Network Working Group R. Gieben
Internet-Draft Google
Intended status: Standards Track M. Groeneweg
Expires: October 05, 2013 R. Ribbers
A.L.J. Verschuren
SIDN Labs
April 03, 2013
Key Relay Mapping for the Extensible Provisioning Protocol
draft-gieben-epp-keyrelay-02
Abstract
This document describes an Extensible Provisioning Protocol (EPP)
extension mapping for the purpose of relaying DNSSEC key material
from one DNS operator to another, by using the administrative
registration channel through the registrant, registrar and registry.
The mapping introduces "<keyrelay>" as a new command in EPP.
This command will help facilitate changing the DNS operator of a
domain while keeping the DNSSEC chain of trust intact.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on October 05, 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
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Table of Contents
1. Conventions Used in This Document . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Relaying Key Material . . . . . . . . . . . . . . . . . . . . 3
4. Rational For a New Command . . . . . . . . . . . . . . . . . 4
5. Key Relay Interface . . . . . . . . . . . . . . . . . . . . . 5
5.1. Example Key Relay Interface . . . . . . . . . . . . . . . 6
6. Server Reply . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Message Queue Interface . . . . . . . . . . . . . . . . . . . 7
7.1. Message Queue Format . . . . . . . . . . . . . . . . . . 7
8. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
10. Security Considerations . . . . . . . . . . . . . . . . . . . 10
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
12.1. Normative References . . . . . . . . . . . . . . . . . . 11
12.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Changelog . . . . . . . . . . . . . . . . . . . . . 12
A.1. -00 . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
A.2. -01 . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
A.3. -02 . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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.
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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].
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 between the two or it is non-scalable.
One of such transactions is changing the DNS operator for DNSSEC
signed zones ([I-D.koch-dnsop-dnssec-operator-change]. We suggest
DNS operators use the administrative channel that is used to
bootstrap the delegation to relay the key material for the zone. 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 "<keyrelay>".
3. Relaying Key Material
The "<keyrelay>" command uses the existing authenticated EPP channel
with the registry. 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| |registrar|
+-----------------+ +---------+
^ |
EPP poll | | EPP keyrelay
| V
+----------------+
| registry |
+----------------+
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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 over the administrative channel through the registrar, the
registry can act as a relay for the key material exchange.
Figure 1
The "<keyrelay>" command uploads new key(s) to the registry for a
given domain. This key material is then relayed to the current
registrar's message queue. This may be the same registrar as the one
that submitted the "<keyrelay>" command in the situation where the
DNS operators change, but the registrar stays the same. 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 "<keyrelay>" message.
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
to the losing DNS operator to validate the correctness of the key
material, and remove duplicate keys (Flags Field, Protocol Field,
Algorithm Field and Public Key Field are equal) when identical keys
are already in the zone.
If for some reason the registry can not process the "<keyrelay>"
command an EPP error response MUST be returned. If the registry does
process the "<keyrelay>" command it MUST put all uploaded keys on to
the current registrar's message queue.
4. Rational For a New Command
The existing commands in EPP all deal with data which either has an
owner, or soon will have one (EPP create). The "<keyrelay>" command
is different, because it allows an upload of key material which will
never have an owner (in the registry system). All the "<keyrelay>"
command does is relay data in preparation for one of the other
existing EPP commands in a processes. This way, existing commands
don't need to change, and backward compatibility for existing
commands is guaranteed. It allows the client to be flexible in
timing the individual steps necessary to complete a complex process
like changing the DNS operator for a zone. Creating a separate
command also allows the command to be used or extended to relay key
or other data for other future processes besides DNS operator
changes.
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5. Key Relay Interface
The Key Relay Interface uses a "<keyrelay>" element for relaying the
key material. It needs a minimum of three elements: a domain name,
the key(s) to upload, a token which indicates the request is
authorized by the registrant, and an OPTIONAL expire element.
Thus a "<keyrelay>" element MUST contain the following child
elements:
o A "<name>" element that contains the domain name for which we
upload the key.
o A "<keyData>" element that contains the key material as described
in [RFC5910], Section 4.2.
o An "<authInfo>" that contains an authorization token ([RFC5731],
Section 3.2.4). This indicates that the registrar has
authorization from the registrant to change the zone data, and a
possible future transfer is authorized. The registry MAY check if
the "<authInfo>" data is correct and if it does, it MUST return an
EPP error response if the authorization token is not correct.
And MAY contain:
o An "<expiry>" element that describes the expected lifetime of the
relayed key(s) in the zone. The losing DNS operator can use this
to decide when to remove the key material from the zone again.
