to change at page 15, line 10 skipping to change at page 16, line 18
o and using a Certificate-Less TLS mutual authentication method (not o and using a Certificate-Less TLS mutual authentication method (not
an autonomic solution because the distribution of symmetric key an autonomic solution because the distribution of symmetric key
material is not autonomic). material is not autonomic).
This document describes additional autonomic methods: This document describes additional autonomic methods:
MASA audit token Audit tokens are obtained by the Registrar from the MASA audit token Audit tokens are obtained by the Registrar from the
MASA service and presented to the New Entity for validation. MASA service and presented to the New Entity for validation.
These indicate to the New Entity that joining the domain has been These indicate to the New Entity that joining the domain has been
logged by a trusted logging server. logged by a logging service.
Ownership Voucher Ownership Vouchers are obtained by the Registrar Ownership Voucher Ownership Vouchers are obtained by the Registrar
from the MASA service and explicitly indicate the fully qualified from the MASA service and explicitly indicate the fully qualified
domain name of the domain the new entity currently belongs to. domain name of the domain the new entity currently belongs to.
The Ownership Voucher is defined in [I-D.ietf-netconf-zerotouch]. The Ownership Voucher is defined in [I-D.ietf-netconf-zerotouch].
Since client authentication occurs during the TLS handshake the Since client authentication occurs during the TLS handshake the
bootstrapping server has sufficient information to apply appropriate bootstrapping server has sufficient information to apply appropriate
policy concerning which method to use. policy concerning which method to use.
An arbitrary basic configuration information package that is signed The audit token contains the domain's public key material as provided
by the domain can be delivered alongside the Audit Token or ownership to the MASA service by the Registrar. This provides sufficient
validation. This information is signed by the domain private keys information to the client to complete automated bootstrapping with
and is a one time delivery containing information such as which the local key infrastructure.
enrollment server to communicate with and which management system to
communicate with. It is intended as a limited basic configuration
for these purposes and is not intended to deliver entire final
configuration to the device.
If the autonomic methods fail the New Entity returns to discovery If the autonomic methods fail the New Entity returns to discovery
state and attempts bootstrapping with the next available discovered state and attempts bootstrapping with the next available discovered
Registrar. Registrar.
3.1.5. Enrollment 3.1.5. Lack of realtime clock
Many devices when bootstrapping do not have knowledge of the current
time. Mechanisms like Network Time Protocols can not be secured
until bootstrapping is complete. Therefore bootstrapping is defined
in a method that does not require knowledge of the current time.
Unfortunately there are moments during bootstrapping when
certificates are verified, such as during the TLS handshake, where
validity periods are confirmed. This paradoxical "catch-22" is
resolved by the New Entity maintaining a concept of the current
"window" of presumed time validity that is continually refined
throughout the bootstrapping process as follows:
o Initially the New Entity does not know the current time. The
nonce included in join attempts provides an alternate mechanism
for the New Entity to ensure responses are associated with a
particular bootstrapping attempt. Nonceless audit tokens from the
MASA server are always valid and thus time is not needed.
o In accordance with IEEE 802.1AR and RFC5280 all manufacturing
installed certificates and trust anchors are assumed to have
infinite lifetimes. All such certificates "SHOULD be assigned the
GeneralizedTime value of 99991231235959Z" [RFC5280]. The New
Entity, Registrar and MASA server MUST ignore any other validity
period information in these credentials and treat the effective
lifetime as 99991231235959Z. This ensures that client
authentication (see Section 3.3.1) and the audit token signature
(see Section 5.3) can always be verified during RFC5280 path
validation.
o Once the audit token is accepted the validity period of the
domainCAcert in the token (see Section 5.3) now describes a valid
time window. Any subsequent certificate validity periods checked
during RFC5280 path validation MUST occur within this window.
o When accepting an enrollment certificate the validity period
within the new end entity certificate is assumed to be valid by
the New Entity. The New Entity is now willing to use this
credential for client authentication.
Once in this state the New Entity has a valid trust anchor with the
local domain and has a locally issued credential. These MAY be used
to secure distribution of more accurate time information although
specification of such a protocol is out-of-scope of this document.
3.1.6. Enrollment
As the final step of bootstrapping a Registrar helps to issue a As the final step of bootstrapping a Registrar helps to issue a
domain specific credential to the New Entity. For simplicity in this domain specific credential to the New Entity. For simplicity in this
document, a Registrar primarily facilitates issuing a credential by document, a Registrar primarily facilitates issuing a credential by
acting as an RFC5280 Registration Authority for the Domain acting as an RFC5280 Registration Authority for the Domain
Certification Authority. Certification Authority.
Enrollment proceeds as described in Enrollment over Secure Transport Enrollment proceeds as described in Enrollment over Secure Transport
(EST) [RFC7030]. The New Entity contacts the Registrar using EST as (EST) [RFC7030]. The New Entity contacts the Registrar using EST as
indicated: indicated:
skipping to change at page 16, line 10 skipping to change at page 18, line 13
credentials. credentials.
o The EST section 4.1.3 CA Certificates Response is verified using o The EST section 4.1.3 CA Certificates Response is verified using
either the Audit Token which provided the domain identity -or- either the Audit Token which provided the domain identity -or-
o The EST server is authenticated by using the Ownership Voucher o The EST server is authenticated by using the Ownership Voucher
indicated fully qualified domain name to build the EST URI such indicated fully qualified domain name to build the EST URI such
that EST section 4.1.1 bootstrapping using the New Entity implicit that EST section 4.1.1 bootstrapping using the New Entity implicit
Trust Anchor database can be used. Trust Anchor database can be used.
3.1.6. Being Managed Once the Audit Token is received, as specified in this document, the
client has sufficient information to leverage the existing
communication channel with the Registrar to continue an EST RFC7030
enrollment. Enrollment picks up at RFC7030 section 4.1.1.
bootstrapping where the audit token provides the "out-of-band" CA
certificate fingerprint (in this case the full CA certificate) such
that the client can now complete the TLS server authentication. At
this point the client continues with EST enrollment operations
including "CA Certificates Request", "CSR Attributes" and "Client
Certificate Request" or "Server-Side Key Generation".
3.1.7. Being Managed
Functionality to provide generic "configuration" information is Functionality to provide generic "configuration" information is
supported. The parsing of this data and any subsequent use of the supported. The parsing of this data and any subsequent use of the
data, for example communications with a Network Management System is data, for example communications with a Network Management System is
out of scope but is expected to occur after bootstrapping enrollment out of scope but is expected to occur after bootstrapping enrollment
is complete. This ensures that all communications with management is complete. This ensures that all communications with management
systems which can divulge local security information (e.g. network systems which can divulge local security information (e.g. network
topology or raw key material) is secured using the local credentials topology or raw key material) is secured using the local credentials
issued during enrollment. issued during enrollment.
skipping to change at page 16, line 33 skipping to change at page 18, line 47
After the device has successfully joined a domain and is being After the device has successfully joined a domain and is being
managed it is plausible that the domain can insert credentials for managed it is plausible that the domain can insert credentials for
other domains depending on the device capabilities. other domains depending on the device capabilities.
See Section 3.5. See Section 3.5.
3.2. Behavior of a Proxy 3.2. Behavior of a 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 New Entity and the Registrar that has forwards packets between the New Entity and the Registrar that has
been configured on the Proxy. The Proxy does not terminate the been configured on the Proxy. The Proxy does not terminate the TLS
(d)TLS handshake. handshake.
