remove security information from a delegation, or a <secDNS:chg>
element to replace security information with new security
information.
The <secDNS:update> element also contains an OPTIONAL "urgent"
attribute that a client can use to ask the server operator to
complete and implement the update request with high priority. This
attribute accepts boolean values as described in Section 2.2; the
default value is boolean false. "High priority" is relative to
standard server operator policies that are determined using an
out-of-band mechanism.
The <secDNS:add> element is used to add DS information to an existing
set. The <secDNS:add> element MUST contain one or more <secDNS:
dsData> elements as described in Section 3.1.2.
The <secDNS:rem> element contains one or more <secDNS:keyTag>
elements that are used to remove DS data from a delegation. The
<secDNS:keyTag> element MUST contain a key tag value as described in
section 5.1.1 of RFC 4034 [6]. Removing all DS information can
remove the ability of the parent to secure the delegation to the
child zone.
The <secDNS:chg> element is used to replace existing DS information
with new DS information. The <secDNS:chg> element MUST contain one
or more <secDNS:dsData> elements as described in Section 3.1.2. The
data in these elements is used to replace whatever other data is
currently archived for the delegation.
The <secDNS:update> element contains an OPTIONAL "urgent" attribute.
In addition, the <secDNS:dsData> element contains OPTIONAL <secDNS:
maxSigLife> and <secDNS:keyData> elements. The server MUST abort
command processing and respond with an appropriate EPP error if the
values provided by the client can not be accepted for syntax or
policy reasons.
Example <update> Command, Adding DS Data:
C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
C: xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0
C: epp-1.0.xsd">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:domain-1.0
C: domain-1.0.xsd">
C: <domain:name>example.com</domain:name>
C: </domain:update>
C: </update>
C: <extension>
C: <secDNS:update
C: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:secDNS-1.0
C: secDNS-1.0.xsd">
C: <secDNS:add>
C: <secDNS:dsData>
C: <secDNS:keyTag>12346</secDNS:keyTag>
C: <secDNS:alg>3</secDNS:alg>
C: <secDNS:digestType>1</secDNS:digestType>
C: <secDNS:digest>38EC35D5B3A34B44C39B</secDNS:digest>
C: </secDNS:dsData>
C: </secDNS:add>
C: </secDNS:update>
C: </extension>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>
Example <update> Command, Removing DS Data:
C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
C: xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0
C: epp-1.0.xsd">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:domain-1.0
C: domain-1.0.xsd">
C: <domain:name>example.com</domain:name>
C: </domain:update>
C: </update>
C: <extension>
C: <secDNS:update
C: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:secDNS-1.0
C: secDNS-1.0.xsd">
C: <secDNS:rem>
C: <secDNS:keyTag>12345</secDNS:keyTag>
C: </secDNS:rem>
C: </secDNS:update>
C: </extension>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>
Example Urgent <update> Command, Changing DS Data:
C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
C: xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0
C: epp-1.0.xsd">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:domain-1.0
C: domain-1.0.xsd">
C: <domain:name>example.com</domain:name>
C: </domain:update>
C: </update>
C: <extension>
C: <secDNS:update urgent="1"
C: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:secDNS-1.0
C: secDNS-1.0.xsd">
C: <secDNS:chg>
C: <secDNS:dsData>
C: <secDNS:keyTag>12345</secDNS:keyTag>
C: <secDNS:alg>3</secDNS:alg>
C: <secDNS:digestType>1</secDNS:digestType>
C: <secDNS:digest>49FD46E6C4B45C55D4AC</secDNS:digest>
C: </secDNS:dsData>
C: </secDNS:chg>
C: </secDNS:update>
C: </extension>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>
Example <update> Command, Changing Data to Include OPTIONAL Data:
C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
C: xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0
C: epp-1.0.xsd">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:domain-1.0
C: domain-1.0.xsd">
C: <domain:name>example.com</domain:name>
C: </domain:update>
C: </update>
C: <extension>
C: <secDNS:update
C: xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.0"
C: xsi:schemaLocation="urn:ietf:params:xml:ns:secDNS-1.0
C: secDNS-1.0.xsd">
C: <secDNS:chg>
C: <secDNS:dsData>
C: <secDNS:keyTag>12345</secDNS:keyTag>
C: <secDNS:alg>3</secDNS:alg>
C: <secDNS:digestType>1</secDNS:digestType>
C: <secDNS:digest>49FD46E6C4B45C55D4AC</secDNS:digest>
C: <secDNS:maxSigLife>604800</secDNS:maxSigLife>
C: <secDNS:keyData>
C: <secDNS:flags>256</secDNS:flags>
C: <secDNS:protocol>3</secDNS:protocol>
C: <secDNS:alg>1</secDNS:alg>
C: <secDNS:pubKey>AQPJ////4Q==</secDNS:pubKey>
C: </secDNS:keyData>
C: </secDNS:dsData>
C: </secDNS:chg>
C: </secDNS:update>
C: </extension>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>
When an extended <update> command has been processed successfully,
the EPP response is as described in the EPP domain mapping [2]. A
server operator MUST return an EPP error result code of 2306 if an
urgent update (noted with an "urgent" attribute value of boolean
true) can not be completed with high priority.
