A Publication Protocol for the Resource Public Key Infrastructure (RPKI)
draft-ietf-sidr-publication-01

Network Working Group                                          S. Weiler
Internet-Draft                                               A. Sonalker
Intended status: Standards Track                            SPARTA, Inc.
Expires: January 12, 2012                                     R. Austein
                                                                     ISC
                                                           July 11, 2011

A Publication Protocol for the Resource Public Key Infrastructure (RPKI)
                     draft-ietf-sidr-publication-01

Abstract

   This document defines a protocol for publishing Resource Public Key
   Infrastructure (RPKI) objects.  Even though the RPKI will have many
   participants issuing certificates and creating other objects, it is
   operationally useful to consolidate the publication of those objects.
   This document provides the protocol for doing so.

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 January 12, 2012.

Copyright Notice

   Copyright (c) 2011 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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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Context  . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Protocol Specification . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Common Details . . . . . . . . . . . . . . . . . . . . . .  4
       3.1.1.  Common XML Message Format  . . . . . . . . . . . . . .  4
     3.2.  Control Sub-Protocol . . . . . . . . . . . . . . . . . . .  5
       3.2.1.  Config Object  . . . . . . . . . . . . . . . . . . . .  5
       3.2.2.  Client Object  . . . . . . . . . . . . . . . . . . . .  5
     3.3.  Publication Sub-Protocol . . . . . . . . . . . . . . . . .  6
     3.4.  Error handling . . . . . . . . . . . . . . . . . . . . . .  7
     3.5.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Operational Considerations . . . . . . . . . . . . . . . . . .  9
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11

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1.  Introduction

   This document assumes a working knowledge of the Resource Public Key
   Infrastructure (RPKI), which is intended to support improved routing
   security on the Internet.  [I-D.ietf-sidr-arch]

   In order to make participation in the RPKI easier, it is helpful to
   have a few consolidated repositories for RPKI objects, thus saving
   every participant from the cost of maintaining a new service.
   Similarly, relying parties using the RPKI objects will find it faster
   and more reliable to retrieve the necessary set from a smaller number
   of repositories.

   These consolidated RPKI object repositories will in many cases be
   outside the administrative scope of the organization issuing a given
   RPKI object.  Hence the need for a protocol to publish RPKI objects.

   This document defines the RPKI publication protocol, including a sub-
   protocol for configuring the publication engine.

1.1.  Terminology

   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].

   "Publication engine" and "publication server" are used
   interchangeably to refer to the server providing the service
   described in this document.

   "Business Public Key Infrastructure" ("Business PKI" or "BPKI")
   refers to a PKI, separate from the RPKI, used to authenticate clients
   to the publication engine.

2.  Context

   This protocol was designed specifically for the case where an
   internet registry, already issuing RPKI certificates to its children,
   also wishes to run a publication service for its children.

   We use the term "Business PKI" here because an internet registry
   might already have a PKI, separate from the RPKI, for authenticating
   its clients and might wish to reuse that PKI for this protocol.  Such
   reuse is not a requirement.

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3.  Protocol Specification

   In summary, the publication protocol uses XML messages wrapped in
   CMS, carried over HTTP transport.

   The publication procotol consists of two separate subprotocols.  The
   first is a control protocol used to configure a publication engine.
   The second subprotocol, which we refer to by the overloaded term
   "publication protocol", is used to request publication of specific
   objects.  The publication engine operates a single HTTP server on a
   single port.  It distinguishes between the two protocols by using
   different URLs for them.

3.1.  Common Details

   This section discusses details that the two subprotocols have in
   common, including the transport and CMS wrappers.

   Both protocols use a simple request/response interaction.  The client
   passes a request to the server, and the server generates a
   corresponding response.

   A message exchange commences with the client initiating an HTTP POST
   with content type of "application/rpki-publication", with the message
   object as the body.  The server's response will similarly be the body
   of the response with a content type of "application/
   rpki-publication".

   The content of the POST and the server's response will be a well-
   formed Cryptographic Message Syntax (CMS) [RFC5652] object with OID =
   1.2.840.113549.1.7.2 as described in Section 3.1 of
   [I-D.ietf-sidr-rescerts-provisioning].

3.1.1.  Common XML Message Format

   The XML schema for this protocol (including both subprotocols) is
   below in Section 3.5.  Both subprotocols use the same basic XML
   message format, which looks like:

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       <?xml version='1.0' encoding='us-ascii'?>
       <msg xmlns="http://www.hactrn.net/uris/rpki/publication-spec/"
          version="2"
          type="message type">
          [one or more PDUs]
       </msg>

       version:
          The value of this attribute is the version of this protocol.
          This document describes version 2.

       type:
          The possible values of this attribute are "reply" and "query".