In order to permit the proxy functionality to be implemented on the In order to permit the proxy functionality to be implemented on the
maximum variety of devices the chosen mechanism SHOULD use the maximum variety of devices the chosen mechanism SHOULD use the
minimum amount of state on the proxy device. While many devices in minimum amount of state on the proxy device. While many devices in
the ANIMA target space will be rather large routers, the proxy the ANIMA target space will be rather large routers, the proxy
function is likely to be implemented in the control plane CPU such a function is likely to be implemented in the control plane CPU such a
device, with available capabilities for the proxy function similar to device, with available capabilities for the proxy function similar to
many class 2 IoT devices. 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
skipping to change at page 17, line 13 skipping to change at page 19, line 27
choice of CoAP as the mandatory to implement protocol rather than choice of CoAP as the mandatory to implement protocol rather than
HTTP maximizes code reuse on the smallest of devices. Unfortunately HTTP maximizes code reuse on the smallest of devices. Unfortunately
this means this document will have to include the EST over CoAP this means this document will have to include the EST over CoAP
details as additional sections. The alternative is to make 'HTTPS details as additional sections. The alternative is to make 'HTTPS
proxy' method the mandatory to implement and provide a less friendly proxy' method the mandatory to implement and provide a less friendly
environment for the smallest of devices. This is a decision we'll environment for the smallest of devices. This is a decision we'll
have to see addressed by the broader team.]] have to see addressed by the broader team.]]
As a result of the Proxy Discovery process in section Section 3.1.1, As a result of the Proxy Discovery process in section Section 3.1.1,
the port number exposed by the proxy does not need to be well known, the port number exposed by the proxy does not need to be well known,
or require an IANA allocation. The address and port of the Registrar or require an IANA allocation.
will be discovered by the GRASP protocol inside the ACP. For the
IPIP encapsulation methods, the port announced by the Proxy MUST be The address and port of the Registrar to which the packets will be
the same as on the registrar. forwarded will be discovered by the GRASP protocol inside the ACP.
For the IPIP encapsulation methods, the port announced by the Proxy
MUST be the same as on the registrar in order for the proxy to remain
stateless.
The IPIP encapsulation allows the proxy to forward traffic which is The IPIP encapsulation allows the proxy to forward traffic which is
otherwise not to be forwarded, as the traffic between New Node and otherwise not to be forwarded, as the traffic between New Node and
Proxy use IPv6 Link Local addresses. Proxy use IPv6 Link Local addresses.
If the Proxy device has more than one interface on which it offers If the Proxy device has more than one interface on which it offers
the proxy function, then it must select a unique IP address per the proxy function, then it must select a unique (ACP) IP address per
interface in order so that the proxy can stateless return the reply interface in order so that the proxy can stateless return the reply
packets to the correct link. packets to the correct link.
3.2.2. HTTPS proxy connection to Registrar 3.2.2. HTTPS proxy connection to Registrar
The proxy SHOULD also provide one of: an IPIP encapsulation of HTTP The proxy SHOULD also provide one of: an IPIP encapsulation of HTTP
traffic on TCP port TBD to the registrar, an HTTP proxy which accepts traffic on TCP port TBD to the registrar, or a TCP circuit proxy that
URLs that reach the Registrar, or a TCP circuit proxy that connects connects the New Node to the Registrar.
the New Node to the Registrar.
In order to make the HTTP choice above transparent to the New Node,
the New Node will always initiate an HTTP connection, and will always
send an appropriate CONNECT message to initiate an HTTPS connection
to the registrar. [[EDNOTE: The CONNECT syntax is that the New
Entity specifies the Registrar server in the CONNECT line. See
RFC7231 s4.3.6. We wish the Proxy to override any value with the
locally known-to-the-proxy Registrar address.]]
When the Proxy provides a circuit proxy to the Registrar the When the Proxy provides a circuit proxy to the Registrar the
Registrar MUST accept HTTP connections, and be willing to perform an Registrar MUST accept HTTPS connections.
HTTP proxy (CONNECT) operation to itself, and then initiate HTTPS.
When the Proxy provides a stateless IPIP encapsulation to the When the Proxy provides a stateless IPIP encapsulation to the
Registrar, then the Registrar will have to perform IPIP Registrar, then the Registrar will have to perform IPIP
decapsulation, remembering the originating outer IPIP source address decapsulation, remembering the originating outer IPIP source address
in order to qualify the inner link-local address. Being able to in order to qualify the inner link-local address. This is a kind of
connect a TCP (HTTP) or UDP (CoAP) socket to a link-local address encapsulation and processing which is similar in many ways to how
with an encapsulated IPIP header requires API extensions beyond mobile IP works.
[RFC3542] for UDP use, and requires a form of connection latching Being able to connect a TCP (HTTP) or UDP (CoAP) socket to a link-
(see section 4.1 of [RFC5386] and all of [RFC5660], except that a local address with an encapsulated IPIP header requires API
simple IPIP tunnel is used rather than an IPsec tunnel). extensions beyond [RFC3542] for UDP use, and requires a form of
connection latching (see section 4.1 of [RFC5386] and all of
[RFC5660], except that a simple IPIP tunnel is used rather than an
IPsec tunnel).
3.3. Behavior of the Registrar (Bootstrap Server) 3.3. Behavior of the Registrar (Bootstrap Server)
Once a Registrar is established it listens for new entities and Once a Registrar is established it listens for new entities and
determines if they can join the domain. The registrar delivers any determines if they can join the domain. The registrar delivers any
necessary authorization information to the new device and facilitates necessary authorization information to the new device and facilitates
enrollment with the domain PKI. enrollment with the domain PKI.
Registrar behavior is as follows: Registrar behavior is as follows:
skipping to change at page 19, line 9 skipping to change at page 21, line 41
| token + config | | Device | | token + config | | Device |
| to the Entity | | | | to the Entity | | |
+------------------+ +------------+ +------------------+ +------------+
Figure 4 Figure 4
3.3.1. Entity Authentication 3.3.1. Entity Authentication
The applicable authentication methods detailed in EST [RFC7030] are: The applicable authentication methods detailed in EST [RFC7030] are:
o the use of an IEEE 802.1AR IDevID credential, o the use of an IEEE 802.1AR IDevID credential during the TLS client
authentication,
o or the use of a secret that is transmitted out of band between the o or the use of a secret that is transmitted out of band between the
New Entity and the Registrar (this use case is not autonomic). New Entity and the Registrar (this use case is not autonomic).
3.3.2. Entity Authorization 3.3.2. Entity Authorization
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
skipping to change at page 21, line 17 skipping to change at page 23, line 50
o Any nonce'd entries are older than when the domain is known to o Any nonce'd entries are older than when the domain is known to
have physical possession of the new entity or that the domainIDs have physical possession of the new entity or that the domainIDs
are recognized by the registrar. are recognized by the registrar.
If any of these criteria are unacceptable to the registrar the entity If any of these criteria are unacceptable to the registrar the entity
is rejected. The Registrar MAY be configured to ignore the history is rejected. The Registrar MAY be configured to ignore the history
of the device but it is RECOMMENDED that this only be configured if of the device but it is RECOMMENDED that this only be configured if
hardware assisted NEA [RFC5209] is supported. hardware assisted NEA [RFC5209] is supported.
