| NETCONF Working Group | K. Watsen |
| Internet-Draft | Watsen Networks |
| Intended status: Standards Track | May 20, 2020 |
| Expires: November 21, 2020 |
A YANG Data Model for a Keystore
draft-ietf-netconf-keystore-17
This document defines a YANG 1.1 module called "ietf-keystore" that enables centralized configuration of both symmetric and asymmetric keys. The secret value for both key types may be encrypted. Asymmetric keys may be associated with certificates. Notifications are sent when certificates are about to expire.
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:
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 document presents a YANG module or modules that is/are part of a collection of drafts that work together to produce the ultimate goal of the NETCONF WG: to define configuration modules for NETCONF client and servers, and RESTCONF client and servers.
The relationship between the various drafts in the collection is presented in the below diagram.
crypto-types
^ ^
/ \
/ \
trust-anchors keystore
^ ^ ^ ^
| +---------+ | |
| | | |
| +------------+ |
tcp-client-server | / | |
^ ^ ssh-client-server | |
| | ^ tls-client-server
| | | ^ ^ http-client-server
| | | | | ^
| | | +-----+ +---------+ |
| | | | | |
| +-----------|--------|--------------+ | |
| | | | | |
+-----------+ | | | | |
| | | | | |
| | | | | |
netconf-client-server restconf-client-server
Full draft names and link to drafts:
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This document defines a YANG 1.1 [RFC7950] module called "ietf-keystore" that enables centralized configuration of both symmetric and asymmetric keys. The secret value for both key types may be encrypted. Asymmetric keys may be associated with certificates. Notifications are sent when certificates are about to expire.
The "ietf-keystore" module defines many "grouping" statements intended for use by other modules that may import it. For instance, there are groupings that defined enabling a key to be either configured locally (within the defining data model) or be a reference to a key in the Keystore.
Special consideration has been given for systems that have cryptographic hardware, such as a Trusted Protection Module (TPM). These systems are unique in that the cryptographic hardware hides the secret key values. To support such hardware, symmetric keys may have the value "hidden-key" and asymmetric keys may have the value "hidden-private-key". While how such keys are created or destroyed is outside the scope of this document, the Keystore can contain entries for such keys, enabling them to be referenced by other configuration elements.
This document in compliant with Network Management Datastore Architecture (NMDA) [RFC8342]. For instance, keys and associated certificates installed during manufacturing (e.g., for a IDevID [Std-802.1AR-2009] certificate), are expected to appear in <operational> (see Section 4).
It is not required that a system has an operating system level Keystore utility to implement this module.
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.
This section provides a tree diagrams [RFC8340] for the "ietf-keystore" module that presents both the protocol-accessible "keystore" as well the all the groupings intended for external usage.
module: ietf-keystore
+--rw keystore
+--rw asymmetric-keys
| +--rw asymmetric-key* [name]
| +--rw name string
| +--rw public-key-format identityref
| +--rw public-key binary
| +--rw private-key-format? identityref
| +--rw (private-key-type)
| | +--:(private-key)
| | | +--rw private-key? binary
| | +--:(hidden-private-key)
| | | +--rw hidden-private-key? empty
| | +--:(encrypted-private-key)
| | +--rw encrypted-private-key
| | +--rw (key-type)
| | | +--:(symmetric-key-ref)
| | | | +--rw symmetric-key-ref? leafref
| | | | {keystore-supported}?
| | | +--:(asymmetric-key-ref)
| | | +--rw asymmetric-key-ref? leafref
| | | {keystore-supported}?
| | +--rw value? binary
| +--rw certificates
| | +--rw certificate* [name]
| | +--rw name string
| | +--rw cert end-entity-cert-cms
| | +---n certificate-expiration
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request ct:csr
+--rw symmetric-keys
+--rw symmetric-key* [name]
+--rw name string
+--rw key-format? identityref
+--rw (key-type)
+--:(key)
| +--rw key? binary
+--:(hidden-key)
| +--rw hidden-key? empty
+--:(encrypted-key)
+--rw encrypted-key
+--rw (key-type)
| +--:(symmetric-key-ref)
| | +--rw symmetric-key-ref? leafref
| | {keystore-supported}?
| +--:(asymmetric-key-ref)
| +--rw asymmetric-key-ref? leafref
| {keystore-supported}?
