regext J. Latour
Internet-Draft CIRA
Intended status: Standards Track O. Gudmundsson
Expires: September 13, 2017 Cloudflare, Inc.
P. Wouters
Red Hat
M. Pounsett
Rightside Group, Ltd.
March 12, 2017
Third Party DNS operator to Registrars/Registries Protocol
draft-ietf-regext-dnsoperator-to-rrr-protocol-03.txt
Abstract
There are several problems that arise in the standard
Registrant/Registrar/Registry model when the operator of a zone is
neither the Registrant nor the Registrar for the delegation.
Historically the issues have been minor, and limited to difficulty
guiding the Registrant through the initial changes to the NS records
for the delegation. As this is usually a one time activity when the
operator first takes charge of the zone it has not been treated as a
serious issue.
When the domain uses DNSSEC it necessary to make regular (sometimes
annual) changes to the delegation, updating DS record(s) in order to
track KSK rollover. Under the current model this is prone to delays
and errors, as the Registrant must participate in updates to DS
records.
This document describes a simple protocol that allows a third party
DNS operator to update DS records for a delegation, in a trusted
manner, without involving the Registrant for each operation. This
same protocol can be used by Registrants.
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
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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 September 13, 2017.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notional Conventions . . . . . . . . . . . . . . . . . . . . 4
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. RFC2119 Keywords . . . . . . . . . . . . . . . . . . . . 4
3. Process Overview . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Identifying the Registrar . . . . . . . . . . . . . . . . 4
3.2. Establishing a Chain of Trust . . . . . . . . . . . . . . 5
3.3. Maintaining the Chain of Trust . . . . . . . . . . . . . 5
3.4. Other Delegation Maintenance . . . . . . . . . . . . . . 5
3.5. Acceptance Processing . . . . . . . . . . . . . . . . . . 5
4. API Definition . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Authentication . . . . . . . . . . . . . . . . . . . . . 7
4.2. RESTful Resources . . . . . . . . . . . . . . . . . . . . 7
4.2.1. CDS resource . . . . . . . . . . . . . . . . . . . . 7
4.2.2. Token resource . . . . . . . . . . . . . . . . . . . 9
4.3. Customized Error Messages . . . . . . . . . . . . . . . . 10
5. Security considerations . . . . . . . . . . . . . . . . . . . 10
6. IANA Actions . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Internationalization Considerations . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Document History . . . . . . . . . . . . . . . . . . 12
A.1. regext Version 03 . . . . . . . . . . . . . . . . . . . . 12
A.2. regext Version 02 . . . . . . . . . . . . . . . . . . . . 13
A.3. regext Version 01 . . . . . . . . . . . . . . . . . . . . 13
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A.4. regext Version 00 . . . . . . . . . . . . . . . . . . . . 13
A.5. Version 03 . . . . . . . . . . . . . . . . . . . . . . . 13
A.6. Version 02 . . . . . . . . . . . . . . . . . . . . . . . 13
A.7. Version 01 . . . . . . . . . . . . . . . . . . . . . . . 13
A.8. Version 00 . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
After a domain has been registered, one of three parties will
maintain the DNS zone loaded on the "primary" DNS servers: the
Registrant, the Registrar, or a third party DNS operator. DNS
registration systems were originally designed around making
registrations easy and fast, however after registration the
complexity of making changes to the delegation differs for each of
these parties. The Registrar can make changes directly in the
Registry systems through some API (typically EPP [RFC5730]). The
Registrant is typically limited to using a web interface supplied by
the Registrar. A third party DNS Operator must to go through the
Registrant to update any delegation information.
In this last case, the operator must contact and engage the
Registrant in updating NS and DS records for the delegation. New
information must be communicated to the Registrant, who must submit
that information to the Registrar. Typically this involves cutting
and pasting between email and a web interface, which is error prone.
Furthermore, involving Registrants in this way does not scale for
even moderately sized DNS operators. Tracking thousands (or
millions) of changes sent to customers, and following up if those
changes are not submitted to the Registrar, or are submitted with
errors, is itself expensive and error prone.
The current system does not work well, as there are many types of
failures that have been reported at all levels in the registration
model. The failures result in either the inability to use DNSSEC or
in validation failures that cause the domain to become unavailable to
users behind validating resolvers.
The goal of this document is to create a protocol for establishing a
secure chain of trust that involves parties not in the traditional
Registrant/Registrar/Registry (RRR) model, and to reduce the friction
in maintaining DNSSEC secured delegations in these cases. It
describes a REST-based [RFC6690] protocol which can be used to
establish DNSSEC initial trust (to enable or bootstrap DNSSEC), and
to trigger maintenance of DS records.
