Resource Public Key Infrastructure (RPKI) object profile for Signed Checklist (RSC)
draft-ietf-sidrops-rpki-rsc-03

Network Working Group                                        J. Snijders
Internet-Draft                                                    Fastly
Intended status: Standards Track                             T. Harrison
Expires: November 28, 2021                                         APNIC
                                                             B. Maddison
                                                              Workonline
                                                            May 27, 2021

  Resource Public Key Infrastructure (RPKI) object profile for Signed
                            Checklist (RSC)
                     draft-ietf-sidrops-rpki-rsc-03

Abstract

   This document defines a Cryptographic Message Syntax (CMS) profile
   for a general purpose listing of checksums (a 'checklist'), for use
   with the Resource Public Key Infrastructure (RPKI).  The objective is
   to allow an attestation, in the form of a listing of one or more
   checksums of arbitrary digital objects (files), to be signed "with
   resources", and for validation to provide a means to confirm a
   specific Internet Resource Holder produced the Signed Checklist.  The
   profile is intended to provide for the signing of an arbitrary
   checksum listing with a specific set of Internet Number Resources.

Requirements Language

   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 BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

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 https://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."

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   This Internet-Draft will expire on November 28, 2021.

Copyright Notice

   Copyright (c) 2021 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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  RSC Profile and Distribution  . . . . . . . . . . . . . . . .   3
   3.  The RSC ContentType . . . . . . . . . . . . . . . . . . . . .   3
   4.  The RSC eContent  . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  version . . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  resources . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.3.  digestAlgorithm . . . . . . . . . . . . . . . . . . . . .   5
     4.4.  checkList . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  RSC Validation  . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Operational Considerations  . . . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION   7
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     9.1.  SMI Security for S/MIME CMS Content Type
           (1.2.840.113549.1.9.16.1) . . . . . . . . . . . . . . . .   8
     9.2.  RPKI Signed Objects sub-registry  . . . . . . . . . . . .   8
     9.3.  File Extension  . . . . . . . . . . . . . . . . . . . . .   8
     9.4.  SMI Security for S/MIME Module Identifier
           (1.2.840.113549.1.9.16.0) . . . . . . . . . . . . . . . .   9
     9.5.  Media Type  . . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     10.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  11
   Appendix B.  Document changelog - RFC EDITOR: REMOVE BEFORE
                PUBLICATION  . . . . . . . . . . . . . . . . . . . .  11
     B.1.  changes from -02 -> -03 . . . . . . . . . . . . . . . . .  11
     B.2.  changes from -01 -> -02 . . . . . . . . . . . . . . . . .  11
     B.3.  changes from -00 -> -01 . . . . . . . . . . . . . . . . .  12

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     B.4.  individual submission phase . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   This document defines a Cryptographic Message Syntax (CMS) [RFC5652]
   profile for a general purpose listing of checksums (a 'checklist'),
   for use with the Resource Public Key Infrastructure (RPKI) [RFC6480].
   The objective is to allow an attestation, in the form of a listing of
   one or more checksums of arbitrary files, to be signed "with
   resources", and for validation to provide a means to confirm a given
   Internet Resource Holder produced the RPKI Signed Checklist (RSC).
   The profile is intended to provide for the signing of a checksum
   listing with a specific set of Internet Number Resources.

   Signed Checklists are expected to facilitate inter-domain business
   use-cases which depend on an ability to verify resource holdership.
   RPKI-based validation processes are expected to become the industry
   norm for automated Bring Your Own IP (BYOIP) on-boarding or
   establishment of physical interconnection between Autonomous Systems.

   The RSC concept borrows heavily from RTA [I-D.ietf-sidrops-rpki-rta],
   Manifests [RFC6486], and OpenBSD's [signify] utility.  The main
   difference between RSC and RTA is that the RTA profile allows
   multiple signers to attest a single digital object through a checksum
   of its content, while the RSC profile allows a single signer to
   attest the existence of multiple digital objects.  A single signer
   profile is considered a simplification for both implementers and
   operators.

2.  RSC Profile and Distribution

   RSC follows the Signed Object Template for the RPKI [RFC6488] with
   one exception.  Because RSCs MUST NOT be distributed through the
   global RPKI repository system, the Subject Information Access (SIA)
   extension MUST be omitted from the RSC's X.509 EE certificate.

   What constitutes suitable transport for RSC files is deliberately
   unspecified.  It might be a USB stick, a web interface secured with
   conventional HTTPS, PGP-signed email, a T-shirt printed with a QR
   code, or a carrier pigeon.

3.  The RSC ContentType

   The ContentType for an RSC is defined as rpkiSignedChecklist, and has
   the numerical value of 1.2.840.113549.1.9.16.1.48.