+--rw value? binary
grouping key-reference-type-grouping
+-- (key-type)
+--:(symmetric-key-ref)
| +-- symmetric-key-ref?
| -> /keystore/symmetric-keys/symmetric-key/name
| {keystore-supported}?
+--:(asymmetric-key-ref)
+-- asymmetric-key-ref?
-> /keystore/asymmetric-keys/asymmetric-key/name
{keystore-supported}?
grouping encrypted-value-grouping
+-- (key-type)
| +--:(symmetric-key-ref)
| | +-- symmetric-key-ref?
| | -> /keystore/symmetric-keys/symmetric-key/name
| | {keystore-supported}?
| +--:(asymmetric-key-ref)
| +-- asymmetric-key-ref?
| -> /keystore/asymmetric-keys/asymmetric-key/name
| {keystore-supported}?
+-- value? binary
grouping symmetric-key-grouping
+-- key-format? identityref
+-- (key-type)
+--:(key)
| +-- key? binary
+--:(hidden-key)
| +-- hidden-key? empty
+--:(encrypted-key)
+-- encrypted-key
+-- (key-type)
| +--:(symmetric-key-ref)
| | +-- symmetric-key-ref? leafref
| | {keystore-supported}?
| +--:(asymmetric-key-ref)
| +-- asymmetric-key-ref? leafref
| {keystore-supported}?
+-- value? binary
grouping asymmetric-key-pair-grouping
+-- public-key-format identityref
+-- public-key binary
+-- private-key-format? identityref
+-- (private-key-type)
+--:(private-key)
| +-- private-key? binary
+--:(hidden-private-key)
| +-- hidden-private-key? empty
+--:(encrypted-private-key)
+-- encrypted-private-key
+-- (key-type)
| +--:(symmetric-key-ref)
| | +-- symmetric-key-ref? leafref
| | {keystore-supported}?
| +--:(asymmetric-key-ref)
| +-- asymmetric-key-ref? leafref
| {keystore-supported}?
+-- value? binary
grouping asymmetric-key-pair-with-cert-grouping
+-- public-key-format identityref
+-- public-key binary
+-- private-key-format? identityref
+-- (private-key-type)
| +--:(private-key)
| | +-- private-key? binary
| +--:(hidden-private-key)
| | +-- hidden-private-key? empty
| +--:(encrypted-private-key)
| +-- encrypted-private-key
| +-- (key-type)
| | +--:(symmetric-key-ref)
| | | +-- symmetric-key-ref? leafref
| | | {keystore-supported}?
| | +--:(asymmetric-key-ref)
| | +-- asymmetric-key-ref? leafref
| | {keystore-supported}?
| +-- value? binary
+-- cert? end-entity-cert-cms
+---n certificate-expiration
| +-- expiration-date yang:date-and-time
+---x generate-certificate-signing-request
{certificate-signing-request-generation}?
+---w input
| +---w subject binary
| +---w attributes? binary
+--ro output
+--ro certificate-signing-request ct:csr
grouping asymmetric-key-pair-with-certs-grouping
+-- public-key-format identityref
+-- public-key binary
+-- private-key-format? identityref
+-- (private-key-type)
| +--:(private-key)
| | +-- private-key? binary
| +--:(hidden-private-key)
| | +-- hidden-private-key? empty
| +--:(encrypted-private-key)
| +-- encrypted-private-key
| +-- (key-type)
| | +--:(symmetric-key-ref)
| | | +-- symmetric-key-ref? leafref
| | | {keystore-supported}?
| | +--:(asymmetric-key-ref)
| | +-- asymmetric-key-ref? leafref
| | {keystore-supported}?
| +-- value? binary
+-- certificates
| +-- certificate* [name]
| +-- name? string
| +-- cert end-entity-cert-cms
| +---n certificate-expiration
| +-- expiration-date yang:date-and-time
+---x generate-certificate-signing-request
{certificate-signing-request-generation}?
