Network Working Group A. Azimov Internet-Draft Yandex Intended status: Standards Track E. Uskov Expires: 27 April 2023 JetLend R. Bush Internet Initiative Japan J. Snijders Fastly R. Housley Vigil Security B. Maddison Workonline 24 October 2022 A Profile for Autonomous System Provider Authorization draft-ietf-sidrops-aspa-profile-11 Abstract This document defines a profile for the Autonomous System Provider Authorization (ASPA) object in the Resource Public Key Infrastructure (RPKI). An ASPA is a digitally signed object that provides a means of validating that a Customer Autonomous System (CAS) has authorized the members of a specified Provider AS set as its upstream provider(s) and/or connected Internet-exchange route server(s). 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/. Azimov, et al. Expires 27 April 2023 [Page 1] Internet-Draft ASPA Profile October 2022 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 27 April 2023. Copyright Notice Copyright (c) 2022 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. ASPA Content Type . . . . . . . . . . . . . . . . . . . . . . 4 3. ASPA eContent . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. version . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. customerASID . . . . . . . . . . . . . . . . . . . . . . 6 3.3. providers . . . . . . . . . . . . . . . . . . . . . . . . 6 3.3.1. ProviderAS . . . . . . . . . . . . . . . . . . . . . 6 3.3.1.1. providerASID . . . . . . . . . . . . . . . . . . 6 3.3.1.2. afiLimit . . . . . . . . . . . . . . . . . . . . 6 4. ASPA Validation . . . . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. Implementation status . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Azimov, et al. Expires 27 April 2023 [Page 2] Internet-Draft ASPA Profile October 2022 1. Introduction The primary purpose of the Resource Public Key Infrastructure (RPKI) is to improve routing security [RFC6480]. As part of this infrastructure, a mechanism is needed to facilitate holders of Autonomous System (AS) numbers in their capacity as Customer to authorize other ASes as their Provider(s). A Provider AS (PAS) is a network that: a. offers its customers outbound (customer to Internet) data traffic connectivity and/or b. further propagates in all directions (towards providers, lateral peers, and customers) any BGP Updates that the customer may send. The digitally signed Autonomous System Provider Authorization (ASPA) object described in this document provides the above-mentioned authorization mechanism. The ASPA object is a cryptographically signed attestation by a Customer AS (CAS) that another AS listed in the ASPA is a Provider. When the CAS has multiple Providers, all Provider ASes are listed in the ASPA including any internet exchange point (IXP) route server (RS) AS that serves the CAS. 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]. Azimov, et al. Expires 27 April 2023 [Page 3] Internet-Draft ASPA Profile October 2022 2. ASPA Content Type The content-type for an ASPA is defined as id-ct-ASPA, which has the numerical value of 1.2.840.113549.1.9.16.1.49. 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. ASPA eContent The content of an ASPA identifies the Customer AS (CAS) as well as the Set of Provider ASes (SPAS) that are authorized by the CAS to be its Providers. Not all route servers (RS) at internet exchange points are transparent, e.g., in some cases the AS number of the RS would be present in the AS_PATH. In this case, the RS AS is acting as a provider AS, which propagates routes between its clients (i.e., customers). Thus, a CAS MUST add both upstream providers and any connected non-transparent RS AS to its SPAS. If a Customer AS is connected to multiple transit providers/non- transparent route servers, all Provider ASes MUST be registered in a single ASPA object. This rule is important to avoid possible race conditions during updates of ASPAs. The eContent of an ASPA is an instance of ASProviderAttestation, formally defined by the following ASN.1 [X680] module: Azimov, et al. Expires 27 April 2023 [Page 4] Internet-Draft ASPA Profile October 2022 RPKI-ASPA-2022 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-rpki-aspa-2022(TBD) } 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) } ; id-ct-ASPA OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) id-smime(16) id-ct(1) 49 } ct-ASPA CONTENT-TYPE ::= { TYPE ASProviderAttestation IDENTIFIED BY id-ct-ASPA } ASProviderAttestation ::= SEQUENCE { version [0] ASPAVersion DEFAULT v0, customerASID ASID, providers ProviderASSet } ASPAVersion ::= INTEGER { v0(0) } ProviderASSet ::= SEQUENCE (SIZE(1..MAX)) OF ProviderAS ProviderAS ::= SEQUENCE { providerASID ASID, afiLimit AddressFamilyIdentifier OPTIONAL } ASID ::= INTEGER (0..4294967295) AddressFamilyIdentifier ::= OCTET STRING (SIZE (2)) END 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. Azimov, et al. Expires 27 April 2023 [Page 5] Internet-Draft ASPA Profile October 2022 3.2. customerASID The customerASID field contains the AS number of the Customer Autonomous System that is the authorizing entity. 3.3. providers The providers field contains the listing of ASes that are authorized as providers or route servers in the specified address family. Each element contained in the providers field is an instance of ProviderAS. In addition to the constraints described by the formal ASN.1 definition, the contents of the providers field MUST satisfy the following constraints: * The CustomerASID value MUST NOT appear in any providerASID field. * The elements of providers MUST be ordered in ascending numerical order by the value of the providerASID field. * Each value of providerASID MUST be unique (with respect to the other elements of providers). 3.3.1. ProviderAS 3.3.1.1. providerASID The providerASID field contains the AS number of an AS that has been authorized by the customer AS as its provider or RS in the specified address family. 