| NETCONF Working Group | K. Watsen |
| Internet-Draft | Juniper Networks |
| Intended status: Standards Track | June 4, 2018 |
| Expires: December 6, 2018 |
YANG Data Model for Global Trust Anchors
draft-ietf-netconf-trust-anchors-00
This document defines a YANG 1.1 data model for configuring global sets of X.509 certificates and SSH host-keys that can be referenced by other data models for trust. While the SSH host-keys are uniquely for the SSH protocol, the X.509 certificates may have multiple uses, including authenticating protocol peers and verifying signatures.
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:
Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement:
The following Appendix section is to be removed prior to publication:
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 6, 2018.
Copyright (c) 2018 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.
This document defines a YANG 1.1 [RFC7950] data model for configuring global sets of X.509 certificates and SSH host-keys that can be referenced by other data models for trust. While the SSH host-keys are uniquely for the SSH protocol, the X.509 certificates may be used for 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 may appear only in <operational>.
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.
Tree diagrams used in this document follow the notation defined in [RFC8340].
The following tree diagram provides an overview of the "ietf-trust-anchors" module.
module: ietf-trust-anchors
+--rw trust-anchors
+--rw pinned-certificates* [name]
| +--rw name string
| +--rw description? string
| +--rw pinned-certificate* [name]
| +--rw name string
| +--rw cert ct:trust-anchor-cert-cms
| +---n certificate-expiration
| +-- expiration-date? yang:date-and-time
+--rw pinned-host-keys* [name]
+--rw name string
+--rw description? string
+--rw pinned-host-key* [name]
+--rw name string
+--rw host-key ct:ssh-host-key
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 five sets of pinned certificates and one set of pinned host keys.
<trust-anchors
xmlns="urn:ietf:params:xml:ns:yang:ietf-trust-anchors"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin">
<!-- Manufacturer's trusted root CA certs -->
<pinned-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>
<pinned-certificate>
<name>Manufacturer Root CA cert 1</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
<pinned-certificate>
<name>Manufacturer Root CA cert 2</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- specific end-entity certs for authenticating servers -->
<pinned-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 pinned CA.
</description>
<pinned-certificate>
<name>Fred Flintstone</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- trusted CA certs for authenticating servers -->
<pinned-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>
<pinned-certificate>
<name>ca.example.com</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- specific end-entity certs for authenticating clients -->
<pinned-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 pinned CA.
</description>
<pinned-certificate>
<name>George Jetson</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- trusted CA certs for authenticating clients -->
<pinned-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>
<pinned-certificate>
<name>ca.example.com</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- trusted CA certs for random HTTPS servers on Internet -->
<pinned-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>
<pinned-certificate>
<name>ex-certificate-authority</name>
<cert>base64encodedvalue==</cert>
</pinned-certificate>
</pinned-certificates>
<!-- specific SSH host keys for authenticating clients -->
<pinned-host-keys or:origin="or:intended">
<name>explicitly-trusted-ssh-host-keys</name>
<description>
Trusted SSH host keys used to authenticate SSH servers.
These host keys would be analogous to those stored in
a known_hosts file in OpenSSH.
</description>
<pinned-host-key>
<name>corp-fw1</name>
<host-key>base64encodedvalue==</host-key>
</pinned-host-key>
</pinned-host-keys>
</trust-anchors>
The following example illustrates the "certificate-expiration" notification in use with the NETCONF protocol.
[Note: '\' line wrapping for formatting only]
<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2018-05-25T00:01:00Z</eventTime>
<trust-anchors
xmlns="urn:ietf:params:xml:ns:yang:ietf-trust-anchors">
<pinned-certificates>
<name>explicitly-trusted-client-certs</name>
<pinned-certificate>
<name>George Jetson</name>
<certificate-expiration>
<expiration-date>2018-08-05T14:18:53-05:00</expiration-dat\
e>
</certificate-expiration>
</pinned-certificate>
</pinned-certificates>
</trust-anchors>
</notification>
This YANG module imports modules from [RFC6536], [RFC6991] and [I-D.ietf-netconf-crypto-types].
<CODE BEGINS> file "ietf-trust-anchors@2018-06-04.yang"
module ietf-trust-anchors {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-trust-anchors";
prefix "ta";
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC YYYY: Common YANG Data Types for Cryptography";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://datatracker.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Author: Kent Watsen
<mailto:kwatsen@juniper.net>";
description
"This module defines a data model for configuring global
trust anchors used by other data models. The data model
enables the configuration of sets of trust anchors.
This data model supports configuring trust anchors for
both X.509 certificates and SSH host keys.