+---w input
| +---w subject binary
| +---w attributes? binary
+--ro output
+--ro certificate-signing-request ct:csr
grouping asymmetric-key-certificate-ref-grouping
+-- asymmetric-key? ks:asymmetric-key-ref
+-- certificate? leafref
grouping local-or-keystore-symmetric-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- key-format? identityref
| +-- (key-type)
| +--:(key)
| | +-- key? binary
| +--:(hidden-key)
| | +-- hidden-key? empty
| +--:(encrypted-key)
| +-- encrypted-key
| +-- (key-type)
| | +--:(symmetric-key-ref)
| | | +-- symmetric-key-ref? leafref
| | | {keystore-supported}?
| | +--:(asymmetric-key-ref)
| | +-- asymmetric-key-ref? leafref
| | {keystore-supported}?
| +-- value? binary
+--:(keystore) {keystore-supported}?
+-- keystore-reference? ks:symmetric-key-ref
grouping local-or-keystore-asymmetric-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- public-key-format identityref
| +-- public-key binary
| +-- private-key-format? identityref
| +-- (private-key-type)
| +--:(private-key)
| | +-- private-key? binary
| +--:(hidden-private-key)
| | +-- hidden-private-key? empty
| +--:(encrypted-private-key)
| +-- encrypted-private-key
| +-- (key-type)
| | +--:(symmetric-key-ref)
| | | +-- symmetric-key-ref? leafref
| | | {keystore-supported}?
| | +--:(asymmetric-key-ref)
| | +-- asymmetric-key-ref? leafref
| | {keystore-supported}?
| +-- value? binary
+--:(keystore) {keystore-supported}?
+-- keystore-reference? ks:asymmetric-key-ref
grouping local-or-keystore-asymmetric-key-with-certs-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- public-key-format identityref
| +-- public-key binary
| +-- private-key-format? identityref
| +-- (private-key-type)
| | +--:(private-key)
| | | +-- private-key? binary
| | +--:(hidden-private-key)
| | | +-- hidden-private-key? empty
| | +--:(encrypted-private-key)
| | +-- encrypted-private-key
| | +-- (key-type)
| | | +--:(symmetric-key-ref)
| | | | +-- symmetric-key-ref? leafref
| | | | {keystore-supported}?
| | | +--:(asymmetric-key-ref)
| | | +-- asymmetric-key-ref? leafref
| | | {keystore-supported}?
| | +-- value? binary
| +-- certificates
| | +-- certificate* [name]
| | +-- name? string
| | +-- cert end-entity-cert-cms
| | +---n certificate-expiration
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request ct:csr
+--:(keystore) {keystore-supported}?
+-- keystore-reference? ks:asymmetric-key-ref
grouping local-or-keystore-end-entity-cert-with-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- public-key-format identityref
| +-- public-key binary
| +-- private-key-format? identityref
| +-- (private-key-type)
| | +--:(private-key)
| | | +-- private-key? binary
| | +--:(hidden-private-key)
| | | +-- hidden-private-key? empty
| | +--:(encrypted-private-key)
| | +-- encrypted-private-key
| | +-- (key-type)
| | | +--:(symmetric-key-ref)
| | | | +-- symmetric-key-ref? leafref
| | | | {keystore-supported}?
| | | +--:(asymmetric-key-ref)
| | | +-- asymmetric-key-ref? leafref
| | | {keystore-supported}?
| | +-- value? binary
| +-- cert?
| | end-entity-cert-cms
| +---n certificate-expiration
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request ct:csr
+--:(keystore) {keystore-supported}?
+-- keystore-reference
+-- asymmetric-key? ks:asymmetric-key-ref
+-- certificate? leafref
grouping keystore-grouping
+-- asymmetric-keys
| +-- asymmetric-key* [name]
| +-- name? string
| +-- public-key-format identityref
| +-- public-key binary
| +-- private-key-format? identityref
| +-- (private-key-type)
| | +--:(private-key)
| | | +-- private-key? binary
| | +--:(hidden-private-key)
| | | +-- hidden-private-key? empty
| | +--:(encrypted-private-key)
| | +-- encrypted-private-key
| | +-- (key-type)
| | | +--:(symmetric-key-ref)
| | | | +-- symmetric-key-ref? leafref
| | | | {keystore-supported}?
| | | +--:(asymmetric-key-ref)
| | | +-- asymmetric-key-ref? leafref
| | | {keystore-supported}?