3.3.5. Forwarding Audit Token plus Configuration This document specifies a simple log format as provided by the MASA
service to the registar. This format could be improved by
The Registrar forwards the received Audit Token to the New Entity. distributed consensus technologies that integrate the audit token
To simplify the message flows an initial configuration package can be with a current technologies such as block-chain or hash trees or the
delivered at this time which is signed by a representative of the like. Doing so is out of the scope of this document but are
domain. anticipated improvements for future work.
[[EDNOTE: format TBD. The configuration package signature data must
contain the full certificate path sufficient for the new entity to
use the domainID information (as a trust anchor) to accept and
validate the configuration)]]
3.4. Behavior of the MASA Service 3.4. Behavior of the MASA Service
The MASA service is provided by the Factory provider on the global The MASA service is provided by the Factory provider on the global
Internet. The URI of this service is well known. The URI SHOULD Internet. The URI of this service is well known. The URI SHOULD
also be provided as an IEEE 802.1AR IDevID X.509 extension (a "MASA also be provided as an IEEE 802.1AR IDevID X.509 extension (a "MASA
Audit Token Distribution Point" extension). Audit Token Distribution Point" extension).
The MASA service provides the following functionalities to The MASA service provides the following functionalities to
Registrars: Registrars:
skipping to change at page 25, line 7 skipping to change at page 27, line 33
anchor it can be assumed "inside" the same organization; if not, as anchor it can be assumed "inside" the same organization; if not, as
outside. See also Section 3.5.1. The certificate can also be used outside. See also Section 3.5.1. The certificate can also be used
to securely establish a connection between devices and central to securely establish a connection between devices and central
control functions. Also autonomic transactions can use the domain control functions. Also autonomic transactions can use the domain
certificates to authenticate and/or encrypt direct interactions certificates to authenticate and/or encrypt direct interactions
between devices. The usage of the domain certificates is outside between devices. The usage of the domain certificates is outside
scope for this document. scope for this document.
5. Protocol Details 5. Protocol Details
For simplicity the bootstrapping protocol is described as extensions A bootstrapping protocol could be implemented as an independent
to EST [RFC7030]. protocol from EST, but for simplicity and to reduce the number of TLS
connections and crypto operations required on the New Entity, it is
EST provides a bootstrapping mechanism for new entities that are described specifically as extensions to EST. These extensions MUST
configured with the URI of the EST server such that the Implicit TA be supported by the Registrar EST server within the same .well-known
database can be used to authenticate the EST server. Alternatively URI tree as the existing EST URIs as described in [RFC7030] section
EST clients can "engage a human user to authorize the CA certificate 3.2.2.
using out-of-band data such as a CA certificate". EST does not
provide a completely automated method of bootstrapping the PKI as
both of these methods require some user input (either of the URI or
authorizing the CA certificate).
This section details additional EST functionality that support The new entity establishes a TLS connection with the Registrar
automated bootstrapping of the public key infrastructure. These through the circuit proxy (see Section 3.2) but the TLS connection is
additions provide for fully automated bootstrapping. These additions with the Registar; so for this section the "New Entity" is the TLS
are to be optionally supported by the EST server within the same client and the "Registrar" is the TLS server.
.well-known URI tree as the existing EST URIs.
The "New Entity" is the EST client and the "Registrar" is the EST Establishment of the TLS connection for bootstrapping is as specified
server. for EST [RFC7030]. In particular server identity and client identity
are as described in EST [RFC7030] section 3.3. In EST [RFC7030]
provisional server authentication for bootstrapping is described in
section 4.1.1 wherein EST clients can "engage a human user to
authorize the CA certificate using out-of-band data such as a CA
certificate" or wherein a human user configures the URI of the EST
server for Implicit TA based authentication. As described in this
document, Section 5.3.1, a new method of bootstrapping now provides a
completely automating method of bootstrapping PKI.
The extensions for the client are as follows: The extensions for the New Entity client are as follows:
o The New Entity provisionally accept the EST server certificate o The New Entity provisionally accept the EST server certificate
during the TLS handshake as detailed in EST section 4.1.1 during the TLS handshake as detailed in Section 5.3.1.
("Bootstrap Distribution of CA Certificates").
o The Registrar requests and validates the Audit Token from the
vendor authorized MASA service.
o The New Entity requests and validates the Audit Token as described o The New Entity requests and validates the Audit Token as described
below. At this point the New Entity has sufficient information to below. At this point the New Entity has sufficient information to
validate domain credentials. validate domain credentials.
o The New Entity calls the EST defined /cacerts method to obtain the o The New Entity calls the EST defined /cacerts method to obtain the
current CA certificate. These are validated using the Audit current CA certificate. These are validated using the Audit
Token. Token.
o The New Entity completes bootstrapping as detailed in EST section o The New Entity completes bootstrapping as detailed in EST section
4.1.1. 4.1.1.
These extensions could be implemented as an independent protocol from
EST but since the overlap with basic enrollment is extensive,
particularly with respect to client authorization, they are presented
here as additions to EST.
In order to obtain a validated Audit Token and Audit Log the In order to obtain a validated Audit Token and Audit Log the
Registrar contacts the MASA service Service using REST calls: Registrar contacts the MASA service Service using REST calls:
+-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+
| New | | | | | | | | New | | Circuit | | | | |
| Entity | | Proxy | | Registrar | | Vendor | | Entity | | Proxy | | Registrar | | Vendor |
| | | | | | | | | | | | | | | |
++----------+ +--+-------+ +-----+-----+ +--------+-+ ++----------+ +--+-------+ +-----+-----+ +--------+-+
| | | | | | | |
| | | | | | | |
| (D)TLS hello | | | | TLS hello | TLS hello | |
Establish +---------------> (D)TLS hello | | Establish +---------------C---------------> |
(D)TLS | |---------------> | TLS | | | |
connection | (forwarding) | | connection | | Server Cert | |
| Server Cert <---------------+ | <---------------C---------------+ |
<---------------+ | |
| Client Cert | | | | Client Cert | | |
+-------------------------------> | +---------------C---------------> |
| | | | | | | |
HTTP REST | POST /requestaudittoken | | HTTP REST | POST /requestaudittoken | |
Data +--------------------nonce------> | Data +--------------------nonce------> |
| . | /requestaudittoken | . | /requestaudittoken
| . +----------------> | . +---------------->
| <----------------+ | <----------------+
| | /requestauditlog | | /requestauditlog
| +----------------> | +---------------->
| audit token or owner voucher <----------------+ | audit token or owner voucher <----------------+
<-------------------------------+ | <-------------------------------+ |
skipping to change at page 27, line 6 skipping to change at page 30, line 6
Figure 5 Figure 5
In some use cases the Registrar may need to contact the Vendor in In some use cases the Registrar may need to contact the Vendor in
advanced, for example when the target network is air-gapped. The advanced, for example when the target network is air-gapped. The
nonceless request format is provided for this and the resulting flow nonceless request format is provided for this and the resulting flow
is slightly different. The security differences associated with not is slightly different. The security differences associated with not
knowing the nonce are discussed below: knowing the nonce are discussed below:
+-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+ +-----------+ +----------+
| New | | | | | | | | New | | Circuit | | | | |
| Entity | | Proxy | | Registrar | | Vendor | | Entity | | Proxy | | Registrar | | Vendor |
| | | | | | | | | | | | | | | |
++----------+ +--+-------+ +-----+-----+ +--------+-+ ++----------+ +--+-------+ +-----+-----+ +--------+-+
| | | | | | | |
| | | | | | | |
| | | /requestaudittoken | | | /requestaudittoken
| | (nonce +----------------> | | (nonce +---------------->
| | unknown) <----------------+ | | unknown) <----------------+
| | | /requestauditlog | | | /requestauditlog
| | +----------------> | | +---------------->
| | <----------------+ | | <----------------+
| (D)TLS hello | | | | TLS hello | TLS hello | |
Establish +---------------> (D)TLS hello | | Establish +---------------C---------------> |
(D)TLS | |---------------> | TLS | | | |
connection | (forwarding) | | connection | | Server Cert | |
| SerVer Cert <---------------+ | <---------------C---------------+ |
<---------------+ | |
| Client Cert | | | | Client Cert | | |
+-------------------------------> |
| | | | | | | |
HTTP REST | POST /requestaudittoken | | HTTP REST | POST /requestaudittoken | |
Data +----------------------nonce----> (discard | Data +----------------------nonce----> (discard |
| audit token or owner Voucher | nonce) | | audit token or owner Voucher | nonce) |
<-------------------------------+ | <-------------------------------+ |
| (optional config information) | | | (optional config information) | |
| . | | | . | |
| . | | | . | |
Figure 6 Figure 6
5.1. IEEE 802.1AR as client identity The extensions for the Registrar server are as follows:
The Registrar authenticates the client and performs authorization
checks to ensure this client is expected to join the domain. This
require a common procedure for representing and verifying the
identity of the client. The methods detailed in [RFC6125] such as
matching DNS Domain Name or Application Service Type are not directly
applicable.