3.3.1.2. afiLimit The afiLimit field optionally constrains the authorization given to the provider AS to a single address family. If present, it contains the two-octet Address Family Identifier (AFI) for which the relation between the customer and provider is authorized. This specification only supports IPv4 and IPv6. Therefore, the value MUST be either 0001 or 0002, as specified in the Address Family Numbers registry [IANA-AF] maintained by IANA. If omitted, the authorization is valid for both IPv4 and IPv6 announcements. Azimov, et al. Expires 27 April 2023 [Page 6] Internet-Draft ASPA Profile October 2022 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 steps. * The Autonomous System Identifier Delegation Extension [RFC3779] MUST be present in the end-entity (EE) certificate (contained within the ASPA), and the Customer ASID in the ASPA eContent MUST be contained within the set of AS numbers specified by the EE certificate's Autonomous System Identifier Delegation Extension. The EE certificate's Autonomous System Identifier Delegation Extension MUST NOT contain any "inherit" elements. * The IP Address Delegation Extension [RFC3779] MUST be absent. 5. IANA Considerations Please add the id-mod-rpki-aspa-2022 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-2022 | [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 ----------------------------------------------------------- 49 | id-ct-ASPA | [ThisRFC] Please add Autonomous System Provider Authorization to the RPKI Signed Object registry (https://www.iana.org/assignments/rpki/ rpki.xhtml#signed-objects) as follows: Name | OID | Specification -------------------------------------------------------------------------------------- Autonomous System Provider Authorization | 1.2.840.113549.1.9.16.1.49 | [ThisRFC] Please add an item for the Autonomous System Provider Authorization file extension to the "RPKI Repository Name Scheme" registry created by [RFC6481] as follows: Azimov, et al. Expires 27 April 2023 [Page 7] Internet-Draft ASPA Profile October 2022 Filename Extension RPKI Object Reference -------------------------------------------------------------------------------------- .asa Autonomous System Provider Authorization [draft-ietf-sidrops-aspa-profile] 6. Security Considerations While it is not technically enforcable, it is highly recommended that for a given Customer AS, a single ASPA object be maintained which contains all providers/route servers. Administrating all providers in a single object helps prevent race conditions during ASPA updates that might affect prefix propagation. The software that provides hosting for ASPA records SHOULD support enforcement of this rule. In the case of the transition process between different CA registries, the ASPA records SHOULD be kept identical in all registries in terms of their authorization contents. 7. Implementation status This section is to be removed before publishing as an RFC. 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". * A validator implementation [rpki-client] (version 8.0 and higher), written in C was provided by Job Snijders from Fastly. * A signer and decoder implementation [rpkimancer] written in Python was provided by Ben Maddison from Workonline. Azimov, et al. Expires 27 April 2023 [Page 8] Internet-Draft ASPA Profile October 2022 * A signer implementation [krill] written in Rust was provided by Tim Bruijnzeels from NLnetLabs. * At IETF114 Ties de Kock from RIPE NCC shared a signer implementation had been developed internally. * Di Ma reported success [rpstir2] in RPSTIR2 validating objects produced by Tim Bruijnzeels. * A signer implementation [koenvh] written in PHP based on OpenSSL was provided by Koen van Hove. * A signer implementation [aspa-demo] written in Perl based on OpenSSL was provided by Tom Harrison from APNIC. 8. Acknowledgments The authors would like to thank Keyur Patel for helping kick-start the ASPA profile project, Ties de Kock & Tim Bruijnzeels for suggesting that the ProviderASSet be in a canonical form, and Kotikalapudi Sriram for review and several suggestions for improvements. 9. References 9.1. 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, . [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, . [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, DOI 10.17487/RFC5652, September 2009, . [RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for Resource Certificate Repository Structure", RFC 6481, DOI 10.17487/RFC6481, February 2012, . Azimov, et al. Expires 27 April 2023 [Page 9] Internet-Draft ASPA Profile October 2022 [RFC6485] Huston, G., "The Profile for Algorithms and Key Sizes for Use in the Resource Public Key Infrastructure (RPKI)", RFC 6485, DOI 10.17487/RFC6485, February 2012, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [X680] ITU-T, "Information technology -- Abstract Syntax Notation One (ASN.1): Specification of basic notation", ITU-T Recommendation X.680, 2015. [X690] ITU-T, "Information Technology -- ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", ITU-T Recommendation X.690, 2015. 9.2. Informative References [aspa-demo] Harrison, T., "RPKI ASPA Demo", 2022, . [IANA-AF] IANA, "Address Family Numbers", . [koenvh] van Hove, K., "Relying Party Resiliency Platform", 2022, . [krill] Bruijnzeels, T., "Krill", 2022, . [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, February 2012, . [rpki-client] Snijders, J., "rpki-client", 2022, . Azimov, et al. Expires 27 April 2023 [Page 10] Internet-Draft ASPA Profile October 2022 [rpkimancer] Maddison, B., "rpkimancer-aspa", 2022, . [rpstir2] Ma, D., "RPSTIR2", 2022, . Authors' Addresses Alexander Azimov Yandex Email: a.e.azimov@gmail.com Eugene Uskov JetLend Email: eu@jetlend.ru Randy Bush Internet Initiative Japan Email: randy@psg.com Job Snijders Fastly Amsterdam Netherlands Email: job@fastly.com Russ Housley Vigil Security, LLC 918 Spring Knoll Drive Herndon, VA 20170 United States of America Email: housley@vigilsec.com Ben Maddison Workonline Cape Town South Africa Email: benm@workonline.africa Azimov, et al. Expires 27 April 2023 [Page 11]