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00 01 02 03 04 05 06 07
NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Intended status: Standards Track H. Birkholz
Expires: May 4, 2020 Fraunhofer SIT
November 1, 2019
A YANG Data Model for a Truststore
draft-ietf-netconf-trust-anchors-07
Abstract
This document defines a YANG 1.1 data model for configuring global
sets of X.509 certificates, SSH host-keys, raw public keys, and PSKs
(pairwise-symmetric or pre-shared keys) that can be referenced by
other data models for trust. While the SSH host-keys are uniquely
for the SSH protocol, certificates, raw public keys, and PSKs may
have multiple uses, including authenticating protocol peers and
verifying signatures.
Editorial Note (To be removed by RFC Editor)
This draft contains many placeholder values that need to be replaced
with finalized values at the time of publication. This note
summarizes all of the substitutions that are needed. No other RFC
Editor instructions are specified elsewhere in this document.
Artwork in this document contains shorthand references to drafts in
progress. Please apply the following replacements:
o "XXXX" --> the assigned RFC value for this draft
o "YYYY" --> the assigned RFC value for draft-ietf-netconf-crypto-
types
Artwork in this document contains placeholder values for the date of
publication of this draft. Please apply the following replacement:
o "2019-11-02" --> the publication date of this draft
The following Appendix section is to be removed prior to publication:
o Appendix A. Change Log
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Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on May 4, 2020.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Tree Diagram Notation . . . . . . . . . . . . . . . . . . 3
2. The Trust Anchors Model . . . . . . . . . . . . . . . . . . . 3
2.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 5
2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 8
3. Security Considerations . . . . . . . . . . . . . . . . . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
4.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 9
4.2. The YANG Module Names Registry . . . . . . . . . . . . . 10
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Normative References . . . . . . . . . . . . . . . . . . 10
5.2. Informative References . . . . . . . . . . . . . . . . . 10
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Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 12
A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 12
A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 12
A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 12
A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 12
A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 12
A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 13
A.7. 06 to 07 . . . . . . . . . . . . . . . . . . . . . . . . 13
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
This document defines a YANG 1.1 [RFC7950] data model for configuring
global sets of X.509 certificates, SSH host-keys, raw public keys,
and PSKs (pairwise-symmetric or pre-shared keys) that can be
referenced by other data models for trust. While the SSH host-keys
are uniquely for the SSH protocol, certificates, raw public keys, and
PSKs may have multiple uses, including authenticating protocol peers
and verifying signatures.
This document in compliant with Network Management Datastore
Architecture (NMDA) [RFC8342]. For instance, to support trust
anchors installed during manufacturing, it is expected that such data
would appear only in <operational>.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Tree Diagram Notation
Tree diagrams used in this document follow the notation defined in
[RFC8340].
2. The Trust Anchors Model
2.1. Tree Diagram
The following tree diagram provides an overview of the "ietf-
truststore" module.
module: ietf-truststore
+--rw truststore
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+--rw certificates* [name] {x509-certificates}?
| +--rw name string
| +--rw description? string
| +--rw certificate* [name]
| +--rw name string
| +--rw cert trust-anchor-cert-cms
| +---n certificate-expiration
| +-- expiration-date yang:date-and-time
+--rw host-keys* [name] {ssh-host-keys}?
| +--rw name string
| +--rw description? string
| +--rw host-key* [name]
| +--rw name string
| +--rw host-key ct:ssh-host-key
+--rw psks* [name] {psks}?
| +--rw name string
| +--rw description? string
| +--rw psk* [name]
| +--rw name string
| +--rw psk ct:psk
+--rw raw-public-keys* [name] {raw-public-keys}?
+--rw name string
+--rw description? string
+--rw raw-public-key* [name]
+--rw name string
+--rw raw-public-key ct:raw-public-key
grouping local-or-truststore-certs-grouping
+-- (local-or-truststore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- cert* trust-anchor-cert-cms
| +---n certificate-expiration
| +-- expiration-date yang:date-and-time
+--:(truststore) {truststore-supported,x509-certificates}?
+-- truststore-reference? ts:certificates-ref
grouping local-or-truststore-host-keys-grouping
+-- (local-or-truststore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- host-key* ct:ssh-host-key
+--:(truststore) {truststore-supported,ssh-host-keys}?
