Internet Engineering Task Force (IETF)                         A. Newton
Request for Comments: 7318                                          ARIN
Updates: 6487                                                  G. Huston
Category: Standards Track                                          APNIC
ISSN: 2070-1721                                                July 2014


     Policy Qualifiers in Resource Public Key Infrastructure (RPKI)
                              Certificates

Abstract

   This document updates RFC 6487 by clarifying the inclusion of policy
   qualifiers in the certificate policies extension of Resource Public
   Key Infrastructure (RPKI) resource certificates.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7318.

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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Update to RFC 6487  . . . . . . . . . . . . . . . . . . . . .   2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   This document introduces policy qualifiers in the certificate
   policies extension of the RPKI resource certificates.  This document
   updates [RFC6487].

   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].

2.  Update to RFC 6487

   [RFC6487] profiles certificates, certificate revocation lists, and
   certificate signing requests specified in [RFC5280] for use in
   routing public key infrastructure.

   [RFC5280] defines an extension to certificates for the listing of
   policy information (see Section 4.2.1.4).  [RFC6487] states in
   Section 4.8.9: "This extension MUST be present and MUST be marked
   critical.  It MUST include exactly one policy, as specified in the
   RPKI CP [RFC6484]".  This references the CertPolicyId of the sequence
   allowed in PolicyInformation as defined by [RFC5280].

   [RFC5280] also specifies that PolicyInformation may optionally have a
   sequence of PolicyQualifierInfo objects.  [RFC6487] does not
   specifically allow or disallow these PolicyQualifierInfo objects,
   although Section 4 also states: "Unless specifically noted as being
   OPTIONAL, all the fields listed here MUST be present, and any other
   fields MUST NOT appear in a conforming resource certificate."

   Because there is a need for some RPKI Certificate Authorities to
   include policy qualifiers in their certificates, this document
   updates Section 4.8.9 of [RFC6487] as follows:

      OLD:

         This extension MUST be present and MUST be marked critical.  It
         MUST include exactly one policy, as specified in the RPKI
         Certificate Policy (CP) [RFC6484].

      NEW:

         This extension MUST be present and MUST be marked critical.  It
         MUST include exactly one policy, as specified in the RPKI CP
         [RFC6484].  Exactly one policy qualifier MAY be included.  If a
         policy qualifier is included, the policyQualifierId MUST be the
         Certification Practice Statement (CPS) pointer qualifier type
         (id-qt-cps).

   As noted in [RFC5280], Section 4.2.1.4: "Optional qualifiers, which
   MAY be present, are not expected to change the definition of the
   policy."  In this case, any optional policy qualifier that MAY be
   present in a resource certificate MUST NOT change the definition of
   the RPKI CP [RFC6484].

3.  Security Considerations

   The Security Considerations of [RFC6487] apply to this document.

   This document updates the RPKI certificate profile to specify that
   the certificate policies extension can include a policy qualifier,
   which is a URI.  While dereferencing the URI is not required for
   certificate validation, doing so could provide a denial-of-service
   (DoS) vector, where the target host may be subjected to bogus work
   dereferencing the URI.  However, this specification, like [RFC5280],
   places no processing requirements on the URI included in the
   qualifier.

   As an update to [RFC6487], this document broadens the class of
   certificates that conform to the RPKI profile by explicitly including
   within the profile those certificates that contain a policy qualifier
   as described here.  A relying party that performs a strict validation
   based on [RFC6487] and fails to support the updates described in this
   document would incorrectly invalidate RPKI objects that include the
   changes in Section 2.

4.  Acknowledgments

   Frank Hill and Adam Guyot helped define the scope of the issue
   covered by this document and identified and worked with RPKI
   validator implementers to clarify the use of policy qualifiers in
   resource certificates.

   Sean Turner provided significant text to this document regarding the
   processing of the CPS URI and limiting the scope of the allowable
   content of the policy qualifier.

5.  Normative References

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

   [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.

   [RFC6484]  Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate
              Policy (CP) for the Resource Public Key Infrastructure
              (RPKI)", BCP 173, RFC 6484, February 2012.

   [RFC6487]  Huston, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates", RFC 6487, February
              2012.

Authors' Addresses

   Andrew Lee Newton
   American Registry for Internet Numbers
   3635 Concorde Parkway
   Chantilly, VA  20151
   USA

   EMail: andy@arin.net
   URI:   http://www.arin.net


   Geoff Huston
   Asia Pacific Network Information Center
   6 Cordelia Street
   South Brisbane  QLD 4101
   Australia

   EMail: gih@apnic.net
   URI:   http://www.apnic.net