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Secure Inter-Domain Routing (sidr)                          M. Lepinski
Internet Draft                                                  S. Kent
Expires: November 9, 2011                                       D. Kong
Intended Status: Proposed Standard                     BBN Technologies
                                                            May 9, 2011

             A Profile for Route Origin Authorizations (ROAs)
                     draft-ietf-sidr-roa-format-12.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on November 9, 2011.

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Abstract

   This document defines a standard profile for Route Origin
   Authorizations (ROAs).  A ROA is a digitally signed object that
   provides a means of verifying that an IP address block holder has
   authorized an Autonomous System (AS) to originate routes to one or
   more prefixes within the address block.

Table of Contents


   1. Introduction...................................................2
      1.1. Terminology...............................................3
   2. The ROA ContentType............................................3
   3. The ROA eContent...............................................3
      3.1. version...................................................4
      3.2. asID......................................................4
      3.3. ipAddrBlocks..............................................4
   4. ROA Validation.................................................5
   5. Security Considerations........................................5
   6. IANA Considerations............................................6
   7. Acknowledgments................................................6
   8. References.....................................................7
      8.1. Normative References......................................7
      8.2. Informative References....................................7
   APPENDIX A: ASN.1 Module..........................................8
   Authors' Addresses................................................9

1. Introduction

   The primary purpose of the Internet IP Address and Autonomous System
   (AS) Number Resource Public Key Infrastructure (RPKI) system is to
   improve routing security. (See [ARCH] for more information.) As part
   of this system, a mechanism is needed to allow entities to verify
   that an AS has been given permission by an IP address block holder to
   advertise routes to one or more prefixes within that block.  A ROA
   provides this function.

   The ROA makes use of the template for RPKI digitally signed objects
   [SIGNOBJ], which defines a Crytopgraphic Message Syntax (CMS)
   [RFC5652] wrapper for the ROA content as well as a generic validation
   procedure for RPKI signed objects. Therefore, to complete the
   specification of the ROA (see Section 4 of [SIGNOBJ]), this document
   defines:



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      1. The OID that identifies the signed object as being a ROA. (This
         OID appears within the eContentType in the encapContentInfo
         object as well as the ContentType signed attribute in the
         signerInfo object.)

      2. The ASN.1 syntax for the ROA eContent. (This is the payload
         that specifies the AS being authorized to originate routes as
         well as the prefixes to which the AS may originate routes.)

      3. An additional step required to validate ROAs (in addition to
         the validation steps specified in [SIGNOBJ]).

1.1. Terminology

   It is assumed that the reader is familiar with the terms and concepts
   described in "Internet X.509 Public Key Infrastructure Certificate
   and Certificate Revocation List (CRL) Profile" [RFC5280] and "X.509
   Extensions for IP Addresses and AS Identifiers" [RFC3779].

   Additionally, this document makes use of the RPKI signed object
   profile [SIGNOBJ] and thus familiarity with that document is assumed.
   Note that the RPKI signed object profile makes use of certificates
   adhering to the RPKI resource certificate profile [RESCERT] and thus
   familiarly with this profile is also assumed.

   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
   RFC-2119 [RFC2119].


2. The ROA ContentType

   The ContentType for a ROA is defined as routeOriginAuthz and has the
   numerical value of 1.2.840.113549.1.9.16.1.24.

   This OID MUST appear both within the eContentType in the
   encapContentInfo object as well as the ContentType signed attribute
   in the signerInfo object (see [SIGNOBJ]).

3. The ROA eContent

   The content of a ROA identifies a single AS that has been authorized
   by the address space holder to originate routes and a list of one or
   more IP address prefixes that will be advertised.  If the address
   space holder needs to authorize multiple ASes to advertise the same



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   set of address prefixes, the holder issues multiple ROAs, one per AS
   number. A ROA is formally defined as:

      RouteOriginAttestation ::= SEQUENCE {
         version [0] INTEGER DEFAULT 0,
         asID  ASID,
         ipAddrBlocks SEQUENCE (SIZE(1..MAX)) OF ROAIPAddressFamily }

      ASID ::= INTEGER

      ROAIPAddressFamily ::= SEQUENCE {
         addressFamily OCTET STRING (SIZE (2..3)),
         addresses SEQUENCE (SIZE (1..MAX)) OF ROAIPAddress }


      ROAIPAddress ::= SEQUENCE {
         address IPAddress,
         maxLength INTEGER OPTIONAL }

      IPAddress ::= BIT STRING

   Note that this content appears as the eContent within the
   encapContentInfo (see [SIGNOBJ]).

3.1. version

   The version number of the RouteOriginAttestation MUST be 0.

3.2. asID

   The asID field contains the AS number that is authorized to originate
   routes to the given IP address prefixes.

3.3. ipAddrBlocks

   The ipAddrBlocks field encodes the set of IP address prefixes to
   which the AS is authorized to originate routes. Note that the syntax
   here is more restrictive than that used in the IP Address Delegation
   extension defined in RFC 3779. That extension can represent arbitrary
   address ranges, whereas ROAs need to represent only prefixes.

   Within the ROAIPAddressFamily structure, addressFamily contains the
   Address Family Identifier (AFI) of an IP address family. This
   specification only supports IPv4 and IPv6. Therefore, addressFamily
   MUST be either 0001 or 0002.




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   Within a ROAIPAddress structure, the addresses field represents
   prefixes as a sequence of type IPAddress. (See [RFC3779] for more
   details). If present, the maxLength MUST be an integer greater than
   or equal to the length of the accompanying prefix and less than or
   equal to the length (in bits) of an IP address in the address family
   (32 for IPv4 and 128 for IPv6). When present, the maxLength specifies
   the maximum length of IP address prefix that the AS is authorized to
   advertise. (For example, if the IP Address prefix is 203.0.113/24 and
   the maxLength is 26, the AS is authorized to advertise any more
   specific prefix having length at most 26. That is, in this example,
   the AS would be authorized to advertise 203.0.113/24,
   203.0.113.128/25, or 203.0.113.0/25, but not 203.0.113.0/27.) When
   the maxLength is not present, the AS is only authorized to advertise
   exactly the prefix specified in the ROA.