| | +-- value? binary
| +-- certificates
| | +-- certificate* [name]
| | +-- name? string
| | +-- cert end-entity-cert-cms
| | +---n certificate-expiration
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request ct:csr
+-- symmetric-keys
+-- symmetric-key* [name]
+-- name? string
+-- key-format? identityref
+-- (key-type)
+--:(key)
| +-- key? binary
+--:(hidden-key)
| +-- hidden-key? empty
+--:(encrypted-key)
+-- encrypted-key
+-- (key-type)
| +--:(symmetric-key-ref)
| | +-- symmetric-key-ref? leafref
| | {keystore-supported}?
| +--:(asymmetric-key-ref)
| +-- asymmetric-key-ref? leafref
| {keystore-supported}?
+-- value? binary
The following example illustrates keys in <running>. Please see Section 4 for an example illustrating built-in values in <operational>.
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<symmetric-keys>
<symmetric-key>
<name>cleartext-symmetric-key</name>
<key-format>ct:octet-string-key-format</key-format>
<key>base64encodedvalue==</key>
</symmetric-key>
<symmetric-key>
<name>hidden-symmetric-key</name>
<hidden-key/>
</symmetric-key>
<symmetric-key>
<name>encrypted-symmetric-key</name> <!-- operator's key -->
<key-format>ct:encrypted-one-symmetric-key-format</key-format>
<encrypted-key>
<asymmetric-key-ref>hidden-asymmetric-key</asymmetric-key-re\
f>
<value>base64encodedvalue==</value>
</encrypted-key>
</symmetric-key>
</symmetric-keys>
<asymmetric-keys>
<asymmetric-key>
<name>ssh-rsa-key</name>
<public-key-format>ct:ssh-public-key-format</public-key-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
</asymmetric-key>
<asymmetric-key>
<name>ssh-rsa-key-with-cert</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>ex-rsa-cert2</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>raw-private-key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
</asymmetric-key>
<asymmetric-key>
<name>rsa-asymmetric-key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>ex-rsa-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>ec-asymmetric-key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:ec-private-key-format</private-key-form\
at>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>ex-ec-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>hidden-asymmetric-key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/> <!-- e.g., TPM protected -->
<certificates>
<certificate>
<name>builtin-idevid-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
<certificate>
<name>my-ldevid-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>encrypted-asymmetric-key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:encrypted-one-asymmetric-key-format</pr\
ivate-key-format>
<encrypted-private-key>
<symmetric-key-ref>encrypted-symmetric-key</symmetric-key-re\
f>
<value>base64encodedvalue==</value>
</encrypted-private-key>
</asymmetric-key>
</asymmetric-keys>
</keystore>
The following non-normative module is used by subsequent examples to illustrate groupings defined in the ietf-keystore module.
module ex-keystore-usage {
yang-version 1.1;
namespace "http://example.com/ns/example-keystore-usage";
prefix "eku";
import ietf-keystore {
prefix ks;
reference
"RFC XXXX: YANG Data Model for a 'Keystore' Mechanism";
}
organization
"Example Corporation";
contact
"Author: YANG Designer <mailto:yang.designer@example.com>";
description
"This module illustrates the grouping in the keystore draft called
'local-or-keystore-asymmetric-key-with-certs-grouping'.";
revision "YYYY-MM-DD" {
description
"Initial version";
reference
"RFC XXXX: YANG Data Model for a 'Keystore' Mechanism";
}
container keystore-usage {
description
"An illustration of the various keystore groupings.";
list just-a-key {
key name;
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks:local-or-keystore-asymmetric-key-grouping;
description
"An asymmetric key, with no certs, that may be configured
locally or be a reference to an asymmetric key in the
keystore. The intent is to reference just the asymmetric
key, not any certificates that may also be associated
with the asymmetric key.";
}
list key-with-certs {
key name;
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks:local-or-keystore-asymmetric-key-with-certs-grouping;
description
"An asymmetric key and its associated certs, that may be
configured locally or be a reference to an asymmetric key
(and its associated certs) in the keystore.";
}
list end-entity-cert-with-key {
key name;
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks:local-or-keystore-end-entity-cert-with-key-grouping;
description
"An end-entity certificate, and its associated private key,
that may be configured locally or be a reference to a
specific certificate (and its associated private key) in
the keystore.";
}
}
}
The following example illustrates what two configured keys, one local and the other remote, might look like. This example consistent with other examples above (i.e., the referenced key is in an example above).
