NETCONF Working Group K. Watsen Internet-Draft Juniper Networks Intended status: Standards Track September 20, 2018 Expires: March 24, 2019 YANG Data Model for a Centralized Keystore Mechanism draft-ietf-netconf-keystore-06 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 "2018-09-20" --> 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/. Watsen Expires March 24, 2019 [Page 1] Internet-Draft A Centralized Keystore Mechanism September 2018 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 March 24, 2019. 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 . . . . . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 19 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 21 5.2. The YANG Module Names Registry . . . . . . . . . . . . . 21 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 21 6.1. Normative References . . . . . . . . . . . . . . . . . . 21 6.2. Informative References . . . . . . . . . . . . . . . . . 22 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 23 A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 23 A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 23 A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 23 A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 23 A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 24 A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 24 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 24 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 24 Watsen Expires March 24, 2019 [Page 2] Internet-Draft A Centralized Keystore Mechanism September 2018 1. Introduction This document defines a YANG 1.1 [RFC7950] module called "ietf- keystore" that enables centralized configuration of asymmetric keys and their associated certificates, and notification for when configured certificates are about to expire. This module also defines Six groupings designed for maximum reuse. These groupings include one for the public half of an asymmetric key, one for both the public and private halves of an asymmetric key, one for both halves of an asymmetric key and a list of associated certificates, one for an asymmetric key that may be configured locally or via a reference to an asymmetric key in the keystore, one for a trust anchor certificate and, lastly, one for an end entity certificate. Special consideration has been given for systems that have cryptographic hardware, such as a Trusted Protection Module (TPM). These systems are unique in that the cryptographic hardware completely hides the private keys and must perform all private key operations. To support such hardware, the "private-key" can be the special value "permanently-hidden" and the actions "generate-hidden- key" and "generate-certificate-signing-request" can be used to direct these operations to the hardware . This document in compliant with Network Management Datastore Architecture (NMDA) [RFC8342]. For instance, to support keys and associated certificates installed during manufacturing (e.g., for a IDevID [Std-802.1AR-2009] certificate), it is expected that such data may appear only in . 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 Watsen Expires March 24, 2019 [Page 3] Internet-Draft A Centralized Keystore Mechanism September 2018 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 +---x generate-hidden-key | +---w input | +---w algorithm ct:key-algorithm-ref +---x install-hidden-key | +---w input | +---w algorithm ct:key-algorithm-ref | +---w public-key? binary | +---w private-key? binary +--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 grouping local-or-keystore-asymmetric-key-grouping +-- (local-or-keystore) +--:(local) {local-keys-supported}? | +-- algorithm? ct:key-algorithm-ref | +-- public-key? binary | +-- private-key? union Watsen Expires March 24, 2019 [Page 4] Internet-Draft A Centralized Keystore Mechanism September 2018 | +---x generate-hidden-key | | +---w input | | +---w algorithm ct:key-algorithm-ref | +---x install-hidden-key | +---w input | +---w algorithm ct:key-algorithm-ref | +---w public-key? binary | +---w private-key? binary +--:(keystore) {keystore-supported}? +-- reference? ks:asymmetric-key-ref grouping local-or-keystore-end-entity-certificate-grouping +-- (local-or-keystore) +--:(local) {local-keys-supported}? | +-- algorithm? ct:key-algorithm-ref | +-- public-key? binary | +-- private-key? union | +---x generate-hidden-key | | +---w input | | +---w algorithm ct:key-algorithm-ref | +---x install-hidden-key | | +---w input | | +---w algorithm ct:key-algorithm-ref | | +---w public-key? binary | | +---w private-key? binary | +-- cert ct:end-entity-cert-cms | +---n certificate-expiration | +-- expiration-date? yang:date-and-time +--:(keystore) {keystore-supported}? +-- reference? ks:asymmetric-key-certificate-ref grouping local-or-keystore-asymmetric-key-with-certs-grouping +-- (local-or-keystore) +--:(local) {local-keys-supported}? | +-- algorithm? | | ct:key-algorithm-ref | +-- public-key? binary | +-- private-key? union | +---x generate-hidden-key | | +---w input | | +---w algorithm ct:key-algorithm-ref | +---x install-hidden-key | | +---w input | | +---w algorithm ct:key-algorithm-ref | | +---w public-key? binary | | +---w private-key? binary | +-- certificates | | +-- certificate* [name] | | +-- name? string Watsen Expires March 24, 2019 [Page 5] Internet-Draft A Centralized Keystore Mechanism September 2018 | | +-- 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-supported}? +-- reference? ks:asymmetric-key-ref 3.2. Example Usage The following example illustrates what a fully configured keystore might look like in , 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. [Note: '\' line wrapping for formatting only] ex-rsa-key ct:rsa1024 base64encodedvalue== base64encodedvalue== ex-rsa-cert