NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Intended status: Standards Track June 17, 2019
Expires: December 19, 2019
A YANG Data Model for a Keystore
draft-ietf-netconf-keystore-11
Abstract
This document defines a YANG 1.1 module called "ietf-keystore" that
enables centralized configuration of asymmetric keys and their
associated certificates, and notification for when configured
certificates are about to expire.
Editorial Note (To be removed by RFC Editor)
This draft contains many placeholder values that need to be replaced
with finalized values at the time of publication. This note
summarizes all of the substitutions that are needed. No other RFC
Editor instructions are specified elsewhere in this document.
Artwork in this document contains shorthand references to drafts in
progress. Please apply the following replacements:
o "VVVV" --> 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:
o "2019-06-17" --> the publication date of this draft
The following Appendix section is to be removed prior to publication:
o Appendix A. Change Log
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. The Keystore Model . . . . . . . . . . . . . . . . . . . . . 4
3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 11
3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 16
4. Security Considerations . . . . . . . . . . . . . . . . . . . 26
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 27
5.2. The YANG Module Names Registry . . . . . . . . . . . . . 28
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.1. Normative References . . . . . . . . . . . . . . . . . . 28
6.2. Informative References . . . . . . . . . . . . . . . . . 29
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 30
A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 30
A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 30
A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 30
A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 30
A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 31
A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 31
A.7. 06 to 07 . . . . . . . . . . . . . . . . . . . . . . . . 31
A.8. 07 to 08 . . . . . . . . . . . . . . . . . . . . . . . . 31
A.9. 08 to 09 . . . . . . . . . . . . . . . . . . . . . . . . 31
A.10. 09 to 10 . . . . . . . . . . . . . . . . . . . . . . . . 32
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A.11. 10 to 11 . . . . . . . . . . . . . . . . . . . . . . . . 32
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 32
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction
This document defines a YANG 1.1 [RFC7950] module called "ietf-
keystore" that enables centralized configuration of asymmetric keys
and their associated certificates, and notification for when
configured certificates are about to expire.
This module also defines Six groupings designed for maximum reuse.
These groupings include one for the public half of an asymmetric key,
one for both the public and private halves of an asymmetric key, one
for both halves of an asymmetric key and a list of associated
certificates, one for an asymmetric key that may be configured
locally or via a reference to an asymmetric key in the keystore, one
for a trust anchor certificate and, lastly, one for an end entity
certificate.
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
completely hides the private keys and must perform all private key
operations. To support such hardware, the "private-key" can be the
special value "permanently-hidden" and the actions "generate-hidden-
key" and "generate-certificate-signing-request" can be used to direct
these operations to the hardware .
This document in compliant with Network Management Datastore
Architecture (NMDA) [RFC8342]. For instance, to support keys and
associated certificates installed during manufacturing (e.g., for a
IDevID [Std-802.1AR-2009] certificate), it is expected that such data
may appear only in <operational>.
While only asymmetric keys are currently supported, the module has
been designed to enable other key types to be introduced in the
future.
The module does not support protecting the contents of the keystore
(e.g., via encryption), though it could be extended to do so in the
future.
It is not required that a system has an operating system level
keystore utility to implement this module.
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2. Requirements 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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. The Keystore Model
3.1. Tree Diagram
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 algorithm
| | asymmetric-key-algorithm-ref
| +--rw public-key binary
| +--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)
| | | | +--rw symmetric-key? leafref
| | | +--:(asymmetric-key)
| | | +--rw asymmetric-key? leafref
| | +--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
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
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| +--ro certificate-signing-request binary
+--rw symmetric-keys
+--rw symmetric-key* [name]
+--rw name string
+--rw algorithm identityref
+--rw (key-type)
+--:(key)
| +--rw key? binary
+--:(hidden-key)
| +--rw hidden-key? empty
+--:(encrypted-key)
+--rw encrypted-key
+--rw (key-type)
| +--:(symmetric-key)
| | +--rw symmetric-key? leafref
| +--:(asymmetric-key)
| +--rw asymmetric-key? leafref
+--rw value? binary
rpcs:
+---x generate-symmetric-key
| +---w input
| | +---w algorithm identityref
| | +---w encrypt-with!
| | +---w (key-type)
| | +--:(symmetric-key)
| | | +---w symmetric-key? leafref
| | +--:(asymmetric-key)
| | +---w asymmetric-key? leafref
| +--ro output
| +--ro algorithm identityref
| +--ro (key-type)
| +--:(key)
| | +--ro key? binary
| +--:(hidden-key)
| | +--ro hidden-key? empty
| +--:(encrypted-key)
| +--ro encrypted-key
| +--ro (key-type)
| | +--:(symmetric-key)
| | | +--ro symmetric-key? leafref
| | +--:(asymmetric-key)
| | +--ro asymmetric-key? leafref
| +--ro value? binary
+---x generate-asymmetric-key
+---w input
| +---w algorithm identityref
| +---w encrypt-with!
