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Versions: 00 01

Network Working Group                                     T. Bruijnzeels
Internet-Draft                                                NLnet Labs
Updates: 6841, 8182 (if approved)                                R. Bush
Intended status: Standards TrackInternet Initiative Japan & Arrcus, Inc.
Expires: October 27, 2020                                  G. Michaelson
                                                                   APNIC
                                                          April 25, 2020


   Resource Public Key Infrastructure (RPKI) Repository Requirements
              draft-sidrops-bruijnzeels-deprecate-rsync-01

Abstract

   This document formulates a plan of a phased transition to a state
   where RPKI repositories and Relying Party software performing RPKI
   Validation will use the RPKI Repository Delta Protocol (RRDP)
   [RFC8182] as the only mandatory to implement access protocol.

   In short this plan consists of the following phases.

   In phase 0, today's deployment, RRDP is supported by most, but not
   all Repositories, and most but not all RP software.

   In the proposed phase 1 RRDP will become mandatory to implement for
   Repositories, in addition to rsync.  This phase can start as soon as
   this document is published.

   Once the proposed updates are implemented by all Repositories phase 2
   will start.  In this phase RRDP will become mandatory to implement
   for all RP software, and rsync must no longer be used.

   Measurements will need to be done to help determine when it will be
   safe to transition to the final phase of this plan.  During this
   phase Repositories will no longer be required to provide rsync access
   for RPKI validation purposes.  However, they may still provide rsync
   access for direct access to files for other purposes, if desired, at
   a best effort basis.

   Although this document currently includes descriptions and updates to
   RFCs for each of these phases, we may find that it will be beneficial
   to have separate documents for the plan, and each phase, so that it
   might be more clear to all when the updates to RFCs take effect.








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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
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   This Internet-Draft will expire on October 27, 2020.

Copyright Notice

   Copyright (c) 2020 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Requirements notation . . . . . . . . . . . . . . . . . . . .   3
   2.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Plan  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Phase 0 - RPKI repositories support rsync, and optionally
           RRDP  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Phase 1 - RPKI repositories support both rsync and RRDP .   4
       3.2.1.  Current Support for RRDP in Repository Software . . .   4
       3.2.2.  Updates to RFC 6481 . . . . . . . . . . . . . . . . .   5
       3.2.3.  Measurements  . . . . . . . . . . . . . . . . . . . .   6
     3.3.  Phase 2 - All RP software prefers RRDP  . . . . . . . . .   6
       3.3.1.  RRDP support in Relying Party software  . . . . . . .   6
       3.3.2.  Updates to RFC 8182 . . . . . . . . . . . . . . . . .   6
       3.3.3.  Measurements  . . . . . . . . . . . . . . . . . . . .   7
     3.4.  Phase 3 - RPKI repositories support RRDP, and optionally



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           rsync . . . . . . . . . . . . . . . . . . . . . . . . . .   7
       3.4.1.  Updates to RFC 6481 . . . . . . . . . . . . . . . . .   7
   4.  Rsync URIs as object identifiers  . . . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Requirements notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Motivation

   The Resource Public Key Infrastructure (RPKI) [RFC6480] as originally
   defined uses rsync as its distribution protocol, as outlined in
   [RFC6481].  Later, the RPKI Repository Delta Protocol (RRDP)
   [RFC8182] was designed to provide an alternative.  In order to
   facilitate incremental deployment RRDP has been deployed as an
   additional optional protocol, while rsync was still mandatory to
   implement.

   A number of issues observed with rsync motivated the design of RRDP,
   e.g.:

   o  rsync is CPU and memory heavy, and easy to DoS

   o  rsync library support is lacking

   o  rsync makes it somewhat difficult to publish sets of object
      atomically

   RRDP was designed to leverage HTTPS CDN infrastructure to provide
   RPKI Repository content in a resilient way, while reducing the load
   on the Repository server.  It supports that updates are published as
   atomic deltas, which can help prevent most of the issues described in
   section 6 of [RFC6486].

