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Versions: (draft-ietf-netconf-system-keychain)
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NETCONF Working Group K. Watsen
Internet-Draft Juniper Networks
Intended status: Standards Track June 4, 2018
Expires: December 6, 2018
YANG Data Model for a Centralized Keystore Mechanism
draft-ietf-netconf-keystore-05
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 "2018-06-04" --> 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.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 6, 2018.
Copyright Notice
Copyright (c) 2018 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. The Keystore Model . . . . . . . . . . . . . . . . . . . . . 4
3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 6
3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 12
4. Security Considerations . . . . . . . . . . . . . . . . . . . 21
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 23
5.2. The YANG Module Names Registry . . . . . . . . . . . . . 23
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1. Normative References . . . . . . . . . . . . . . . . . . 23
6.2. Informative References . . . . . . . . . . . . . . . . . 24
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 26
A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 26
A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 26
A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 26
A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 26
A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 27
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 27
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 27
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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 "hardware-protected" and the actions "generate-private-
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.
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
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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
| | ct:key-algorithm-ref
| +--rw public-key binary
| +--rw private-key union
| +--rw certificates
| | +--rw certificate* [name]
| | +--rw name string
| | +--rw cert
| | | ct: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
+---x generate-asymmetric-key
+---w input
+---w name string
+---w algorithm ct:key-algorithm-ref
grouping end-entity-cert-grouping
+-- cert ct:end-entity-cert-cms
+---n certificate-expiration
+-- expiration-date? yang:date-and-time
grouping local-or-keystore-end-entity-certificate-grouping
+-- (local-or-keystore)
+--:(local)
| +-- algorithm ct:key-algorithm-ref
| +-- public-key binary
| +-- private-key union
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| +-- cert ct:end-entity-cert-cms
| +---n certificate-expiration
| +-- expiration-date? yang:date-and-time
+--:(keystore) {keystore-implemented}?
+-- reference
ks:asymmetric-key-certificate-ref
grouping local-or-keystore-asymmetric-key-with-certs-grouping
+-- (local-or-keystore)
+--:(local)
| +-- algorithm
| | ct:key-algorithm-ref
| +-- public-key binary
| +-- private-key union
| +-- certificates
| | +-- certificate* [name]
| | +-- name? string
| | +-- cert ct: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-implemented}?
+-- reference
ks:asymmetric-key-ref
grouping trust-anchor-cert-grouping
+-- cert ct:trust-anchor-cert-cms
grouping asymmetric-key-pair-grouping
+-- algorithm ct:key-algorithm-ref
+-- public-key binary
+-- private-key union
grouping public-key-grouping
+-- algorithm ct:key-algorithm-ref
+-- public-key binary
grouping asymmetric-key-pair-with-certs-grouping
+-- algorithm ct:key-algorithm-ref
+-- public-key binary
+-- private-key union
+-- certificates
| +-- certificate* [name]
| +-- name? string
| +-- cert ct:end-entity-cert-cms
| +---n certificate-expiration
| +-- expiration-date? yang:date-and-time
+---x generate-certificate-signing-request
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+---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)
| +-- algorithm ct:key-algorithm-ref
| +-- public-key binary
| +-- private-key union
+--:(keystore) {keystore-implemented}?
+-- reference ks:asymmetric-key-ref
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 three keys, two having one associated
certificate and one having two associated certificates.
<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">
<asymmetric-keys>
<asymmetric-key or:origin="or:intended">
<name>ex-rsa-key</name>
<algorithm>ct:rsa1024</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-key>
<certificates>
<certificate>
<name>ex-rsa-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key or:origin="or:intended">
<name>tls-ec-key</name>
<algorithm>ct:secp256r1</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-key>
<certificates>
<certificate>
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<name>tls-ec-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key or:origin="or:system">
<name>tpm-protected-key</name>
<algorithm>ct:rsa2048</algorithm>
<private-key>hardware-protected</private-key>
<public-key>base64encodedvalue==</public-key>
<certificates>
<certificate>
<name>builtin-idevid-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
<certificate or:origin="or:intended">
<name>my-ldevid-cert</name>
<cert>base64encodedvalue==</cert>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
The following example illustrates the "generate-private-key" action
in use with the NETCONF protocol.
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REQUEST
-------
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<action xmlns="urn:ietf:params:xml:ns:yang:1">
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
<asymmetric-keys>
<generate-asymmetric-key>
<name>ex-key-sect571r1</name>
<algorithm
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
ct:secp521r1
</algorithm>
</generate-asymmetric-key>
</asymmetric-keys>
</keystore>
</action>
</rpc>
RESPONSE
--------
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
The following example illustrates the "generate-certificate-signing-
request" action in use with the NETCONF protocol.