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<keystore-usage xmlns="http://example.com/ns/example-keystore-usage"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<!-- ks:local-or-keystore-asymmetric-key-grouping -->
<just-a-key>
<name>a locally-defined key</name>
<local-definition>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
</local-definition>
</just-a-key>
<just-a-key>
<name>a keystore-defined key (and its associated certs)</name>
<keystore-reference>rsa-asymmetric-key</keystore-reference>
</just-a-key>
<!-- ks:local-or-keystore-key-and-end-entity-cert-grouping -->
<key-with-certs>
<name>a locally-defined key with certs</name>
<local-definition>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>a locally-defined cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</local-definition>
</key-with-certs>
<key-with-certs>
<name>a keystore-defined key (and its associated certs)</name>
<keystore-reference>rsa-asymmetric-key</keystore-reference>
</key-with-certs>
<!-- ks:local-or-keystore-end-entity-cert-with-key-grouping -->
<end-entity-cert-with-key>
<name>a locally-defined end-entity cert with key</name>
<local-definition>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>ct:rsa-private-key-format</private-key-for\
mat>
<private-key>base64encodedvalue==</private-key>
<cert>base64encodedvalue==</cert>
</local-definition>
</end-entity-cert-with-key>
<end-entity-cert-with-key>
<name>a keystore-defined certificate (and its associated key)</n\
ame>
<keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</keystore-reference>
</end-entity-cert-with-key>
</keystore-usage>
This YANG module has normative references to [RFC8341] and [I-D.ietf-netconf-crypto-types], and an informative reference to [RFC8342].
<CODE BEGINS> file "ietf-keystore@2020-05-20.yang"
module ietf-keystore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-keystore";
prefix ks;
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC AAAA: 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:kent+ietf@watsen.net>";
description
"This module defines a Keystore to centralize management
of security credentials.
Copyright (c) 2020 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC CCCC
(https://www.rfc-editor.org/info/rfcCCCC); 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 2020-05-20 {
description
"Initial version";
reference
"RFC CCCC: A YANG Data Model for a Keystore";
}
/****************/
/* Features */
/****************/
feature keystore-supported {
description
"The 'keystore-supported' feature indicates that the server
supports the Keystore.";
}
feature local-definitions-supported {
description
"The 'local-definitions-supported' feature indicates that the
server supports locally-defined keys.";
}
/****************/
/* Typedefs */
/****************/
typedef symmetric-key-ref {
type leafref {
path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key"
+ "/ks:name";
}
description
"This typedef enables modules to easily define a reference
to a symmetric key stored in the Keystore.";
}
typedef asymmetric-key-ref {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "/ks:name";
}
description
"This typedef enables modules to easily define a reference
to an asymmetric key stored in the Keystore.";
}
/*****************/
/* Groupings */
/*****************/
grouping key-reference-type-grouping {
description
"A reusable grouping for a choice for the type of key
referenced in the Keystore.";
choice key-type {
mandatory true;
description
"A choice between a reference to a symmetric or asymmetric
key in the Keystore.";
leaf symmetric-key-ref {
if-feature "keystore-supported";
type leafref {
path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key/"
+ "ks:name";
}
description
"Identifies a symmetric key used to encrypt this key.";
}
leaf asymmetric-key-ref {
if-feature "keystore-supported";
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key/"
+ "ks:name";
}
description
"Identifies an asymmetric key used to encrypt this key.";
}
}
}
grouping encrypted-value-grouping {
description
"A reusable grouping for a value that has been encrypted by
a symmetric or asymmetric key in the Keystore.";
uses "key-reference-type-grouping";
leaf value {
type binary;
description
"The private key, encrypted using the specified symmetric
or asymmetric key.";
}
}
grouping symmetric-key-grouping {
description
"This grouping is identical to the one in ietf-crypto-types
except that it adds a case statement enabling the key
value to be encrypted by a symmetric or an asymmetric
key known to the Keystore.";
uses ct:symmetric-key-grouping {
augment "key-type" {
description
"Augments a new 'case' statement into the 'choice'
statement defined by the ietf-crypto-types module.";
container encrypted-key {
must "../key-format";
description
"A container for the encrypted symmetric key value.";
uses encrypted-value-grouping;
}
}
}
}
grouping asymmetric-key-pair-grouping {