Clients presents an IEEE 802.AR certificate complete with subject
field identifying the device uniquely in the Distinguished Name
serialNumber subfield. The subjectAltName MAY contain a
hardwareModuleName as specified in RFC4108. The Registrar extracts
this information and compares against a per vendor access control
list. (This can be implemented with a single database table so long
as the authority key identifier is also maintained and checked to
ensure that no two vendors collide in their use of serialNumber's).
When enrollment is complete and a local certificate is issued to the
new device the local CA has complete control over the namespace. If
this credential is intended for RFC6125 style TLS connections where
servers are identified by a server's DNS-ID identity the CA is likely
to ensure the dNSName field is populated. For Anima purposes the
IEEE 802.1AR serialNumber and hardwareModuleName fields MUST be
propagated to the issued certificate.
[[EDNOTE: the above authority key identifier trick works for database o The Registrar requests and validates the Audit Token from the
lookups and here the inclusion of the DNS name would serve the same vendor authorized MASA service.
purpose. Alternatively an Anima specified domain specific identifier
must be indicated.]]
5.2. EST over CoAP o The Registrar forwards the Audit Token to the New Entity when
requested.
[[EDNOTE: In order to support smaller devices the above section on o The Registar performs log verifications in addition to local
Proxy behavior introduces mandatory to implement support for CoAP authorization checks before accepting the New Entity device.
support by the Proxy. This implies similar support by the New Entity
and Registrar and means that the EST protocol operation encapsulation
into CoAP needs to be described. EST is HTTP based and "CoaP is
designed to easily interface with HTTP for integration" [RFC7252] so
this section is anticipated to be relatively straightforward. A
complexity is that the large message sizes necessary for
bootstrapping will require support for [draft-ietf-core-block].]]
5.3. Request Audit Token 5.1. Request Audit Token from the Registrar
When the New Entity reaches the EST section 4.1.1 "Bootstrap When the New Entity reaches the EST section 4.1.1 "Bootstrap
Distribution of CA Certificates" state but wishes to proceed in a Distribution of CA Certificates" state but wishes to proceed in a
fully automated fashion it makes a request for a MASA authorization fully automated fashion it makes a request for a MASA authorization
token from the Registrar. token from the 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
"/requestaudittoken". "/requestaudittoken".
The request format is JSON object containing a nonce. The request format is JSON object containing a 64bit nonce generated
by the client for each request. This nonce MUST be a
cryptographically strong random or pseudo-random number that can not
be easily predicted. The nonce MUST NOT be reused for multiple
attempts to join a network domain. The nonce assures the New Entity
that the audit token response is associated with this bootstrapping
attempt and is not a replay.
Request media type: application/auditnonce Request media type: application/auditnonce
Request format: a JSON file with the following: Request format: a JSON file with the following:
{"nonce":"<64bit nonce value>", "OwnershipValidation":boolean} {
"version":"1",
"nonce":"<64bit nonce value>",
}
[[EDNOTE: exact format TBD. There is an advantage to having the [[EDNOTE: Even if the nonce was signed it would provide no defense
client sign the nonce (similar to a PKI Certification Signing against rogue registrars; although it would assure the MASA that a
Request) since this allows the MASA service to confirm the actual certified new entity exists. To protect against rogue registrars a
device identity. It is not clear that there is a security benefit nonce component generated by the MASA (a new round trip) would be
from this since its the New Entity that verifies the nonce.]] required). Instead this is addressed by requiring MASA & Registrar
authentications but it is worth exploring additional protections.
This to be explored more at IETF96.]]
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 performs authorization as [RFC7030] section 3.3.2. The registrar performs authorization as
detailed in Section 3.3.2. If authorization is successful the detailed in Section 3.3.2. If authorization is successful the
Registrar obtains an Audit Token from the MASA service (see Registrar obtains an Audit Token from the MASA service (see
Section 5.2). Section 5.2).
The received MASA authorization token is returned to the New Entity. The received MASA authorization token is returned to the New Entity.
As indicated in EST [RFC7030] the bootstrapping server can redirect As indicated in EST [RFC7030] the bootstrapping server can redirect
the client to an alternate server. If the New Entity authenticated the client to an alternate server. If the New Entity authenticated
the Registrar using the well known URI method then the New Entity the Registrar using the well known URI method then the New Entity
MUST follow the redirect automatically and authenticate the new MUST follow the redirect automatically and authenticate the new
Registrar against the redirect URI provided. If the New Entity had Registrar against the redirect URI provided. If the New Entity had
not yet authenticated the Registrar because it was discovered and was not yet authenticated the Registrar because it was discovered and was
not a known-to-be-valid URI then the new Registrar must be not a known-to-be-valid URI then the new Registrar must be
authenticated using one of the two autonomic methods described in authenticated using one of the two autonomic methods described in
this document. this document. Similarly the Registar MAY respond with an HTTP 202
("the request has been accepted for processing, but the processing
has not been completed") as described in EST [RFC7030] section 4.2.3.
5.4. Request Audit Token from MASA Recall that during this communication with the Registar the TLS
authentication is only provisional. The New Entity client MUST
handle all data from the Registrar with upmost care. In particular
the New Entity MUST only allow a single redirection and MUST only
support a delay of five seconds before declaring the Registrar a
failure and moving on to the next discovered Registrar. As detailed
in Section 3.1.1 if no suitable Registrar is found the New Entity
restarts the state machine and tries again. So a Registrar that is
unable to complete the transaction the first time will have future
chances.