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| +---w (key-type)
| +--:(symmetric-key)
| | +---w symmetric-key? leafref
| +--:(asymmetric-key)
| +---w asymmetric-key? leafref
+--ro output
+--ro algorithm
| asymmetric-key-algorithm-ref
+--ro public-key binary
+--ro (private-key-type)
+--:(private-key)
| +--ro private-key? binary
+--:(hidden-private-key)
| +--ro hidden-private-key? empty
+--:(encrypted-private-key)
+--ro encrypted-private-key
+--ro (key-type)
| +--:(symmetric-key)
| | +--ro symmetric-key? leafref
| +--:(asymmetric-key)
| +--ro asymmetric-key? leafref
+--ro value? binary
grouping encrypted-value-grouping
+-- (key-type)
| +--:(symmetric-key)
| | +-- symmetric-key?
| | -> /keystore/symmetric-keys/symmetric-key/name
| +--:(asymmetric-key)
| +-- asymmetric-key?
| -> /keystore/asymmetric-keys/asymmetric-key/name
+-- value? binary
grouping symmetric-key-grouping
+-- algorithm identityref
+-- (key-type)
+--:(key)
| +-- key? binary
+--:(hidden-key)
| +-- hidden-key? empty
+--:(encrypted-key)
+-- encrypted-key
+-- (key-type)
| +--:(symmetric-key)
| | +-- symmetric-key? leafref
| +--:(asymmetric-key)
| +-- asymmetric-key? leafref
+-- value? binary
grouping asymmetric-key-pair-grouping
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+-- algorithm asymmetric-key-algorithm-ref
+-- public-key binary
+-- (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)
| | +-- symmetric-key? leafref
| +--:(asymmetric-key)
| +-- asymmetric-key? leafref
+-- value? binary
grouping asymmetric-key-pair-with-cert-grouping
+-- algorithm
| asymmetric-key-algorithm-ref
+-- public-key binary
+-- (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)
| | | +-- symmetric-key? leafref
| | +--:(asymmetric-key)
| | +-- asymmetric-key? leafref
| +-- value? binary
+-- cert? end-entity-cert-cms
+---n certificate-expiration
| +-- expiration-date yang:date-and-time
+---x generate-certificate-signing-request
+---w input
| +---w subject binary
| +---w attributes? binary
+--ro output
+--ro certificate-signing-request binary
grouping asymmetric-key-pair-with-certs-grouping
+-- algorithm
| asymmetric-key-algorithm-ref
+-- public-key binary
+-- (private-key-type)
| +--:(private-key)
| | +-- private-key? binary
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| +--:(hidden-private-key)
| | +-- hidden-private-key? empty
| +--:(encrypted-private-key)
| +-- encrypted-private-key
| +-- (key-type)
| | +--:(symmetric-key)
| | | +-- symmetric-key? leafref
| | +--:(asymmetric-key)
| | +-- asymmetric-key? leafref
| +-- 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
+---w input
| +---w subject binary
| +---w attributes? binary
+--ro output
+--ro certificate-signing-request binary
grouping asymmetric-key-certificate-ref-grouping
+-- asymmetric-key? ks:asymmetric-key-ref
+-- certificate? leafref
grouping local-or-keystore-asymmetric-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- algorithm
| | asymmetric-key-algorithm-ref
| +-- public-key binary
| +-- (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)
| | | +-- symmetric-key? leafref
| | +--:(asymmetric-key)
| | +-- asymmetric-key? leafref
| +-- value? binary
+--:(keystore) {keystore-supported}?
+-- keystore-reference? ks:asymmetric-key-ref
grouping local-or-keystore-asymmetric-key-with-certs-grouping
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+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +-- algorithm
| | asymmetric-key-algorithm-ref
| +-- public-key binary
| +-- (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)
| | | | +-- symmetric-key? leafref
| | | +--:(asymmetric-key)
| | | +-- asymmetric-key? leafref
| | +-- 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
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request binary
+--:(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
| +-- algorithm
| | asymmetric-key-algorithm-ref
| +-- public-key binary
| +-- (private-key-type)
| | +--:(private-key)
| | | +-- private-key? binary
| | +--:(hidden-private-key)
| | | +-- hidden-private-key? empty
| | +--:(encrypted-private-key)
| | +-- encrypted-private-key
| | +-- (key-type)
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| | | +--:(symmetric-key)
| | | | +-- symmetric-key? leafref
| | | +--:(asymmetric-key)
| | | +-- asymmetric-key? leafref
| | +-- value? binary
| +-- cert?
| | end-entity-cert-cms
| +---n certificate-expiration
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| +---w input
| | +---w subject binary
| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request binary
+--:(keystore) {keystore-supported}?
