Network Working Group S. Weiler
Internet-Draft SPARTA, Inc.
Intended status: Standards Track A. Sonalker
Expires: August 16, 2014 Battelle Memorial Institute
R. Austein
Dragon Research Labs
February 12, 2014
A Publication Protocol for the Resource Public Key Infrastructure (RPKI)
draft-ietf-sidr-publication-05
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 August 16, 2014.
Copyright Notice
Copyright (c) 2014 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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Specification . . . . . . . . . . . . . . . . . . . 3
2.1. Common XML Message Format . . . . . . . . . . . . . . . . 4
2.2. Publication and Withdrawal . . . . . . . . . . . . . . . 4
2.3. Error handling . . . . . . . . . . . . . . . . . . . . . 5
2.4. XML Schema . . . . . . . . . . . . . . . . . . . . . . . 5
3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Query . . . . . . . . . . . . . . . . . . . . 7
3.2. Reply . . . . . . . . . . . . . . . . . . . . 8
3.3. Query . . . . . . . . . . . . . . . . . . . . 9
3.4. Reply . . . . . . . . . . . . . . . . . . . . 9
3.5. With Text . . . . . . . . . . . . . . . . 9
3.6. Without Text . . . . . . . . . . . . . . 9
4. Operational Considerations . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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. [RFC6480]
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. In some cases, outsourcing operation of the repository
will be an explicit goal: some resource holders who stringly wish to
control their own RPKI private keys may lack the resources to operate
a 24x7 repository, or may simply not wish to do so.
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The operator of an RPKI publication repository may well be an
Internet registry which issues certificates to its customers, but it
need not be; conceptually, operation of a an RPKI publication
repository is separate from operation of RPKI CA.
This document defines an RPKI publication protocol which allows
publication either within or across organizational boundaries, and
which makes fairly minimal demands on either the CA engine or the
publication service.
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. We use the term "Business PKI" here
because an internet registry might already have a PKI for
authenticating its clients and might wish to reuse that PKI for this
protocol. There is, however, no requirement to reuse such a PKI.
2. Protocol Specification
The publication protocol uses XML messages wrapped in signed CMS
messages, carried over HTTP transport.
The publication protocol uses 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 [RFC6492].
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2.1. Common XML Message Format
The XML schema for this protocol is below in Section 2.4. The basic
XML message format looks like this:
Common attributes:
version: The value of this attribute is the version of this
protocol. This document describes version 3.
type: The possible values of this attribute are "reply" and "query".
A query PDU may be one of two types: publish_query, or
withdraw_query.
A reply PDU may be one of three types: 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.
2.2. Publication and Withdrawal
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 and objects have a payload of an
optional tag and a URI. The query also contains the DER
object to be published, encoded in Base64.
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Note that every publish and withdraw action requires a new manifest,
thus every publish or withdraw action will involve at least two
objects.
2.3. Error handling
Errors are 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 message
which takes the place of the expected protocol response message.
messages are CMS-signed XML messages like the rest of
this protocol, and thus can be archived to provide an audit trail.
messages only appear in replies, never in queries.
The message can appear in both the control and
publication subprotocols.
Like all other messages in this protocol, the 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 element itself is an optional text
string; if present, this is debugging information.
2.4. XML Schema
The following is a RelaxNG compact form schema describing the
Publication Protocol.
# $Id: rpki-publication.rnc 2698 2013-12-13 23:33:07Z sra $
# RelaxNG schema for RPKI publication protocol.
default namespace =
"http://www.hactrn.net/uris/rpki/publication-spec/"
# This is version 3 of the protocol.
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version = "3"
# Top level PDU is either a query or a reply.
start = element msg {
attribute version { version } ,
( ( attribute type { "query" }, query_elt* ) |
( attribute type { "reply" }, reply_elt* ) )
}
# PDUs allowed in queries and replies.
query_elt = publish_query | withdraw_query
reply_elt = 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 URIs.
uri = attribute uri { xsd:anyURI { maxLength="4096" } }
# Handles on remote objects (replaces passing raw SQL IDs).
object_handle = xsd:string {
maxLength = "255"
pattern="[\-_A-Za-z0-9/]*"
}
# Error codes.
error = xsd:token { maxLength="1024" }
# element
publish_query |= element publish { tag?, uri, base64 }
publish_reply |= element publish { tag?, uri }
# element
withdraw_query |= element withdraw { tag?, uri }
withdraw_reply |= element withdraw { tag?, uri }
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# element
report_error_reply = element report_error {
tag?,
attribute error_code { error },
xsd:string { maxLength="512000" }?
