YANG Data Model for Global Trust AnchorsWatsen Networkskent+ietf@watsen.net
Operations
NETCONF Working GroupThis 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:
XXXX --> the assigned RFC value for this draftYYYY --> the assigned RFC value for draft-ietf-netconf-crypto-typesArtwork in this document contains placeholder values for the date
of publication of this draft. Please apply the following replacement:
2019-03-09 --> the publication date of this draftThe following Appendix section is to be removed prior to publication:
Appendix A. Change LogThis 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 be used for multiple uses, including
authenticating protocol peers and verifying signatures.This document in compliant with Network Management Datastore Architecture
(NMDA) . 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
when, and only when, they appear in all capitals, as shown here.Tree diagrams used in this document follow the notation
defined in .The following tree diagram provides an overview of the
"ietf-trust-anchors" module.The following example illustrates trust anchors in <operational> as described
by Section 5.3 in . 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.manufacturers-root-ca-certs
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.
Manufacturer Root CA cert 1base64encodedvalue==Manufacturer Root CA cert 2base64encodedvalue==explicitly-trusted-server-certs
Specific server authentication certificates for explicitly
trusted servers. These are needed for server certificates
that are not signed by a pinned CA.
Fred Flintstonebase64encodedvalue==explicitly-trusted-server-ca-certs
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.
ca.example.combase64encodedvalue==explicitly-trusted-client-certs
Specific client authentication certificates for explicitly
trusted clients. These are needed for client certificates
that are not signed by a pinned CA.
George Jetsonbase64encodedvalue==explicitly-trusted-client-ca-certs
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.
ca.example.combase64encodedvalue==common-ca-certs
Trusted certificates to authenticate common HTTPS servers.
These certificates are similar to those that might be
shipped with a web browser.
ex-certificate-authoritybase64encodedvalue==explicitly-trusted-ssh-host-keys
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.
corp-fw1base64encodedvalue==
]]>The following example illustrates the "certificate-expiration"
notification in use with the NETCONF protocol.2018-05-25T00:01:00Zexplicitly-trusted-client-certsGeorge Jetson2018-08-05T14:18:53-05:00
]]>This YANG module imports modules from
and . file "ietf-trust-anchors@2019-03-09.yang"
module ietf-trust-anchors {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-trust-anchors";
prefix ta;
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
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:
WG List:
Author: Kent Watsen ";
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.
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.
Copyright (c) 2019 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 2019-03-09 {
description
"Initial version";
reference
"RFC XXXX: YANG Data Model for Global Trust Anchors";
}
/************************************************************/
/* Typedefs for leafrefs to commonly referenced objects */
/************************************************************/
feature x509-certificates {
description
"The 'x509-certificates' feature indicates that the server
implements the /trust-anchors/pinned-certificates subtree.";
}
feature ssh-host-keys {
description
"The 'ssh-host-keys' feature indicates that the server
implements the /trust-anchors/pinned-host-keys subtree.";
}
/************************************************************/
/* 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 .";
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 .";
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container trust-anchors {
nacm:default-deny-write;
description
"Contains sets of X.509 certificates and SSH host keys.";
list pinned-certificates {
if-feature "x509-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
RESTCONF server's configuration might use a specific list
of pinned certificates for when authenticating RESTCONF
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.";
}
uses ct:trust-anchor-cert-grouping {
refine "cert" {
mandatory true;
}
}
}
}
list pinned-host-keys {
if-feature "ssh-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";
}
}
}
}
}
]]>The YANG module defined in this document is designed to be accessed via YANG
based management protocols, such as NETCONF and
RESTCONF . Both of these protocols have mandatory-to-implement
secure transport layers (e.g., SSH, TLS) with mutual authentication.The NETCONF access control model (NACM) 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.This document registers one URI in the "ns" subregistry of
the IETF XML Registry . Following the
format in , the following registration
is requested:This document registers one YANG module in the
YANG Module Names registry .
Following the format in , the
the following registration is requested:Added features "x509-certificates" and "ssh-host-keys".Added nacm:default-deny-write to "trust-anchors" container.Switched "list pinned-certificate" to use the
"trust-anchor-cert-grouping" from crypto-types.
Effectively the same definition as before.Updated copyright date, boilerplate template, affiliation,
folding algorithm, and reformatted the YANG module.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.