   For a longer discussion please see section 1 of [RFC8182].

   In conclusion: we believe that RRDP is the better solution.
   Therefore, this document outlines a transition plan where RRDP




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   becomes mandatory to implement, and rsync becomes optional and
   eventually deprecated.

3.  Plan

   Changing the RPKI infrastructure to rely on RRDP instead of rsync is
   a delicate operation.  There is current deployment of Certification
   Authorities, Repository Servers and Relying Party software which
   relies on rsync, and which may not yet support RRDP.

   Therefore we need to have a plan that ultimately updates the relevant
   RFCs, but which uses a phased approach combined with measurements to
   limit the operational impact of doing this to (almost) zero.

   The general outline of the plan is as follows.  We will describe each
   step in more detail below.

     +-------+------------------------------------------------------+
     | Phase |                     Description                      |
     +-------+------------------------------------------------------+
     |   0   | RPKI repositories support rsync, and optionally RRDP |
     |   1   |    RPKI repositories support both rsync and RRDP     |
     |   2   |             All RP software prefers RRDP             |
     |   3   | RPKI repositories support RRDP, and optionally rsync |
     +-------+------------------------------------------------------+

3.1.  Phase 0 - RPKI repositories support rsync, and optionally RRDP

   This is the situation at the time of writing this document.  Relying
   Parties can prefer RRDP over rsync today, but they need to support
   rsync until all RPKI repositories support RRDP.  Therefore all
   repositories should support RRDP at their earliest convenience.

3.2.  Phase 1 - RPKI repositories support both rsync and RRDP

   During this phase we will make RRDP mandatory to support for
   Repository Servers, and measure whether the deployed Repository
   Servers have been upgraded to do so, in as far as they don't support
   RRDP already.

3.2.1.  Current Support for RRDP in Repository Software

   The currently known support for RRDP for repositories is as follows:








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             +---------------------------+------------------+
             | Repository Implementation | Support for RRDP |
             +---------------------------+------------------+
             |          afrinic          |       yes        |
             |           apnic           |       yes        |
             |            arin           |       yes        |
             |           lacnic          |     planned      |
             |          ripe ncc         |       yes        |
             |    Dragon Research Labs   |     yes(1,2)     |
             |           krill           |      yes(1)      |
             +---------------------------+------------------+

   (1) in use at various National Internet Registries, as well as other
   resource holders under RIRs. (2) not all organizations using this
   software have upgraded to using RRDP.

3.2.2.  Updates to RFC 6481

   During this phase the updates are applied to section 3 of [RFC6481].

   OLD:

   o  The publication repository SHOULD be hosted on a highly available
      service and high-capacity publication platform.

   o  The publication repository MUST be available using rsync [RFC5781]
      [RSYNC].  Support of additional retrieval mechanisms is the choice
      of the repository operator.  The supported retrieval mechanisms
      MUST be consistent with the accessMethod element value(s)
      specified in the SIA of the associated CA or EE certificate.

   NEW:

   o  The publication repository MUST be available using the RPKI
      Repository Delta Protocol [RFC8182].  The RRDP server SHOULD be
      hosted on a highly available platform.

   o  The publication repository MUST be available using rsync [RFC5781]
      [RSYNC].  The rsync server SHOULD be hosted on a highly available
      platform.

   o  Support of additional retrieval mechanisms is the choice of the
      repository operator.  The supported retrieval mechanisms MUST be
      consistent with the accessMethod element value(s) specified in the
      SIA of the associated CA or EE certificate.






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3.2.3.  Measurements

   We can find out whether all RPKI repositories support RRDP by running
   (possibly) modified Relying Party software that keeps track of this.

   When it is found that Repositories do not yet support RRDP, outreach
   should be done to them individually.  Since the number of
   Repositories is fairly low, and it is in their interest to run RRDP
   because it addresses availability concerns, we have confidence that
   we will find these Repositories willing to make changes.