5.2. Request Audit Token from MASA
The Registrar requests the Audit Token from the MASA service using a The Registrar requests the Audit Token from the MASA service using a
REST interface. For simplicity this is defined as an optional EST REST interface. For simplicity this is defined as an optional EST
message between the Registrar and an EST server running on the MASA message between the Registrar and an EST server running on the MASA
service although the Registrar is not required to make use of any service although the Registrar is not required to make use of any
other EST functionality when communicating with the MASA service. other EST functionality when communicating with the MASA service.
(The MASA service MUST properly reject any EST functionality requests (The MASA service MUST properly reject any EST functionality requests
it does not wish to service; a requirement that holds for any REST it does not wish to service; a requirement that holds for any REST
interface). interface).
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
"/requestaudittoken". "/requestaudittoken".
The request format is a JSON object optionally containing the nonce The request format is a JSON object optionally containing the nonce
value (as obtained from the bootstrap request) and the IEEE 802.1AR value (as obtained from the bootstrap request) and the IEEE 802.1AR
identity of the device as a serial number (the full certificate is identity of the device as a serial number (the full certificate is
not needed and no proof-of-possession information for the device not needed and no proof-of-possession information for the device
identity is included). The New Entity's serial number is extracted identity is included). The AuthorityKeyIdentifier value from the
from the IEEE 802.1AR subject name: certificate is included to ensure a statistically unique identity.
The New Entity's serial number is extracted from the IEEE 802.1AR
subject name id-at-serialNumber or it is the base64 encoded RFC4108
hardwareModuleName hwSerialNum:
{"nonce":"<64bit nonce value>", "serialnumber", "<subjectname/ {
subjectaltname serial number>"} "version":"1",
"nonce":"<64bit nonce value>",
"IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier">,
"DevIDSerialNumber":"<id-at-serialNumber or base64 encoded
hardwareModuleName hwSerialNum>",
}
The Registrar MAY exclude the nonce from the request. Doing so The Registrar MAY exclude the nonce from the request. Doing so
allows the Registrar to request an authorization token when the New allows the Registrar to request an authorization token when the New
Entity is not online, or when the target bootstrapping environment is Entity is not online, or when the target bootstrapping environment is
not on the same network as the MASA server. If a nonce is not not on the same network as the MASA server (this requires the
provided the MASA server MUST authenticate the client as described in Registrar to learn the appropriate DevIDSerialNumber field from the
EST [RFC7030] section 3.3.2. The registrar performs authorization as physical device labeling or from the sales channel -- how this occurs
detailed in Section 3.3.2. If authorization is successful the is out-of-scope of this document). If a nonce is not provided the
Registrar obtains an Audit Token from the MASA service (see MASA server MUST authenticate the client as described in EST
Section 5.4). [RFC7030] section 3.3.2 to reduce the risk of DDoS attacks. The
registrar performs authorization as detailed in Section 3.3.2. If
The JSON message information is encapsulated in a PKCS7 signed data authorization is successful the Registrar obtains an Audit Token from
structure that is signed by the Registrar. The entire certificate the MASA service (see Section 5.2).
chain, up to and including the Domain CA, MUST be included in the
PKCS7.
The MASA service checks the internal consistency of the PKCS7 but MAY The JSON message information is encapsulated in a [RFC5652] Signed-
not authenticate the domain identity information. The domain is not data that is signed by the Registrar. The entire certificate chain,
know to the MASA server in advance and a shared trust anchor is not up to and including the Domain CA, MUST be included in the
implied. The MASA server MUST verify that the PKCS7 is signed by a CertificateSet structure. The MASA service checks the internal
Registrar certificate (by checking for the cmc-idRA field) that was consistency of the CMS but does not authenticate the domain identity
issued by a the root certificate included in the PKCS7. This ensures information. The domain is not know to the MASA server in advance
that the Registrar is in fact an authorized Registrar of the unknown and a shared trust anchor is not implied. The MASA server MUST
domain. verify that the CMS is signed by a Registrar certificate (by checking
for the cmc-idRA field) that was issued by a the root certificate
included in the CMS. This ensures that the Registrar making the
claim is an authorized Registrar of the unauthenticated domain. The
EST style client authentication (TLS and HTTP) is used to provide a
DDoS prevention strategy.
The domain ID (e.g. hash of the public key of the domain) is The domain ID (e.g. hash of the public key of the domain) is
extracted from the root certificate and is used to populate the MASA extracted from the root certificate and is used to populate the MASA
authorization token and to update the audit log. The authorization authorization token and to update the audit log.
token consists of the nonce, if supplied, the serialnumber and the
domain identity:
{"nonce":"<64bit nonce value>", "serialnumber", "<subjectname/ 5.3. Audit Token Response
subjectaltname serial number>","domainID":}
[[EDNOTE: There is a strong similarity between this and the previous The authorization token response to requests from the device and
section. Both involve requesting the Audit Token from the upstream requests from the Registrar are in the same format. The Registrar
element. Because there are differing requirements on the data either caches prior MASA responses or dynamically requests a new
submitted and the signing of that data they are specified in distinct Audit Token based on local policy.
sections. The design team should have a meeting to discuss how to
unify these sections or make the distinctions more clear]]
5.5. Basic Configuration Information Package If the the join operation is successful, the server response MUST
contain an HTTP 200 response code with a content-type of
"application/authorization-token". The server MUST answer with a
suitable 4xx or 5xx HTTP [RFC2616] error code when a problem occurs.
The response data from the MASA server MUST be a plaintext human-
readable error message containing explanatory information describing
why the request was rejected.
When the MASA authorization token is returned to the New Entity an The authorization token consists of the nonce, if supplied, the
arbitrary information package can be signed and delivered along side serial number information identifying the device and the domain CA
it. This is signed by the Domain Registrar. The New Entity first certificate extracted from the request:
verifies the Audit Token and, if it is valid, then uses the domain's
TA to validate the Information Package.
[[EDNOTE: The domainID as included in the log and as sent in the {
authorization token is only a hash of the domain root certificate. "version":"1",
"nonce":"<64bit nonce value>",
"IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier>",
"DevIDSerialNumber":"<id-at-serialNumber>",
"domainCAcert":"<the base64 encoded domain CA's certificate>"
}
This is insufficient for the new entity to move out of the The audit token response is encapsulated in a [RFC5652] Signed-data
provisional state as it needs a full root certificate to validate the that is signed by the MASA server. The New Entity verifies this
TLS certificate chain. This information package could be used to signed message using the IEEE 802.1AR manufacturer installed trust
deliver the full certificate or the full certificate could be anchor.
included in the authorization token. Lacking either the new entity
needs to stay in the provisional state until it performs an RFC7030
/getcacerts to obtain the full certificate chain.]]
[[EDNOTE: The package format to be specified here. Any signed format [[EDNOTE: Using CMS is consistent with the alignment of this
is viable and ideally one can simply be specified from netconf. The bootstrapping document with EST, a PKIX enrollment protocol that
Registar knows the New Entity device type from the 802.1AR credential includes Certificate Management over CMS. An alternative format
and so is able to determine the proper format for the would be the RFC7515 JSON Web Signature (JWS), which would allow
configuration.]] clients that do not use fullCMC messages to avoid CMS entirely. Use
of JWS would likely include a discussion of CBOR in order ensure the
base64 expansions of the certs and signatures within the JWS message
are of minimal size -- it is not yet clear to this author how that
would work out]]
5.6. Request MASA authorization log The 'domainCAcert' element of this message contains the domain CA's
public key. This is specific to bootstrapping a public key
infrastructure. To support bootstrapping other key infrastructures
additional domain identity types might be defined in the future.
