A YANG Data Model for a TruststoreWatsen Networkskent+ietf@watsen.net
Operations
NETCONF Working GroupThis document defines a YANG module for configuring
bags of certificates and bags of public keys that can be
referenced by other data models for trust. Notifications
are sent when certificates are about to expire.Editorial Note (To be removed by RFC Editor)This draft contains 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:
AAAA --> the assigned RFC value for draft-ietf-netconf-crypto-types
BBBB --> the assigned RFC value for this draft
Artwork in this document contains placeholder values for the date
of publication of this draft. Please apply the following replacement:
2022-10-19 --> the publication date of this draft
The "Relation to other RFCs" section contains
the text "one or more YANG modules" and, later, "modules". This text is sourced
from a file in a context where it is unknown how many modules a draft defines.
The text is not wrong as is, but it may be improved by stating more directly how
many modules are defined.The "Relation to other RFCs" section contains
a self-reference to this draft, along with a corresponding Informative Reference in
the Appendix.The following Appendix section is to be removed prior to publication:
. Change Log
IntroductionThis document defines a YANG 1.1 module having
the following characteristics:
Provide a central truststore for storing raw public keys and/or certificates.
Provide support for storing named bags of raw public keys and/or named bags
of certificates.
Provide types that can be used to reference raw public keys or certificates
stored in the central truststore.
Provide groupings that enable raw public keys and certificates to be
configured locally or as references truststore instances.
Enable the truststore to be instantiated in other data models, in addition
to or in lieu of the central truststore instance.
Relation to other RFCsThis document presents one or more YANG modules
that are part of a collection of RFCs that work together to,
ultimately, enable the configuration of the clients and
servers of both the NETCONF and RESTCONF
protocols.These modules have been defined in a modular fashion to enable
their use by other efforts, some of which are known to be in
progress at the time of this writing, with many more expected
to be defined in time.The normative dependency relationship between the various RFCs in the collection
is presented in the below diagram. The labels in the diagram
represent the primary purpose provided by each RFC. Hyperlinks to
each RFC are provided below the diagram.
Label to RFC Mapping
Label in Diagram
Originating RFC
crypto-types
truststore
keystore
tcp-client-server
ssh-client-server
tls-client-server
http-client-server
netconf-client-server
restconf-client-server
Specification LanguageThe 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.Adherence to the NMDAThis document is compliant with the Network Management Datastore Architecture
(NMDA) . For instance, trust anchors installed
during manufacturing (e.g., for trusted well-known services), are expected
to appear in <operational> (see ).ConventionsVarious examples used in this document use a placeholder
value for binary data that has been base64 encoded (e.g.,
"BASE64VALUE="). This placeholder value is used as real
base64 encoded structures are often many lines long and
hence distracting to the example being presented.The "ietf-truststore" ModuleThis section defines a YANG 1.1 module called
"ietf-truststore". A high-level overview of the module is provided in
. Examples illustrating the module's use
are provided in Examples. The YANG
module itself is defined in .Data Model OverviewThis section provides an overview of the "ietf-truststore" module
in terms of its features, typedefs, groupings, and protocol-accessible
nodes.FeaturesThe following diagram lists all the "feature" statements
defined in the "ietf-truststore" module:TypedefsThe following diagram lists the "typedef" statements defined in
the "ietf-truststore" module:Comments:
All the typedefs defined in the "ietf-truststore" module
extend the base "leafref" type defined in .
The leafrefs refer to certificates, public keys, and bags
in the central truststore, when this module is implemented.
These typedefs are provided as an aid to downstream
modules that import the "ietf-truststore" module.
GroupingsThe "ietf-truststore" module defines the following "grouping" statements:
local-or-truststore-certs-grouping
local-or-truststore-public-keys-grouping
truststore-grouping
Each of these groupings are presented in the following subsections.The "local-or-truststore-certs-grouping" GroupingThe following tree diagram illustrates the
"local-or-truststore-certs-grouping" grouping:Comments:
The "local-or-truststore-certs-grouping" grouping is provided
soley as convenience to downstream modules that wish to offer
an option whether a bag of certificates can be defined locally
or as a reference to a bag in the truststore.