The <expiry> element MUST contain one of the following child
elements:
* "<absolute/>": The policy is valid from the current date and
time until it expires on the specified date and time.
* "<relative/>": The policy is valid from the current date and
time until the end of the specified duration.
The current date and time are taken from the "<keyrelay>" service
message's "<qDate>" element, see Section 7.1.
o An "<clTRID>" (client transaction identifier) as described in
[RFC5730], Section 2.5.
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5.1. Example Key Relay Interface
The following is an example of the "<keyrelay>" command, where a key
is uploaded with a relative expire date of one month and 13 days.
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
C: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.1"
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
C: xmlns:ext="urn:ietf:params:xml:ns:keyrelay-1.0">
C: <extension>
C: <ext:command>
C: <ext:keyrelay>
C: <ext:name>example.org</ext:name>
C: <ext:keyData>
C: <secDNS:flags>256</secDNS:flags>
C: <secDNS:protocol>3</secDNS:protocol>
C: <secDNS:alg>8</secDNS:alg>
C: <secDNS:pubKey>cmlraXN0aGViZXN0</secDNS:pubKey>
C: </ext:keyData>
C: <ext:authInfo>
C: <domain:pw>JnSdBAZSxxzJ</domain:pw>
C: </ext:authInfo>
C: <ext:expiry>
C: <ext:relative>P1M13D</ext:relative>
C: </ext:expiry>
C: </ext:keyrelay>
C: <ext:clTRID>ABC-12345</ext:clTRID>
C: </ext:command>
C: </extension>
C:</epp>
6. Server Reply
Example "<keyrelay>" response:
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S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
S: <response>
S: <result code="1000">
S: <msg>Command completed succesfully</msg>
S: </result>
S: <trID>
S: <clTRID>ABC-12345</clTRID>
S: <svTRID>54321-ZYX</svTRID>
S: </trID>
S: </response>
S:</epp>
As stated an EPP error response MUST be returned if a "<keyrelay>"
command can not be processed for any reason.
7. Message Queue Interface
The message queue interface uses the interface as defined in
[RFC5730], Section 2.6. All elements that are present in the
"<keyrelay>" EPP message are put on the message queue of the current
registrar for the domain in the "<name>" element.
7.1. Message Queue Format
This is an example "<keyrelay>" service message. Note that the
optional clTRID in this message is the clTRID value from the command
that polls the message queue. It is not the clTRID value used in the
EPP "<keyrelay>" command.
S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
S: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.1"
S: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
S: xmlns:keyrelay="urn:ietf:params:xml:ns:keyrelay-1.0">
S: <response>
S: <result code="1301">
S: <msg>Command completed successfully; ack to dequeue</msg>
S: </result>
S: <msgQ count="5" id="12345">
S: <qDate>1999-04-04T22:01:00.0Z</qDate>
S: <msg>Key Relay action completed successfully.</msg>
S: </msgQ>
S: <resData>
S: <keyrelay:response>
S: <keyrelay:panData>
S: <keyrelay:name paResult="true">example.org
S: </keyrelay:name>
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S: <keyrelay:paDate>1999-04-04T22:01:00.0Z
S: </keyrelay:paDate>
S: <keyrelay:keyData>
S: <secDNS:flags>256</secDNS:flags>
S: <secDNS:protocol>3</secDNS:protocol>
S: <secDNS:alg>8</secDNS:alg>
S: <secDNS:pubKey>cmlraXN0aGViZXN0</secDNS:pubKey>
S: </keyrelay:keyData>
S: <keyrelay:authInfo>
S: <domain:pw>JnSdBAZSxxzJ</domain:pw>
S: </keyrelay:authInfo>
S: <keyrelay:expiry>
S: <keyrelay:relative>P24D</keyrelay:relative>
S: </keyrelay:expiry>
S: <keyrelay:reID>ClientX</keyrelay:reID>
S: <keyrelay:acID>ClientY</keyrelay:acID>
S: </keyrelay:panData>
S: </keyrelay:response>
S: </resData>
S: <trID>
S: <clTRID>BCD-23456</clTRID>
S: <svTRID>65432-WXY</svTRID>
S: </trID>
S: </response>
S:</epp>
8. 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.
