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 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 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 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 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 Weiler, et al. Expires January 12, 2012 [Page 1] Internet-Draft RPKI Publication Protocol July 2011 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 Weiler, et al. Expires January 12, 2012 [Page 2] Internet-Draft RPKI Publication Protocol July 2011 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. Weiler, et al. Expires January 12, 2012 [Page 3] Internet-Draft RPKI Publication Protocol July 2011 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: Weiler, et al. Expires January 12, 2012 [Page 4] Internet-Draft RPKI Publication Protocol July 2011 [one or more PDUs] 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 object allows configuration of data that apply to the entire publication server rather than a particular client. There is exactly one 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 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 object, the object represents one client authorized to use the publication server. There may well be Weiler, et al. Expires January 12, 2012 [Page 5] Internet-Draft RPKI Publication Protocol July 2011 more than one object on each publication server. Again, its use is typically restricted to the respository operator. The 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 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 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. Note that every publish and withdraw action requires a new manifest, Weiler, et al. Expires January 12, 2012 [Page 6] Internet-Draft RPKI Publication Protocol July 2011 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 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. 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*) | Weiler, et al. Expires January 12, 2012 [Page 7] Internet-Draft RPKI Publication Protocol July 2011 (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/]*" } # 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 } # 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 } Weiler, et al. Expires January 12, 2012 [Page 8] Internet-Draft RPKI Publication Protocol July 2011 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 } # 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 } # 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: Weiler, et al. Expires January 12, 2012 [Page 9] Internet-Draft RPKI Publication Protocol July 2011 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 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. Weiler, et al. Expires January 12, 2012 [Page 10] Internet-Draft RPKI Publication Protocol July 2011 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 Weiler, et al. Expires January 12, 2012 [Page 11]