A "choice" statement is used to expose the various options.
Each option is enabled by a "feature" statement. Additional
"case" statements MAY be augmented in if, e.g., there is a
need to reference a bag in an alternate location.
For the "local-definition" option, the "certificate" node
uses the "trust-anchor-cert-grouping" grouping discussed in
.
For the "truststore" option, the "truststore-reference" is an
instance of the "certificate-bag-ref" discussed in .
The "local-or-truststore-public-keys-grouping" GroupingThe following tree diagram illustrates the
"local-or-truststore-public-keys-grouping" grouping:Comments:
The "local-or-truststore-public-keys-grouping" grouping is provided
soley as convenience to downstream modules that wish to offer
an option whether a bag of public keys can be defined locally
or as a reference to a bag in the truststore.
A "choice" statement is used to expose the various options.
Each option is enabled by a "feature" statement. Additional
"case" statements MAY be augmented in if, e.g., there is a
need to reference a bag in an alternate location.
For the "local-definition" option, the "public-key" node uses the
"public-key-grouping" grouping discussed in .
For the "truststore" option, the "truststore-reference" is an
instance of the "certificate-bag-ref" discussed in .
The "truststore-grouping" GroupingThe following tree diagram illustrates the
"truststore-grouping" grouping:Comments:
The "truststore-grouping" grouping defines a truststore instance
as being composed of certificates and/or public keys, both of which
are enabled by "feature" statements. The structure supporting
certificates and public keys is essentially the same, having an
outer list of "bags" containing in inner list of objects
(certificates or public keys). The bags enable trust anchors
serving a common purpose to be grouped and referenced together.
For certificates, each certificate is defined by the
"trust-anchor-cert-grouping" grouping . Thus the "cert-data"
node is a CMS structure that can be composed of a chain of one or
more certificates. Additionally, the "certificate-expiration"
notification enables the server to alert clients when certificates
are nearing or have already expired.
For public keys, each public key is defined by the
"public-key-grouping" grouping . Thus the "public-key"
node can be one of any number of structures specified by the
"public-key-format" identity node.
Protocol-accessible NodesThe following tree diagram lists all the
protocol-accessible nodes defined in the "ietf-truststore" module, without
expanding the "grouping" statements:The following tree diagram lists all the
protocol-accessible nodes defined in the "ietf-truststore" module, with
all "grouping" statements expanded, enabling the truststore's full
structure to be seen:Comments:
Protocol-accessible nodes are those nodes that are accessible
when the module is "implemented", as described in .
The protcol-accessible nodes for the "ietf-truststore" module
are an instance of the "truststore-grouping" grouping discussed in
.
The top-level node "truststore" is additionally constrained
by the feature "central-truststore-supported".
The "truststore-grouping" grouping is discussed in
.
The reason for why the "truststore-grouping" exists separate
from the protocol-accessible nodes definition is to enable
instances of the truststore to be instantiated in other
locations, as may be needed or desired by some modules.
Example UsageThe examples in this section are encoded using XML, such as might
be the case when using the NETCONF protocol. Other encodings MAY
be used, such as JSON when using the RESTCONF protocol.A Truststore InstanceThis section presents an example illustrating trust anchors
in <intended>, as per .
Please see for an example illustrating
built-in values in <operational>.The example contained in this section defines eight bags of trust
anchors. There are four certificate-based bags and four public
key based bags. The following diagram provides an overview of the
contents in the example:Following is the full example:trusted-server-ca-certs
Trust anchors (i.e. CA certs) used to authenticate server
certificates. A server certificate is authenticated if its
end-entity certificate has a chain of trust to one of these
certificates.
Server Cert Issuer #1BASE64VALUE=Server Cert Issuer #2BASE64VALUE=trusted-server-ee-certs
Specific end-entity certificates used to authenticate server
certificates. A server certificate is authenticated if its
end-entity certificate is an exact match to one of these
certificates.