base64encodedvalue== tls-ec-key ct:secp256r1 Watsen Expires March 24, 2019 [Page 6] Internet-Draft A Centralized Keystore Mechanism September 2018 base64encodedvalue== base64encodedvalue== tls-ec-cert base64encodedvalue== tpm-protected-key ct:rsa2048 permanently-hidden base64encodedvalue== builtin-idevid-cert base64encodedvalue== my-ldevid-cert base64encodedvalue== empty-key The following example module has been constructed to illustrate the "local-or-keystore-asymmetric-key-grouping" grouping defined in the "ietf-keystore" module. Watsen Expires March 24, 2019 [Page 7] Internet-Draft A Centralized Keystore Mechanism September 2018 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 "; 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."; } } } Watsen Expires March 24, 2019 [Page 8] Internet-Draft A Centralized Keystore Mechanism September 2018 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). locally-defined key ct:secp521r1 base64encodedvalue== base64encodedvalue== keystore-defined key ex-rsa-key 3.3. YANG Module This YANG module has normative references to [RFC8341] and [I-D.ietf-netconf-crypto-types], and an informative reference to [RFC8342]. file "ietf-keystore@2018-09-20.yang" [Note: '\' line wrapping for formatting only] 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"; } Watsen Expires March 24, 2019 [Page 9] Internet-Draft A Centralized Keystore Mechanism September 2018 organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: Author: Kent Watsen "; 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 "2018-09-20" { description "Initial version"; reference "RFC VVVV: YANG Data Model for a Centralized Keystore Mechanism"; } // Features feature keystore-supported { description "The 'keystore-supported' feature indicates that the server supports the keystore."; } feature local-keys-supported { description "The 'local-keys-supported' feature indocates that the server supports locally-defined keys."; Watsen Expires March 24, 2019 [Page 10] Internet-Draft A Centralized Keystore Mechanism September 2018 } // Typedefs typedef asymmetric-key-ref { type leafref { 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 ."; 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 ."; reference "RFC 8342: Network Management Datastore Architecture (NMDA)"; } // Groupings // MOVED TO CRYPTO TYPES DRAFT? - OKAY TO REMOVE HERE NOW? // // grouping public-key-grouping { // description // "A public key."; // leaf algorithm { // type ct:key-algorithm-ref; // description // "Identifies the key's algorithm. More specifically, // this leaf specifies how the 'public-key' binary leaf Watsen Expires March 24, 2019 [Page 11] Internet-Draft A Centralized Keystore Mechanism September 2018 // is encoded."; // reference // "RFC CCCC: Common YANG Data Types for Cryptography"; // } // leaf public-key { // type binary; // 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 ct:public-key-grouping; // leaf private-key { // nacm:default-deny-all; // type union { // type binary; // type enumeration { // enum "permanently-hidden" { // description // "The private key is inaccessible due to being // protected by the system (e.g., a cryptographic // hardware module). It is not possible to // configure a permanently hidden key, as a real // private key value must be set. Permanently // hidden keys cannot be archived or backed up."; // } // } // } // 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."; Watsen Expires March 24, 2019 [Page 12] Internet-Draft A Centralized Keystore Mechanism September 2018 // reference // "RFC 3447: Public-Key Cryptography Standards (PKCS) #1: // RSA Cryptography Specifications Version 2.1. // RFC 5915: Elliptic Curve Private Key Structure."; // } // action generate-hidden-key { // description // "Requests the device to generate a hidden key using the // specified asymmetric key algorithm. This action is // used to request the system the generate a key that // is 'permanently-hidden', perhaps protected by a // cryptographic hardware module. The resulting // asymmetric key values are considered operational // state and hence present only in ."; // input { // 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-hidden-key // action install-hidden-key { // description // "Requests the device to load the specified values into // a hidden key. The resulting asymmetric key values are // considered operational state and hence present only in // ."; // input { // 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"; // } // leaf public-key { // type binary; // 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 Watsen Expires March 24, 2019 [Page 13] Internet-Draft A Centralized Keystore Mechanism September 2018 // 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."; // } // leaf private-key { // type binary; // description // "A binary that contains the value of the private key. // The interpretation of the content is defined by the k\ ey // 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."; // } // } // } // end install-hidden-key // } // // 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; Watsen Expires March 24, 2019 [Page 14] Internet-Draft A Centralized Keystore Mechanism September 2018 // 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 ct:asymmetric-key-pair-grouping; // container certificates { // description // "Certificates associated with this asymmetric key. // More than one certificate supports, for instance, // a TPM-protected asymmetric key that has both IDevID // and LDevID certificates associated."; // list certificate { // must "../../algorithm // and ../../public-key // and ../../private-key"; // key name; // description // "A certificate for this asymmetric key."; // leaf name { // type string; // description // "An arbitrary name for the certificate."; // } // uses ct:end-entity-cert-grouping; // } // end certifcate // } // end certificates // action generate-certificate-signing-request { Watsen Expires March 24, 2019 [Page 15] Internet-Draft A Centralized Keystore Mechanism September 2018 // 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, // 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; Watsen Expires March 24, 2019 [Page 16] Internet-Draft A Centralized Keystore Mechanism September 2018 // 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 // } // // MOVED TO CRYPTO TYPES DRAFT? - OKAY TO REMOVE HERE NOW? 