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2. Notional Conventions
2.1. Definitions
For the purposes of this draft, a third-party DNS Operator is any DNS
Operator responsible for a zone, where the operator is neither the
Registrant nor the Registrar of record for the delegation.
Uses of "child" and "parent" refer to the relationship between DNS
zone operators. In this document, unless otherwise noted, the child
is the third-party DNS operator and the parent is the Registry.
Uses of the words "Registrar" or "Registration Entity" in this
document may also be applied to Resellers or to Registries that
engage in registration activities directly with Registrants. Unless
otherwise noted, they are used to refer to the entity which has a
direct business relationship with the Registrant.
2.2. RFC2119 Keywords
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 [RFC2119].
3. Process Overview
3.1. Identifying the Registrar
As of publication of this document, there has never been a
standardized or widely deployed method for easily and scalably
identifying the Registar for a particular registration.
At this time, WHOIS [RFC3912] is the only widely deployed protocol to
carry such information, but WHOIS responses are unstructured text,
and each implementor can lay out its text responses differently. In
addition, Registries may include referrals in this unstructured text
to the WHOIS interfaces of their Registrars, and those Registrar
WHOIS interface in turn have their own layouts. This presents a text
parsing problem which is infeasible to solve.
RDAP, the successor to WHOIS, described in [RFC7480], solves the
problems of unstructured responses, and a consistently implemented
referral system, however at this time RDAP has yet to be deployed at
most Registries.
With no current mechanism in place to scalably discover the Registar
for a particular registration, the problem of automatic discovery of
the base URL of the API is considered out of scope of this document.
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The authors recommend standardization of an RDAP extension to obtain
this information from the Registry.
3.2. Establishing a Chain of Trust
After signing the zone, the child operator needs to upload the DS
record(s) to the parent. The child can signal its desire to have
DNSSEC validation enabled by publishing one of the special DNS
records CDS and/or CDNSKEY as defined in [RFC7344] and [RFC8078].
[RFC Editor: The above I-D reference should be replaced with the
correct RFC number upon publication.]
In the case of an insecure delegation, the Registrar will normally
not be scanning the child zone for CDS/CDNSKEY records. The child
operator can use this protocol to notify the Registrar to begin such
a scan.
Once the Registrar sees these records it SHOULD start acceptance
processing.
3.3. Maintaining the Chain of Trust
One the secure chain of trust is established, the Registrar SHOULD
regularly check the child zone for CDS/CDNSKEY record changes. The
Registrar SHOULD also accept signals via this protocol to immediately
check the child zone for CDS/CDNSKEY records.
Server implementations of this protocol MAY include rate limiting to
protect their systems and the systems of child operators from abuse.
Each parent operator and Registrar is responsible for developing,
implementing, and communicating their DNSSEC maintenance policies.
3.4. Other Delegation Maintenance
[ Not yet defined ]
3.5. Acceptance Processing
The Registrar, upon receiving a signal or detecting through polling
that the child desires to have its delegation updated, SHOULD run a
series of tests to ensure that updating the parent zone will not
create or exacerbate any problems with the child zone. The basic
tests SHOULD include:
o checking that the child zone is is properly signed as per the
Registrar and parent DNSSEC policy
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o if updating the DS record, checking that the child CDS RRset
references a KSK which is present in the child DNSKEY RRset and
signs the CDS RRset
o ensuring all name servers in the apex NS RRset of the child zone
agree on the apex NS RRset and CDS RRset contents
The Registrar SHOULD NOT make any changes to the DS RRset if the
child name servers do not agree on the CDS/CDNSKEY content.
[NOTE: Do we need a new section in the DPS for the CDS management
policy [RFC6841]?]
Registrars MAY require compliance with additional tests, particularly
in the case of establishing a new chain of trust, such as:
o checking that all child name servers to respond with a consistent
CDS/CDNSKEY RRset for a number of queries over an extended period
of time to minimise the possibility of an attacker spoofing
responses
o requiring the child name servers to respond with identical CDS/
CDNSKEY RRsets over TCP
o ensuring zone delegation best practices (for examples, see
[I-D.wallstrom-dnsop-dns-delegation-requirements]
o requiring the child operator to prove they can add data to the
zone (for example, by publishing a particular token)
4. API Definition
This protocol is partially synchronous, meaning the server can elect
to hold connections open until operations have completed, or it can
return a status code indicating that it has received a request, and
close the connection. It is up to the child to monitor the parent
for completion of the operation, and issue possible follow-up calls
to the Registrar.
Clients may be denied access to change the DS records for domains
that are Registry Locked (HTTP Status code 401). Registry Lock is a
mechanism provided by certain Registries or Registrars that prevents
domain hijacking by ensuring no attributes of the domain are
changeable, and no transfer or deletion transactions can be processed
against the domain name without manual intervention.