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   This OID MUST appear both within the eContentType in the
   encapContentInfo object as well as the ContentType signed attribute
   in the signerInfo object (see [RFC6488]).

4.  The RSC eContent

   The content of an RSC indicates that a checklist for arbitrary
   digital objects has been signed "with resources".  An RSC is formally
   defined as:

   RpkiSignedChecklist-2021
     { iso(1) member-body(2) us(840) rsadsi(113549)
       pkcs(1) pkcs9(9) smime(16) mod(0) TBD }

   DEFINITIONS EXPLICIT TAGS ::=
   BEGIN

   IMPORTS
     CONTENT-TYPE, Digest, DigestAlgorithmIdentifier
     FROM CryptographicMessageSyntax-2009 -- in [RFC5911]
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-9(9) smime(16) modules(0) id-mod-cms-2004-02(41) }

     ASIdOrRange, IPAddressOrRange
     FROM IPAddrAndASCertExtn -- in [RFC3779]
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) mod(0)
         id-mod-ip-addr-and-as-ident(30) } ;

   ct-rpkiSignedChecklist CONTENT-TYPE ::=
       { TYPE RpkiSignedChecklist IDENTIFIED BY
         id-ct-signedChecklist }

   id-ct-signedChecklist OBJECT IDENTIFIER ::=
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-9(9) id-smime(16) id-ct(1) 48 }

   RpkiSignedChecklist ::= SEQUENCE {
     version  [0]          INTEGER DEFAULT 0,
     resources             ResourceBlock,
     digestAlgorithm       DigestAlgorithmIdentifier,
     checkList             SEQUENCE SIZE (1..MAX) OF FileNameAndHash }

   FileNameAndHash ::= SEQUENCE {
     fileName        IA5String OPTIONAL,
     hash            Digest }

   ResourceBlock ::= SEQUENCE {

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       asID         [0]       AsList OPTIONAL,
       ipAddrBlocks [1]       IPList OPTIONAL }
       -- at least one of asID or ipAddrBlocks MUST be present
       ( WITH COMPONENTS { ..., asID PRESENT} |
         WITH COMPONENTS { ..., ipAddrBlocks PRESENT } )

   AsList ::= SEQUENCE (SIZE(1..MAX)) OF ASIdOrRange

   IPList ::= SEQUENCE (SIZE(1..MAX)) OF IPAddressFamilyItem

   IPAddressFamilyItem ::= SEQUENCE {    -- AFI & optional SAFI --
      addressFamily        OCTET STRING (SIZE (2..3)),
      iPAddressOrRange     IPAddressOrRange }

   END

4.1.  version

   The version number of the RpkiSignedChecklist MUST be 0.

4.2.  resources

   The resources contained here are the resources used to mark the
   attestation, and MUST match the set of resources listed by the EE
   certificate carried in the CMS certificates field.

4.3.  digestAlgorithm

   The digest algorithm used to create the message digest of the
   attested digital object.  This algorithm MUST be a hashing algorithm
   defined in [RFC7935].

4.4.  checkList

   This field is a sequence of FilenameAndHash objects.  There is one
   FilenameAndHash entry for each arbitrary object referenced on the
   Signed Checklist.  Each FilenameAndHash is an ordered pair of the
   name of the directory entry containing the digital object and the
   message digest of the digital object.  The filename field is
   OPTIONAL.

5.  RSC Validation

   Before a relying party can use an RSC to validate a set of digital
   objects, the relying party MUST first validate the RSC.  To validate
   an RSC, the relying party MUST perform all the validation checks
   specified in [RFC6488] as well as the following additional RSC-
   specific validation steps.

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   o  The IP address delegation extension [RFC3779] is present in the
      end-entity (EE) certificate (contained within the RSC), and each
      IP address prefix(es) in the RSC is contained within the set of IP
      addresses specified by the EE certificate's IP address delegation
      extension.

   o  For each FilenameAndHash entry in the RSC, if a filename field is
      present, the field's content MUST contain only characters
      specified in the Portable Filename Character Set as defined in
      [POSIX].

   To validate a set of digital objects against an RSC:

   o  The message digest of each referenced digital object, using the
      digest algorithm specified in the the digestAlgorithm field, MUST
      be calculated and MUST match the value given in the messageDigest
      field of the associated FilenameAndHash, for the digital object to
      be considered valid as against the RSC.

6.  Operational Considerations

   When creating digital objects of a plain-text nature (such as ASCII,
   UTF-8, HTML, Javascript, XML, etc) it is RECOMMENDED to convert such
   objects into a lossless compressed form.  Distributing plain-text
   objects within a compression envelope (such as GZIP [RFC1952]) might
   help avoid unexpected canonicalization at intermediate systems (which
   in turn would lead to checksum verification errors).  Validator
   implementations are expected to treat a checksummed digital object as
   string of arbitrary single octets.

