ACME Working Group                                          R. Shoemaker
Internet-Draft                                                      ISRG
Intended status: Standards Track                           July 27, 2018
Expires: January 28, 2019


                ACME IP Identifier Validation Extension
                         draft-ietf-acme-ip-04

Abstract

   This document specifies identifiers and challenges required to enable
   the Automated Certificate Management Environment (ACME) to issue
   certificates for IP addresses.

Status of This Memo

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   This Internet-Draft will expire on January 28, 2019.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  IP Identifier . . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  Identifier Validation Challenges  . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
     5.1.  Identifier Types  . . . . . . . . . . . . . . . . . . . .   3
     5.2.  Challenge Types . . . . . . . . . . . . . . . . . . . . .   3
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The Automatic Certificate Management Environment (ACME)
   [I-D.ietf-acme-acme] only defines challenges for validating control
   of DNS host name identifiers which limits its use to being used for
   issuing certificates for DNS identifiers.  In order to allow
   validation of IPv4 and IPv6 identifiers for inclusion in X.509
   certificates this document specifies how challenges defined in the
   original ACME specification and the TLS-ALPN extension specification
   [I-D.ietf-acme-tls-alpn] can be used to validate IP identifiers.

2.  Terminology

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in BCP 14,
   [RFC2119].

3.  IP Identifier

   [I-D.ietf-acme-acme] only defines the identifier type "dns" which is
   used to refer to fully qualified domain names.  If a ACME server
   wishes to request proof that a user controls a IPv4 or IPv6 address
   it MUST create an authorization with the identifier type "ip".  The
   value field of the identifier MUST contain the textual form of the
   address as defined in [RFC1123] Section 2.1 for IPv4 and in [RFC4291]
   Section 2.2 for IPv6.

   An identifier for the IPv6 address 2001:db8::1 would be formatted
   like so:

   {"type": "ip", "value": "2001:db8::1"}





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4.  Identifier Validation Challenges

   IP identifiers MAY be used with the existing "http-01" and "tls-alpn-
   01" challenges from [I-D.ietf-acme-acme] Section 8.3 and
   [I-D.ietf-acme-tls-alpn] Section 3 respectively.  To use IP
   identifiers with these challenges their initial DNS resolution step
   MUST be skipped and the IP address used for validation MUST be the
   value of the identifier.

   For the "http-01" challenge the Host header MUST be set to the IP
   address being used for validation per [RFC7230].

   For the "tls-alpn-01" the subjectAltName extension in the validation
   certificate MUST contain a single iPAddress which matches the address
   being validated.  As [RFC6066] does not permit IP addresses to be
   used in the SNI extension the server MUST instead use the IN-
   ADDR.ARPA [RFC1034] or IP6.ARPA [RFC3596] reverse mapping of the IP
   address as the SNI value instead of the literal IP address.

   The existing "dns-01" challenge MUST NOT be used to validate IP
   identifiers.

5.  IANA Considerations

5.1.  Identifier Types

   Adds a new type to the Identifier list defined in Section 9.7.7 of
   [I-D.ietf-acme-acme] with the label "ip" and reference I-D.ietf-acme-
   ip.

5.2.  Challenge Types

   Adds the value "ip" to the Identifier Type column in the Validation
   Methods list defined in Section 9.7.8 of [I-D.ietf-acme-acme] for the
   "http-01" and "tls-alpn-01" challenges.

6.  Security Considerations

   Given the often short delegation periods for IP addresses provided by
   various service providers CAs MAY want to impose shorter lifetimes
   for certificates which contain IP identifiers.  They MAY also impose
   restrictions on IP identifiers which are in CIDRs known to be
   assigned to service providers who dynamically assign addresses to
   users for indeterminate periods of time.







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7.  Acknowledgments

   The author would like to thank those who contributed to this document
   and offered editorial and technical input, especially Jacob Hoffman-
   Andrews and Daniel McCarney.

8.  Normative References

   [FIPS180-4]
              Department of Commerce, National., "NIST FIPS 180-4,
              Secure Hash Standard", March 2012,
              <http://csrc.nist.gov/publications/fips/fips180-4/
              fips-180-4.pdf>.

   [I-D.ietf-acme-acme]
              Barnes, R., Hoffman-Andrews, J., McCarney, D., and J.
              Kasten, "Automatic Certificate Management Environment
              (ACME)", draft-ietf-acme-acme-13 (work in progress), July
              2018.

   [I-D.ietf-acme-tls-alpn]
              Shoemaker, R., "ACME TLS ALPN Challenge Extension", draft-
              ietf-acme-tls-alpn-01 (work in progress), May 2018.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1123]  Braden, R., Ed., "Requirements for Internet Hosts -
              Application and Support", STD 3, RFC 1123,
              DOI 10.17487/RFC1123, October 1989,
              <https://www.rfc-editor.org/info/rfc1123>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3596]  Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
              "DNS Extensions to Support IP Version 6", STD 88,
              RFC 3596, DOI 10.17487/RFC3596, October 2003,
              <https://www.rfc-editor.org/info/rfc3596>.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.





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   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
              <https://www.rfc-editor.org/info/rfc4648>.

   [RFC6066]  Eastlake 3rd, D., "Transport Layer Security (TLS)
              Extensions: Extension Definitions", RFC 6066,
              DOI 10.17487/RFC6066, January 2011,
              <https://www.rfc-editor.org/info/rfc6066>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

Author's Address

   Roland Bracewell Shoemaker
   Internet Security Research Group

   Email: roland@letsencrypt.org































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