}
3. Examples
Following are examples of various queries and the corresponding
replies for the RPKI publication protocol
3.1. Query
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MIIE+jCCA+KgAwIBAgIBDTANBgkqhkiG9w0BAQsFADAzMTEwLwYDVQQDEyhE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3.2. Reply
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3.3. Query
3.4. Reply
3.5. With Text
Shampooing with sterno again, are we?
3.6. Without Text
4. Operational Considerations
There are two basic options open to the repository operator as to how
the publication tree is laid out. The first option is simple: each
publication client is given its own directory one level below the top
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of the rcynic module, and there is no overlap between the publication
spaces used by different clients. For example:
rsync://example.org/rpki/Alice/
rsync://example.org/rpki/Bob/
rsync://example.org/rpki/Carol/
This has the advantage of being very easy for the publication
operator to manage, but has the drawback of making it difficult for
relying parties to fetch published objects both safely and as
efficiently as possible.
Given that the mandatory-to-implement retrieval protocol for relying
parties is rsync, a more efficient repository structure would be one
which minimized the number of rsync fetches required. One such
structure would be one in which the publication directories for
subjects were placed underneath the publication directories of their
issuers: since the normal synchronization tree walk is top-down, this
can significantly reduce the total number of rsync connections
required to synchronize. For example:
rsync://example.org/rpki/Alice/
rsync://example.org/rpki/Alice/Bob/
rsync://example.org/rpki/Alice/Bob/Carol/
Preliminary measurement suggests that, in the case of large numbers
of small publication directories, the time needed to set up and tear
down individual rsync connections becomes significant, and that a
properly optimized tree structure can reduce synchronization time by
an order of magnitude.
The more complex tree structure does require careful attention to the
base_uri attribute values when setting up clients. In the example
above, assuming that Alice issues to Bob who in turn issues to Carol,
Alice has ceded control of a portion of her publication space to Bob,
who has in turn ceded a portion of that to Carol, and the base_uri
attributes in the setup messages should reflect this.
The details of how the repository operator determines that Alice has
given Bob permission to nest Bob's publication directory under
Alice's is outside the scope of this protocol.
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
Intended usage: COMMON
Author/Change controller: Rob Austein
6. Security Considerations
The RPKI publication protocol and the data it publishes use entirely
separate PKIs for authentication. The published data is
authenticated within the RPKI, and this protocol has nothing to do
with that authentication, nor does it require that the published
objects be valid in the RPKI. The publication protocol uses a
separate Business PKI (BPKI) to authenticate its messages.
Each of the RPKI publication protocol messages is CMS-signed.
Because of that protection at the application layer, this protocol
does not require the use of HTTPS or other transport security
mechanisms.
Compromise of a publication server, perhaps through mismanagement of
BPKI keys, could lead to a denial-of-service attack on the RPKI. An
attacker gaining access to BPKI keys could use this protocol delete
(withdraw) RPKI objects, leading to routing changes or failures.
Accordingly, as in most PKIs, good key management practices are
important.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, BCP 14, March 1997.
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[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", RFC
5652, STD 70, September 2009.
[RFC6492] Huston, G., Loomans, R., Ellacott, B., and R. Austein, "A
Protocol for Provisioning Resource Certificates", RFC
6492, February 2012.
7.2. Informative References
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, February 2012.
Authors' Addresses
Samuel Weiler
SPARTA, Inc.
7110 Samuel Morse Drive
Columbia, Maryland 21046
US
Email: weiler@tislabs.com
Anuja Sonalker
Battelle Memorial Institute
Email: sonalkera@battelle.org
Rob Austein
Dragon Research Labs
Email: sra@hactrn.net
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