   A query PDU may be one of four types: config_query, client_query,
   publish_query, or withdraw_query.  The first two are used by the
   control sub-protocol, the latter two by the publication sub-protocol.

   A reply PDU may be one of five types: config_reply, client_reply,
   publish_reply, withdraw_reply, or report_error_reply.

   Each of these PDUs may include an optional tag to facilitate bulk
   operation.  If a tag is set in a query PDU, the corresponding
   reply(s) MUST have the tag attribute set to the same value.

3.2.  Control Sub-Protocol

   The control sub-protocol is used to configure a publication server.
   It can set global variables (at the moment, limited to a BPKI CRL)
   and manage clients who are allowed to publish data on the server.

3.2.1.  Config Object

   The <config/> object allows configuration of data that apply to the
   entire publication server rather than a particular client.  There is
   exactly one <config/> object in the publication server, and it only
   supports the "set" and "get" actions -- it cannot be created or
   destroyed.  Its use is typically restricted to the repository
   operator.

   The <config/> object only has one data element that can be set: the
   bpki_crl.  This is used by the publication server when authenticating
   clients.

3.2.2.  Client Object

   Unlike the <config/> object, the <client/> object represents one
   client authorized to use the publication server.  There may well be

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   more than one <client/> object on each publication server.  Again,
   its use is typically restricted to the respository operator.

   The <client/> object supports five actions: "create", "set", "get",
   "list", and "destroy".  Each client has a "client_handle" attribute,
   which is used in responses and must be specified in "create", "set",
   "get", or "destroy" actions.

   Payload data which can be configured in a <client/> object include:

   o  base_uri (attribute): This attribute represents the base URI below
      which the client will be allowed to publish data.  Additional
      constraints may be imposed by the publication server in certain
      cases, for e.g., a child publishing directly under its parent.

   o  bpki_cert (element): This represents the X.509 BPKI CA certificate
      for this client.  This should be used as part of the certificate
      chain when validating incoming CMS messages.  Two valid approaches
      exist.  If the optional bpki_glue certificate is being used, then
      the bpki_cert certificate should be issued by the bpki_glue
      certificate; otherwise, the bpki_cert certificate should be issued
      by the publication engine's bpki_ta certificate.

   o  bpki_glue (element): This is an additional (optional) type of
      X.509 certificate for this client.  It may be used in certain
      pathological cross-certification cases which require a two-
      certificate chain due to issuer name conflicts.  When being used,
      issuing order is that the bpki_glue certificate should be the
      issuer of the bpki_cert certificate.  Otherwise, it should be
      issued by the publication engine's bpki_ta certificate.  Since
      this is an optional use certificate, it may be left unset if not
      needed.

3.3.  Publication Sub-Protocol

   The sub-publication protocol requests publication or withdrawal from
   publication of RPKI objects.

   The publication protocol uses a common message format to request
   publication of any RPKI object.  This format was chosen specifically
   to allow this protocol to accommodate new types of RPKI objects
   without needing changes to this protocol.

   Both the <publish/> and <withdraw/> objects have a payload of an
   optional tag and a URI.  The <publish/> query also contains the DER
   object to be published, encoded in Base64.

   Note that every publish and withdraw action requires a new manifest,

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   thus every publish or withdraw action will involve at least two
   objects.

3.4.  Error handling

   Errors are handled similarly in both subprotocols, and they're
   handled at two levels.

   Since all messages in this protocol are conveyed over HTTP
   connections, basic errors are indicated via the HTTP response code.
   4xx and 5xx responses indicate that something bad happened.  Errors
   that make it impossible to decode a query or encode a response are
   handled in this way.

   Where possible, errors will result in an XML <report_error/> message
   which takes the place of the expected protocol response message.
   <report_error/> messages are CMS-signed XML messages like the rest of
   this protocol, and thus can be archived to provide an audit trail.

   <report_error/> messages only appear in replies, never in queries.
   The <report_error/> message can appear in both the control and
   publication subprotocols.

   Like all other messages in this protocol, the <report_error/> message
   includes a "tag" attribute to assist in matching the error with a
   particular query when using batching.  It is optional to set the tag
   on queries but, if set on the query, it MUST be set on the reply or
   error.

   The error itself is conveyed in the error_code (attribute).  The
   value of this attribute is a token indicating the specific error that
   occurred.

   The body of the <report_error/> element itself is an optional text
   string; if present, this is debugging information.