My Application #1BASE64VALUE=My Application #2BASE64VALUE=trusted-client-ca-certs
Trust anchors (i.e. CA certs) used to authenticate client
certificates. A client certificate is authenticated if its
end-entity certificate has a chain of trust to one of these
certificates.
Client Identity Issuer #1BASE64VALUE=Client Identity Issuer #2BASE64VALUE=trusted-client-ee-certs
Specific end-entity certificates used to authenticate client
certificates. A client certificate is authenticated if its
end-entity certificate is an exact match to one of these
certificates.
George JetsonBASE64VALUE=Fred FlintstoneBASE64VALUE=trusted-ssh-public-keys
Specific SSH public keys used to authenticate SSH server
public keys. An SSH server public key is authenticated if
its public key is an exact match to one of these public keys.
This list of SSH public keys is analogous to OpenSSH's
"/etc/ssh/ssh_known_hosts" file.
corp-fw1ct:ssh-public-key-format
BASE64VALUE=corp-fw2ct:ssh-public-key-format
BASE64VALUE=SSH Public Keys for Application A
SSH public keys used to authenticate application A's SSH
public keys. An SSH public key is authenticated if it
is an exact match to one of these public keys.
Application Instance #1ct:ssh-public-key-format
BASE64VALUE=Application Instance #2ct:ssh-public-key-format
BASE64VALUE=Raw Public Keys for TLS ServersRaw Public Key #1ct:subject-public-key-info-format
BASE64VALUE=Raw Public Key #2ct:subject-public-key-info-format
BASE64VALUE=Raw Public Keys for TLS ClientsRaw Public Key #1ct:subject-public-key-info-format
BASE64VALUE=Raw Public Key #2ct:subject-public-key-info-format
BASE64VALUE=
]]>A Certificate Expiration NotificationThe following example illustrates the "certificate-expiration"
notification (per )
for a certificate configured in the truststore in .2018-05-25T00:01:00Ztrusted-client-ee-certsGeorge Jetson2018-08-05T14:18:53-05:00
]]>The "Local or Truststore" GroupingsThis section illustrates the various "local-or-truststore" groupings
defined in the "ietf-truststore" module, specifically the
"local-or-truststore-certs-grouping"
() and
"local-or-truststore-public-keys-grouping"
()
groupings.These examples assume the existence of an example module called "ex-truststore-usage"
having the namespace "http://example.com/ns/example-truststore-usage".The ex-truststore-usage module is first presented using tree diagrams
, followed by an instance example illustrating
all the "local-or-truststore" groupings in use, followed by the YANG
module itself.The following tree diagram illustrates "ex-truststore-usage" without
expanding the "grouping" statements:The following tree diagram illustrates the "ex-truststore-usage"
module, with all "grouping" statements expanded, enabling the
truststore's full structure to be seen:The following example provides two equivalent instances of
each grouping, the first being a reference to a truststore
and the second being locally-defined. The instance having
a reference to a truststore is consistent with the truststore
defined in . The two instances are
equivalent, as the locally-defined instance example contains
the same values defined by the truststore instance referenced
by its sibling example.example 1atrusted-client-ca-certs
example 1bmy-trusted-client-ca-certsClient Identity Issuer #1BASE64VALUE=Client Identity Issuer #2BASE64VALUE=example 2atrusted-ssh-public-keys
example 2btrusted-ssh-public-keyscorp-fw1
ct:ssh-public-key-format
BASE64VALUE=corp-fw2
ct:ssh-public-key-format
BASE64VALUE=
]]>Following is the "ex-truststore-usage" module's YANG definition:";
description
"This module illustrates notable groupings defined in
the 'ietf-truststore' module.";
revision 2022-10-19 {
description
"Initial version";
reference
"RFC BBBB: A YANG Data Model for a Truststore";
}
container truststore-usage {
description
"An illustration of the various truststore groupings.";
list cert {
key "name";
leaf name {
type string;
description
"An arbitrary name for this cert.";
}
uses ts:local-or-truststore-certs-grouping;
description
"An cert that may be configured locally or be
a reference to a cert in the truststore.";
}
list public-key {
key "name";
leaf name {
type string;
description
"An arbitrary name for this cert.";
}
uses ts:local-or-truststore-public-keys-grouping;
description
"An public key that may be configured locally or be
a reference to a public key in the truststore.";
}
}
}
]]>YANG ModuleThis YANG module imports modules from
and .<CODE BEGINS> file "ietf-truststore@2022-10-19.yang"
Author : Kent Watsen ";
description
"This module defines a 'truststore' to centralize management
of trust anchors including certificates and public keys.