Clients MUST be prepared to ignore additional fields they do not
recognize. Clients MUST be prepared to parse and fail gracefully
from an audit token response that does not contain a 'domainCAcert'
field at all.
To minimize the size of the audit token response message the
domainCAcert is not a complete distribution of the EST section 4.1.3
CA Certificate Response.
The New Entity installs the domainCAcert trust anchor. As indicated
in Section 3.1.2 the newly installed trust anchor is used as an EST
RFC7030 Explicit Trust Anchor. The New Entity MUST use the
domainCAcert trust anchor to immediately validate the currently
provisional TLS connection to the Registrar.
5.3.1. Completing authentication of Provisional TLS connection
If the Registrar's credential can not be verified using the
domainCAcert trust anchor the TLS connection is immediately discarded
and the New Entity abandons attempts to bootstrap with this
discovered registrar.
The following behaviors on the Registrar and New Entity are in
addition to normal PKIX operations:
o The EST server MUST use a certificate that chains to the
domainCAcert. This means that when the EST server obtains renewed
credentials the credentials included in the Section 5.2 request
match the chain used in the current provisional TLS connection.
o The New Entity PKIX path validation of the Registrar validity
period information is as described in Section 3.1.5.
Because the domainCAcert trust anchor is installed as an Explicit
Trust Anchor it can be used to authenticate any dynamically
discovered EST server that contain the id-kp-cmcRA extended key usage
extension as detailed in EST RFC7030 section 3.6.1; but to reduce
system complexity the New Entity SHOULD avoid additional discovery
operations. Instead the New entity SHOULD communicate directly with
the Registrar as the EST server to complete PKI local certificate
enrollment. Additionally the New Entity SHOULD use the existing TLS
connection to proceed with EST enrollment, thus reducing the total
amount of cryptographic and round trip operations required during
bootstrapping. [[EDNOTE: It is reasonable to mandate that the
existing TLS connection be re-used? e.g. MUST >> SHOULD?]]
5.4. Audit Token Status Telemetry
For automated bootstrapping of devices the adminstrative elements
providing bootstrapping also provide indications to the system
administrators concerning device lifecycle status. To facilitate
this those elements need telemetry information concerning the
device's status.
To indicate New Entity status regarding the audit token the client
SHOULD post a status message.
The client HTTP POSTs the following to the server at the EST well
known URI /requestaudittoken_status. The Status field indicates if
the audit token was acceptable. If it was not acceptable the Reason
string indicates why. In the failure case this message is being sent
to an unauthenticated, potentially malicious Registrar and therefore
the Reason string SHOULD NOT provide information beneficial to an
attacker. The operational benefit of this telemetry information is
balanced against the operational costs of not recording that an audit
token was ignored by a client the registar expected to continue
joining the domain.
{
"version":"1",
"Status":FALSE /* TRUE=Success, FALSE=Fail"
"Reason":"Informative human readable message"
}
The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error. The client ignores any response. Within the
server logs the server SHOULD capture this telemetry information.
5.5. MASA authorization log Request
A registrar requests the MASA authorization log from the MASA service A registrar requests the MASA authorization log from the MASA service
using this EST extension. using this EST extension.
This is done with an HTTP GET using the operation path value of This is done with an HTTP GET using the operation path value of
"/requestMASAlog". "/requestMASAlog".
The log data returned is a file consisting of all previous log The client HTTP POSTs the same Audit Token Request as for requesting
entries. For example: an audit token but now posts it the /requestMASAlog URI instead. The
IDevIDAuthorityKeyIdentifier and DevIDSerialNumber informs the MASA
server which log is requested so the appropriate log can be prepared
for the response.
"log":[ 5.6. MASA authorization log Response
{"date":"<date/time of the entry>"},
"domainID":"<domainID as extracted from the root
certificate within the PKCS7 of the
audit token request>",
"nonce":"<any nonce if supplied (or NULL)>"},
{"date":"<date/time of the entry>"}, A log data file is returned consisting of all log entries. For
"domainID":"<domainID as extracted from the root example:
certificate within the PKCS7 of the
audit token request>",
"nonce":"<any nonce if supplied (or NULL)>"},
]
{
"version":"1",
"events":[
{
"date":"<date/time of the entry>",
"domainID":"<domainID as extracted from the domain CA certificate
within the CMS of the audit token request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>"
},
{
"date":"<date/time of the entry>",
"domainID":"<domainID as extracted from the domain CA certificate
within the CMS of the audit token request>",
"nonce":"<any nonce if supplied (or the exact string 'NULL')>"
}
]
}
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: All nonce-less entries for the same domainID be optimized as follows: All nonce-less entries for the same domainID
can be condensed into the single most recent nonceless entry. MAY be condensed into the single most recent nonceless entry.
The Registrar uses this log information to make an informed decision The Registrar uses this log information to make an informed decision
regarding the continued bootstrapping of the New Entity. For example regarding the continued bootstrapping of the New Entity. For example
if the log includes unexpected domainIDs this is indicative of if the log includes unexpected domainIDs this is indicative of
problematic imprints by the new entity. If unexpected nonce-less problematic imprints by the new entity. If the log includes nonce-
entries exist this is indicative of the permanent ability for the less entries this is indicative of the permanent ability for the
unknown domain to trigger a reset of the device and take over indicated domain to trigger a reset of the device and take over
management of it. Equipment that is purchased pre-owned can be management of it. Equipment that is purchased pre-owned can be
expected to have an extensive history. expected to have an extensive history.
Log entries containing the Domain's ID can be compared against local Log entries containing the Domain's ID can be compared against local
history logs in search of discrepancies. history logs in search of discrepancies.
[[EDNOTE: certificate transparency style use of merkle tree hash's 5.7. EST Integration for PKI bootstrapping
might offer an alternative log entry method]]
The prior sections describe EST extensions necessary to enable fully
automated bootstrapping. Although the audit token request/response
structure members IDevIDAuthorityKeyIdentifier and DevIDSerialNumber
are specific to PKI bootstrapping these are the only PKI specific
aspects of the extensions and future work might replace them with
non-PKI structures.
The prior sections provide functionality for the New Entity to obtain
a trust anchor representative of the Domain. The following section
describe using EST to obtain a locally issued PKI certificate. The
New Entity MAY perform alternative enrollment methods or proceed to
use its IDevID credential indefinately, but those that leverage the
discovered Registrar to proceed with certificate enrollment MUST
implement the following EST choices.
5.7.1. EST Distribution of CA Certificates
The New Entity MUST request the full EST Distribution of CA
Certificates message. See RFC7030, section 4.1.
This ensures that the New Entity has the complete set of current CA
certificates beyond the domainCAcert (see Section 5.3 for a
discussion of the limitations). Although these restrictions are
acceptable for the Registrar integrated with initial bootstrapping
they are not appropriate for ongoing PKIX end entity certificate
validation.
5.7.2. EST CSR Attributes
Automated bootstrapping occurs without local administrative
configuration of the New Entity. In some deployments its plausible
that the New Entity generates a certificate request containing only
identity information known to the New Entity (essentially the IDevID
information) and ultimately receives a certificate containing domain
specific identity information. Conceptually the CA has complete
control over all fields issued in the end entity certificate.
