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Versions: (draft-ietf-netconf-system-keychain) 00 01 02 03 04 05 06 07

NETCONF Working Group                                          K. Watsen
Internet-Draft                                          Juniper Networks
Intended status: Standards Track                           June 13, 2017
Expires: December 15, 2017


                             Keystore Model
                     draft-ietf-netconf-keystore-02

Abstract

   This document defines a YANG data module for a system-level keystore
   mechanism, that might be used to hold onto private keys and
   certificates that are trusted by the system advertising support for
   this module.

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  "2017-06-13" --> 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 http://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 15, 2017.

Copyright Notice

   Copyright (c) 2017 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
   (http://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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.2.  Tree Diagram Notation . . . . . . . . . . . . . . . . . .   3
   2.  The Keystore Model  . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  10
   3.  Design Considerations . . . . . . . . . . . . . . . . . . . .  21
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  22
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  23
     5.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  23
     5.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  23
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  24
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  24
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  25
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  26
     A.1.  server-model-09 to 00 . . . . . . . . . . . . . . . . . .  26
     A.2.  keychain-00 to keystore-00  . . . . . . . . . . . . . . .  26
     A.3.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  26
     A.4.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  26
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  26





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1.  Introduction

   This document defines a YANG [RFC6020] data module for a system-level
   keystore mechanism, which can be used to hold onto private keys and
   certificates that are trusted by the system advertising support for
   this module.

   This module provides a centralized location for security sensitive
   data, so that the data can be then referenced by other modules.
   There are two types of data that are maintained by this module:

   o  Private keys, and any associated public certificates.

   o  Sets of trusted certificates.

   This document extends special consideration for systems that have
   Trusted Protection Modules (TPMs).  These systems are unique in that
   the TPM must be directed to generate new private keys (it is not
   possible to load a private key into a TPM) and it is not possible to
   backup/restore the TPM's private keys as configuration.

   It is not required that a system has an operating system level
   keystore utility to implement this module.

1.1.  Requirements Language

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

1.2.  Tree Diagram Notation

   A simplified graphical representation of the data models is used in
   this document.  The meaning of the symbols in these diagrams is as
   follows:

   o  Brackets "[" and "]" enclose list keys.

   o  Braces "{" and "}" enclose feature names, and indicate that the
      named feature must be present for the subtree to be present.

   o  Abbreviations before data node names: "rw" means configuration
      (read-write) and "ro" state data (read-only).

   o  Symbols after data node names: "?" means an optional node, "!"
      means a presence container, and "*" denotes a list and leaf-list.





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   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.

2.  The Keystore Model

   The keystore module defined in this section provides a configurable
   object having the following characteristics:

   o  A semi-configurable list of private keys, each with one or more
      associated certificates.  Private keys MUST be either preinstalled
      (e.g., a key associated to an IDevID [Std-802.1AR-2009]
      certificate), be generated by request, or be loaded by request.
      Each private key is MAY have associated certificates, either
      preinstalled or configured after creation.

   o  A configurable list of lists of trust anchor certificates.  This
      enables the server to have use-case specific trust anchors.  For
      instance, one list of trust anchors might be used to authenticate
      management connections (e.g., client certificate-based
      authentication for NETCONF or RESTCONF connections), and a
      different list of trust anchors might be used for when connecting
      to a specific Internet-based service (e.g., a zero touch bootstrap
      server).

   o  An RPC to generate a certificate signing request for an existing
      private key, a passed subject, and an optional attributes.  The
      signed certificate returned from an external certificate authority
      (CA) can be later set using a standard configuration change
      request (e.g., <edit-config>).

   o  An RPC to request the server to generate a new private key using
      the specified algorithm and key length.

   o  An RPC to request the server to load a new private key.

2.1.  Overview

   The keystore module has the following tree diagram.  Please see
   Section 1.2 for information on how to interpret this diagram.