Copyright (c) 2022 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 Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC BBBB
(https://www.rfc-editor.org/info/rfcBBBB); see the RFC
itself for full legal notices.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision 2022-10-19 {
description
"Initial version";
reference
"RFC BBBB: A YANG Data Model for a Truststore";
}
/****************/
/* Features */
/****************/
feature central-truststore-supported {
description
"The 'central-truststore-supported' feature indicates that
the server supports the truststore (i.e., implements the
'ietf-truststore' module).";
}
feature local-definitions-supported {
description
"The 'local-definitions-supported' feature indicates that
the server supports locally-defined trust anchors.";
}
feature certificates {
description
"The 'certificates' feature indicates that the server
implements the /truststore/certificate-bags subtree.";
}
feature public-keys {
description
"The 'public-keys' feature indicates that the server
implements the /truststore/public-key-bags subtree.";
}
/****************/
/* Typedefs */
/****************/
typedef certificate-bag-ref {
type leafref {
path "/ts:truststore/ts:certificate-bags/"
+ "ts:certificate-bag/ts:name";
}
description
"This typedef defines a reference to a certificate bag
in the truststore, when this module is implemented.";
}
typedef certificate-ref {
type leafref {
path "/ts:truststore/ts:certificate-bags/ts:certificate-bag"
+ "[ts:name = current()/../ts:certificate-bag]/"
+ "ts:certificate/ts:name";
}
description
"This typedef defines a reference to a specific certificate
in a certificate bag in the truststore, when this module
is implemented. This typedef requires that there exist a
sibling 'leaf' node called 'certificate-bag' that SHOULD
have the typedef 'certificate-bag-ref'.";
}
typedef public-key-bag-ref {
type leafref {
path "/ts:truststore/ts:public-key-bags/"
+ "ts:public-key-bag/ts:name";
}
description
"This typedef defines a reference to a public key bag
in the truststore, when this module is implemented.";
}
typedef public-key-ref {
type leafref {
path "/ts:truststore/ts:public-key-bags/ts:public-key-bag"
+ "[ts:name = current()/../ts:public-key-bag]/"
+ "ts:public-key/ts:name";
}
description
"This typedef defines a reference to a specific public key
in a public key bag in the truststore, when this module is
implemented. This typedef requires that there exist a
sibling 'leaf' node called 'public-key-bag' that SHOULD
have the typedef 'public-key-bag-ref'.";
}
/*****************/
/* Groupings */
/*****************/
grouping local-or-truststore-certs-grouping {
description
"A grouping that allows the certificates to be either
configured locally, within the using data model, or be a
reference to a certificate bag stored in the truststore.
Servers that do not 'implement' this module, and hence
'central-truststore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate truststore locations.";
choice local-or-truststore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the truststore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"A container for locally configured trust anchor
certificates.";
list certificate {
key "name";
min-elements 1;
description
"A trust anchor certificate.";
leaf name {
type string;
description
"An arbitrary name for this certificate.";
}
uses ct:trust-anchor-cert-grouping {
refine "cert-data" {
mandatory true;
}
}
}
}
}
case truststore {
if-feature "central-truststore-supported";
if-feature "certificates";
leaf truststore-reference {
type ts:certificate-bag-ref;
description
"A reference to a certificate bag that exists in the
truststore, when this module is implemented.";
}
}
}
}
grouping local-or-truststore-public-keys-grouping {
description
"A grouping that allows the public keys to be either
configured locally, within the using data model, or be a
reference to a public key bag stored in the truststore.