Realistically this is operationally difficult with the current status
of PKI certificate authority deployments where the CSR is submitted
to the CA via a number of non-standard protocols.
To alleviate operational difficulty the New Entity MUST request the
EST "CSR Attributes" from the EST server. This allows the local
infrastructure to inform the New Entity of the proper fields to
include in the generated CSR.
[[EDNOTE: The following is specific to anima purposes and should be
moved to an appropriate anima document so as to keep bootstrapping as
generic as possible: What we want are a 'domain name' stored in [TBD]
and an 'ACP IPv6 address' stored in the iPAddress field as specified
in RFC5208 s4.2.1.6. ref ACP draft where certificate verification
[TBD]. These should go into the subjectaltname in the [TBD]
fields.]]. If the hardwareModuleName in the IDevID is populated then
it SHOULD by default be propagated to the LDevID along with the
hwSerialNum. The registar SHOULD support local policy concerning
this functionality. [[EDNOTE: extensive use of EST CSR Attributes
might need an new OID definition]].]]
The Registar MUST also confirm the resulting CSR is formatted as
indicated before forwarding the request to a CA. If the Registar is
communicating with the CA using a protocol like full CMC which
provides mechanisms to override the CSR attributes, then these
mechanisms MAY be used even if the client ignores CSR Attribute
guidance.
5.7.3. EST Client Certificate Request
The New Entity MUST request a new client certificate. See RFC7030,
section 4.2.
5.7.4. Enrollment Status Telemetry
For automated bootstrapping of devices the adminstrative elements
providing bootstrapping also provide indications to the system
administrators concerning device lifecycle status. This might
include information concerning attempted bootstrapping messages seen
by the client, MASA provides logs and status of credential
enrollment. The EST protocol assumes an end user and therefore does
not include a final success indication back to the server. This is
insufficient for automated use cases.
To indicate successful enrollment the client SHOULD re-negotiate the
EST TLS session using the newly obtained credentials. This occurs by
the client initiating a new TLS ClientHello message on the existing
TLS connection. The client MAY simply close the old TLS session and
start a new one. The server MUST support either model.
In the case of a failure the Reason string indicates why the most
recent enrollment failed. The SubjectKeyIdentifier field MUST be
included if the enrollment attempt was for a keypair that is locally
known to the client. If EST /serverkeygen was used and failed then
the this field is ommited from the status telemetry.
The client HTTP POSTs the following to the server at the new EST well
known URI /enrollstatus.
{
"version":"1",
"Status":TRUE /* TRUE=Success, FALSE=Fail"
"Reason":"Informative human readable message"
"SubjectKeyIdentifier":"<base64 encoded subjectkeyidentifier for the
enrollment that failed>"
}
The server SHOULD respond with an HTTP 200 but MAY simply fail with
an HTTP 404 error.
Within the server logs the server MUST capture if this message was
recieved over an TLS session with a matching client certificate.
This allows for clients that wish to minimize their crypto operations
to simpy 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.
5.7.5. EST over CoAP
[[EDNOTE: In order to support smaller devices the above section on
Proxy behavior introduces mandatory to implement support for CoAP
support by the Proxy. This implies similar support by the New Entity
and Registrar and means that the EST protocol operation encapsulation
into CoAP needs to be described. EST is HTTP based and "CoaP is
designed to easily interface with HTTP for integration" [RFC7252].
Use of CoAP implies Datagram TLS (DTLS) wherever this document
describes TLS handshake specifics. A complexity is that the large
message sizes necessary for bootstrapping will require support for
[draft-ietf-core-block].]]
6. Reduced security operational modes 6. 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 New Entity, Registrar and MASA sections detail specific ways that the New Entity, Registrar and MASA
can be configured to run in a less secure mode for the indicated can be configured to run in a less secure mode for the indicated
reasons. reasons.
6.1. Trust Model 6.1. Trust Model
+--------+ +-------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
| New | | Proxy | | Domain | | Vendor | | New | | Circuit | | Domain | | Vendor |
| Entity | | | | Registrar | | Service | | Entity | | Proxy | | Registrar | | Service |
| | | | | | | (Internet | | | | | | | | (Internet |
+--------+ +-------+ +------------+ +------------+ +--------+ +---------+ +------------+ +------------+
Figure 7 Figure 7
New Entity: The New Entity could be compromised and providing an New Entity: The New Entity could be compromised and providing an
attack vector for malware. The entity is trusted to only imprint attack vector for malware. The entity is trusted to only imprint
using secure methods described in this document. Additional using secure methods described in this document. Additional
endpoint assessment techniques are RECOMMENDED but are out-of- endpoint assessment techniques are RECOMMENDED but are out-of-
scope of this document. scope of this document.
Proxy: Provides proxy functionalities but is not involved in Proxy: Provides proxy functionalities but is not involved in
security considerations. security considerations.
Registrar: When interacting with a MASA server the Registrar makes Registrar: When interacting with a MASA server the Registrar makes
all decisions. When ownership vouchers are involved the Registrar all decisions. When ownership vouchers are involved the Registrar
is only a conduit and all security decisions are made on the is only a conduit and all security decisions are made on the
vendor service. vendor service.
Vendor Service, MASA: This form of vendor service is trusted to Vendor Service, MASA: This form of vendor service is trusted to
accurately log all claim attempts and to provide authoritative log accurately log all claim attempts and to provide authoritative log
information to Registrars. The MASA does not know which devices information to Registrars. The MASA does not know which devices
are associated with which domains. [[EDNOTE: these claims could are associated with which domains. These claims could be
be strengthened using by using cryptographic log techniques to strengthened by using cryptographic log techniques to provide
provide append only", cryptographic assured, publicly auditable append only, cryptographic assured, publicly auditable logs.
logs. Current text provides for a fully trusted vendor.]] Current text provides only for a trusted vendor.
Vendor Service, Ownership Validation: This form of vendor service is Vendor Service, Ownership Validation: This form of vendor service is
trusted to accurately know which device is owned by which domain. trusted to accurately know which device is owned by which domain.
6.2. New Entity security reductions 6.2. New Entity security reductions
Although New Entity can choose to run in less secure modes this is Although New Entity can choose to run in less secure modes this is
MUST NOT be the default state because it permanently degrades the MUST NOT be the default state because it permanently degrades the
security for all other uses cases. security for all other uses cases.
skipping to change at page 33, line 30 skipping to change at page 41, line 25
available via local configuration or physical presence methods to available via local configuration or physical presence methods to
ensure new entities can always be deployed even when autonomic ensure new entities can always be deployed even when autonomic
methods fail. This allows for unsecure imprint. methods fail. This allows for unsecure imprint.
It is RECOMMENDED that this only be available if hardware assisted It is RECOMMENDED that this only be available if hardware assisted
NEA [RFC5209] is supported. NEA [RFC5209] is supported.
6.3. Registrar security reductions 6.3. Registrar security reductions
The Registrar can choose to accept devices using less secure methods. The Registrar can choose to accept devices using less secure methods.