4. 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. The BEGIN and END tags are not part of the schema; they
are used to note the beginning and ending of the schema for URI
registration purposes.
BEGIN
<?xml version="1.0" encoding="UTF-8"?>
<schema targetNamespace="urn:ietf:params:xml:ns:secDNS-1.0"
xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.0"
xmlns="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
<annotation>
<documentation>
Extensible Provisioning Protocol v1.0
domain name extension schema for provisioning
DNS security (DNSSEC) extensions.
</documentation>
</annotation>
<!--
Child elements found in EPP commands.
-->
<element name="create" type="secDNS:dsType"/>
<element name="update" type="secDNS:updateType"/>
<!--
Child elements of the <create> command.
-->
<complexType name="dsType">
<sequence>
<element name="dsData" type="secDNS:dsDataType"
maxOccurs="unbounded"/>
</sequence>
</complexType>
<complexType name="dsDataType">
<sequence>
<element name="keyTag" type="unsignedShort"/>
<element name="alg" type="unsignedByte"/>
<element name="digestType" type="unsignedByte"/>
<element name="digest" type="hexBinary"/>
<element name="maxSigLife" type="secDNS:maxSigLifeType"
minOccurs="0"/>
<element name="keyData" type="secDNS:keyDataType"
minOccurs="0"/>
</sequence>
</complexType>
<simpleType name="maxSigLifeType">
<restriction base="int">
<minInclusive value="1"/>
</restriction>
</simpleType>
<complexType name="keyDataType">
<sequence>
<element name="flags" type="unsignedShort"/>
<element name="protocol" type="unsignedByte"/>
<element name="alg" type="unsignedByte"/>
<element name="pubKey" type="secDNS:keyType"/>
</sequence>
</complexType>
<simpleType name="keyType">
<restriction base="base64Binary">
<minLength value="1"/>
</restriction>
</simpleType>
<!--
Child elements of the <update> command.
-->
<complexType name="updateType">
<choice>
<element name="add" type="secDNS:dsType"/>
<element name="chg" type="secDNS:dsType"/>
<element name="rem" type="secDNS:remType"/>
</choice>
<attribute name="urgent" type="boolean" default="false"/>
</complexType>
<complexType name="remType">
<sequence>
<element name="keyTag" type="unsignedShort"
maxOccurs="unbounded"/>
</sequence>
</complexType>
<!--
Child response elements.
-->
<element name="infData" type="secDNS:dsType"/>
<!--
End of schema.
-->
</schema>
END
5. Internationalization Considerations
EPP is represented in XML, which provides native support for encoding
information using the Unicode character set and its more compact
representations including UTF-8 [14]. Conformant XML processors
recognize both UTF-8 and UTF-16 [15]. Though XML includes provisions
to identify and use other character encodings through use of an
"encoding" attribute in an <?xml?> declaration, use of UTF-8 is
RECOMMENDED in environments where parser encoding support
incompatibility exists.
As an extension of the EPP domain mapping [2], the elements, element
content, attributes, and attribute values described in this document
MUST inherit the internationalization conventions used to represent
higher-layer domain and core protocol structures present in an XML
instance that includes this extension.
6. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemas
conforming to a registry mechanism described in RFC 3688 [10]. Two
URI assignments have been completed by the IANA.
Registration request for the extension namespace:
URI: urn:ietf:params:xml:ns:secDNS-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:secDNS-1.0
Registrant Contact: IESG
XML: See the "Formal Syntax" section of this document.