   Note that a valid ROA may contain an IP Address prefix (within a
   ROAIPAddress element) that is encompassed by another IP Address
   prefix (within a separate ROAIPAddress element). For example, a ROA
   may contain the prefix 203.0.113/24 with maxLength 26, as well as the
   prefix 203.0.113.0/28 with maxLength 28. (Such a ROA would authorize
   the indicated AS to advertise any prefix beginning with 203.0.113
   with length at least 24 and no greater than 26, as well as the
   specific prefix 203.0.113.0/28.) Additionally, a ROA MAY contain two
   ROAIPAddress elements where the IP Address prefix is identical in
   both cases. However, this is NOT RECOMMENDED as in such a case the
   ROAIPAddress with the shorter maxLength grants no additional
   privileges to the indicated AS and thus can be omitted without
   changing the meaning of the ROA.

4. ROA Validation

   Before a relying party can use a ROA to validate a routing
   announcement, the relying party MUST first validate the ROA. To
   validate a ROA the relying party MUST perform all the validation
   checks specified in [SIGNOBJ] as well as the following additional
   ROA-specific validation step.

   o  The IP Address Delegation extension [RFC3779] is present in the
      End-Entity (EE) certificate (contained within the ROA) and each IP
      address prefix(es) in ROA is contained within the set of IP
      addresses specified by the EE certificate's IP address delegation
      extension.

5. Security Considerations

   There is no assumption of confidentiality for the data in a ROA; it
   is anticipated that ROAs will be stored in repositories that are


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   accessible to all ISPs, and perhaps to all Internet users. There is
   no explicit authentication associated with a ROA, since the PKI used
   for ROA validation provides authorization but not authentication.
   Although the ROA is a signed, application layer object, there is no
   intent to convey non-repudiation via a ROA.

   The purpose of a ROA is to convey authorization for an AS to
   originate a route to the prefix(es) in the ROA. Thus the integrity of
   a ROA MUST be established. The ROA specification makes use of the
   RPKI signed object format, thus all security considerations in
   [SIGNOBJ] also apply to ROAs. Additionally, the signed object profile
   uses the CMS signed message format for integrity, and thus ROA
   inherit all security considerations associated with that data
   structure.

   The right of the ROA signer to authorize the target AS to originate
   routes to the prefix(es) is established through use of the address
   space and AS number PKI described in [ARCH]. Specifically one MUST
   verify the signature on the ROA using an X.509 certificate issued
   under this PKI, and check that the prefix(es) in the ROA match those
   in the address space extension in the certificate.

6. IANA Considerations

   None.

7. Acknowledgments

   The authors wish to thank Charles Gardiner and Russ Housley for their
   help and contributions. Additionally, the authors would like to thank
   Rob Austein, Roque Gagliano, Danny McPherson and Sam Weiler for their
   careful reviews and helpful comments.

















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8. References

8.1. Normative References

   [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", RFC 5652,
             September 2009.

   [RFC3779] Lynn, C., Kent, S., and Seo, K., "X.509 Extensions for IP
             Addresses and AS Identifiers", RFC 3779, June 2004.

   [RFC5280] Cooper, D., et. al., "Internet X.509 Public Key
             Infrastructure and Certificate Revocation List (CRL)
             Profile", RFC 5280, May 2008.

   [RESCERT] Huston, G., Michaelson, G., and Loomans, R., "A Profile for
             X.509 PKIX Resource Certificates", draft-ietf-sidr-res-
             certs, November 2010.

   [SIGNOBJ] Lepinski, M., Chi, A., and Kent, S., "Generic Signed
             Objects for the Resource Public Key Infrastructure", draft-
             ietf-sidr-signed-object, February 2011.



8.2. Informative References

   [ARCH]    Lepinski, M. and Kent, S., "An Infrastructure to Support
             Secure Internet Routing," draft-ietf-sidr-arch, February
             2011.

















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APPENDIX A: ASN.1 Module

   This normative appendix provides an ASN.1 module that specifies the
   ROA content in ASN.1 syntax.

   RPKI-ROA { iso(1) member-body(2) us(840) rsadsi(113549)
      pkcs(1) pkcs9(9) smime(16) mod(0) 61 }

   DEFINITIONS EXPLICIT TAGS ::=
   BEGIN

   RouteOriginAttestation ::= SEQUENCE {
      version [0] INTEGER DEFAULT 0,
      asID  ASID,
      ipAddrBlocks SEQUENCE (SIZE(1..MAX)) OF ROAIPAddressFamily }

   ASID ::= INTEGER

   ROAIPAddressFamily ::= SEQUENCE {
      addressFamily OCTET STRING (SIZE (2..3)),
      addresses SEQUENCE (SIZE (1..MAX)) OF ROAIPAddress }

   ROAIPAddress ::= SEQUENCE {
      address IPAddress,
      maxLength INTEGER OPTIONAL }

   IPAddress ::= BIT STRING

   END
















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Authors' Addresses

   Matt Lepinski
   BBN Technologies
   10 Moulton Street
   Cambridge MA 02138

   Email: mlepinski@bbn.com

   Stephen Kent
   BBN Technologies
   10 Moulton Street
   Cambridge MA 02138

   Email: skent@bbn.com

   Derrick Kong
   BBN Technologies
   10 Moulton Street
   Cambridge MA 02138

   Email: dkong@bbn.com



























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