+-- truststore-reference? ts:host-keys-ref
grouping local-or-truststore-psks-grouping
+-- (local-or-truststore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- psk* ct:psk
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+--:(truststore) {truststore-supported,psks}?
+-- truststore-reference? ts:psks-ref
grouping local-or-truststore-raw-pub-keys-grouping
+-- (local-or-truststore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- raw-public-key* ct:raw-public-key
+--:(truststore) {truststore-supported,raw-public-keys}?
+-- truststore-reference? ts:raw-public-keys-ref
grouping truststore-grouping
+-- certificates* [name] {x509-certificates}?
| +-- name? string
| +-- description? string
| +-- certificate* [name]
| +-- name? string
| +-- cert trust-anchor-cert-cms
| +---n certificate-expiration
| +-- expiration-date yang:date-and-time
+-- host-keys* [name] {ssh-host-keys}?
| +-- name? string
| +-- description? string
| +-- host-key* [name]
| +-- name? string
| +-- host-key ct:ssh-host-key
+-- psks* [name] {psks}?
| +-- name? string
| +-- description? string
| +-- psk* [name]
| +-- name? string
| +-- psk ct:psk
+-- raw-public-keys* [name] {raw-public-keys}?
+-- name? string
+-- description? string
+-- raw-public-key* [name]
+-- name? string
+-- raw-public-key ct:raw-public-key
2.2. Example Usage
The following example illustrates trust anchors in <operational> as
described by Section 5.3 in [RFC8342]. This datastore view
illustrates data set by the manufacturing process alongside
conventional configuration. This trust anchors instance has six sets
of pinned certificates and one set of pinned host keys.
<truststore
xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin">
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<!-- Manufacturer's trusted root CA certs -->
<certificates or:origin="or:system">
<name>manufacturers-root-ca-certs</name>
<description>
Certificates built into the device for authenticating
manufacturer-signed objects, such as TLS server certificates,
vouchers, etc. Note, though listed here, these are not
configurable; any attempt to do so will be denied.
</description>
<certificate>
<name>Manufacturer Root CA cert 1</name>
<cert>base64encodedvalue==</cert>
</certificate>
<certificate>
<name>Manufacturer Root CA cert 2</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
<!-- specific end-entity certs for authenticating servers -->
<certificates or:origin="or:intended">
<name>explicitly-trusted-server-certs</name>
<description>
Specific server authentication certificates for explicitly
trusted servers. These are needed for server certificates
that are not signed by a CA.
</description>
<certificate>
<name>Fred Flintstone</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
<!-- trusted CA certs for authenticating servers -->
<certificates or:origin="or:intended">
<name>explicitly-trusted-server-ca-certs</name>
<description>
Trust anchors (i.e. CA certs) that are used to authenticate
server connections. Servers are authenticated if their
certificate has a chain of trust to one of these CA
certificates.
</description>
<certificate>
<name>ca.example.com</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
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<!-- specific end-entity certs for authenticating clients -->
<certificates or:origin="or:intended">
<name>explicitly-trusted-client-certs</name>
<description>
Specific client authentication certificates for explicitly
trusted clients. These are needed for client certificates
that are not signed by a CA.
</description>
<certificate>
<name>George Jetson</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
<!-- trusted CA certs for authenticating clients -->
<certificates or:origin="or:intended">
<name>explicitly-trusted-client-ca-certs</name>
<description>
Trust anchors (i.e. CA certs) that are used to authenticate
client connections. Clients are authenticated if their
certificate has a chain of trust to one of these CA
certificates.
</description>
<certificate>
<name>ca.example.com</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
<!-- trusted CA certs for random HTTPS servers on Internet -->
<certificates or:origin="or:system">
<name>common-ca-certs</name>
<description>
Trusted certificates to authenticate common HTTPS servers.
These certificates are similar to those that might be
shipped with a web browser.
</description>
<certificate>
<name>ex-certificate-authority</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
<!-- specific SSH host keys for authenticating clients -->
<host-keys or:origin="or:intended">
<name>explicitly-trusted-ssh-host-keys</name>
<description>
Trusted SSH host keys used to authenticate SSH servers.
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These host keys would be analogous to those stored in
a known_hosts file in OpenSSH.
</description>
<host-key>
<name>corp-fw1</name>
<host-key>base64encodedvalue==</host-key>
</host-key>
</host-keys>
</truststore>
The following example illustrates the "certificate-expiration"
notification in use with the NETCONF protocol.