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4.1. Authentication
The API does not impose any unique server authentication
requirements. The server authentication provided by TLS fully
addresses the needs of this protocol. The API MUST be provided over
TLS-protected transport (e.g., HTTPS) or VPN.
Client authentication is considered out of scope of this document.
The publication of CDS/CDNSKEY records in the child zone is an
indication that the child operator intends to perform DS-record-
updating activities (add/delete) in the parent zone. Since this
protocol is simply a signal to the Registrar that they should examine
the child zone for such intentions, additional authentication of the
client making the request is considered unnecessary.
Registrars MAY implement their own policy to protect access to the
API, such as with IP whitelisting, client TLS certificates, etc..
Registrars SHOULD take steps to ensure that a lack of additional
authentication does not open up a denial of service mechanism against
the systems of the Registrar, the Registry, or the child operator.
4.2. RESTful Resources
In the following text, "{domain}" is the child zone to be operated
on.
4.2.1. CDS resource
Path: /domains/{domain}/cds
4.2.1.1. Establishing Initial Trust (Enabling DNSSEC)
4.2.1.1.1. Request
Syntax: POST /domains/{domain}/cds
Request that an initial set of DS records based on the CDS record in
the child zone be inserted into the Registry and the parent zone upon
the successful completion of the request. If there are multiple CDS
records in the CDS RRset, multiple DS records will be added.
The body of the POST SHOULD be empty, however server implementations
SHOULD NOT reject nonempty requests.
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4.2.1.1.2. Response
o HTTP Status code 201 indicates a success.
o HTTP Status code 400 indicates a failure due to validation.
o HTTP Status code 401 indicates an unauthorized resource access.
o HTTP Status code 403 indicates a failure due to an invalid
challenge token.
o HTTP Status code 404 indicates the domain does not exist.
o HTTP Status code 409 indicates the delegation already has a DS
RRset.
o HTTP Status code 429 indicates the client has been rate-limited.
o HTTP Status code 500 indicates a failure due to unforeseeable
reasons.
This request is for setting up initial trust in the delegation. The
Registrar SHOULD return a status code 409 if it already has a DS
RRset for the child zone.
Upon receipt of a 403 response the child operator SHOULD issue a POST
for the "token" resource to fetch a challenge token to insert into
the zone.
4.2.1.2. Removing DS Records
4.2.1.2.1. Request
Syntax: DELETE /domains/{domain}/cds
Request that the Registrar check for a null CDS or CDNSKEY record in
the child zone, indicating a request that the entire DS RRset be
removed. This will make the delegation insecure.
4.2.1.2.2. Response
o HTTP Status code 200 indicates a success.
o HTTP Status code 400 indicates a failure due to validation.
o HTTP Status code 401 indicates an unauthorized resource access.
o HTTP Status code 404 indicates the domain does not exist.
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o HTTP Status code 412 indicates the parent does not have a DS RRset
o HTTP Status code 429 indicates the client has been rate-limited.
o HTTP Status code 500 indicates a failure due to unforeseeable
reasons.
4.2.1.3. Modifying DS Records
4.2.1.3.1. Request
Syntax: PUT /domains/{domain}/cds
Request that the Registrar modify the DS RRset based on the CDS/
CDNSKEY available in the child zone. As a result of this request the
Registrar SHOULD add or delete DS records as indicated by the CDS/
CDNSKEY RRset, but MUST NOT delete the entire DS RRset.
4.2.1.3.2. Response
o HTTP Status code 200 indicates a success.
o HTTP Status code 400 indicates a failure due to validation.
o HTTP Status code 401 indicates an unauthorized resource access.
o HTTP Status code 404 indicates the domain does not exist.
o HTTP Status code 412 indicates the parent does not have a DS RRset
o HTTP Status code 429 indicates the client has been rate-limited.
o HTTP Status code 500 indicates a failure due to unforeseeable
reasons.
4.2.2. Token resource
Path: /domains/{domain}/token
4.2.2.1. Establish Initial Trust with Challenge
4.2.2.1.1. Request
Syntax: GET /domains/{domain}/token
The DNSSEC policy of the Registrar may require proof that the DNS
Operator is in control of the domain. The token API call returns a
random token to be included as a TXT record for the _delegate.@
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domain name (where @ is the apex of the child zone) prior
establishing the DNSSEC initial trust. This is an additional trust
control mechanism to establish the initial chain of trust.
Once the child operator has received a token, it SHOULD be inserted
in the zone and the operator SHOULD proceed with a POST of the cds
resource.
The Registrar MAY expire the token after a reasonable period. The
Registrar SHOULD document an explanation of whether and when tokens
are expired in their DNSSEC policy.
Note that the _delegate TXT record is publicly available and not a
secret token.