+-- keystore-reference
+-- asymmetric-key? ks:asymmetric-key-ref
+-- certificate? leafref
grouping keystore-grouping
+-- asymmetric-keys
| +-- asymmetric-key* [name]
| +-- name? string
| +-- algorithm
| | asymmetric-key-algorithm-ref
| +-- public-key binary
| +-- (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)
| | | | +-- symmetric-key? leafref
| | | +--:(asymmetric-key)
| | | +-- asymmetric-key? leafref
| | +-- 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
| +---w input
| | +---w subject binary
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| | +---w attributes? binary
| +--ro output
| +--ro certificate-signing-request binary
+-- symmetric-keys
+-- symmetric-key* [name]
+-- name? string
+-- algorithm identityref
+-- (key-type)
+--:(key)
| +-- key? binary
+--:(hidden-key)
| +-- hidden-key? empty
+--:(encrypted-key)
+-- encrypted-key
+-- (key-type)
| +--:(symmetric-key)
| | +-- symmetric-key? leafref
| +--:(asymmetric-key)
| +-- asymmetric-key? leafref
+-- value? binary
3.2. Example Usage
The following example illustrates what a fully configured keystore
might look like in <operational>, as described by Section 5.3 in
[RFC8342]. This datastore view illustrates data set by the
manufacturing process alongside conventional configuration. This
keystore instance has four keys, two having one associated
certificate, one having two associated certificates, and one empty
key.
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
or:origin="or:intended">
<asymmetric-keys>
<asymmetric-key>
<name>ex-rsa-key</name>
<algorithm>ct:rsa2048</algorithm>
<public-key>base64encodedvalue==</public-key>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>ex-rsa-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
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</asymmetric-key>
<asymmetric-key>
<name>tls-ec-key</name>
<algorithm>ct:secp256r1</algorithm>
<public-key>base64encodedvalue==</public-key>
<private-key>base64encodedvalue==</private-key>
<certificates>
<certificate>
<name>tls-ec-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<!-- all except 'my-ldevid-cert' copied from <operational> -->
<asymmetric-key>
<name>tpm-protected-key</name>
<algorithm>ct:rsa2048</algorithm>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/>
<certificates>
<certificate>
<name>builtin-idevid-cert</name>
</certificate>
<certificate>
<name>my-ldevid-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
The following example module has been constructed to illustrate the
"local-or-keystore-asymmetric-key-grouping" grouping 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;
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reference
"RFC VVVV: 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.";
}
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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 XX (RFC XXXX) ===========
<keystore-usage xmlns="http://example.com/ns/example-keystore-usage">
<!-- ks:local-or-keystore-asymmetric-key-grouping -->
<just-a-key>
<name>a locally-defined key</name>
<local-definition>
<algorithm
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
ct:rsa2048
</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-key>
</local-definition>
</just-a-key>
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<just-a-key>
<name>a keystore-defined key (and its associated certs)</name>
<keystore-reference>ex-rsa-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>
<algorithm
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
ct:rsa2048
</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-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>ex-rsa-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>
<algorithm
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
ct:rsa2048
</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-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>
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<keystore-reference>
<asymmetric-key>ex-rsa-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</keystore-reference>
</end-entity-cert-with-key>
</keystore-usage>
3.3. YANG Module
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@2019-06-17.yang"
module ietf-keystore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-keystore";
prefix ks;
import ietf-crypto-types {
prefix ct;
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
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) 2019 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
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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 XXXX
(https://www.rfc-editor.org/info/rfcXXXX); 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 2019-06-17 {
description
"Initial version";
reference
"RFC VVVV: 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.";
}
feature key-generation {
description
"Indicates that the server supports the actions related to
the life cycling keys in <operational>. To be used by
configuration, keys in <operational> must be copied to
<running>.";
}
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/****************/
/* Typedefs */
/****************/
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 encrypted-value-grouping {
description
"A reusable grouping for a value that has been encrypted by
a symmeteric or asymmetric key in the keystore.";
choice key-type {
mandatory true;
description
"A choice between a reference to a symmtric or asymmetric
key in the keystore.";
leaf symmetric-key {
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 {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key/"
+ "ks:name";
}
description
"Identifies an asymmetric key used to encrypt this key.";
}
}
leaf value {
type binary;
description
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"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-crypt-types
except that it adds a couple case statements 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 {
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-crypt-types
except that it adds a couple case statements 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 {
description
"A container for the encrypted asymmetric private
key value.";
uses encrypted-value-grouping;
}
}
}
}
grouping asymmetric-key-pair-with-cert-grouping {