"<keyrelay>" command schema:
<?xml version="1.0" encoding="UTF-8"?>
<schema targetNamespace="urn:ietf:params:xml:ns:keyrelay-1.0"
xmlns:keyrelay="urn:ietf:params:xml:ns:keyrelay-1.0"
xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.1"
xmlns:epp="urn:ietf:params:xml:ns:epp-1.0"
xmlns:eppcom="urn:ietf:params:xml:ns:eppcom-1.0"
xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
xmlns="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
<annotation>
<documentation>
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Extensible Provisioning Protocol v1.0 domain name
extension schema for relaying key material.
</documentation>
</annotation>
<import namespace="urn:ietf:params:xml:ns:epp-1.0"
schemaLocation="epp-1.0.xsd" />
<import namespace="urn:ietf:params:xml:ns:eppcom-1.0"
schemaLocation="eppcom-1.0.xsd" />
<import namespace="urn:ietf:params:xml:ns:secDNS-1.1"
schemaLocation="secdns-1.1.xsd" />
<import namespace="urn:ietf:params:xml:ns:domain-1.0"
schemaLocation="domain-1.0.xsd" />
<element name="command" type="keyrelay:commandType" />
<element name="response" type="keyrelay:responseType" />
<complexType name="responseType">
<sequence>
<element name="panData"
type="keyrelay:panKeyRelayDataType"/>
</sequence>
</complexType>
<complexType name="commandType">
<sequence>
<element name="keyrelay"
type="keyrelay:keyRelayType" />
<element name="clTRID" type="epp:trIDStringType"
minOccurs="0"/>
</sequence>
</complexType>
<complexType name="keyRelayExpiryType">
<choice>
<element name="absolute" type="dateTime" />
<element name="relative" type="duration" />
</choice>
</complexType>
<complexType name="keyRelayType">
<sequence>
<element name="name" type="eppcom:labelType" />
<element name="keyData" type="secDNS:keyDataType"
minOccurs="1" maxOccurs="unbounded" />
<element name="authInfo"
type="domain:authInfoType" />
<element name="expiry"
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type="keyrelay:keyRelayExpiryType"/>
</sequence>
</complexType>
<complexType name="panKeyRelayDataType">
<sequence>
<element name="name" type="domain:paNameType" />
<element name="paDate" type="dateTime" />
<element name="keyData" type="secDNS:keyDataType"
minOccurs="1" maxOccurs="unbounded" />
<element name="authInfo" type="domain:authInfoType" />
<element name="expiry"
type="keyrelay:keyRelayExpiryType"/>
<element name="reID" type="eppcom:clIDType"/>
<element name="acID" type="eppcom:clIDType"/>
</sequence>
</complexType>
</schema>
9. 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.
10. Security Considerations
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The "<keyrelay>" 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. A
correct "<ext:authInfo>" element can be used as an indication that
putting the key material on the losing registrar's message queue is
authorized by the registrant of that registrar.
Communication between a registrar and registry is mostly done over
EPP, but communication between DNS operators, registrants or
registrars often 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 with other methods than EPP.
11. Acknowledgements
Maarten Wullink, Marco Davids, Ed Lewis, James Mitchell, David Peal
and Patrik Faltstrom for their review.
Klaus Malorny. Mandated authInfo, added Expiry and reID based on
Klaus feedback.
James Gould. For his review, suggestions and additional support for
mandatory authInfo.
Patrick Mevzek. He also noticed our missing clTRID in the message,
and gave useful feedback for clarifications. Many thanks also for
building the first EPP client to support keyrelay.
12. References
12.1. 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.
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[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, August 2009.
[RFC5910] Gould, J. and S. Hollenbeck, "Domain Name System (DNS)
Security Extensions Mapping for the Extensible
Provisioning Protocol (EPP)", RFC 5910, May 2010.
12.2. Informative References
[I-D.koch-dnsop-dnssec-operator-change]
Koch, P. and M. Sanz, "Changing DNS Operators for DNSSEC
signed Zones", draft-koch-dnsop-dnssec-operator-change-04
(work in progress), March 2012.
[RFC5731] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
Domain Name Mapping", STD 69, RFC 5731, August 2009.
[This section should be removed by the RFC editor before publishing]
1. Initial document.
1. Style and grammar changes;
2. Added an expire element;
3. Make the authInfo element mandatory and make the registry check
it.
1. Added element to identify the relaying EPP client;
2. Corrected XML for missing and excess clTRID;
3. Added clarifications for the examples based on feedback;
4. Reviewed the consistency of using DNS operator versus registrar.
Authors' Addresses
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R. (Miek) Gieben
Google
Email: miek@google.com
M. Groeneweg
SIDN Labs
Meander 501
Arnhem 6825 MD
NL
Email: marc.groeneweg@sidn.nl
URI: https://www.sidn.nl/
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/
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