Watsen Networks

kent+ietf@watsen.net

Operations NETCONF Working Group This 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:

• 2022-03-07 --> the publication date of this draft

The following Appendix section is to be removed prior to publication:

• . Change Log

Introduction This 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 trusttore instance.

Relation to other RFCs This 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. The 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 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 when, and only when, they appear in all capitals, as shown here.

Adherence to the NMDA This 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 ).

Conventions Various 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" Module This section defines a YANG 1.1 module that defines a "truststore" and groupings supporting downstream modules to reference the truststore or have locally-defined definitions. This 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 Overview This section provides an overview of the "ietf-truststore" module in terms of its features, typedefs, groupings, and protocol-accessible nodes.

Features The following diagram lists all the "feature" statements defined in the "ietf-truststore" module:

Typedefs The 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.

Groupings The "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" Grouping The 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" Grouping The 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" Grouping The 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 Nodes The 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 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 Usage The 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 Instance This 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 #1 BASE64VALUE= Server Cert Issuer #2 BASE64VALUE= 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 #1 BASE64VALUE= My Application #2 BASE64VALUE= 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 #1 BASE64VALUE= Client Identity Issuer #2 BASE64VALUE= 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 Jetson BASE64VALUE= Fred Flintstone BASE64VALUE= 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-fw1 ct:ssh-public-key-format BASE64VALUE= corp-fw2 ct: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 #1 ct:ssh-public-key-format BASE64VALUE= Application Instance #2 ct:ssh-public-key-format BASE64VALUE= Raw Public Keys for TLS Servers Raw Public Key #1 ct:subject-public-key-info-format BASE64VALUE= Raw Public Key #2 ct:subject-public-key-info-format BASE64VALUE= Raw Public Keys for TLS Clients Raw Public Key #1 ct:subject-public-key-info-format BASE64VALUE= Raw Public Key #2 ct:subject-public-key-info-format BASE64VALUE= ]]>

A Certificate Expiration Notification The following example illustrates the "certificate-expiration" notification (per ) for a certificate configured in the truststore in . 2018-05-25T00:01:00Z trusted-client-ee-certs George Jetson 2018-08-05T14:18:53-05:00 ]]>

The "Local or Truststore" Groupings This 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 1a trusted-client-ca-certs example 1b my-trusted-client-ca-certs Client Identity Issuer #1 BASE64VALUE= Client Identity Issuer #2 BASE64VALUE= example 2a trusted-ssh-public-keys example 2b trusted-ssh-public-keys corp-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 2022-03-07 { 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 Module This YANG module imports modules from and . <CODE BEGINS> file "ietf-truststore@2022-03-07.yang" Author : Kent Watsen "; description "This module defines a 'truststore' to centralize management of trust anchors including certificates and public keys. Copyright (c) 2021 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 2022-03-07 { 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 { nacm:default-deny-write; description "The truststore contains bags of certificates and public keys."; uses truststore-grouping; } } ]]> <CODE ENDS>

Support for Built-in Trust Anchors In 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 Cert BASE64VALUE= 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 1 BASE64VALUE= Public Root CA Cert 2 BASE64VALUE= Public Root CA Cert 3 BASE64VALUE= ]]> 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 3 BASE64VALUE= ]]>

Security Considerations

Security of Data at Rest The 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 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 Usage This 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). This module also enables the configuration of certificates, where each certificate may constrain the usage of the public key according to local policy.

The "ietf-truststore" YANG Module 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. 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 Considerations

The "IETF XML" Registry This 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" Registry This document registers one YANG module in the YANG Module Names registry . Following the format in , the following registration is requested:

References Normative References In 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. YANG 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). RFC 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. The 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 References This 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 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] 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] This 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). This 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. 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. 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 Log

00 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.
• Removed spurious "uses ct:trust-anchor-certs-grouping" line.
• Removed PSK from model.

08 to 09

• Removed remaining PSK references from text.
• Wrapped each top-level list with a container.
• Introduced "bag" term.
• 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

Acknowledgements The 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, Eric Voit, Juergen Schoenwaelder, Liang Xia, Martin Bjoerklund, Nick Hancock, and Yoav Nir.