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REQUEST
-------
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<action xmlns="urn:ietf:params:xml:ns:yang:1">
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
<asymmetric-keys>
<asymmetric-key>
<name>ex-key-sect571r1</name>
<generate-certificate-signing-request>
<subject>base64encodedvalue==</subject>
<attributes>base64encodedvalue==</attributes>
</generate-certificate-signing-request>
</asymmetric-key>
</asymmetric-keys>
</keystore>
</action>
</rpc>
RESPONSE
--------
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<certificate-signing-request
xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
base64encodedvalue==
</certificate-signing-request>
</rpc-reply>
The following example illustrates the "certificate-expiration"
notification in use with the NETCONF protocol.
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<notification
xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
<eventTime>2018-05-25T00:01:00Z</eventTime>
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
<asymmetric-keys>
<asymmetric-key>
<name>tpm-protected-key</name>
<certificates>
<certificate>
<name>my-ldevid-cert</name>
<certificate-expiration>
<expiration-date>
2018-08-05T14:18:53-05:00
</expiration-date>
</certificate-expiration>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
</notification>
The following example module has been constructed to illustrate the
"local-or-keystore-asymmetric-key-grouping" grouping defined in the
"ietf-keystore" module.
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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 defined in the keystore
draft called 'local-or-keystore-asymmetric-key-grouping'.";
revision "YYYY-MM-DD" {
description
"Initial version";
reference
"RFC XXXX: YANG Data Model for a 'Keystore' Mechanism";
}
container keys {
description
"A container of keys.";
list key {
key name;
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks:local-or-keystore-asymmetric-key-grouping;
description
"A key which may be configured locally or be a reference to
a key in the keystore.";
}
}
}
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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).
<keys xmlns="http://example.com/ns/example-keystore-usage">
<key>
<name>locally-defined key</name>
<algorithm
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
ct:secp521r1
</algorithm>
<private-key>base64encodedvalue==</private-key>
<public-key>base64encodedvalue==</public-key>
</key>
<key>
<name>keystore-defined key</name>
<reference>ex-rsa-key</reference>
</key>
</keys>
3.3. YANG Module
This YANG module imports modules defined in [RFC6536], [RFC6991], and
[I-D.ietf-netconf-crypto-types]. This module uses data types defined
in [RFC2986], [RFC3447], [RFC5652], [RFC5915], [RFC6125], and
[ITU.X690.2015].
<CODE BEGINS> file "ietf-keystore@2018-06-04.yang"
module ietf-keystore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-keystore";
prefix "ks";
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
organization
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"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:kwatsen@juniper.net>";
description
"This module defines a keystore to centralize management
of security credentials.
Copyright (c) 2018 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
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC VVVV; see
the RFC itself for full legal notices.";
revision "2018-06-04" {
description
"Initial version";
reference
"RFC VVVV: YANG Data Model for a 'Keystore' Mechanism";
}
// Features
feature keystore-implemented {
description
"The 'keystore-implemented' feature indicates that the server
implements the keystore, and therefore groupings defined in
this module that reference the keystore are usable.";
}
// Typedefs
typedef asymmetric-key-ref {
type leafref {
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path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "/ks:name";
require-instance false;
}
description
"This typedef enables modules to easily define a reference
to an asymmetric key stored in the keystore. The require
instance attribute is false to enable the referencing of
asymmetric keys that exist only in <operational>.";
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
typedef asymmetric-key-certificate-ref {
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "/ks:certificates/ks:certificate/ks:name";
require-instance false;
}
description
"This typedef enables modules to easily define a reference
to a specific certificate associated with an asymmetric key
stored in the keystore. The require instance attribute is
false to enable the referencing of certificates that exist
only in <operational>.";
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
// Groupings
//
// These groupings are factored out more than needed for
// reusability purposes.
grouping public-key-grouping {
description
"A public key.";
leaf algorithm {
type ct:key-algorithm-ref;
mandatory true;
description
"Identifies the key's algorithm. More specifically,
this leaf specifies how the 'public-key' binary leaf
is encoded.";
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
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leaf public-key {
type binary;
mandatory true;
description
"A binary that contains the value of the public key. The
interpretation of the content is defined by the key
algorithm. For example, a DSA key is an integer, an RSA
key is represented as RSAPublicKey as defined in
RFC 3447, and an Elliptic Curve Cryptography (ECC) key
is represented using the 'publicKey' described in
RFC 5915.";
reference
"RFC 3447: Public-Key Cryptography Standards (PKCS) #1:
RSA Cryptography Specifications Version 2.1.