3.3.  Phase 2 - All RP software prefers RRDP

   Once all Repositories support RRDP we can proceed to make RRDP
   mandatory to implement for Relying Party software.

3.3.1.  RRDP support in Relying Party software

   The currently known support for RRDP in Relying Party software is as
   follows:

       +------------------------------+------+---------+----------+
       | Relying Party Implementation | RRDP | version |  since   |
       +------------------------------+------+---------+----------+
       |             FORT             | yes  |    ?    |    ?     |
       |           OctoRPKI           | yes  |    ?    |    ?     |
       |            rcynic            | yes  |    ?    |    ?     |
       | RIPE NCC RPKI Validator 2.x  | yes  |    ?    |    ?     |
       | RIPE NCC RPKI Validator 3.x  | yes  |    ?    |    ?     |
       |          Routinator          | yes  |  0.6.0  | Sep 2019 |
       |         rpki-client          |  no  |    ?    |    ?     |
       |            RPSTIR            | yes  |    ?    |    ?     |
       +------------------------------+------+---------+----------+

   The authors kindly request Relying Party software implementers to let
   us know in which version of their tool support for RRDP was
   introduced, and when that version was released.

3.3.2.  Updates to RFC 8182

   From this phase onwards the updates are applied to section 3.4.1 of
   [RFC8182].

   OLD: When a Relying Party performs RPKI validation and learns about a
   valid certificate with an SIA entry for the RRDP protocol, it SHOULD
   use this protocol as follows.





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   NEW: When a Relying Party performs RPKI validation and learns about a
   valid certificate with an SIA entry for the RRDP protocol, it MUST
   use this protocol.  It MUST NOT depend on object retrieval for this
   certificate over rsync for validation, although it MAY still use
   rsync access for other purposes under the understanding that
   availability is not guaranteed.

3.3.3.  Measurements

   Although the tools may support RRDP, users will still need to install
   updated versions of these tools in their infrastructure.  Any
   Repository operator can measure this transition by observing access
   to their RRDP and rsync repositories respectively.

   But even after new versions have been available, it is expected that
   there will be long, low volume, tail of users who did not upgrade and
   still depend on rsync.

   It is hard to quantify here now, what would be an acceptable moment
   to conclude that it's safe to move to the next phase and make rsync
   optional.  A parallel to the so-called DNS Flag Day comes to mind.

3.4.  Phase 3 - RPKI repositories support RRDP, and optionally rsync

   The end goal of this phase is that there will be no operational
   dependencies on rsync for Repositories, although they MAY still
   choose to operate rsync at a best effort basis.

3.4.1.  Updates to RFC 6481

   From this phase onwards these updates are applied to section 3 of
   [RFC6481] as it was updated during Phase 2 described above:

   OLD:

   o  The publication repository MUST be available using the RPKI
      Repository Delta Protocol [RFC8182].  The RRDP server SHOULD be
      hosted on a highly available platform.

   o  The publication repository MUST be available using rsync [RFC5781]
      [RSYNC].  The rsync server SHOULD be hosted on a highly available
      platform.

   o  Support of additional retrieval mechanisms is the choice of the
      repository operator.  The supported retrieval mechanisms MUST be
      consistent with the accessMethod element value(s) specified in the
      SIA of the associated CA or EE certificate.




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   NEW:

   o  The publication repository MUST be available using the RPKI
      Repository Delta Protocol [RFC8182].  The RRDP server SHOULD be
      hosted on a highly available platform.

   o  The publication repository MAY be available using rsync [RFC5781]
      [RSYNC].

   o  Support of additional retrieval mechanisms is the choice of the
      repository operator.  The supported retrieval mechanisms MUST be
      consistent with the accessMethod element value(s) specified in the
      SIA of the associated CA or EE certificate.

4.  Rsync URIs as object identifiers

   If and when RPKI Repositories no longer need to support rsync, this
   begs the question whether rsync should still be used in URIs used in
   RPKI objects.