Servers that do not 'implement' this module, and hence
'central-truststore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate truststore locations.";
choice local-or-truststore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the truststore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"A container to hold local public key definitions.";
list public-key {
key "name";
description
"A public key definition.";
leaf name {
type string;
description
"An arbitrary name for this public key.";
}
uses ct:public-key-grouping;
}
}
}
case truststore {
if-feature "central-truststore-supported";
if-feature "public-keys";
leaf truststore-reference {
type ts:public-key-bag-ref;
description
"A reference to a bag of public keys that exists
in the truststore, when this module is implemented.";
}
}
}
}
grouping truststore-grouping {
description
"A grouping definition that enables use in other contexts.
Where used, implementations MUST augment new 'case'
statements into the various local-or-truststore 'choice'
statements to supply leafrefs to the model-specific
location(s).";
container certificate-bags {
nacm:default-deny-write;
if-feature "certificates";
description
"A collection of certificate bags.";
list certificate-bag {
key "name";
description
"A bag of certificates. Each bag of certificates SHOULD
be for a specific purpose. For instance, one bag could
be used to authenticate a specific set of servers, while
another could be used to authenticate a specific set of
clients.";
leaf name {
type string;
description
"An arbitrary name for this bag of certificates.";
}
leaf description {
type string;
description
"A description for this bag of certificates. The
intended purpose for the bag SHOULD be described.";
}
list certificate {
key "name";
description
"A trust anchor certificate.";
leaf name {
type string;
description
"An arbitrary name for this certificate.";
}
uses ct:trust-anchor-cert-grouping {
refine "cert-data" {
mandatory true;
}
}
}
}
}
container public-key-bags {
nacm:default-deny-write;
if-feature "public-keys";
description
"A collection of public key bags.";
list public-key-bag {
key "name";
description
"A bag of public keys. Each bag of keys SHOULD be for
a specific purpose. For instance, one bag could be used
authenticate a specific set of servers, while another
could be used to authenticate a specific set of clients.";
leaf name {
type string;
description
"An arbitrary name for this bag of public keys.";
}
leaf description {
type string;
description
"A description for this bag public keys. The
intended purpose for the bag SHOULD be described.";
}
list public-key {
key "name";
description
"A public key.";
leaf name {
type string;
description
"An arbitrary name for this public key.";
}
uses ct:public-key-grouping;
}
}
}
}
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container truststore {
if-feature central-truststore-supported;
nacm:default-deny-write;
description
"The truststore contains bags of certificates and
public keys.";
uses truststore-grouping;
}
}
]]><CODE ENDS>Support for Built-in Trust AnchorsIn some implementations, a server may define some built-in trust anchors.
For instance, there may be built-in trust anchors enabling the server to
securely connect to well-known services (e.g., an SZTP
bootstrap server) or public CA certificates to connect to arbitrary services
using public PKI.Built-in trust anchors are expected to be set by a vendor-specific process.
Any ability for operators to modify built-in trust anchors is outside the
scope of this document.As built-in trust anchors are provided by the server, they are present in
<operational> (and <system> ,
if used). The example below illustrates what the truststore in <operational>
might look like for a server in its factory default state.Built-In Manufacturer Trust Anchor Certificates
Certificates built into the device for authenticating
manufacturer-signed objects, such as TLS server certificates,
vouchers, etc.
Manufacturer Root CA CertBASE64VALUE=Built-In Public Trust Anchor Certificates
Certificates built into the device for authenticating
certificates issued by public certificate authorities,
such as the end-entity certificate for web servers.