RFC 5915: Elliptic Curve Private Key Structure.";
}
}
grouping asymmetric-key-pair-grouping {
description
"A private/public key pair.";
uses public-key-grouping;
leaf private-key {
type union {
type binary;
type enumeration {
enum "hardware-protected" {
description
"The private key is inaccessible due to being
protected by a cryptographic hardware module
(e.g., a TPM).";
}
}
}
mandatory true;
description
"A binary that contains the value of the private key. The
interpretation of the content is defined by the key
algorithm. For example, a DSA key is an integer, an RSA
key is represented as RSAPrivateKey as defined in
RFC 3447, and an Elliptic Curve Cryptography (ECC) key
is represented as ECPrivateKey as defined in RFC 5915.";
reference
"RFC 3447: Public-Key Cryptography Standards (PKCS) #1:
RSA Cryptography Specifications Version 2.1.
RFC 5915: Elliptic Curve Private Key Structure.";
}
}
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grouping trust-anchor-cert-grouping {
description
"A certificate, and a notification for when it might expire.";
leaf cert {
type ct:trust-anchor-cert-cms;
mandatory true;
description
"The binary certificate data for this certificate.";
reference
"RFC YYYY: Common YANG Data Types for Cryptography";
}
}
grouping end-entity-cert-grouping {
description
"A certificate, and a notification for when it might expire.";
leaf cert {
type ct:end-entity-cert-cms;
mandatory true;
description
"The binary certificate data for this certificate.";
reference
"RFC YYYY: Common YANG Data Types for Cryptography";
}
notification certificate-expiration {
description
"A notification indicating that the configured certificate
is either about to expire or has already expired. When to
send notifications is an implementation specific decision,
but it is RECOMMENDED that a notification be sent once a
month for 3 months, then once a week for four weeks, and
then once a day thereafter until the issue is resolved.";
leaf expiration-date {
type yang:date-and-time;
//mandatory true;
description
"Identifies the expiration date on the certificate.";
}
}
}
grouping asymmetric-key-pair-with-certs-grouping {
description
"A private/public key pair and associated certificates.";
uses asymmetric-key-pair-grouping;
container certificates {
description
"Certificates associated with this asymmetric key.
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More than one certificate supports, for instance,
a TPM-protected asymmetric key that has both IDevID
and LDevID certificates associated.";
list certificate {
key name;
description
"A certificate for this asymmetric key.";
leaf name {
type string;
description
"An arbitrary name for the certificate.";
}
uses end-entity-cert-grouping;
} // end certifcate
} // end certificates
action generate-certificate-signing-request {
description
"Generates a certificate signing request structure for
the associated asymmetric key using the passed subject
and attribute values. The specified assertions need
to be appropriate for the certificate's use. For
example, an entity certificate for a TLS server
SHOULD have values that enable clients to satisfy
RFC 6125 processing.";
input {
leaf subject {
type binary;
mandatory true;
description
"The 'subject' field per the CertificationRequestInfo
structure as specified by RFC 2986, Section 4.1
encoded using the ASN.1 distinguished encoding
rules (DER), as specified in ITU-T X.690.";
reference
"RFC 2986:
PKCS #10: Certification Request Syntaxi
Specification Version 1.7.
ITU-T X.690:
Information technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER),
Canonical Encoding Rules (CER) and Distinguished
Encoding Rules (DER).";
}
leaf attributes {
type binary;
description
"The 'attributes' field from the structure
CertificationRequestInfo as specified by RFC 2986,
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Section 4.1 encoded using the ASN.1 distinguished
encoding rules (DER), as specified in ITU-T X.690.";
reference
"RFC 2986:
PKCS #10: Certification Request Syntax
Specification Version 1.7.
ITU-T X.690:
Information technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER),
Canonical Encoding Rules (CER) and Distinguished
Encoding Rules (DER).";
}
}
output {
leaf certificate-signing-request {
type binary;
mandatory true;
description
"A CertificationRequest structure as specified by
RFC 2986, Section 4.2 encoded using the ASN.1
distinguished encoding rules (DER), as specified
in ITU-T X.690.";
reference
"RFC 2986:
PKCS #10: Certification Request Syntax
Specification Version 1.7.
