A Profile for Autonomous System Provider Authorization
draft-ietf-sidrops-aspa-profile-02

Abstract

This document defines a standard profile for Autonomous System Provider Authorization in the Resource Public Key Infrastructure. An Autonomous System Provider Authorization is a digitally signed object that provides a means of verifying that a Customer Autonomous System holder has authorized members of Provider set to be its upstream providers and for the Providers to send prefixes received from the Customer Autonomous System in all directions including providers and peers.

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."

This Internet-Draft will expire on September 10, 2020.

Copyright Notice

Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. The ASPA Content Type
• 3. The ASPA eContent
• 3.1. version
• 3.2. AFI
• 3.3. customerASID
• 3.4. providerASSET
• 4. ASPA Validation
• 5. ASN.1 Module for the ASPA Content Type
• 6. IANA Considerations
• 7. Security Considerations
• 8. Acknowledgments
• 9. References
• 9.1. Normative References
• 9.2. Informative References
• Authors' Addresses

1. Introduction

The primary purpose of the Resource Public Key Infrastructure (RPKI) is to improve routing security. (See [RFC6480] for more information.) As part of this infrastructure, a mechanism is needed to verify that a AS has permission from a Customer AS (CAS) holder to send routes in all directions. The digitally signed Autonomous System Provider Authorization (ASPA) object provides this verification mechanism.

The ASPA uses the template for RPKI digitally signed objects [RFC6488], which defines a Cryptographic Message Syntax (CMS) [RFC5652] wrapper for the ASPA content as well as a generic validation procedure for RPKI signed objects. As ASPAs need to be validated with RPKI certificates issued by the current infrastructure, we assume the mandatory-to-implement algorithms in [RFC6485], or its successor.

To complete the specification of the ASPA (see Section 4 of [RFC6488]), this document defines:

1. The object identifier (OID) that identifies the ASPA signed object. This OID appears in the eContentType field of the encapContentInfo object as well as the content-type signed attribute within the signerInfo structure).
2. The ASN.1 syntax for the ASPA content, which is the payload signed by the CAS. The ASPA content is encoded using the ASN.1 [X680] Distinguished Encoding Rules (DER) [X690].
3. The steps required to validate an ASPA beyond the validation steps specified in [RFC6488]).

2. The ASPA Content Type

The content-type for an ASPA is defined as id-cct-ASPA, which has the numerical value of 1.2.840.113549.1.9.16.1.TBD. This OID MUST appear both within the eContentType in the encapContentInfo structure as well as the content-type signed attribute within the signerInfo structure (see [RFC6488]).

3. The ASPA eContent

The content of an ASPA identifies the Customer AS (CAS) as well as the Set of Provider ASes (SPAS) that are authorized to further propagate announcements received from the customer. If customer has multiple providers they MUST be registered in a single ASPA object. This rule is important to avoid possible race conditions during updates. An ASPA is formally defined as:

    ct-ASPA CONTENT-TYPE ::=
        { ASProviderAttestation IDENTIFIED BY id-ct-ASPA }

    id-ct-ASPA OBJECT IDENTIFIER ::= { id-ct TBD }

    ASProviderAttestation ::= SEQUENCE {
        version [0] ASPAVersion DEFAULT v0,
        AFI  AddressFamilyIdentifier,
        customerASID  ASID,
        providerASSET  SEQUENCE (SIZE(1..MAX)) OF ASID }

    ASPAVersion ::= INTEGER  { v0(0) }

    AddressFamilyIdentifier ::= OCTET STRING (SIZE (2..3))

    ASID ::= INTEGER
                

Note that this content appears as the eContent within the encapContentInfo as specified in [RFC6488].

3.1. version

The version number of the ASProviderAttestation MUST be v0.

3.2. AFI

The AFI field contains Address Family Identifier for which the relation between customer and provider ASes is authorized. Presently defined values for the Address Family Identifier field are specified in the IANA's Address Family Numbers registry [IANA-AF].

3.3. customerASID

The customerASID field contains the AS number of the Autonomous System that authorizes an upstream providers (listed in the providerASSET) to propagate prefixes in the specified address family other ASes.

3.4. providerASSET

The providerASSET contains the sequence (set) of AS numbers that are authorized to further propagate announcements in the specified address family received from the customer.

4. ASPA Validation

Before a relying party can use an ASPA to validate a routing announcement, the relying party MUST first validate the ASPA object itself. To validate an ASPA, the relying party MUST perform all the validation checks specified in [RFC6488] as well as the following additional ASPA-specific validation step.

• The autonomous system identifier delegation extension [RFC3779] is present in the end-entity (EE) certificate (contained within the ASPA), and the customer AS number in the ASPA is contained within the set of AS numbers specified by the EE certificate's autonomous system identifier delegation extension.

5. ASN.1 Module for the ASPA Content Type

    RPKI-ASPA-2018
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
           pkcs-9(9) smime(16) modules(0) id-mod-rpki-aspa-2018(TBD2) }
    DEFINITIONS IMPLICIT TAGS ::=
    BEGIN
    IMPORTS
  
    CONTENT-TYPE
    FROM CryptographicMessageSyntax-2010  -- RFC 6268
        { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
           pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) } ;

    ContentSet CONTENT-TYPE ::= { ct-ASPA, ... }

    --
    -- ASPA Content Type
    --

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

    id-ct OBJECT IDENTIFIER ::= { id-smime 1 }
  
    id-ct-ASPA OBJECT IDENTIFIER ::= { id-ct TBD }
  
    ct-ASPA CONTENT-TYPE ::=
        { TYPE ASProviderAttestation IDENTIFIED BY id-ct-ASPA }

    ASProviderAttestation ::= SEQUENCE {
        version [0] ASPAVersion DEFAULT v0,
        AFI  AddressFamilyIdentifier,
        customerASID  ASID,
        providerASSET  SEQUENCE (SIZE(1..MAX)) OF ASID }

    ASPAVersion ::= INTEGER  { v0(0) }

    AddressFamilyIdentifier ::= INTEGER

    ASID ::= INTEGER

    END
                

6. IANA Considerations

Please add the id-mod-rpki-aspa-2018 to the SMI Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0) registry (https://www.iana.org/assignments/smi-numbers/smi-numbers.xml#security-smime-0) as follows:

    Decimal   | Description                   | Specification
    -----------------------------------------------------------
    TBD2      | id-mod-rpki-aspa-2018         | [ThisRFC]
                   

Please add the ASPA to the SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1) registry (https://www.iana.org/assignments/smi-numbers/smi-numbers.xml#security-smime-1) as follows:

    Decimal   | Description                   | Specification
    -----------------------------------------------------------
    TBD       | id-ct-ASPA                    | [ThisRFC]
                   

Please add the ASPA to the RPKI Signed Object registry (https://www.iana.org/assignments/rpki/rpki.xhtml#signed-objects) as follows:

    Name      | OID                           | Specification
    -----------------------------------------------------------
    ASPA      | 1.2.840.113549.1.9.16.1.TBD   | [ThisRFC]
                   

7. Security Considerations

8. Acknowledgments

9. References

9.1. Normative References

9.2. Informative References

Authors' Addresses