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  module: ietf-keystore
      +--rw keystore
         +--rw keys
         |  +--rw key* [name]
         |  |  +--rw name                                    string
         |  |  +--rw algorithm-identifier                    identityref
         |  |  +--rw private-key                             union
         |  |  +--ro public-key                              binary
         |  |  +--rw certificates
         |  |  |  +--rw certificate* [name]
         |  |  |     +--rw name     string
         |  |  |     +--rw value?   binary
         |  |  +---x generate-certificate-signing-request
         |  |     +---w input
         |  |     |  +---w subject       binary
         |  |     |  +---w attributes?   binary
         |  |     +--ro output
         |  |        +--ro certificate-signing-request    binary
         |  +---x generate-private-key
         |     +---w input
         |        +---w name         string
         |        +---w algorithm    identityref
         +--rw trusted-certificates* [name]
         |  +--rw name                   string
         |  +--rw description?           string
         |  +--rw trusted-certificate* [name]
         |     +--rw name           string
         |     +--rw certificate?   binary
         +--rw trusted-host-keys* [name]
            +--rw name                string
            +--rw description?        string
            +--rw trusted-host-key* [name]
               +--rw name        string
               +--rw host-key    binary

    notifications:
      +---n certificate-expiration
         +--ro certificate        instance-identifier
         +--ro expiration-date    yang:date-and-time

2.2.  Example Usage

   The following example illustrates what a fully configured keystore
   object might look like.  The private-key shown below is consistent
   with the generate-private-key and generate-certificate-signing-
   request examples above.  This example also assumes that the resulting
   CA-signed certificate has been configured back onto the server.




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   Lastly, this example shows that three lists of trusted certificates
   having been configured.

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">

     <!-- private keys and associated certificates -->
     <keys>
       <key>
         <name>ex-rsa-key</name>
         <algorithm-identifier>rsa1024</algorithm-identifier>
         <private-key>Base64-encoded RSA Private Key</private-key>
         <public-key>Base64-encoded RSA Public Key</public-key>
         <certificates>
           <certificate>
             <name>ex-rsa-cert</name>
             <value>Base64-encoded PKCS#7</value>
           </certificate>
         </certificates>
       </key>

       <key>
         <name>tls-ec-key</name>
         <algorithm-identifier>secp256r1</algorithm-identifier>
         <private-key>Base64-encoded EC Private Key</private-key>
         <public-key>Base64-encoded EC Public Key</public-key>
         <certificates>
           <certificate>
             <name>tls-ec-cert</name>
             <value>Base64-encoded PKCS#7</value>
           </certificate>
         </certificates>
       </key>

       <key>
         <name>tpm-protected-key</name>
         <algorithm-identifier>rsa2048</algorithm-identifier>
         <private-key>Base64-encoded RSA Private Key</private-key>
         <public-key>Base64-encoded RSA Public Key</public-key>
         <certificates>
           <certificate>
             <name>builtin-idevid-cert</name>
             <value>Base64-encoded PKCS#7</value>
           </certificate>
           <certificate>
             <name>my-ldevid-cert</name>
             <value>Base64-encoded PKCS#7</value>
           </certificate>
         </certificates>



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       </key>
     </keys>

     <!-- trusted netconf/restconf client certificates -->
     <trusted-certificates>
       <name>explicitly-trusted-client-certs</name>
       <description>
         Specific client authentication certificates for explicitly
         trusted clients.  These are needed for client certificates
         that are not signed by a trusted CA.
       </description>
       <trusted-certificate>
         <name>George Jetson</name>
         <certificate>Base64-encoded X.509v3</certificate>
       </trusted-certificate>
     </trusted-certificates>

     <trusted-certificates>
       <name>explicitly-trusted-server-certs</name>
       <description>
         Specific server authentication certificates for explicitly
         trusted servers.  These are needed for server certificates
         that are not signed by a trusted CA.
       </description>
       <trusted-certificate>
         <name>Fred Flintstone</name>
         <certificate>Base64-encoded X.509v3</certificate>
       </trusted-certificate>
     </trusted-certificates>