3.5.  XML Schema

   The following is a RelaxNG compact form schema describing the
   Publication Protocol.

    default namespace = "http://www.hactrn.net/uris/rpki/publication-spec/"

    # Top level PDU
    start = element msg {
       attribute version { "2" } ,
       ( ( attribute type { "query" }, query_elt*) |

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       (attribute type { "reply" }, reply_elt*))
    }

    # PDUs allowed in a query
    query_elt = ( config_query | client_query | publish_query |
       withdraw_query )

    # PDUs allowed in a reply
    reply_elt = ( config_reply | client_reply | publish_reply |
       withdraw_reply | report_error_reply )

    # Tag attributes for bulk operations
    tag = attribute tag { xsd:token {maxLength="1024" } }

    # Base64 encoded DER stuff
    base64 = xsd:base64Binary

    # Publication URLs
    uri_t = xsd:anyURI { maxLength="4096" }
    uri = attribute uri { uri_t }

    # Handles on remote objects (replaces passing raw SQL IDs).  NB:
    # Unlike the up-down protocol, handles in this protocol allow
    # "/" as a hierarchy delimiter.
    object_handle = xsd:string {
       maxLength="255" pattern="[\-_A-Za-z0-9/]*" }

    # <config/> element (use restricted to repository operator)
    # config_handle attribute: create, list, and destroy commands
    # omitted deliberately.
    config_payload = (element bpki_crl { base64 }?)
    config_query |= element config { attribute action { "set" }, tag?,
       config_payload }
    config_reply |= element config { attribute action { "set" }, tag? }
    config_query |= element config { attribute action { "get" }, tag? }
    config_reply |= element config { attribute action { "get" }, tag?,
       config_payload }

    # <client/> element (use restricted to repository operator)
    client_handle = attribute client_handle { object_handle }
    client_payload = (attribute base_uri { uri_t }?, element bpki_cert {
       base64 }?, element bpki_glue { base64 }?)
    client_query |= element client { attribute action { "create" },
       tag?, client_handle, client_payload }
    client_reply |= element client { attribute action { "create" },
       tag?, client_handle }
    client_query |= element client { attribute action { "set" }, tag?,
       client_handle, client_payload }

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    client_reply |= element client { attribute action { "set" }, tag?,
       client_handle }
    client_query |= element client { attribute action { "get" }, tag?,
       client_handle }
    client_reply |= element client { attribute action { "get" }, tag?,
       client_handle, client_payload }
    client_query |= element client { attribute action { "list" }, tag? }
    client_reply |= element client { attribute action { "list" }, tag?,
       client_handle, client_payload }
    client_query |= element client { attribute action { "destroy" },
       tag?, client_handle }
    client_reply |= element client { attribute action { "destroy" },
       tag?, client_handle }

    # <publish/> element
    publish_query |= element publish { tag?, uri, base64 }
    publish_reply |= element publish { tag?, uri }

    # <withdraw/> element
    withdraw_query |= element withdraw { tag?, uri }
    withdraw_reply |= element withdraw { tag?, uri }

    # <report_error/> element
    error = xsd:token { maxLength="1024" }
    report_error_reply = element report_error {
       tag?,
       attribute error_code { error },
       xsd:string { maxLength="512000" }?
       }

4.  Operational Considerations

   Placeholder section to talk about nesting children under parents in
   the same repository, to allow for a single rsync to fetch both
   (observing that the rsync setup times tends to dominate over the sync
   time).  And, more distressingly, talk about the access control
   impacts of that nesting.

5.  IANA Considerations

   IANA is asked to register the application/rpki-publication MIME media
   type as follows:

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      MIME media type name:  application
      MIME subtype name:  rpki-publication
      Required parameters:  None
      Optional parameters:  None
      Encoding considerations:  binary
      Security considerations:  Carries an RPKI Publication Protocol
         Message, as defined in this document.
      Interoperability considerations:  None
      Published specification:  This document
      Applications which use this media type: HTTP
      Additional information:
         Magic number(s):  None
         File extension(s):
         Macintosh File Type Code(s):
      Person & email address to contact for further information:
         Rob Austein <sra@isc.org>
      Intended usage:  COMMON
      Author/Change controller: Rob Austein <sra@isc.org>

6.  Security Considerations

7.  References

7.1.  Normative References

   [I-D.ietf-sidr-rescerts-provisioning]
              Huston, G., Loomans, R., Ellacott, B., and R. Austein, "A
              Protocol for Provisioning Resource Certificates",
              draft-ietf-sidr-rescerts-provisioning-10 (work in
              progress), June 2011.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, September 2009.

7.2.  Informative References

   [I-D.ietf-sidr-arch]
              Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", draft-ietf-sidr-arch-13 (work in
              progress), May 2011.

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Authors' Addresses

   Samuel Weiler
   SPARTA, Inc.
   7110 Samuel Morse Drive
   Columbia, Maryland  21046
   US

   Email: weiler@tislabs.com

   Anuja Sonalker
   SPARTA, Inc.
   7110 Samuel Morse Drive
   Columbia, Maryland  21046
   US

   Email: Anuja.Sonalker@sparta.com

   Rob Austein
   ISC
   950 Charter Street
   Redwood City, CA  94063
   USA

   Email: sra@isc.org

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