description
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"This grouping is identical to the one in ietf-crypt-types
except that it adds a couple case statements 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 {
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-crypt-types
except that it adds a couple case statements 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 {
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 {
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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.";
}
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, not any certificates that may also
be associated with the asymmetric key.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
}
}
grouping local-or-keystore-asymmetric-key-with-certs-grouping {
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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";
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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;
}
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}
} // grouping keystore-grouping
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container keystore {
nacm:default-deny-write;
description
"The keystore contains a list of keys.";
uses keystore-grouping;
}
rpc generate-symmetric-key {
//nacm:default-deny-all;
description
"Requests the device to generate an symmetric key using
the specified key algorithm, optionally encrypted using
a key in the keystore. The output is this RPC can be
used as input to a subsequent configuration request.";
input {
leaf algorithm {
type identityref {
base "ct:encryption-algorithm";
}
mandatory true;
description
"The algorithm to be used when generating the key.";
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
container encrypt-with {
presence
"Indicates that the key should be encrypted using
the specified symmetric or asymmetric key. If not
specified, then the private key is not encrypted
when returned.";
description
"A container for the 'key-type' choice.";
choice key-type {
mandatory true;
description
"Choice between a symmetric and asymmetric key.";
leaf symmetric-key {
type leafref {
path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key/"
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+ "ks:name";
}
description
"Identifies a symmetric key used to encrypt this key.";
}
leaf asymmetric-key {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-"
+ "key/ks:name";
}
description
"Identifies an asymmetric key used to encrypt this
key.";
}
}
}
}
output {
uses ks:symmetric-key-grouping;
}
} // end generate-symmetric-key
rpc generate-asymmetric-key {
//nacm:default-deny-all;
description
"Requests the device to generate an asymmetric key using
the specified key algorithm, optionally encrypted using
a key in the keystore. The output is this RPC can be
used as input to a subsequent configuration request.";
input {
leaf algorithm {
type identityref {
base "ct:asymmetric-key-algorithm";
}
mandatory true;
description
"The algorithm to be used when generating the key.";
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
container encrypt-with {
presence
"Indicates that the key should be encrypted using
the specified symmetric or asymmetric key. If not
specified, then the private key is not encrypted
when returned.";
description
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"A container for the 'key-type' choice.";
choice key-type {
mandatory true;
description
"Choice between a symmetric and asymmetric key.";
leaf symmetric-key {
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 {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-"
+ "key/ks:name";
}
description
"Identifies an asymmetric key used to encrypt this
key.";
}
}
}
}
output {
uses ks:asymmetric-key-pair-grouping;
}
} // end generate-asymmetric-key
}
<CODE ENDS>
4. Security Considerations
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
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in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
/: The entire data tree defined by this module is sensitive to
write operations. For instance, the addition or removal of
keys, certificates, etc., can dramatically alter the
implemented security policy. For this reason, the NACM
extension "default-deny-write" has been set for the entire data
tree.
/keystore/asymmetric-keys/asymmetric-key/private-key: When
writing this node, implementations MUST ensure that the
strength of the key being configured is not greater than the
strength of the underlying secure transport connection over
which it is communicated. Implementations SHOULD fail the
write-request if ever the strength of the private key is
greater then the strength of the underlying transport, and
alert the client that the strength of the key may have been
compromised. Additionally, when deleting this node,
implementations SHOULD automatically (without explicit request)
zeroize these keys in the most secure manner available, so as
to prevent the remnants of their persisted storage locations
from being analyzed in any meaningful way.
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:
/keystore/asymmetric-keys/asymmetric-key/private-key: This node
is additionally sensitive to read operations such that, in
normal use cases, it should never be returned to a client. The
best reason for returning this node is to support backup/
restore type workflows. For this reason, the NACM extension
"default-deny-all" has been set for this data node.
5. IANA Considerations
5.1. The IETF XML Registry
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:
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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.
5.2. The YANG Module Names Registry
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 VVVV
6. References
6.1. Normative References
[I-D.ietf-netconf-crypto-types]
Watsen, K. and H. Wang, "Common YANG Data Types for
Cryptography", draft-ietf-netconf-crypto-types-06 (work in
progress), April 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
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6.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[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,
<https://www.rfc-editor.org/info/rfc8342>.
