Network Working Group S. Weiler
Internet-Draft A. Sonalker
Intended status: Standards Track SPARTA, Inc.
Expires: January 6, 2011 July 5, 2010
A Publication Protocol for the Resource Public Key Infrastructure (RPKI)
draft-weiler-sidr-publication-00
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 that.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 6, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 Protocol . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. Config Object . . . . . . . . . . . . . . . . . . . . 5
3.2.2. Client Object . . . . . . . . . . . . . . . . . . . . 5
3.3. Publication Protocol . . . . . . . . . . . . . . . . . . . 6
3.4. Error handling . . . . . . . . . . . . . . . . . . . . . . 6
3.5. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Operational Considerations . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 11
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 to suggest that 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. This portion of
the protocol is largely inherited from the provisioning protocol
([I-D.ietf-sidr-rescerts-provisioning]).
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/x-rpki",
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/x-rpki".
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 publication protocol uses the same message passing design as the
provisioning protocol. 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:
<?xml version='1.0' encoding='us-ascii'?>
<msg xmlns="http://www.hactrn.net/uris/rpki/publication-spec/"
version="1"
type="message type">
[one or more PDUs]
</msg>
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version:
The value of this attribute is the version of this protocol.
This document describes version 1.
type:
The possible values of this attribute are "reply" and "query".
3.2. Control Protocol
The control 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.
The control protocol has two objects: the <config/> object, and the
<client/> object.
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.
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.
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 X509 BPKI CA certificate
for this client. This should be used as part of the certificate
chain when validating incoming TLS and 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
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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 X509
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 Protocol
The publication protocol is structured differently from the control
protocol in that objects in the publication protocol represent
objects to be published or objects to be withdrawn from publication.
Each kind of object supports two actions: "publish" and "withdraw".
In each case the XML element representing the object to be published
or withdrawn has a "uri" attribute which contains the publication
URI. For "publish" actions, the XML element body contains the DER
object to be published, encoded in Base64; for "withdraw" actions,
the XML element body is empty.
The publication protocol uses four types of objects:
o Certificate Object: The <certificate/> object represents an RPKI
certificate to be published or withdrawn.
o CRL Object: The <crl/> object represents an RPKI CRL to be
published or withdrawn.
o Manifest Object: The <manifest/> object represents an RPKI
publication manifest to be published or withdrawn. See
[I-D.ietf-sidr-rpki-manifests] for more information on manifests.
o ROA Object: The <roa/> object represents a ROA to be published or
withdrawn. See [I-D.ietf-sidr-roa-format] for more information on
ROAs.
Note that every publication or withdrawal action requires a new
manifest, thus every publication or withdrawal 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.
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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.
The <report_error/> message includes an optional "tag" attribute to
assist in matching the error with a particular query when using
batching.
The error itself is conveyed in the error_code (attribute). The
value of this attribute is a token indicating the specific error that
occurred. [TODO: define these tokens]
The body of the <report_error/> element itself is an optional text
string; if present, this is debugging information. At present this
capabilty is not used, debugging information goes to syslog.
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 { xsd:positiveInteger {
maxInclusive="1" } }, ((attribute type { "query" }, query_elt*) |
(attribute type { "reply" }, reply_elt*)) }
# PDUs allowed in a query
query_elt = ( config_query | client_query | certificate_query |
crl_query | manifest_query | roa_query )
# PDUs allowed in a reply
reply_elt = ( config_reply | client_reply | certificate_reply |
crl_reply | manifest_reply | roa_reply | report_error_reply )
# Tag attributes for bulk operations
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tag = attribute tag { xsd:token {maxLength="1024" } }
# Base64 encoded DER stuff
base64 = xsd:base64Binary { maxLength="512000" }
# 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, see code for details
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 }
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?,
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client_handle, client_payload }
client_query |= element client { attribute action { "destroy" }, tag?,
client_handle }
client_reply |= element client { attribute action { "destroy" }, tag?,
client_handle }
# <certificate/> element
certificate_query |= element certificate { attribute action {
"publish" }, tag?, uri, base64 }
certificate_reply |= element certificate { attribute action {
"publish" }, tag?, uri }
certificate_query |= element certificate { attribute action {
"withdraw" }, tag?, uri }
certificate_reply |= element certificate { attribute action {
"withdraw" }, tag?, uri }
# <crl/> element
crl_query |= element crl { attribute action { "publish" }, tag?, uri,
base64 }
crl_reply |= element crl { attribute action { "publish" }, tag?, uri }
crl_query |= element crl { attribute action { "withdraw" }, tag?, uri }
crl_reply |= element crl { attribute action { "withdraw" }, tag?, uri }
# <manifest/> element
manifest_query |= element manifest { attribute action { "publish" },
tag?, uri, base64 }
manifest_reply |= element manifest { attribute action { "publish" },
tag?, uri }
manifest_query |= element manifest { attribute action { "withdraw" },
tag?, uri }
manifest_reply |= element manifest { attribute action { "withdraw" },
tag?, uri }
# <roa/> element
roa_query |= element roa { attribute action { "publish" }, tag?, uri,
base64 }
roa_reply |= element roa { attribute action { "publish" }, tag?, uri }
roa_query |= element roa { attribute action { "withdraw" }, tag?, uri }
roa_reply |= element roa { attribute action { "withdraw" }, tag?, uri }
# <report_error/> element
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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 sameso 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
This document specifies no IANA Actions.
6. Security Considerations
7. References
7.1. Normative References
[I-D.ietf-sidr-res-certs]
Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates",
draft-ietf-sidr-res-certs-18 (work in progress), May 2010.
[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-06 (work in
progress), May 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
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[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)",
RFC 5652, September 2009.
[X.690] Postel, J., "ITU-T Recommendation X.690: ISO/IEC 8825-
1:2002, Information technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER)", 2002.
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-09 (work in
progress), October 2009.
[I-D.ietf-sidr-roa-format]
Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
Origin Authorizations (ROAs)",
draft-ietf-sidr-roa-format-06 (work in progress),
October 2009.
[I-D.ietf-sidr-rpki-manifests]
Austein, R., Huston, G., Kent, S., and M. Lepinski,
"Manifests for the Resource Public Key Infrastructure",
draft-ietf-sidr-rpki-manifests-07 (work in progress),
May 2010.
Appendix A. Acknowledgments
We acknowledge the editors of [I-D.ietf-sidr-rescerts-provisioning]
(Geoff Huston, Robert Loomans, Byron Ellacott, and Rob Austein), from
whom we took some of the text for this document.
We especially thank Rob Austein, who implemented the publication
protocol and helped us to understand it.
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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
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