4.2.2.1.2. Response
o HTTP Status code 200 indicates a success. A token is included in
the body of the response, as a valid TXT record
o HTTP Status code 404 indicates the domain does not exist.
o HTTP Status code 500 indicates a failure due to unforeseeable
reasons.
4.3. Customized Error Messages
Registrars MAY provide a customized error message in the response
body in addition to the HTTP status code defined in the previous
section. This response MAY include an identifying number/string that
can be used to track the request.
5. Security considerations
When zones are properly provisioned, and delegations follow standards
and best practices (e.g.
[I-D.wallstrom-dnsop-dns-delegation-requirements]), the Registrar or
Registry can trust the DNS information it receives from multiple
child name servers, over time, and/or over TCP to establish the
initial chain of trust.
In addition, the Registrar or Registry can require the DNS Operator
to prove they control the zone by requiring the child operator to
navigate additional hurdles, such as adding a challenge token to the
zone.
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This protocol should increase the adoption of DNSSEC, enabling more
zones to become validated thus overall the security gain outweighs
the possible drawbacks.
Registrants and DNS Operators always have the option to establish the
chain of trust in band via the standard Registrant/Registrar/Registry
model.
6. IANA Actions
This document has no actions for IANA
7. Internationalization Considerations
This protocol is designed for machine to machine communications.
Clients and servers should use punycode [RFC3492] when operating on
internationalized domain names.
8. References
8.1. Normative References
[RFC3492] Costello, A., "Punycode: A Bootstring encoding of Unicode
for Internationalized Domain Names in Applications
(IDNA)", RFC 3492, DOI 10.17487/RFC3492, March 2003,
<http://www.rfc-editor.org/info/rfc3492>.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
<http://www.rfc-editor.org/info/rfc6690>.
[RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating
DNSSEC Delegation Trust Maintenance", RFC 7344, DOI
10.17487/RFC7344, September 2014,
<http://www.rfc-editor.org/info/rfc7344>.
[RFC8078] Gudmundsson, O. and P. Wouters, "Managing DS Records from
the Parent via CDS/CDNSKEY", RFC 8078, DOI 10.17487/
RFC8078, March 2017,
<http://www.rfc-editor.org/info/rfc8078>.
8.2. Informative References
[I-D.wallstrom-dnsop-dns-delegation-requirements]
Wallstrom, P. and J. Schlyter, "DNS Delegation
Requirements", draft-wallstrom-dnsop-dns-delegation-
requirements-03 (work in progress), October 2016.
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[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>.
[RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912, DOI
10.17487/RFC3912, September 2004,
<http://www.rfc-editor.org/info/rfc3912>.
[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
<http://www.rfc-editor.org/info/rfc5730>.
[RFC6841] Ljunggren, F., Eklund Lowinder, AM., and T. Okubo, "A
Framework for DNSSEC Policies and DNSSEC Practice
Statements", RFC 6841, DOI 10.17487/RFC6841, January 2013,
<http://www.rfc-editor.org/info/rfc6841>.
[RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
Registration Data Access Protocol (RDAP)", RFC 7480, DOI
10.17487/RFC7480, March 2015,
<http://www.rfc-editor.org/info/rfc7480>.
Appendix A. Document History
A.1. regext Version 03
o simplify abstract
o move all justification text to Intro
o added HTTP response codes for rate limiting (429), missing DS
RRsets (412)
o expanded on Internationalization Considerations
o corrected informative/normative document references
o clarify parent/Registrar references in the draft
o general spelling/grammar/style cleanup
o removed references to NS and glue maintenance
o clarify content of POST body for 'cds' resource
o change verb for obtaining a 'token' to GET
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o Updated refernce to RFC8078
A.2. regext Version 02
o Clarified based on comments and questions from early implementors
(JL)
o Text edits and clarifications.
A.3. regext Version 01
o Rewrote Abstract and Into (MP)
o Introduced code 401 when changes are not allowed
o Text edits and clarifications.
A.4. regext Version 00
o Working group document same as 03, just track changed to standard
A.5. Version 03
o Clarified based on comments and questions from early implementors
A.6. Version 02
o Reflected comments on mailing lists
A.7. Version 01
o This version adds a full REST definition this is based on
suggestions from Jakob Schlyter.
A.8. Version 00
o First rough version
Authors' Addresses
Jacques Latour
CIRA
Ottawa, ON
Email: jacques.latour@cira.ca
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Olafur Gudmundsson
Cloudflare, Inc.
San Francisco, CA
Email: olafur+ietf@cloudflare.com
Paul Wouters
Red Hat
Toronto, ON
Email: paul@nohats.ca
Matthew Pounsett
Rightside Group, Ltd.
Toronto, ON
Email: matt@conundrum.com
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