[Std-802.1AR-2009]
Group, W. -. H. L. L. P. W., "IEEE Standard for Local and
metropolitan area networks - Secure Device Identity",
December 2009, <http://standards.ieee.org/findstds/
standard/802.1AR-2009.html>.
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Appendix A. Change Log
A.1. 00 to 01
o Replaced the 'certificate-chain' structures with PKCS#7
structures. (Issue #1)
o Added 'private-key' as a configurable data node, and removed the
'generate-private-key' and 'load-private-key' actions. (Issue #2)
o Moved 'user-auth-credentials' to the ietf-ssh-client module.
(Issues #4 and #5)
A.2. 01 to 02
o Added back 'generate-private-key' action.
o Removed 'RESTRICTED' enum from the 'private-key' leaf type.
o Fixed up a few description statements.
A.3. 02 to 03
o Changed draft's title.
o Added missing references.
o Collapsed sections and levels.
o Added RFC 8174 to Requirements Language Section.
o Renamed 'trusted-certificates' to 'pinned-certificates'.
o Changed 'public-key' from config false to config true.
o Switched 'host-key' from OneAsymmetricKey to definition from RFC
4253.
A.4. 03 to 04
o Added typedefs around leafrefs to common keystore paths
o Now tree diagrams reference ietf-netmod-yang-tree-diagrams
o Removed Design Considerations section
o Moved key and certificate definitions from data tree to groupings
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A.5. 04 to 05
o Removed trust anchors (now in their own draft)
o Added back global keystore structure
o Added groupings enabling keys to either be locally defined or a
reference to the keystore.
A.6. 05 to 06
o Added feature "local-keys-supported"
o Added nacm:default-deny-all and nacm:default-deny-write
o Renamed generate-asymmetric-key to generate-hidden-key
o Added an install-hidden-key action
o Moved actions inside fo the "asymmetric-key" container
o Moved some groupings to draft-ietf-netconf-crypto-types
A.7. 06 to 07
o Removed a "require-instance false"
o Clarified some description statements
o Improved the keystore-usage examples
A.8. 07 to 08
o Added "local-definition" containers to avoid posibility of the
action/notification statements being under a "case" statement.
o Updated copyright date, boilerplate template, affiliation, folding
algorithm, and reformatted the YANG module.
A.9. 08 to 09
o Added a 'description' statement to the 'must' in the /keystore/
asymmetric-key node explaining that the descendent values may
exist in <operational> only, and that implementation MUST assert
that the values are either configured or that they exist in
<operational>.
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o Copied above 'must' statement (and description) into the local-or-
keystore-asymmetric-key-grouping, local-or-keystore-asymmetric-
key-with-certs-grouping, and local-or-keystore-end-entity-cert-
with-key-grouping statements.
A.10. 09 to 10
o Updated draft title to match new truststore draft title
o Moved everything under a top-level 'grouping' to enable use in
other contexts.
o Renamed feature from 'local-keys-supported' to 'local-definitions-
supported' (same name used in truststore)
o Removed the either-all-or-none 'must' expressions for the key's
3-tuple values (since the values are now 'mandatory true' in
crypto-types)
o Example updated to reflect 'mandatory true' change in crypto-types
draft
A.11. 10 to 11
o Replaced typedef asymmetric-key-certificate-ref with grouping
asymmetric-key-certificate-ref-grouping.
o Added feature feature 'key-generation'.
o Cloned groupings symmetric-key-grouping, asymmetric-key-pair-
grouping, asymmetric-key-pair-with-cert-grouping, and asymmetric-
key-pair-with-certs-grouping from crypto-keys, augmenting into
each new case statements for values that have been encrypted by
other keys in the keystore. Refactored keystore model to use
these groupings.
o Added new 'symmetric-keys' lists, as a sibling to the existing
'asymmetric-keys' list.
o Added RPCs (not actions) 'generate-symmetric-key' and 'generate-
asymmetric-key' to *return* a (potentially encrypted) key.
Acknowledgements
The authors would like to thank for following for lively discussions
on list and in the halls (ordered by last name): Andy Bierman, Martin
Bjorklund, Benoit Claise, Ramkumar Dhanapal, Mehmet Ersue, Balazs
Kovacs, David Lamparter, Ladislav Lhotka, Alan Luchuk, Mahesh
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Jethanandani, Radek Krejci, Reshad Rahman, Tom Petch, Juergen
Schoenwaelder, Phil Shafer, Sean Turner, Eric Voit, Bert Wijnen, and
Liang Xia.
Author's Address
Kent Watsen
Watsen Networks
EMail: kent+ietf@watsen.net
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