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 { if-feature "local-keys-supported"; uses ct:asymmetric-key-pair-grouping; } case keystore { if-feature "keystore-supported"; leaf reference { type ks:asymmetric-key-ref; 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."; } } Watsen Expires March 24, 2019 [Page 17] Internet-Draft A Centralized Keystore Mechanism September 2018 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 { if-feature "local-keys-supported"; uses ct:asymmetric-key-pair-with-certs-grouping; } case keystore { if-feature "keystore-supported"; leaf reference { type ks:asymmetric-key-ref; 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 { if-feature "local-keys-supported"; uses ct:asymmetric-key-pair-grouping; uses ct:end-entity-cert-grouping; } case keystore { if-feature "keystore-supported"; leaf reference { type ks:asymmetric-key-certificate-ref; description "A reference to a value that exists in the keystore."; } } description "A choice between an inlined definition and a definition Watsen Expires March 24, 2019 [Page 18] Internet-Draft A Centralized Keystore Mechanism September 2018 that exists in the keystore."; } } // protocol accessible nodes container keystore { nacm:default-deny-write; description "The keystore contains a list of keys."; container asymmetric-keys { description "A list of asymmetric keys."; list asymmetric-key { must "(algorithm and public-key and private-key) or not (algorithm or public-key or private-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; } // end asymmetric-key } // end asymmetric-keys } // end keystore } 4. Security Considerations The YANG module defined in this document is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to- implement secure transport layers (e.g., SSH, TLS) with mutual authentication. The NETCONF access control model (NACM) [RFC8341] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. Watsen Expires March 24, 2019 [Page 19] Internet-Draft A Centralized Keystore Mechanism September 2018 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, etc., can dramatically alter the implemented security policy. For this reason, the NACM extension "default-deny-write" has been set for the entire data tree. /keystore/asymmetric-keys/asymmetric-key/private-key: When writing this node, implementations MUST ensure that the strength of the key being configured is not greater than the strength of the underlying secure transport connection over which it is communicated. Implementations SHOULD fail the write-request if ever the strength of the private key is greater then the strength of the underlying transport, and alert the client that the strength of the key may have been compromised. Additionally, when deleting this node, implementations SHOULD automatically (without explicit request) zeroize these keys in the most secure manner available, so as to prevent the remnants of their persisted storage locations from being analyzed in any meaningful way. Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: /keystore/asymmetric-keys/asymmetric-key/private-key: This node is additionally sensitive to read operations such that, in normal use cases, it should never be returned to a client. The best reason for returning this node is to support backup/ restore type workflows. For this reason, the NACM extension "default-deny-all" has been set for this data node. Note that this extension is inherited from the grouping in the [I-D.ietf-netconf-crypto-types] module. Watsen Expires March 24, 2019 [Page 20] Internet-Draft A Centralized Keystore Mechanism September 2018 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. [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., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . Watsen Expires March 24, 2019 [Page 21] Internet-Draft A Centralized Keystore Mechanism September 2018 [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . 6.2. Informative References [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [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, . [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, Ed., "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] IEEE SA-Standards Board, "IEEE Standard for Local and metropolitan area networks - Secure Device Identity", December 2009, . Watsen Expires March 24, 2019 [Page 22] Internet-Draft A Centralized Keystore Mechanism September 2018 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 Watsen Expires March 24, 2019 [Page 23] Internet-Draft A Centralized Keystore Mechanism September 2018 A.5. 04 to 05 o Removed trust anchors (now in their own draft) o Added back global keystore structure o Added groupings enabling keys to either be locally defined or a reference to the keystore. A.6. 05 to 06 o Added feature "local-keys-supported" o Added nacm:default-deny-all and nacm:default-deny-write o Renamed generate-asymmetric-key to generate-hidden-key o Added an install-hidden-key action o Moved actions inside fo the "asymmetric-key" container o Moved some groupings to draft-ietf-netconf-crypto-types 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 Watsen Expires March 24, 2019 [Page 24]