     <!-- trust anchors (CA certs) for authenticating clients -->
     <trusted-certificates>
       <name>deployment-specific-ca-certs</name>
       <description>
         Trust anchors (i.e. CA certs) that are used to authenticate
         client connections.  Clients are authenticated if their
         certificate has a chain of trust to one of these configured
         CA certificates.
       </description>
       <trusted-certificate>
         <name>ca.example.com</name>
         <certificate>Base64-encoded X.509v3</certificate>
       </trusted-certificate>
     </trusted-certificates>

     <!-- trust anchors for random HTTPS servers on Internet -->
     <trusted-certificates>
       <name>common-ca-certs</name>



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       <description>
         Trusted certificates to authenticate common HTTPS servers.
         These certificates are similar to those that might be
         shipped with a web browser.
       </description>
       <trusted-certificate>
         <name>ex-certificate-authority</name>
         <certificate>Base64-encoded X.509v3</certificate>
       </trusted-certificate>
     </trusted-certificates>

     <!-- trusted SSH host keys -->
     <trusted-host-keys>
       <name>explicitly-trusted-ssh-host-keys</name>
       <description>
         Trusted SSH host keys used to authenticate SSH servers.
         These host keys would be analogous to those stored in
         a known_hosts file in OpenSSH.
       </description>
       <trusted-host-key>
         <name>corp-fw1</name>
         <host-key>Base64-encoded OneAsymmetricKey</host-key>
       </trusted-host-key>
     </trusted-host-keys>

   </keystore>

   The following example illustrates the "generate-certificate-signing-
   request" action in use with the NETCONF protocol.

   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">
           <keys>
             <key>
               <name>ex-key-sect571r1</name>
               <generate-certificate-signing-request>
                 <subject>
                  cztvaWRoc2RmZ2tqaHNkZmdramRzZnZzZGtmam5idnNvO2R
                  manZvO3NkZmJpdmhzZGZpbHVidjtvc2lkZmhidml1bHNlmO
                  Z2aXNiZGZpYmhzZG87ZmJvO3NkZ25iO29pLmR6Zgo=
                 </subject>
                 <attributes>



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                  bwtakWRoc2RmZ2tqaHNkZmdramRzZnZzZGtmam5idnNvut4
                  arnZvO3NkZmJpdmhzZGZpbHVidjtvc2lkZmhidml1bHNkYm
                  Z2aXNiZGZpYmhzZG87ZmJvO3NkZ25iO29pLmC6Rhp=
                 </attributes>
               </generate-certificate-signing-request>
             </key>
           </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">
          LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUNrekNDQWZ5Z
          0F3SUJBZ0lKQUpRT2t3bGpNK2pjTUEwR0NTcUdTSWIzRFFFQkJRVU
          FNRFF4Q3pBSkJnTlYKQkFZVEFsVlRNUkF3RGdZRFZRUUtFd2RsZUd
          GdGNHeGxNUk13RVFZRFZRUURFd3BEVWt3Z1NYTnpkV1Z5TUI0WApE
          diR1V4RXpBUkJnTlZCQU1UQ2tOU1RDQkpjM04xWlhJd2daOHdEUVl
          KS29aSWh2Y04KQVFFQkJRQURnWTBBTUlHSkFvR0JBTXVvZmFPNEV3
          El1QWMrQ1RsTkNmc0d6cEw1Um5ydXZsOFRIcUJTdGZQY3N0Zk1KT1
          FaNzlnNlNWVldsMldzaHE1bUViCkJNNitGNzdjbTAvU25FcFE0TnV
          bXBDT2YKQWdNQkFBR2pnYXd3Z2Frd0hRWURWUjBPQkJZRUZKY1o2W
          URiR0lPNDB4ajlPb3JtREdsRUNCVTFNR1FHQTFVZApJd1JkTUZ1QU
          ZKY1o2WURiR0lPNDB4ajlPb3JtREdsRUNCVTFvVGlrTmpBME1Rc3d
          mMKTUE0R0ExVWREd0VCL3dRRUF3SUNCREFTQmdOVkhSTUJBZjhFQ0
          RBR0FRSC9BZ0VBTUEwR0NTcUdTSWIzRFFFQgpCUVVBQTRHQkFMMmx
          rWmFGNWcyaGR6MVNhZnZPbnBneHA4eG00SHRhbStadHpLazFlS3Bx
          TXp4YXJCbFpDSHlLCklVbC9GVzRtV1RQS1VDeEtFTE40NEY2Zmk2d
          c4d0tSSElkYW1WL0pGTmlQS0VXSTF4K1I1aDZmazcrQzQ1QXg1RWV
          SWHgzZjdVM2xZTgotLS0tLUVORCBDRVJUSUZJQ0FURS0tLS0tCg==
        </certificate-signing-request>
     </rpc-reply>