description
"This grouping is identical to the one in ietf-crypto-types
except that it adds a case statement enabling the key
value to be encrypted by a symmetric or an asymmetric
key known to the Keystore.";
uses ct:asymmetric-key-pair-grouping {
augment "private-key-type" {
description
"Augments a new 'case' statement into the 'choice'
statement defined by the ietf-crypto-types module.";
container encrypted-private-key {
must "../private-key-format";
description
"A container for the encrypted asymmetric private
key value.";
uses encrypted-value-grouping;
}
}
}
}
grouping asymmetric-key-pair-with-cert-grouping {
description
"This grouping is identical to the one in ietf-crypto-types
except that it adds a case statement enabling the key
value to be encrypted by a symmetric or an asymmetric
key known to the Keystore.";
uses ct:asymmetric-key-pair-with-cert-grouping {
augment "private-key-type" {
description
"Augments a new 'case' statement into the 'choice'
statement defined by the ietf-crypto-types module.";
container encrypted-private-key {
must "../private-key-format";
description
"A container for the encrypted asymmetric private
key value.";
uses encrypted-value-grouping;
}
}
}
}
grouping asymmetric-key-pair-with-certs-grouping {
description
"This grouping is identical to the one in ietf-crypto-types
except that it adds a case statement enabling the key
value to be encrypted by a symmetric or an asymmetric
key known to the Keystore.";
uses ct:asymmetric-key-pair-with-certs-grouping {
augment "private-key-type" {
description
"Augments a new 'case' statement into the 'choice'
statement defined by the ietf-crypto-types module.";
container encrypted-private-key {
must "../private-key-format";
description
"A container for the encrypted asymmetric private
key value.";
uses encrypted-value-grouping;
}
}
}
}
grouping asymmetric-key-certificate-ref-grouping {
leaf asymmetric-key {
type ks:asymmetric-key-ref;
must '../certificate';
description
"A reference to an asymmetric key in the Keystore.";
}
leaf certificate {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key[ks:"
+ "name = current()/../asymmetric-key]/ks:certificates"
+ "/ks:certificate/ks:name";
}
must '../asymmetric-key';
description
"A reference to a specific certificate of the
asymmetric key in the Keystore.";
}
description
"This grouping defines a reference to a specific certificate
associated with an asymmetric key stored in the Keystore.";
}
// local-or-keystore-* groupings
grouping local-or-keystore-symmetric-key-grouping {
description
"A grouping that expands to allow the symmetric key to be
either stored locally, within the using data model, or be
a reference to a symmetric key stored in the Keystore.";
choice local-or-keystore {
mandatory true;
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses symmetric-key-grouping;
}
}
case keystore {
if-feature "keystore-supported";
leaf keystore-reference {
type ks:symmetric-key-ref;
description
"A reference to an symmetric key that exists in
the Keystore.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the Keystore.";
}
}
grouping local-or-keystore-asymmetric-key-grouping {
description
"A grouping that expands to allow the asymmetric key to be
either stored locally, within the using data model, or be
a reference to an asymmetric key stored in the Keystore.";
choice local-or-keystore {
mandatory true;
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses asymmetric-key-pair-grouping;
}
}
case keystore {
if-feature "keystore-supported";
leaf keystore-reference {
type ks:asymmetric-key-ref;
description
"A reference to an asymmetric key that exists in
the Keystore. The intent is to reference just the
asymmetric key without any regard for any certificates
that may be associated with it.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the Keystore.";
}
}
grouping local-or-keystore-asymmetric-key-with-certs-grouping {
description
"A grouping that expands to allow an asymmetric key and its
associated certificates to be either stored locally, within
the using data model, or be a reference to an asymmetric key
(and its associated certificates) stored in the Keystore.";
choice local-or-keystore {
mandatory true;
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses asymmetric-key-pair-with-certs-grouping;
}
}
case keystore {
if-feature "keystore-supported";
leaf keystore-reference {
type ks:asymmetric-key-ref;
description
"A reference to an asymmetric-key (and all of its
associated certificates) in the Keystore.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the Keystore.";
}
}
grouping local-or-keystore-end-entity-cert-with-key-grouping {
description
"A grouping that expands to allow an end-entity certificate
(and its associated private key) to be either stored locally,
within the using data model, or be a reference to a specific
certificate in the Keystore.";
choice local-or-keystore {