   If a filename field is present, but no referenced digital object has
   a filename that matches the content of that field, a validator
   implementation SHOULD compare the message digest of each digital
   object to the value from the messageDigest field of the associated
   FilenameAndHash, and report matches to the client for further
   consideration.

7.  Security Considerations

   Relying parties are hereby warned that the data in a RPKI Signed
   Checklist is self-asserted.  When determining the meaning of any data
   contained in an RPKI Signed Checklist, Relying Parties MUST NOT make
   any assuptions about the signer beyond the fact that it had
   sufficient control of the issuing CA to create the object.  These
   data have not been verified by the Certificate Authority (CA) that
   issued the CA certificate to the entity that issued the EE
   certificate used to validate the Signed Checklist.

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   RPKI Certificates are not bound to real world identities, see
   [I-D.ymbk-sidrops-rpki-has-no-identity] for an elaboration.  Relying
   Parties can only associate real world entities to Internet Number
   Resources by additionally consulting an exogenous authority.  Signed
   Checklists are a tool to communicate assertions 'signed with Internet
   Number Resources', not about any other aspect of the resource
   holder's business operations such as the identity of the resource
   holder itself.

   RSC objects are not distributed through the global RPKI repository
   system, so whether a given CA is making use of them is not
   immediately apparent from the state of the repository.  However,
   because RSC objects depend on EE certificates, and because all
   existing applications for EE certificates involve their publication
   in the repository, an observer may be able to infer indirectly from
   the state of the repository that RSC objects are in use.  For
   example, if the CA sets the serial number on a new EE certificate to
   be one greater than the serial number used for the previous EE
   certificate, then an observer could infer that RSCs are in use if
   there is a gap between serial numbers used in published EE
   certificates.  Similarly, if the CA includes an unpublished serial
   number in a CRL, an observer could infer that an RSC object has been
   revoked.

8.  Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in RFC 7942.
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   According to RFC 7942, "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.
   It is up to the individual working groups to use this information as
   they see fit".

   o  A signer and validator implementation [rpki-rsc-demo] written in
      Perl based on OpenSSL was provided by Tom Harrison from APNIC.

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   o  A signer implementation [rpkimancer] written in Python was
      developed by Ben Maddison.

   o  Example .sig files were created by Job Snijders with the use of
      OpenSSL.

   o  A validator implementation based on OpenBSD rpki-client and
      LibreSSL was developed by Job Snijders.

9.  IANA Considerations

9.1.  SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1)

   The IANA has permanently allocated for this document in the SMI
   Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1)
   registry:

      Decimal   Description             References
      ---------------------------------------------------------------
         48     id-ct-signedChecklist   [draft-ietf-sidrops-rpki-rsc]

   Upon publication of this document, IANA is requested to reference the
   RFC publication instead of this draft.

9.2.  RPKI Signed Objects sub-registry

   The IANA is requested to register the OID for the RPKI Signed
   Checklist in the registry created by [RFC6488] as following:

   Name               OID                          Specification
   -------------------------------------------------------------
   Signed Checklist   1.2.840.113549.1.9.16.1.48   [draft-ietf-sidrops-rpki-rsc]

9.3.  File Extension

   The IANA is requested to add an item for the Signed Checklist file
   extension to the "RPKI Repository Name Scheme" registry created by
   [RFC6481] as follows:

   Filename Extension  RPKI Object           Reference
   -----------------------------------------------------------------------
      .sig             Signed Checklist      [draft-ietf-sidrops-rpki-rsc]

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9.4.  SMI Security for S/MIME Module Identifier
      (1.2.840.113549.1.9.16.0)

   The IANA is requested to add an item to the "SMI Security for S/MIME
   Module Identifier" registry as follows:

   Decimal   Description                       References
   -------------------------------------------------------------------------
     TBD     id-mod-rpkiSignedChecklist-2021   [draft-ietf-sidrops-rpki-rsc]

9.5.  Media Type

   The IANA is requested to register the media type application/rpki-
   checklist in the Provisional Standard Media Type registry as follows:

      Type name: application
      Subtype name: rpki-checklist
      Required parameters: None
      Optional parameters: None
      Encoding considerations: binary
      Security considerations: Carries an RPKI Signed Checklist
                               [RFC-TBD].
      Interoperability considerations: None
      Published specification: This document.
      Applications that use this media type: RPKI operators.
      Additional information:
        Content: This media type is a signed object, as defined
            in [RFC6488], which contains a payload of a list of
            checksums as defined above in this document.
        Magic number(s): None
        File extension(s): .sig
        Macintosh file type code(s):
      Person & email address to contact for further information:
        Job Snijders <job@fastly.com>
      Intended usage: COMMON
      Restrictions on usage: None
      Author: Job Snijders <job@fastly.com>
      Change controller: Job Snijders <job@fastly.com>

10.  References

10.1.  Normative References

   [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>.