   The following example illustrates the "generate-private-key" action
   in use with the RESTCONF protocol and JSON encoding.









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   REQUEST
   -------

     ['\' line wrapping added for formatting only]

     POST https://example.com/restconf/data/ietf-keystore:keystore/\
     keys/generate-private-key HTTP/1.1
     HOST: example.com
     Content-Type: application/yang.operation+json

     {
       "ietf-keystore:input" : {
         "name" : "ex-key-sect571r1",
         "algorithm" : "sect571r1"
       }
     }


   RESPONSE
   --------

     HTTP/1.1 204 No Content
     Date: Mon, 31 Oct 2015 11:01:00 GMT
     Server: example-server


   The following example illustrates a "certificate-expiration"
   notification in XML.

   ['\' line wrapping added for formatting only]

   <notification
     xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
     <eventTime>2016-07-08T00:01:00Z</eventTime>
     <certificate-expiration
       xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
       <certificate>/ks:keystore/ks:private-keys/ks:private-key\
       /ks:certificate-chains/ks:certificate-chain/ks:certificate[3]\
       </certificate>
       <expiration-date>2016-08-08T14:18:53-05:00</expiration-date>
     </certificate-expiration>
   </notification>

2.3.  YANG Module

   This YANG module makes extensive use of data types defined in
   [RFC5280] and [RFC5958].




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<CODE BEGINS> file "ietf-keystore@2017-06-13.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-netconf-acm {
    prefix nacm;
    reference
      "RFC 6536: Network Configuration Protocol (NETCONF) Access
       Control Model";
  }

  organization
   "IETF NETCONF (Network Configuration) Working Group";

  contact
   "WG Web:   <http://tools.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) 2014 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.";



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  revision "2017-06-13" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  // Identities

  identity key-algorithm {
    description
      "Base identity from which all key-algorithms are derived.";
  }

  identity rsa1024 {
    base key-algorithm;
    description
      "The RSA algorithm using a 1024-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:
                RSA Cryptography Specifications Version 2.1.";
  }

  identity rsa2048 {
    base key-algorithm;
    description
      "The RSA algorithm using a 2048-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:
                RSA Cryptography Specifications Version 2.1.";
  }

  identity rsa3072 {
    base key-algorithm;
    description
      "The RSA algorithm using a 3072-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:
                RSA Cryptography Specifications Version 2.1.";
  }

  identity rsa4096 {
    base key-algorithm;
    description
      "The RSA algorithm using a 4096-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:



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                RSA Cryptography Specifications Version 2.1.";
  }

  identity rsa7680 {
    base key-algorithm;
    description
      "The RSA algorithm using a 7680-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:
                RSA Cryptography Specifications Version 2.1.";
  }

  identity rsa15360 {
    base key-algorithm;
    description
      "The RSA algorithm using a 15360-bit key.";
    reference
      "RFC3447: Public-Key Cryptography Standards (PKCS) #1:
                RSA Cryptography Specifications Version 2.1.";
  }

  identity secp192r1 {
    base key-algorithm;
    description
      "The secp192r1 algorithm.";
    reference
      "RFC5480:
         Elliptic Curve Cryptography Subject Public Key Information.";
  }

  identity secp256r1 {
    base key-algorithm;
    description
      "The secp256r1 algorithm.";
    reference
      "RFC5480:
         Elliptic Curve Cryptography Subject Public Key Information.";
  }

  identity secp384r1 {
    base key-algorithm;
    description
      "The secp384r1 algorithm.";
    reference
      "RFC5480:
         Elliptic Curve Cryptography Subject Public Key Information.";
  }




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  identity secp521r1 {
    base key-algorithm;
    description
      "The secp521r1 algorithm.";
    reference
      "RFC5480:
         Elliptic Curve Cryptography Subject Public Key Information.";
  }

  // data model

  container keystore {
    nacm:default-deny-write;
    description
      "The keystore contains both active material (e.g., private keys
       and passwords) and passive material (e.g., trust anchors).

       The active material can be used to support either a server (e.g.,
       a TLS/SSH server's private) or a client (a private key used for
       TLS/SSH client-certificate based authentication, or a password
       used for SSH/HTTP-client authentication).

       The passive material can be used to support either a server
       (e.g., client certificates to trust) or clients (e.g., server
       certificates to trust).";

    container keys {
      description
        "A list of keys maintained by the keystore.";
      list key {
        key name;
        description
          "A key maintained by the keystore.";
        leaf name {
          type string;
          description
            "An arbitrary name for the key.";
        }
        leaf algorithm-identifier {
          type identityref {
            base "key-algorithm";
          }
          mandatory true;
          description
            "Identifies which algorithm is to be used to generate the
             key.";
             // no 'params' like in RFC 5912? - none are set for
             // algs we care about, but what about the future?



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        }
        leaf private-key {
          nacm:default-deny-all;
          type union {
            type binary;
            type enumeration {
              enum "INACCESSIBLE" {
                description
                 "The private key is inaccessible due to being protected
                  by a cryptographic hardware module (e.g., a TPM).";
              }
            }
          }
          mandatory true;
          description
            "A binary string that contains the value of the private
             key. The interpretation of the content is defined in the
             registration of the key algorithm.  For example, a DSA key
             is an INTEGER, an RSA key is represented as RSAPrivateKey
             as defined in [RFC3447], and an Elliptic Curve Cryptography
             (ECC) key is represented as ECPrivateKey as defined in
             [RFC5915]"; // text lifted from RFC5958
        }

        // no key usage (ref: RFC 5912, pg 101 -- too X.509 specific?)

        leaf public-key {
          type binary;
          config false;
          mandatory true;
          description
            "A binary string that contains the value of the public
             key. The interpretation of the content is defined in the
             registration of the key algorithm.  For example, a DSA key
             is an INTEGER, an RSA key is represented as RSAPublicKey
             as defined in [RFC3447], and an Elliptic Curve Cryptography
             (ECC) key is represented using the 'publicKey' described in
             [RFC5915]";
        }
        container certificates {
          description
            "Certificates associated with this private key.  More
             than one certificate per key is enabled to support,
             for instance, a TPM-protected key that has associated
             both IDevID and LDevID certificates.";
          list certificate {
            key name;
            description



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              "A certificate for this private key.";
            leaf name {
              type string;
              description
                "An arbitrary name for the certificate.  The name
                 must be a unique across all keys, not just within
                 this key.";
            }
            leaf value {
              type binary;
              description
               "An unsigned PKCS #7 SignedData structure, as specified
                by Section 9.1 in RFC 2315, containing just certificates
                (no content, signatures, or CRLs), encoded using ASN.1
                distinguished encoding rules (DER), as specified in
                ITU-T X.690.