mandatory true;
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses asymmetric-key-pair-with-cert-grouping;
}
}
case keystore {
if-feature "keystore-supported";
container keystore-reference {
uses asymmetric-key-certificate-ref-grouping;
description
"A reference to a specific certificate (and its
associated private key) in the Keystore.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the Keystore.";
}
}
grouping keystore-grouping {
description
"Grouping definition enables use in other contexts. If ever
done, implementations SHOULD augment new 'case' statements
into local-or-keystore 'choice' statements to supply leafrefs
to the new location.";
container asymmetric-keys {
description
"A list of asymmetric keys.";
list asymmetric-key {
key "name";
description
"An asymmetric key.";
leaf name {
type string;
description
"An arbitrary name for the asymmetric key.";
}
uses ks:asymmetric-key-pair-with-certs-grouping;
}
}
container symmetric-keys {
description
"A list of symmetric keys.";
list symmetric-key {
key "name";
description
"A symmetric key.";
leaf name {
type string;
description
"An arbitrary name for the symmetric key.";
}
uses ks:symmetric-key-grouping;
}
}
} // grouping keystore-grouping
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container keystore {
nacm:default-deny-write;
description
"The Keystore contains a list of symmetric keys and a list
of asymmetric keys.";
uses keystore-grouping;
}
}
<CODE ENDS>
In some implementations, a server may support built-in keys. Built-in built-in keys MAY be set during the manufacturing process or be dynamically generated the first time the server is booted or a particular service (e.g., SSH) is enabled.
The key characteristic of the built-in keys is that they are provided by the system, as opposed to configuration. As such, they are present in <operational>. The example below illustrates what the truststore in <operational> might look like for a server in its factory default state.
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<asymmetric-keys>
<asymmetric-key or:origin="or:system">
<name>Manufacturer-Generated Hidden Key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/> <!-- e.g., TPM protected -->
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
In order for the built-in keys to be referenced by configuration, the referenced nodes MUST first be copied into <running>. They SHOULD be copied into <running> using the same "key" values, so that the system can bind the references to the built-in entries. Only the referenced nodes need to be copied. When using the same key values as in <operational> no new values can be added and no existing values can be changed; that which is in <running> can only be a subset of that which is in <operational>.
For instance, the following example illustrates how a single built-in key definition from the previous example has been propagated to <running>:
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<asymmetric-keys>
<asymmetric-key>
<name>Manufacturer-Generated Hidden Key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/> <!-- e.g., TPM protected -->
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
<certificate>
<name>Deployment-Specific LDevID Cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
After the above configuration is applied, <operational> should appear as follows:
========== NOTE: '\' line wrapping per BCP XXX (RFC XXXX) ===========
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<asymmetric-keys>
<asymmetric-key or:origin="or:system">
<name>Manufacturer-Generated Hidden Key</name>
<public-key-format>ct:subject-public-key-info-format</public-k\
ey-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/> <!-- e.g., TPM protected -->
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
<certificate or:origin="or:intended">
<name>Deployment-Specific LDevID Cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
This section describes an approach that enables all the private keys on a server to be encrypted, such that traditional backup/restore procedures can be used without concern for keys being compromised when in transit.
The cornerstone to this solution is the existence of a "root" key that can be used to encrypt all the other keys. The server MUST be able to use this key to decrypt the other keys in the configuration.
The root key SHOULD be a hidden key, i.e., one whose private data has no presence in <running> or <operational> (see "hidden-key" and "hidden-private-key" in "ietf-crypto-types" [I-D.ietf-netconf-crypto-types]). If the server implementation does not support hidden keys, then the private data part of key MUST be protected by access control with access granted only to an administrator with special access control rights (e.g., an organization's crypto officer). Given the long lifetime of built-in keys (see Section 4), built-in keys MUST be hidden.