7. Security Considerations
The mapping extensions described in this document do not provide any
security services beyond those described by EPP [1], the EPP domain
name mapping [2], and protocol layers used by EPP. The security
considerations described in these other specifications apply to this
specification as well.
As with other domain object transforms, the EPP transform operations
described in this document MUST be restricted to the sponsoring
client as authenticated using the mechanisms described in sections
2.9.1.1 and 7 of RFC 3730 [1]. Any attempt to perform a transform
operation on a domain object by any client other than the sponsoring
client MUST be rejected with an appropriate EPP authorization error.
The provisioning service described in this document involves the
exchange of information that can have an operational impact on the
DNS. A trust relationship MUST exist between the EPP client and
server, and provisioning of public key information MUST only be done
after the identities of both parties have been confirmed using a
strong authentication mechanism.
An EPP client might be acting as an agent for a zone administrator
who wants to send delegation information to be signed and published
by the server operator. Man-in-the-middle attacks are thus possible
as a result of direct client activity or inadvertent client data
manipulation.
Acceptance of a false key by a server operator can produce
significant operational consequences. The child and parent zones
MUST be consistent to secure the delegation properly. In the absence
of consistent signatures, the delegation will not appear in the
secure name space, yielding untrustworthy query responses. If a key
is compromised, a client can either remove the compromised
information or update the delegation information via EPP commands
using the "urgent" attribute.
Operational scenarios requiring quick removal of a secure domain
delegation can be implemented using a two-step process. First,
security credentials can be removed using an "urgent" update as just
described. The domain can then be removed from the parent zone by
changing the status of the domain to either of the EPP "clientHold"
or "serverHold" domain status values. The domain can also be removed
from the zone using the EPP <delete> command, but this is a more
drastic step that needs to be considered carefully before use.
Data validity checking at the server requires computational
resources. A purposeful or inadvertent denial-of-service attack is
possible if a client requests some number of update operations that
exceed a server’s processing capabilities. Server operators SHOULD
take steps to manage command load and command processing requirements
to minimize the risk of a denial-of-service attack.
The signature lifetime values provided by clients are requests that
can be rejected. Blind acceptance by a server operator can have an
adverse impact on a server’s processing capabilities. Server
operators SHOULD seriously consider adopting implementation rules to
limit the range of acceptable signature lifetime values to counter
potential adverse situations.
8. Acknowledgements
The author would like to thank the following people who have provided
significant contributions to the development of this document:
David Blacka, Olafur Gudmundsson, Mark Kosters, Ed Lewis, Dan Massey,
Marcos Sanz, Sam Weiler, and Ning Zhang.
9. References
9.1. Normative References
[1] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
RFC 3730, March 2004.
[2] Hollenbeck, S., "Extensible Provisioning Protocol (EPP) Domain
Name Mapping", RFC 3731, March 2004.
[3] Paoli, J., Sperberg-McQueen, C., Bray, T., and E. Maler,
"Extensible Markup Language (XML) 1.0 (Second Edition)", W3C
FirstEdition REC-xml-20001006, October 2000.
[4] Maloney, M., Beech, D., Mendelsohn, N., and H. Thompson, "XML
Schema Part 1: Structures", W3C REC REC-xmlschema-1-20010502,
May 2001.
[5] Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes", W3C
REC REC-xmlschema-2-20010502, May 2001.
[6] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"Resource Records for the DNS Security Extensions", RFC 4034,
March 2005.
[7] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"Protocol Modifications for the DNS Security Extensions",
RFC 4035, March 2005.
[8] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[9] Kolkman, O., Schlyter, J., and E. Lewis, "Domain Name System
KEY (DNSKEY) Resource Record (RR) Secure Entry Point (SEP)
Flag", RFC 3757, April 2004.
[10] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
9.2. Informative References
[11] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[12] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[13] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"DNS Security Introduction and Requirements", RFC 4033,
March 2005.
[14] Yergeau, F., "UTF-8, a transformation format of ISO 10646",
STD 63, RFC 3629, November 2003.
[15] Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO 10646",
RFC 2781, February 2000.
Author’s Address
Scott Hollenbeck
VeriSign, Inc.
21345 Ridgetop Circle
Dulles, VA 20166-6503
US
EMail: shollenbeck@verisign.com
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