                This structure contains, in order, the certificate
                itself and all intermediate certificates leading up
                to a trust anchor certificate.  The certificate MAY
                optionally include the trust anchor certificate.";
              reference
                "RFC 2315:
                   PKCS #7: Cryptographic Message Syntax Version 1.5.
                 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).";
            }
          }
        }
        action generate-certificate-signing-request {
          description
            "Generates a certificate signing request structure for
             the associated private 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 from the CertificationRequestInfo
                 structure as specified by RFC 2986, Section 4.1 encoded



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                 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).";
            }
            leaf attributes {
              type binary;
              description
               "The 'attributes' field from 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 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 4.1 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).";




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            }
          }
        }
      } // end key

      action generate-private-key {
        description
          "Requests the device to generate a private key using the
           specified key algorithm.  This action is primarily to
           support cryptographic processors that MUST generate
           the private key themselves.  The resulting key is
           considered operational state and hence initially only
           present in the <operational> datastore, as defined in
           [I-D.netmod-revised-datastores].";
        input {
          leaf name {
            type string;
            mandatory true;
            description
              "The name this private-key should have when listed
               in /keys/key.  As such, the passed value MUST NOT
               match any existing 'name' value.";
          }
          leaf algorithm {
            type identityref {
              base "key-algorithm";
            }
            mandatory true;
            description
              "The algorithm to be used when generating the key.";
          }
        }
      } // end generate-private-key
    } // end keys

    list trusted-certificates {
      key name;
      description
        "A list of trusted certificates.  These certificates
         can be used by a server to authenticate clients, or by
         clients to authenticate servers.  The certificates may
         be endpoint specific or for certificate authorities,
         to authenticate many clients at once.  Each list of
         certificates SHOULD be specific to a purpose, as the
         list as a whole may be referenced by other modules.
         For instance, a NETCONF server model might point to
         a list of certificates to use when authenticating
         client certificates.";



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      leaf name {
        type string;
        description
          "An arbitrary name for this list of trusted certificates.";
      }
      leaf description {
        type string;
        description
          "An arbitrary description for this list of trusted
           certificates.";
      }
      list trusted-certificate {
        key name;
        description
          "A trusted certificate for a specific use.  Note, this
           'certificate' is a list in order to encode any
           associated intermediate certificates.";
        leaf name {
          type string;
          description
            "An arbitrary name for this trusted certificate. Must
             be unique across all lists of trusted certificates
             (not just this list) so that a leafref to it from
             another module can resolve to unique values.";
        }
        leaf certificate {  // rename to 'data'?
          type binary;
          description
            "An X.509 v3 certificate structure as specified by RFC
             5280, Section 4 encoded using the ASN.1 distinguished
             encoding rules (DER), as specified in ITU-T X.690.";
          reference
            "RFC 5280:
               Internet X.509 Public Key Infrastructure Certificate
               and Certificate Revocation List (CRL) Profile.
             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).";
        }
      }
    }

    list trusted-host-keys {
      key name;
      description
        "A list of trusted host-keys.  These host-keys can be used



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         by clients to authenticate SSH servers.  The host-keys are
         endpoint specific.  Each list of host-keys SHOULD be
         specific to a purpose, as the list as a whole may be
         referenced by other modules.  For instance, a NETCONF
         client model might point to a list of host-keys to use
         when authenticating servers host-keys.";
      leaf name {
        type string;
        description
          "An arbitrary name for this list of trusted SSH host keys.";
      }
      leaf description {
        type string;
        description
          "An arbitrary description for this list of trusted SSH host
           keys.";
      }
      list trusted-host-key {
        key name;
        description
          "A trusted host key.";
        leaf name {
          type string;
          description
            "An arbitrary name for this trusted host-key. Must be
             unique across all lists of trusted host-keys (not just
             this list) so that a leafref to it from another module
             can resolve to unique values.