Public Root CA Cert 1BASE64VALUE=Public Root CA Cert 2BASE64VALUE=Public Root CA Cert 3BASE64VALUE=
]]>In order for the built-in bags of trust anchors and/or their trust anchors to
be referenced by configuration, they MUST first be copied into <running>.The built-in bags and/or their trust anchors MUST be copied into <running>
using the same "key" values if it is desired for the server to maintain/update
them (e.g., a software update may update a bag of trusted public CA
certificates used for TLS-client connections).Built-in bags and/or their trust anchors MAY be copied into other parts
of the configuration but, by doing so, they lose their association to the
built-in entries and any assurances afforded by knowing they are/were built-in.The built-in bags and/or their trust anchors are immutable by configuration
operations. Servers MUST ignore attempts to modify any aspect of built-in
bags and/or their trust anchors from <running>.The following example illustrates how a single built-in public CA
certificate from the previous example has been propagated to <running>:Built-In Public Trust Anchor Certificates
Certificates built into the device for authenticating
certificates issued by public certificate authorities,
such as the end-entity certificate for web servers.
Only the subset of the certificates that are referenced
by other configuration nodes need to be copied. For
instance, only "Public Root CA Cert 3" is present here.
No new certificates can be added, nor existing certificate
values changed. Missing certificates have no effect on
"operational" when the configuration is applied.
Public Root CA Cert 3BASE64VALUE=
]]>Security ConsiderationsSecurity of Data at RestThe YANG module defined in this document defines a mechanism called a
"truststore" that, by its name, suggests that its contents are protected
from unauthorized modification.Security controls for the API (i.e., data in motion) are
discussed in , but controls for the
data at rest (e.g., on disk) cannot be specified by the YANG module.In order to satisfy the expectations of a "truststore", it
is RECOMMENDED that implementations ensure that the truststore
contents are protected from unauthorized modifications when
at rest.Unconstrained Public Key UsageThis module enables the configuration of public keys without
constraints on their usage, e.g., what operations the key is
allowed to be used for (encryption, verification, both).Trust anchors configured via this module are implicitly trusted
to validate certification paths that may include any name, be
used for any purpose and etc., subject to constraints imposed
by an intermediate CA or by context in which the truststore is
used. Implementations are free to use alternative or auxiliary
structures and validation rules to define constraints that
limit the applicability of any trust anchor.The "ietf-truststore" YANG ModuleThe 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 Network 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.None of the readable data nodes defined in this YANG module are considered sensitive
or vulnerable in network environments. The NACM "default-deny-all" extension
has not been set for any data nodes defined in this module.All the writable data nodes defined by this module, both in the
"grouping" statements as well as the protocol-accessible "truststore"
instance, may be considered sensitive or vulnerable in some network
environments. For instance, any modification to a trust anchor or
reference to a trust anchor may dramatically alter the implemented
security policy. For this reason, the NACM extension "default-deny-write"
has been set for all data nodes defined in this module.This module does not define any "rpc" or "action" statements, and
thus the security considerations for such is not provided here.IANA ConsiderationsThe "IETF XML" RegistryThis document registers one URI in the "ns" subregistry of
the IETF XML Registry . Following the
format in , the following registration
is requested:The "YANG Module Names" RegistryThis document registers one YANG module in the
YANG Module Names registry .
Following the format in , the
following registration is requested:ReferencesNormative ReferencesKey words for use in RFCs to Indicate Requirement LevelsIn many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.The YANG 1.1 Data Modeling LanguageYANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF).Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsRFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.Network Configuration Access Control ModelThe standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.This document obsoletes RFC 6536.Informative ReferencesThe IETF XML RegistryThis document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]Network Configuration Protocol (NETCONF)The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]RESTCONF ProtocolThis document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).YANG Tree DiagramsThis document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.Network Management Datastore Architecture (NMDA)Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.Secure Zero Touch Provisioning (SZTP)This document presents a technique to securely provision a networking device when it is booting in a factory-default state. Variations in the solution enable it to be used on both public and private networks. The provisioning steps are able to update the boot image, commit an initial configuration, and execute arbitrary scripts to address auxiliary needs. The updated device is subsequently able to establish secure connections with other systems. For instance, a device may establish NETCONF (RFC 6241) and/or RESTCONF (RFC 8040) connections with deployment-specific network management systems.Change Log00 to 01
Added features "x509-certificates" and "ssh-host-keys".
