Network Working Group R. Gieben Internet-Draft M. Groeneweg Intended status: Standards Track R. Ribbers Expires: July 22, 2013 A.L.J. Verschuren SIDN Labs January 20, 2013 Key Relay Mapping for the Extensible Provisioning Protocol draft-gieben-epp-keyrelay-00 Abstract This document describes an Extensible Provisioning Protocol (EPP) extension mapping for the purpose of relaying DNSSEC key material from a one registrar to another. The mapping introduces as a new command in EPP. This command will help facilitating a transfer of a domain while keeping DNSSEC's chain of trust intact. 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/. 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 July 22, 2013. Copyright Notice Copyright (c) 2013 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. Gieben, et al. Expires July 22, 2013 [Page 1] Internet-Draft EPP Key Relay January 2013 Table of Contents 1. Conventions Used in This Document . . . . . . . . . . . . . . 2 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Relaying Key Material . . . . . . . . . . . . . . . . . . . . 3 4. Rational For a New Command . . . . . . . . . . . . . . . . . . 4 5. Key Relay Interface . . . . . . . . . . . . . . . . . . . . . 4 6. Example Key Relay Interface . . . . . . . . . . . . . . . . . 4 7. Server Reply . . . . . . . . . . . . . . . . . . . . . . . . . 5 8. Message Queue Interface . . . . . . . . . . . . . . . . . . . 6 9. Message Queue Format . . . . . . . . . . . . . . . . . . . . . 6 10. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 7 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 12. Security Considerations . . . . . . . . . . . . . . . . . . . 9 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 14.1. Normative References . . . . . . . . . . . . . . . . . . 10 14.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 1. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, RFC 2119 [RFC2119]. In examples, "C:" represents lines sent by a protocol client, and "S:" represents lines returned by a protocol server. "////" is used to note element values that have been shortened to better fit page boundaries. Indentation and white space in examples is provided only to illustrate element relationships and is not a mandatory feature of this protocol. XML is case sensitive. Unless stated otherwise, XML specifications and examples provided in this document MUST be interpreted in the character case presented in order to develop a conforming implementation. The term "key material" denotes one more DNSKEY resource records [RFC4034]. In Section 1.2 of [I-D.koch-dnsop-dnssec-operator-change] the terms "losing DNS operator" and "gaining DNS operator" are defined. With EPP a registry can only talk to its registrars, so in this document we will use the terms "loosing registrar" and "gaining registrar". 2. Introduction Certain transactions for DNSSEC signed zones require an authenticated exchange of DNSSEC key material between DNS operators. Often there is no direct secure channel or it is non-scalable. Gieben, et al. Expires July 22, 2013 [Page 2] Internet-Draft EPP Key Relay January 2013 One of such transactions is changing the DNS operator for DNSSEC signed zones ([I-D.koch-dnsop-dnssec-operator-change]. In this document we define a protocol extension for use in EPP that helps to implement and automate this transaction. This protocol extension introduces a new command called "". 3. Relaying Key Material The "" command uses the existing authenticated EPP channel with the registry. Both registrars can securely talk to the registry and as such the registry can serve as a drop box for relaying key material between them (see Figure 1). +-------------------+ DNSKEY +--------------------+ |losing DNS operator| <~~~~~~~ |gaining DNS operator| +-------------------+ +--------------------+ ^ | | v +-----------------+ +-----------------+ |current registrar| |gaining registrar| +-----------------+ +-----------------+ ^ | EPP poll | | EPP keyrelay | V +----------------+ | registry | +----------------+ The gaining and losing dns-operators should talk directly to each other (the ~ arrow) to exchange the DNSKEY, but often there is no trusted path between the two. As both can securely interact with the registry through the registrar it can act as a relay for the key material exchange. Figure 1 The "" command uploads a new key to the registry. This key material is then relayed to the current registrar's message queue. There is no need for the registry to store the relayed key in the registry system, although the registry MAY save the key for administrative purposes. The registrar may upload multiple keys in one "" message. If keys are identical (Flags Field, Protocol Field, Algorithm Field and Public Key Field are equal), the duplicate keys MUST be dropped. There is no restriction on the type (for instance Key Signing Keys or Zone Signing Keys) of keys that can be put in the message. It is up Gieben, et al. Expires July 22, 2013 [Page 3] Internet-Draft EPP Key Relay January 2013 to the losing registrar to validate the correctness of the key material. If for some reason the registry can not process the "" command an EPP error response MUST be returned. If the registry does process the "" command it MUST put all (discarding any duplicates) uploaded keys on to the losing registrars' message queue. 