   [RFC6481] defines a profile for the Resource Certificate Repository
   Structure.  In this profile objects are identified through rsync
   URIs.  E.g. a CA certificate has an Subject Information Access
   descriptor which uses an rsync URI to identify its manifest
   [RFC6486].  The manifest enumerates the relative names and hashes for
   all objects published under the private key of the CA certificate.
   The full rsync URI identifiers for each object can be resolved
   relative to the manifest URI.

   Though it would be possible in principle to build up an RPKI tree
   hierarchy of objects based on key identifiers and hashes [RFC8488],
   most Relying Party implementations have found it very useful to use
   rsync URIs for this purpose.  Furthermore, these identifiers make it
   much easier to name object in case of validation problems, which help
   operators to address issues.

   For these reasons, RRDP still includes rsync URIs in the definition
   of the publish, update and withdraw elements in the snapshot and
   delta files that it uses.  See section 3.5 of [RFC8182].  Thus,
   objects retrieved through RRDP can be mapped easily to files and
   URIs, similar to as though rsync would have been used to retrieve
   them.

   Even though objects are no longer guaranteed to be available over
   rsync, we still use rsync as the mandatory scheme in the CRL
   Distribution Points, Authority Information Access, and Subject
   Information Access defined in [RFC6487].  Changing this would
   introduce breaking changes which make deployment very hard indeed: we



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   would need to invent an alternative naming scheme, which would need
   to be supported by all Relying Parties, before Certification
   Authorities can issue any certificate or RPKI signed objects using
   these schemes.

   Furthermore, it is very convenient to have direct access to RPKI
   objects using rsync for troubleshooting, debugging and research
   purposes.  Therefore Repository operators MAY still choose to make an
   rsync repository available for these purposes.

5.  IANA Considerations

   This document has no IANA actions.

6.  Security Considerations

   TBD

7.  Acknowledgements

   TBD

8.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5781]  Weiler, S., Ward, D., and R. Housley, "The rsync URI
              Scheme", RFC 5781, DOI 10.17487/RFC5781, February 2010,
              <https://www.rfc-editor.org/info/rfc5781>.

   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
              February 2012, <https://www.rfc-editor.org/info/rfc6480>.

   [RFC6481]  Huston, G., Loomans, R., and G. Michaelson, "A Profile for
              Resource Certificate Repository Structure", RFC 6481,
              DOI 10.17487/RFC6481, February 2012,
              <https://www.rfc-editor.org/info/rfc6481>.

   [RFC6486]  Austein, R., Huston, G., Kent, S., and M. Lepinski,
              "Manifests for the Resource Public Key Infrastructure
              (RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012,
              <https://www.rfc-editor.org/info/rfc6486>.





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   [RFC6487]  Huston, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates", RFC 6487,
              DOI 10.17487/RFC6487, February 2012,
              <https://www.rfc-editor.org/info/rfc6487>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8182]  Bruijnzeels, T., Muravskiy, O., Weber, B., and R. Austein,
              "The RPKI Repository Delta Protocol (RRDP)", RFC 8182,
              DOI 10.17487/RFC8182, July 2017,
              <https://www.rfc-editor.org/info/rfc8182>.

   [RFC8488]  Muravskiy, O. and T. Bruijnzeels, "RIPE NCC's
              Implementation of Resource Public Key Infrastructure
              (RPKI) Certificate Tree Validation", RFC 8488,
              DOI 10.17487/RFC8488, December 2018,
              <https://www.rfc-editor.org/info/rfc8488>.

Authors' Addresses

   Tim Bruijnzeels
   NLnet Labs

   Email: tim@nlnetlabs.nl
   URI:   https://www.nlnetlabs.nl/


   Randy Bush
   Internet Initiative Japan & Arrcus, Inc.

   Email: randy@psg.com


   George Michaelson
   APNIC

   Email: ggm@apnic.net
   URI:   http://www.apnic.net











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