Added nacm:default-deny-write to "trust-anchors" container.
01 to 02
Switched "list pinned-certificate" to use the
"trust-anchor-cert-grouping" from crypto-types.
Effectively the same definition as before.
02 to 03
Updated copyright date, boilerplate template, affiliation,
folding algorithm, and reformatted the YANG module.
03 to 04
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!
Related to above, also added features 'truststore-supported'
and 'local-trust-anchors-supported'.
04 to 05
Renamed "trust-anchors" to "truststore"
Removed "pinned." prefix everywhere, to match truststore rename
Moved everything under a top-level 'grouping' to enable use in other contexts.
Renamed feature from 'local-trust-anchors-supported' to 'local-definitions-supported' (same name used in keystore)
Removed the "require-instance false" statement from the "*-ref" typedefs.
Added missing "ssh-host-keys" and "x509-certificates" if-feature statements
05 to 06
Editorial changes only.
06 to 07
Added Henk Birkholz as a co-author (thanks Henk!)
Added PSKs and raw public keys to truststore.
07 to 08
Added new "Support for Built-in Trust Anchors" section.
Merged "SSH Public Keys" and "Raw Public Keys" in a single "Public Keys" bag.
Consuming downstream modules (i.e., "ietf-[ssh/tls]-[client/server]) refine
the "public-key-format" to be either SSH or TLS specific as needed.
09 to 10
Removed "algorithm" node from examples.
Removed the no longer used statements supporting the old "ssh-public-key" and "raw-public-key" nodes.
Added a "Note to Reviewers" note to first page.
10 to 11
Corrected module prefix registered in the IANA Considerations section.
Modified 'local-or-truststore-certs-grouping' to use a list (not a leaf-list).
Added new example section "The Local or Truststore Groupings".
Clarified expected behavior for "built-in" certificates in <operational>
Expanded "Data Model Overview section(s) [remove "wall" of tree diagrams].
Updated the Security Considerations section.
11 to 12
Fixed a copy/paste issue in the "Data at Rest" Security Considerations section.
12 to 13
Fixed issues found by the SecDir review of the "keystore" draft.
13 to 14
Added an "Unconstrained Public Key Usage" Security Consideration to address
concern raised by SecDir.
Addressed comments raised by YANG Doctor.
14 to 15
Added prefixes to 'path' statements per trust-anchors/issues/1
Renamed feature "truststore-supported" to "central-truststore-supported".
Associated with above, generally moved text to refer to a "central" truststore.
Removed two unecessary/unwanted "min-elements 1" and associated "presence" statements.
Aligned modules with `pyang -f` formatting.
Fixed nits found by YANG Doctor reviews.
15 to 16
Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.
Minor editorial nits
16 to 17
fixup the 'WG Web' and 'WG List' lines in YANG module(s)
fixup copyright (i.e., s/Simplified/Revised/) in YANG module(s)
Added Informative reference to ma-netmod-with-system
17 to 18
Updated Security Considerations section to address comment
received from Carl Wallace.
Fixed examples to not have line-returns around "identity" encodings.
Fixed a couple tree diagrams to not create diagrams for "groupings" too.
Added "if-feature central-truststore-supported" to top-level "trustore" container.
18 to 19
Updated per Shepherd reviews.
AcknowledgementsThe authors especially thank Henk Birkholz for contributing YANG
to the ietf-truststore module supporting raw public keys and PSKs
(pre-shared or pairwise-symmetric keys). While these contributions
were eventually replaced by reusing the existing support for
asymmetric and symmetric trust anchors, respectively, it was only
thru Henk's initiative that the WG was able to come to that result.The authors additionally thank the following for helping give shape
to this work (ordered by first name):
Balazs Kovacs,
Carl Wallace,
Eric Voit,
Juergen Schoenwaelder,
Liang Xia,
Martin Bjoerklund,
Nick Hancock,
Qin Wu,
and Yoav Nir.