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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Update to RFC 6487 . . . . . . . . . . . . . . . . . . . . . 2
3. Security Considerations . . . . . . . . . . . . . . . . . . . 3
4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 3
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 this 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