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2018-05-25T00:01:00Z</eventTime>
<truststore xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore">
<certificates>
<name>explicitly-trusted-client-certs</name>
<certificate>
<name>George Jetson</name>
<certificate-expiration>
<expiration-date>2018-08-05T14:18:53-05:00</expiration-dat\
e>
</certificate-expiration>
</certificate>
</certificates>
</truststore>
</notification>
2.3. YANG Module
This YANG module imports modules from [RFC8341] and
[I-D.ietf-netconf-crypto-types].
<CODE BEGINS> file "ietf-truststore@2019-11-02.yang"
<CODE ENDS>
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3. Security Considerations
The YANG module defined in this document is designed to be accessed
via YANG based management protocols, such as NETCONF [RFC6241] and
RESTCONF [RFC8040]. Both of these protocols have mandatory-to-
implement secure transport layers (e.g., SSH, TLS) with mutual
authentication.
The NETCONF access control model (NACM) [RFC8341] provides the means
to restrict access for particular users to a pre-configured subset of
all available protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., config true, which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
/: The entire data tree defined by this module is sensitive to
write operations. For instance, the addition or removal of any
trust anchor may dramatically alter the implemented security
policy. For this reason, the NACM extension "default-deny-
write" has been set for the entire data tree.
None of the readable data nodes in this YANG module are considered
sensitive or vulnerable in network environments.
This module does not define any RPCs, actions, or notifications, and
thus the security consideration for such is not provided here.
4. IANA Considerations
4.1. The IETF XML Registry
This document registers one URI in the "ns" subregistry of the IETF
XML Registry [RFC3688]. Following the format in [RFC3688], the
following registration is requested:
URI: urn:ietf:params:xml:ns:yang:ietf-truststore
Registrant Contact: The NETCONF WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
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4.2. The YANG Module Names Registry
This document registers one YANG module in the YANG Module Names
registry [RFC6020]. Following the format in [RFC6020], the the
following registration is requested:
name: ietf-truststore
namespace: urn:ietf:params:xml:ns:yang:ietf-truststore
prefix: ta
reference: RFC XXXX
5. References
5.1. Normative References
[I-D.ietf-netconf-crypto-types]
Watsen, K. and H. Wang, "Common YANG Data Types for
Cryptography", draft-ietf-netconf-crypto-types-11 (work in
progress), October 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
5.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
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[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
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Appendix A. Change Log
A.1. 00 to 01
o Added features "x509-certificates" and "ssh-host-keys".
o Added nacm:default-deny-write to "trust-anchors" container.
A.2. 01 to 02
o Switched "list pinned-certificate" to use the "trust-anchor-cert-
grouping" from crypto-types. Effectively the same definition as
before.
A.3. 02 to 03
o Updated copyright date, boilerplate template, affiliation, folding
algorithm, and reformatted the YANG module.
A.4. 03 to 04
o Added groupings 'local-or-truststore-certs-grouping' and 'local-
or-truststore-host-keys-grouping', matching similar definitions in
the keystore draft. Note new (and incomplete) "truststore" usage!
o Related to above, also added features 'truststore-supported' and
'local-trust-anchors-supported'.
A.5. 04 to 05
o Renamed "trust-anchors" to "truststore"
o Removed "pinned." prefix everywhere, to match truststore rename
o Moved everything under a top-level 'grouping' to enable use in
other contexts.
o Renamed feature from 'local-trust-anchors-supported' to 'local-
definitions-supported' (same name used in keystore)
o Removed the "require-instance false" statement from the "*-ref"
typedefs.
o Added missing "ssh-host-keys" and "x509-certificates" if-feature
statements
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A.6. 05 to 06
o Editorial changes only.
A.7. 06 to 07
o Added Henk Birkholz as a co-author (thanks Henk!)
o Added PSKs and raw public keys to Truststore.
Acknowledgements
The authors would like to thank for following for lively discussions
on list and in the halls (ordered by last name): Martin Bjorklund,
Nick Hancock, Balazs Kovacs, Eric Voit, and Liang Xia.
Authors' Addresses
Kent Watsen
Watsen Networks
EMail: kent+ietf@watsen.net
Henk Birkholz
Fraunhofer SIT
EMail: henk.birkholz@sit.fraunhofer.de
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