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   [RFC3779]  Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
              Addresses and AS Identifiers", RFC 3779,
              DOI 10.17487/RFC3779, June 2004,
              <https://www.rfc-editor.org/info/rfc3779>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <https://www.rfc-editor.org/info/rfc5652>.

   [RFC6481]  Huston, G., Loomans, R., and G. Michaelson, "A Profile for
              Resource Certificate Repository Structure", RFC 6481,
              DOI 10.17487/RFC6481, February 2012,
              <https://www.rfc-editor.org/info/rfc6481>.

   [RFC6486]  Austein, R., Huston, G., Kent, S., and M. Lepinski,
              "Manifests for the Resource Public Key Infrastructure
              (RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012,
              <https://www.rfc-editor.org/info/rfc6486>.

   [RFC6488]  Lepinski, M., Chi, A., and S. Kent, "Signed Object
              Template for the Resource Public Key Infrastructure
              (RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012,
              <https://www.rfc-editor.org/info/rfc6488>.

   [RFC7935]  Huston, G. and G. Michaelson, Ed., "The Profile for
              Algorithms and Key Sizes for Use in the Resource Public
              Key Infrastructure", RFC 7935, DOI 10.17487/RFC7935,
              August 2016, <https://www.rfc-editor.org/info/rfc7935>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

10.2.  Informative References

   [I-D.ietf-sidrops-rpki-rta]
              Michaelson, G., Huston, G., Harrison, T., Bruijnzeels, T.,
              and M. Hoffmann, "A profile for Resource Tagged
              Attestations (RTAs)", draft-ietf-sidrops-rpki-rta-00 (work
              in progress), January 2021.

   [I-D.ymbk-sidrops-rpki-has-no-identity]
              Bush, R. and R. Housley, "The I in RPKI does not stand for
              Identity", draft-ymbk-sidrops-rpki-has-no-identity-00
              (work in progress), March 2021.

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   [POSIX]    IEEE and The Open Group, "The Open Group's Base
              Specifications, Issue 7", 2016,
              <https://publications.opengroup.org/standards/unix/c165>.

   [RFC1952]  Deutsch, P., "GZIP file format specification version 4.3",
              RFC 1952, DOI 10.17487/RFC1952, May 1996,
              <https://www.rfc-editor.org/info/rfc1952>.

   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
              February 2012, <https://www.rfc-editor.org/info/rfc6480>.

   [rpki-rsc-demo]
              Harrison, T., "A proof-of-concept for constructing and
              validating RPKI Signed Checklists (RSCs).", February 2021,
              <https://github.com/APNIC-net/rpki-rsc-demo>.

   [rpkimancer]
              Maddison, B., "rpkimancer", May 2021,
              <https://github.com/benmaddison/rpkimancer>.

   [signify]  Unangst, T. and M. Espie, "signify - cryptographically
              sign and verify files", May 2014,
              <https://man.openbsd.org/signify>.

Appendix A.  Acknowledgements

   The authors wish to thank George Michaelson, Tom Harrison, Geoff
   Huston, Randy Bush, Stephen Kent, Matt Lepinski, Rob Austein, Ted
   Unangst, and Marc Espie for prior art.  The authors thank Russ
   Housley for reviewing the ASN.1 notation and providing suggestions.
   The authors would like to thank Nimrod Levy, and Tim Bruijnzeels for
   document review and suggestions.

Appendix B.  Document changelog - RFC EDITOR: REMOVE BEFORE PUBLICATION

B.1.  changes from -02 -> -03

   o  Reference the IANA assigned OID

   o  Clarify validation rules

B.2.  changes from -01 -> -02

   o  Clarify RSC is part of a puzzle, not panacea.  Thanks Randy & Russ

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B.3.  changes from -00 -> -01

   o  Readability improvements

   o  Update document category to match the registry allocation policy
      requirement.

B.4.  individual submission phase

   o  On-the-wire change: the 'Filename' switched from 'required' to
      'optional'.  Some SIDROPS Working Group participants proposed a
      checksum itself is the most minimal information required to
      address digital objects.

Authors' Addresses

   Job Snijders
   Fastly
   Amsterdam
   Netherlands

   Email: job@fastly.com

   Tom Harrison
   Asia Pacific Network Information Centre
   6 Cordelia St
   South Brisbane, QLD  4101
   Australia

   Email: tomh@apnic.net

   Ben Maddison
   Workonline Communications
   Cape Town
   South Africa

   Email: benm@workonline.africa

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