A hidden root key MAY be either a symmetric key or an asymmetric key. If the hidden root key is symmetric, then the server MUST provide APIs enabling other keys (ideally generated by the server) to be encrypted. If the hidden root key is asymmetric, then the server SHOULD provide APIs enabling other keys to be both generated and encrypted by it, but MAY alternatively enable administrators with special access control rights to generate and encrypt the other keys themselves, using the hidden key's public part. For practical reasons, an unhidden root key SHOULD be asymmetric, so that its public part can be accessed by other administrators without concern.
Each time a new key is to be configured, it SHOULD be encrypted by the root key.
In "ietf-crypto-types" [I-D.ietf-netconf-crypto-types], the format for an encrypted symmetric key is described by the "encrypted-one-symmetric-key-format" identity, while the format for an encrypted asymmetric key is described by the "encrypted-one-asymmetric-key-format" identity
Ideally, the server implementation provides an API to generate a symmetric or asymmetric key, and encrypt the generated key using another key known to the system (e.g., the root key). Thusly administrators can safely call this API to configure new keys.
In case the server implementation does not provide such an API, then the generating and encrypting steps MAY be performed outside the server, e.g., by an administrator with special access control rights.
In either case, the encrypted key can be configured into the Keystore using either the "encrypted-key" (for symmetric keys) or the "encrypted-private-key" (for asymmetric keys) nodes. These two nodes contain both the encrypted value as well as a reference to the other key in the Keystore that it was encrypted by.
One concern that arose during discourse was how it could be possible migrate configuration from one server to another server, if both servers used different root keys (e.g., a TPM-protected built-in key). It was noted that, in this case, the second server would be unable to decrypt any of the keys encrypted by the first server.
The solution to this issue is simply to ensure that the same key is known to both servers. How this is achieved may vary. If the first server is still accessible, it may be possible to ask it to encrypt the key using the second server's root key. That said, a common scenario for needing to migrate configuration to another server is because the first server is no longer available. Thus it is more likely the case that the shared root key is known to administrators with special access control rights (an organization's crypto officer), such that the shared key can be provided to the second server to unlock all the other keys in the configuration.
For systems that have a built-in key protected by hardware, the shared root key SHOULD be encrypted by the built-in key. In this way, at least from the system's perspective, it is more like an intermediate key than a root key.
As a concrete example, assuming both servers have built-in asymmetric keys, the shared key could be a symmetric key that an organization's crypto officer encrypts offline knowing each server's public key, which may be, e.g., in the server's IDevID certificate. The crypto officer can then safely handoff the encrypted shared key to other administrators responsible for server installations, including migrations.
In order to migrate a configuration, the administrator would need to make just a single modification to the configuration before loading it onto the second server, which is to replace the shared key's Keystore entry from the first server (an encrypted key), with the shared key encrypted by the second server's built-in key.
The YANG module defined in this document is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.
The NETCONF access control model (NACM) [RFC8341] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content.
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:
Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:
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-keystore 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-keystore namespace: urn:ietf:params:xml:ns:yang:ietf-keystore prefix: ks reference: RFC CCCC
| [I-D.ietf-netconf-crypto-types] | Watsen, K., "Common YANG Data Types for Cryptography", Internet-Draft draft-ietf-netconf-crypto-types-15, May 2020. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [RFC6020] | Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010. |
| [RFC7950] | Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016. |
| [RFC8341] | Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018. |
| [RFC3688] | Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004. |
| [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. |
| [RFC8174] | Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 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. |
| [Std-802.1AR-2009] | Group, W. -. H. L. L. P. W., "IEEE Standard for Local and metropolitan area networks - Secure Device Identity", December 2009. |
The authors would like to thank for following for lively discussions on list and in the halls (ordered by first name): Alan Luchuk, Andy Bierman, Benoit Claise, Bert Wijnen, Balázs Kovács, David Lamparter, Eric Voit, Ladislav Lhotka, Liang Xia, Juergen Schoenwaelder, Mahesh Jethanandani, Martin Bjorklund, Mehmet Ersue, Phil Shafer, Radek Krejci, Ramkumar Dhanapal, Reshad Rahman, Sean Turner, and Tom Petch.