These methods are RECOMMENDED when low security models are needed as These methods are acceptable when low security models are needed, as
the security decisions are being made by the local administrator: the security decisions are being made by the local administrator, but
they MUST NOT be the default behavior:
1. The registrar MAY choose to accept all devices, or all devices of 1. The registrar MAY choose to accept all devices, or all devices of
a particular type, at the administrator's discretion. This could a particular type, at the administrator's discretion. This could
occur when informing the Registrar of unique identifiers of new occur when informing the Registrar of unique identifiers of new
entities might be operationally difficult. entities might be operationally difficult.
2. The registrar MAY choose to accept devices that claim a unique 2. The registrar MAY choose to accept devices that claim a unique
identity without the benefit of authenticating that claimed identity without the benefit of authenticating that claimed
identity. This could occur when the New Entity does not include identity. This could occur when the New Entity does not include
an IEEE 802.1AR factory installed credential. an IEEE 802.1AR factory installed credential. New Entities
without an IDevID credential MAY form the Section 5.1 request
using the Section 5.2 format to ensure the New Entity's serial
number information is provided to the Registar (this includes the
IDevIDAuthorityKeyIdentifier value which would be statically
configured on the New Entity). The New Entity MAY refused to
provide a TLS client certificate (as one is not available). The
New Entity SHOULD support HTTP-based or certificate-less TLS
authentication as described in EST RFC7030 section 3.3.2.
3. The registrar MAY request nonce-less Audit Tokens from the MASA 3. The registrar MAY request nonce-less Audit Tokens from the MASA
service. These tokens can then be transmitted to the Registrar service. These tokens can then be transmitted to the Registrar
and stored until they are needed during bootstrapping operations. and stored until they are needed during bootstrapping operations.
This is for use cases where target network is protected by an air This is for use cases where target network is protected by an air
gap and therefore can not contact the MASA service during New gap and therefore can not contact the MASA service during New
Entity deployment. Entity deployment.
4. The registrar MAY ignore unrecognized nonce-less Audit Log 4. The registrar MAY ignore unrecognized nonce-less Audit Log
entries. This could occur when used equipment is purchased with entries. This could occur when used equipment is purchased with
skipping to change at page 35, line 31 skipping to change at page 43, line 33
for the attacker to use the Audit Token to take control of the New for the attacker to use the Audit Token to take control of the New
Entity but then proceed to enroll with the target domain. Possible Entity but then proceed to enroll with the target domain. Possible
prevention mechanisms include: prevention mechanisms include:
o Per device rate limits on the MASA service ensure such timing o Per device rate limits on the MASA service ensure such timing
attacks are difficult. attacks are difficult.
o In the advent of an unexpectedly lost bootstrapping connection the o In the advent of an unexpectedly lost bootstrapping connection the
Registrar repeats the request for audit log information. Registrar repeats the request for audit log information.
To facilitate auditing the New Entity reports on audit token parsing
status. In the case of a failure this information is informative to
the potentially malicious Registar but this is included because the
operational benefits are concidered beneficial.
As indicated in EST [RFC7030] the connection is provisional and As indicated in EST [RFC7030] the connection is provisional and
untrusted until the server is successfully authorized. If the server untrusted until the server is successfully authorized. If the server
provides a redirect response the client MUST follow the redirect but provides a redirect response the client MUST follow the redirect but
the connection remains provisional. If the client uses a well known the connection remains provisional. If the client uses a well known
URI for contacting a well known Registrar the EST Implicit Trust URI for contacting a well known Registrar the EST Implicit Trust
Anchor database is used as is described in RFC6125 to authenticate Anchor database is used as is described in RFC6125 to authenticate
the well known URI. In this case the connection is not provisional the well known URI. In this case the connection is not provisional
and RFC6125 methods can be used for each subsequent redirection. and RFC6125 methods can be used for each subsequent redirection.
To facilitate truely limited clients EST RFC7030 section 3.3.2
requirements that the client MUST support a client authentication
model have been reduced in Section 6 to a statement that clients only
"SHOULD" support such a model. This reflects current (not great)
practices but is NOT RECOMMENDED.
The MASA service could lock a claim and refuse to issue a new token The MASA service could lock a claim and refuse to issue a new token
or the MASA service could go offline (for example if a vendor went or the MASA service could go offline (for example if a vendor went
out of business). This functionality provides benefits such as theft out of business). This functionality provides benefits such as theft
resistance, but it also implies an operational risk to the Domain resistance, but it also implies an operational risk to the Domain
that Vendor behavior could limit future bootstrapping of the device that Vendor behavior could limit future bootstrapping of the device
by the Domain. This can be mitigated by Registrars that request by the Domain. This can be mitigated by Registrars that request
nonce-less authorization tokens. nonce-less authorization tokens.
8. Acknowledgements 8. 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 Markus Stenberg, Brian Carpenter, Fuyu Eleven. particular Markus Stenberg, Brian Carpenter, Fuyu Eleven, Toerless
Eckert, Eliot Lear and Sergey Kasatkin.
9. References 9. References
9.1. Normative References 9.1. Normative References
[IDevID] IEEE Standard, , "IEEE 802.1AR Secure Device Identifier", [IDevID] IEEE Standard, , "IEEE 802.1AR Secure Device Identifier",
December 2009, <http://standards.ieee.org/findstds/ December 2009, <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
skipping to change at page 36, line 38 skipping to change at page 44, line 47
Configuration of IPv4 Link-Local Addresses", RFC 3927, May Configuration of IPv4 Link-Local Addresses", RFC 3927, May
2005. 2005.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
[RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing [RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing
Security: An Unauthenticated Mode of IPsec", RFC 5386, Security: An Unauthenticated Mode of IPsec", RFC 5386,
November 2008. November 2008.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<http://www.rfc-editor.org/info/rfc5652>.
[RFC5660] Williams, N., "IPsec Channels: Connection Latching", [RFC5660] Williams, N., "IPsec Channels: Connection Latching",
RFC 5660, October 2009. RFC 5660, October 2009.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013, DOI 10.17487/RFC6762, February 2013,
<http://www.rfc-editor.org/info/rfc6762>. <http://www.rfc-editor.org/info/rfc6762>.
[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,
<http://www.rfc-editor.org/info/rfc6763>. <http://www.rfc-editor.org/info/rfc6763>.
skipping to change at page 37, line 27 skipping to change at page 45, line 40
[I-D.ietf-ace-actors] [I-D.ietf-ace-actors]
Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An
architecture for authorization in constrained architecture for authorization in constrained
environments", draft-ietf-ace-actors-03 (work in environments", draft-ietf-ace-actors-03 (work in
progress), March 2016. progress), March 2016.
[I-D.ietf-netconf-zerotouch] [I-D.ietf-netconf-zerotouch]
Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning
for NETCONF or RESTCONF based Management", draft-ietf- for NETCONF or RESTCONF based Management", draft-ietf-
netconf-zerotouch-07 (work in progress), March 2016. netconf-zerotouch-08 (work in progress), April 2016.
[I-D.irtf-nmrg-autonomic-network-definitions] [I-D.irtf-nmrg-autonomic-network-definitions]
Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A., 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", draft-irtf- Networking - Definitions and Design Goals", draft-irtf-
nmrg-autonomic-network-definitions-07 (work in progress), nmrg-autonomic-network-definitions-07 (work in progress),
March 2015. March 2015.
[I-D.lear-mud-framework] [I-D.lear-mud-framework]
Lear, E., "Manufacturer Usage Description Framework", Lear, E., "Manufacturer Usage Description Framework",
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