             Note that, for when the SSH client is able to listen
             for call-home connections as well, there is no reference
             identifier (e.g., hostname, IP address, etc.) that it
             can use to uniquely identify the server with.  The
             call-home draft recommends SSH servers use X.509v3
             certificates (RFC6187) when calling home.";
        }
        leaf host-key {  // rename to 'data'?
          type binary;
          mandatory true;
          description  // is this the correct type?
            "An OneAsymmetricKey 'publicKey' structure as specified
             by RFC 5958, Section 2 encoded using the ASN.1
             distinguished encoding rules (DER), as specified
             in ITU-T X.690.";
          reference
            "RFC 5958:
                Asymmetric Key Packages
             ITU-T X.690:



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                Information technology - ASN.1 encoding rules:
                Specification of Basic Encoding Rules (BER),
                Canonical Encoding Rules (CER) and Distinguished
                Encoding Rules (DER).";
        }
      }
    }
  }

  notification certificate-expiration {
    description
      "A notification indicating that a 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.";
    leaf certificate {
      type instance-identifier;
      mandatory true;
      description
        "Identifies which certificate is expiring or is expired.";
    }
    leaf expiration-date {
      type yang:date-and-time;
      mandatory true;
      description
        "Identifies the expiration date on the certificate.";
    }
  }

}


<CODE ENDS>

3.  Design Considerations

   This document uses PKCS #10 [RFC2986] for the "generate-certificate-
   signing-request" action.  The use of Certificate Request Message
   Format (CRMF) [RFC4211] was considered, but is was unclear if there
   was market demand for it, and so support for CRMF has been left out
   of this specification.  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.





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   This document puts a limit of the number of elliptical curves
   supported by default.  This was done to match industry trends in IETF
   best practice (e.g., matching work being done in TLS 1.3).  If
   additional algorithms are needed, they MAY be augmented in by another
   module, or added directly in a future version of this document.

   For the trusted-certificates list, Trust Anchor Format [RFC5914] was
   evaluated and deemed inappropriate due to this document's need to
   also support pinning.  That is, pinning a client-certificate to
   support NETCONF over TLS client authentication.

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:

      /: 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.  This being the case,
         the top-level node in this module is marked with the NACM value
         'default-deny-write'.

      /keystore/keys/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



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         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/keys/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.  This being the case, this node is marked with the
         NACM value 'default-deny-all'.

   Some of the RPC 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 RPC operation, 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.

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:







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      name:         ietf-keystore
      namespace:    urn:ietf:params:xml:ns:yang:ietf-keystore
      prefix:       kc
      reference:    RFC VVVV


6.  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, Radek Krejci, Tom Petch,
   Juergen Schoenwaelder; Phil Shafer, Sean Turner, and Bert Wijnen.

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://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,
              <http://www.rfc-editor.org/info/rfc2986>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <http://www.rfc-editor.org/info/rfc5280>.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <http://www.rfc-editor.org/info/rfc5958>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://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,
              <http://www.rfc-editor.org/info/rfc6536>.




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7.2.  Informative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.

   [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              DOI 10.17487/RFC4211, September 2005,
              <http://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,
              <http://www.rfc-editor.org/info/rfc5056>.

   [RFC5914]  Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor
              Format", RFC 5914, DOI 10.17487/RFC5914, June 2010,
              <http://www.rfc-editor.org/info/rfc5914>.

   [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,
              <http://www.rfc-editor.org/info/rfc6241>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <http://www.rfc-editor.org/info/rfc8040>.

   [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.  server-model-09 to 00

   o  This draft was split out from draft-ietf-netconf-server-model-09.

   o  Removed key-usage parameter from generate-private-key action.

   o  Now /private-keys/private-key/certificates/certificate/name must
      be globally unique (unique across all private keys).

   o  Added top-level 'trusted-ssh-host-keys' and 'user-auth-
      credentials' to support SSH client modules.

A.2.  keychain-00 to keystore-00

   o  Renamed module from "keychain" to "keystore" (Issue #3)

A.3.  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.4.  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.

Author's Address

   Kent Watsen
   Juniper Networks

   EMail: kwatsen@juniper.net








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