| NETCONF Working Group | K. Watsen |
| Internet-Draft | Watsen Networks |
| Intended status: Standards Track | June 7, 2019 |
| Expires: December 9, 2019 |
A YANG Data Model for a Keystore
draft-ietf-netconf-keystore-10
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.
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:
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:
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Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
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.
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 algorithm
| asymmetric-key-algorithm-ref
+--rw public-key binary
+--rw private-key union
+--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
+--ro certificate-signing-request binary
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 union
+--:(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
| +-- algorithm
| | asymmetric-key-algorithm-ref
| +-- public-key binary
| +-- private-key union
| +-- 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 union
| +-- 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-certificate-ref
grouping keystore-grouping
+-- asymmetric-keys
+-- asymmetric-key* [name]
+-- name? string
+-- algorithm
| asymmetric-key-algorithm-ref
+-- public-key binary
+-- private-key union
+-- 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
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>
</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>
<private-key>permanently-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;
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.";
}
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>
<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>
<keystore-reference>ex-rsa-cert</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@2019-06-07.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
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 2019-06-07 {
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.";
}
/****************/
/* 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.";
}
typedef asymmetric-key-certificate-ref {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "/ks:certificates/ks:certificate/ks:name";
}
description
"This typedef enables modules to easily define a reference
to a specific certificate associated with an asymmetric key
stored in the keystore.";
}
/*****************/
/* Groupings */
/*****************/
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 ct: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 {
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 ct: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 ct:asymmetric-key-pair-with-cert-grouping;
}
}
case keystore {
if-feature "keystore-supported";
leaf keystore-reference {
type ks:asymmetric-key-certificate-ref;
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 ct:asymmetric-key-pair-with-certs-grouping;
}
}
}
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container keystore {
nacm:default-deny-write;
description
"The keystore contains a list of keys.";
uses keystore-grouping;
}
}
<CODE ENDS>
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 VVVV
| [I-D.ietf-netconf-crypto-types] | Watsen, K. and H. Wang, "Common YANG Data Types for Cryptography", Internet-Draft draft-ietf-netconf-crypto-types-06, 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. |
| [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 last name): Andy Bierman, Martin Bjorklund, Benoit Claise, Ramkumar Dhanapal, Mehmet Ersue, Balázs Kovács, David Lamparter, Ladislav Lhotka, Alan Luchuk, Mahesh Jethanandani, Radek Krejci, Reshad Rahman, Tom Petch, Juergen Schoenwaelder, Phil Shafer, Sean Turner, Eric Voit, Bert Wijnen, and Liang Xia.