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Versions: (draft-latour-dnsoperator-to-rrr-protocol) 00 01 02 03

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

   Copyright (c) 2017 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.

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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