Copyright (c) 2018 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Simplified
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision "2018-06-04" {
description
"Initial version";
reference
"RFC XXXX: YANG Data Model for Global Trust Anchors";
}
/************************************************************/
/* Typedefs for leafrefs to commonly referenced objects */
/************************************************************/
typedef pinned-certificates-ref {
type leafref {
path "/ta:trust-anchors/ta:pinned-certificates/ta:name";
require-instance false;
}
description
"This typedef enables importing modules to easily define a
leafref to a 'pinned-certificates' object. The require
instance attribute is false to enable the referencing of
pinned certificates that exist only in <operational>.";
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
typedef pinned-host-keys-ref {
type leafref {
path "/ta:trust-anchors/ta:pinned-host-keys/ta:name";
require-instance false;
}
description
"This typedef enables importing modules to easily define a
leafref to a 'pinned-host-keys' object. The require
instance attribute is false to enable the referencing of
pinned host keys that exist only in <operational>.";
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container trust-anchors {
description
"Contains sets of X.509 certificates and SSH host keys.";
list pinned-certificates {
key name;
description
"A list of pinned certificates. These certificates can be
used by a server to authenticate clients, or by a client
to authenticate servers. Each list of pinned certificates
SHOULD be specific to a purpose, as the list as a whole
may be referenced by other modules. For instance, a
NETCONF server's configuration might use a specific list
of pinned certificates for when authenticating NETCONF
client connections.";
leaf name {
type string;
description
"An arbitrary name for this list of pinned
certificates.";
}
leaf description {
type string;
description
"An arbitrary description for this list of pinned
certificates.";
}
list pinned-certificate {
key name;
description
"A pinned certificate.";
leaf name {
type string;
description
"An arbitrary name for this pinned certificate. The
name must be unique across all lists of pinned
certificates (not just this list) so that leafrefs
from another module can resolve to unique values.";
}
leaf cert {
type ct:trust-anchor-cert-cms;
mandatory true;
description
"The binary certificate data for this pinned
certificate.";
reference
"RFC YYYY: Common YANG Data Types for Cryptography";
}
notification certificate-expiration {
description
"A notification indicating that the configured trust
anchor is either about to expire or has already expired.
When to send notifications is an implementation specific
decision, but it is RECOMMENDED that a notification be
sent once a month for 3 months, then once a week for
four weeks, and then once a day thereafter until the
issue is resolved.";
leaf expiration-date {
type yang:date-and-time;
//mandatory true;
description
"Identifies the expiration date on the certificate.";
}
}
}
}
list pinned-host-keys {
key name;
description
"A list of pinned host keys. These pinned host-keys can
be used by clients to authenticate SSH servers. Each
list of pinned host keys SHOULD be specific to a purpose,
so the list as a whole may be referenced by other modules.
For instance, a NETCONF client's configuration might
point to a specific list of pinned host keys for when
authenticating specific SSH servers.";
leaf name {
type string;
description
"An arbitrary name for this list of pinned SSH
host keys.";
}
leaf description {
type string;
description
"An arbitrary description for this list of pinned SSH
host keys.";
}
list pinned-host-key {
key name;
description
"A pinned host key.";
leaf name {
type string;
description
"An arbitrary name for this pinned host-key. Must be
unique across all lists of pinned host-keys (not just
this list) so that a leafref to it from another module
can resolve to unique values.";
}
leaf host-key {
type ct:ssh-host-key;
mandatory true;
description
"The binary public key data for this pinned host key.";
reference
"RFC YYYY: Common YANG Data Types for Cryptography";
}
}
}
}
}
<CODE ENDS>
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) [RFC6536] 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:
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.
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-trust-anchors Registrant Contact: The NETCONF WG of the IETF. XML: N/A, the requested URI is an XML namespace.
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-trust-anchors namespace: urn:ietf:params:xml:ns:yang:ietf-trust-anchors prefix: ta reference: RFC XXXX
| [I-D.ietf-netconf-crypto-types] | Watsen, K., "Common YANG Data Types for Cryptography", Internet-Draft draft-ietf-netconf-crypto-types-00, June 2018. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [RFC6536] | Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012. |
| [RFC6991] | Schoenwaelder, J., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013. |
| [RFC7950] | Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016. |
| [RFC8174] | Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017. |
| [RFC3688] | Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004. |
| [RFC6020] | Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010. |
| [RFC6241] | Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011. |
| [RFC8040] | Bierman, A., Bjorklund, M. and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017. |
| [RFC8340] | Bjorklund, M. and L. Berger, "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018. |
| [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. |
The authors would like to thank for following for lively discussions on list and in the halls (ordered by last name): Martin Bjorklund, Balázs Kovács, Eric Voit, and Liang Xia.