4. Rational For a New Command The keyrelay command is different than the existing EPP commands, because it allows someone to manipulate data without actually being to owner of that data. The EPP transfer command comes close with respect to this functionality. We did not want to overload the transfer command for this purpose, because a keyrelay has nothing to do with that operation. 5. Key Relay Interface The Key Relay Interface uses a "" element for relay the key material. It needs a maximum of three elements: a domain name, the key to upload and optionally a token which indicates a future transfer is imminent. The "" element MUST contain the following child elements: o A "" element that contains the domain name for which we upload the key. o A "" element that contains the key material as described in [RFC5910], Section 4.2. And MAY contain: o A "" that contains an authorization token ([RFC5931], Section 3.2.4) This can be used as an extra indication that the losing and gaining registrar had prior contact and a possible, future transfer is authorized. 6. Example Key Relay Interface The following is an example of the "" command: Gieben, et al. Expires July 22, 2013 [Page 4] Internet-Draft EPP Key Relay January 2013 C: C: C: C: C: C: example.org C: C: JnSdBAZSxxzJ C: C: C: 256 C: 3 C: 8 C: AwEAAc////Vesz C: C: C: C: C: 7. Server Reply Gieben, et al. Expires July 22, 2013 [Page 5] Internet-Draft EPP Key Relay January 2013 Example "" response: S: S: S: S: S: Command completed succesfully S: S: S: ABC-12345 S: 54321-ZYX S: S: S: As stated an EPP error response MUST be returned if a "" command can not be processed for any reason. 8. Message Queue Interface 9. Message Queue Format Example "Key Relay" service message: Gieben, et al. Expires July 22, 2013 [Page 6] Internet-Draft EPP Key Relay January 2013 S: S: S: S: S: Command completed successfully; ack to dequeue S: S: S: 1999-04-04T22:01:00.0Z S: Key Relay action completed successfully. S: S: S: S: S: example.org S: S: S: BCD-23456 S: 65432-WXY S: S: 1999-04-04T22:01:00.0Z S: S: S: JnSdBAZSxxzJ S: S: S: 256 S: 3 S: 8 S: AwEAAc////Vesz S: S: S: S: S: S: BCD-23456 S: 65432-WXY S: S: S: 10. Formal Syntax An EPP object mapping is specified in XML Schema notation. The formal syntax presented here is a complete schema representation of the object mapping suitable for automated validation of EPP XML instances. "" command schema: Gieben, et al. Expires July 22, 2013 [Page 7] Internet-Draft EPP Key Relay January 2013 Extensible Provisioning Protocol v1.0 domain name extension schema for relaying key material. Gieben, et al. Expires July 22, 2013 [Page 8] Internet-Draft EPP Key Relay January 2013 11. IANA Considerations This document uses URNs to describe XML namespaces and XML schemas conforming to a registry mechanism described in RFC 3688 [RFC3688]. Two URI assignments must be completed by the IANA. Registration request for the extension namespace: URI: urn:ietf:params:xml:ns:keyrelay-1.0 Registrant Contact: IESG XML: None. Namespace URIs do not represent an XML specification. Registration request for the extension XML schema: URI: urn:ietf:params:xml:schema:keyrelay-1.0 Registrant Contact: IESG XML: See the "Formal Syntax" section of this document. 12. Security Considerations The "" EPP extension does not allow for any object transformations. Any registrar can use this mechanism to put key material on the message queue of another registrar, thus mounting a denial of service attack. However this can, and should be detected by the registry. The "" element can be used as an indication that putting the key material on the losing registar's message queue is allowed. Communication between a registrar and registry is mostly done over EPP, but communication between dns-operators, registrants or registrars mostly is not. If EPP is not used between these entities, relaying the key between a dns-operator and registrar should be adequately authenticated for the complete relay channel to remain secure. It's out of scope for this document to describe how to authenticate other methods than EPP. Gieben, et al. Expires July 22, 2013 [Page 9] Internet-Draft EPP Key Relay January 2013 13. Acknowledgements Maarten Wullink, Marco Davids and Ed Lewis. 14. References 14.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. [RFC5910] Gould, J. and S. Hollenbeck, "Domain Name System (DNS) Security Extensions Mapping for the Extensible Provisioning Protocol (EPP)", RFC 5910, May 2010. 14.2. Informative References [I-D.koch-dnsop-dnssec-operator-change] Koch, P. and M. Sanz, "Changing DNS Operators for DNSSEC signed Zones", Internet-Draft draft-koch-dnsop-dnssec- operator-change-04, March 2012. [RFC5931] Harkins, D. and G. Zorn, "Extensible Authentication Protocol (EAP) Authentication Using Only a Password", RFC 5931, August 2010. Authors' Addresses R. (Miek) Gieben SIDN Labs Meander 501 Arnhem 6825 MD NL Email: miek@miek.nl URI: http://miek.nl/ M. Groeneweg SIDN Labs Meander 501 Arnhem 6825 MD NL Email: marc.groeneweg@sidn.nl URI: https://www.sidn.nl/ Gieben, et al. Expires July 22, 2013 [Page 10] Internet-Draft EPP Key Relay January 2013 Rik Ribbers SIDN Labs Meander 501 Arnhem 6825 MD NL Email: rik.ribbers@sidn.nl URI: https://www.sidn.nl/ Antoin Verschuren SIDN Labs Meander 501 Arnhem 6825 MD NL Email: antoin.verschuren@sidn.nl URI: https://www.sidn.nl/ Gieben, et al. Expires July 22, 2013 [Page 11]