ITU-T X.690:
Information technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER),
Canonical Encoding Rules (CER) and Distinguished
Encoding Rules (DER).";
}
} // end output
} // end generate-certificate-signing-request
}
grouping local-or-keystore-asymmetric-key-grouping {
description
"A grouping that expands to allow the 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 {
uses asymmetric-key-pair-grouping;
}
case keystore {
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if-feature "keystore-implemented";
leaf reference {
type ks:asymmetric-key-ref;
mandatory true;
description
"A reference to a value 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-with-certs-grouping {
description
"A grouping that expands to allow the 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 {
uses asymmetric-key-pair-with-certs-grouping;
}
case keystore {
if-feature "keystore-implemented";
leaf reference {
type ks:asymmetric-key-ref;
mandatory true;
description
"A reference to a value that exists in the keystore.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
}
}
grouping local-or-keystore-end-entity-certificate-grouping {
description
"A grouping that expands to allow the end-entity certificate
(and the 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 {
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uses ks:asymmetric-key-pair-grouping;
uses ks:end-entity-cert-grouping;
}
case keystore {
if-feature "keystore-implemented";
leaf reference {
type ks:asymmetric-key-certificate-ref;
mandatory true;
description
"A reference to a value that exists in the keystore.";
}
}
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
}
}
// protocol accessible nodes
container keystore {
description
"The keystore contains a list of keys.";
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 asymmetric-key-pair-with-certs-grouping;
} // end asymmetric-key
action generate-asymmetric-key {
description
"Requests the device to generate an asymmetric key using
the specified asymmetric key algorithm. This action is
primarily to support cryptographic processors that must
generate the asymmetric key themselves. The resulting
asymmetric key is considered operational state and hence
present only in <operational>.";
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input {
leaf name {
type string;
mandatory true;
description
"The name the asymmetric key should have when listed
in /keystore/asymmetric-keys/asymmetric-key, in
<operational>.";
}
leaf algorithm {
type ct:key-algorithm-ref;
mandatory true;
description
"The algorithm to be used when generating the
asymmetric key.";
reference
"RFC CCCC: Common YANG Data Types for Cryptography";
}
}
} // end generate-asymmetric-key
} // end asymmetric-keys
} // end keystore
}
<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) [RFC6536] 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:
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/: The entire data tree defined by this module is sensitive to
write operations. For instance, the addition or removal of
keys, certificates, trusted anchors, etc., can dramatically
alter the implemented security policy. However, no NACM
annotations are applied as the data SHOULD be editable by users
other than a designated 'recovery session'.
/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. However, no NACM annotations are
applied as the data SHOULD be editable by users other than a
designated 'recovery session'.
Some of the operations in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control access to these operations. These are the
operations and their sensitivity/vulnerability:
generate-certificate-signing-request: For this action, it is
RECOMMENDED that implementations assert channel binding
[RFC5056], so as to ensure that the application layer that sent
the request is the same as the device authenticated when the
secure transport layer was established.
This document uses PKCS #10 [RFC2986] for the "generate-certificate-
signing-request" action. The use of Certificate Request Message
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Format (CRMF) [RFC4211] was considered, but is was unclear if there
was market demand for it. If it is desired to support CRMF in the
future, placing a "choice" statement in both the input and output
statements, along with an "if-feature" statement on the CRMF option,
would enable a backwards compatible solution.
5. IANA Considerations
5.1. The IETF XML Registry
This document registers one URI in 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.
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., "Common YANG Data Types for Cryptography",
draft-ietf-netconf-crypto-types-00 (work in progress),
June 2018.
[ITU.X690.2015]
International Telecommunication Union, "Information
Technology - ASN.1 encoding rules: Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER)", ITU-T Recommendation
X.690, ISO/IEC 8825-1, August 2015,
<https://www.itu.int/rec/T-REC-X.690/>.
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[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>.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000,
<https://www.rfc-editor.org/info/rfc2986>.
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, DOI 10.17487/RFC3447, February
2003, <https://www.rfc-editor.org/info/rfc3447>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>.
[RFC5915] Turner, S. and D. Brown, "Elliptic Curve Private Key
Structure", RFC 5915, DOI 10.17487/RFC5915, June 2010,
<https://www.rfc-editor.org/info/rfc5915>.
[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>.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
DOI 10.17487/RFC6536, March 2012,
<https://www.rfc-editor.org/info/rfc6536>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[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>.
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>.
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[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211,
DOI 10.17487/RFC4211, September 2005,
<https://www.rfc-editor.org/info/rfc4211>.
[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure
Channels", RFC 5056, DOI 10.17487/RFC5056, November 2007,
<https://www.rfc-editor.org/info/rfc5056>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>.
[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]
IEEE SA-Standards Board, "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 FIXME
o FIXME
o FIXME
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, Mehmet Ersue, Balazs Kovacs, David
Lamparter, Alan Luchuk, Ladislav Lhotka, Mahesh 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
Juniper Networks
EMail: kwatsen@juniper.net
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