]> Fastly

Amsterdam The Netherlands job@fastly.com

Workonline

Cape Town South Africa benm@workonline.africa

Carleton College

mlepinski@carleton.edu

Raytheon

derrick.kong@raytheon.com

Independent

kent@alum.mit.edu

Operations and Management Area (OPS) sidrops RPKI Routing Security BGP This document defines a standard profile for Route Origin Authorizations (ROAs). A ROA is a digitally signed object that provides a means of verifying that an IP address block holder has authorized an Autonomous System (AS) to originate routes to one or more prefixes within the address block. This document obsoletes RFC 6482.

Introduction The primary purpose of the Resource Public Key Infrastructure (RPKI) is to improve routing security. (See for more information.) As part of this system, a mechanism is needed to allow entities to verify that an Autonomous System (AS) has been given permission by an IP address block holder to advertise routes to one or more prefixes within that block. A Route Origin Authorization (ROA) provides this function. The ROA makes use of the template for RPKI digitally signed objects , which defines a Cryptographic Message Syntax (CMS) wrapper for the ROA content as well as a generic validation procedure for RPKI signed objects. Therefore, to complete the specification of the ROA (see ), this document defines:

• The OID that identifies the signed object as being a ROA. (This OID appears within the eContentType in the encapContentInfo object as well as the content-type signed attribute in the signerInfo object.)
• The ASN.1 syntax for the ROA eContent. (This is the payload that specifies the AS being authorized to originate routes as well as the prefixes to which the AS may originate routes.) The ROA eContent is ASN.1 encoded using the Distinguished Encoding Rules (DER) .
• Additional steps required to validate ROAs (in addition to the validation steps specified in ).

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 when, and only when, they appear in all capitals, as shown here.

Changes from RFC 6482 This section summarizes the significant changes between and the profile described in this document.

• Clarified the requirements for the IP address and AS identifier X.509 certificate extensions.
• Strengthened the ASN.1 formal notation and definitions.
• Incorporated errata for RFC 6482.
• Added an example ROA eContent payload, and a complete ROA (Appendix A).
• Specified a canonicalization procedure for the content of ipAddrBlocks.

Related Work It is assumed that the reader is familiar with the terms and concepts described in "" and "" . Additionally, this document makes use of the RPKI signed object profile ; thus, familiarity with that document is assumed. Note that the RPKI signed object profile makes use of certificates adhering to the RPKI resource certificate profile ; thus, familiarity with that profile is also assumed.

The ROA Content Type The content-type for a ROA is defined as id-ct-routeOriginAuthz and has the numerical value 1.2.840.113549.1.9.16.1.24. This OID MUST appear within both the eContentType in the encapContentInfo object and the content-type signed attribute in the signerInfo object (see ).

The ROA eContent The content of a ROA identifies a single AS that has been authorized by the address space holder to originate routes and a list of one or more IP address prefixes that will be advertised. If the address space holder needs to authorize multiple ASes to advertise the same set of address prefixes, the holder issues multiple ROAs, one per AS number. A ROA is formally defined as: RPKI-ROA-2023 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) mod(0) id-mod-rpkiROA-2023(75) } DEFINITIONS EXPLICIT TAGS ::= BEGIN IMPORTS CONTENT-TYPE FROM CryptographicMessageSyntax-2010 -- in [RFC6268] { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) } ; ct-routeOriginAttestation CONTENT-TYPE ::= { TYPE RouteOriginAttestation IDENTIFIED BY id-ct-routeOriginAuthz } id-ct-routeOriginAuthz OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) id-smime(16) id-ct(1) routeOriginAuthz(24) } RouteOriginAttestation ::= SEQUENCE { version [0] INTEGER DEFAULT 0, asID ASID, ipAddrBlocks SEQUENCE (SIZE(1..2)) OF ROAIPAddressFamily } ASID ::= INTEGER (0..4294967295) ROAIPAddressFamily ::= SEQUENCE { addressFamily ADDRESS-FAMILY.&afi ({AddressFamilySet}), addresses ADDRESS-FAMILY.&Addresses ({AddressFamilySet}{@addressFamily}) } ADDRESS-FAMILY ::= CLASS { &afi OCTET STRING (SIZE(2)) UNIQUE, &Addresses } WITH SYNTAX { AFI &afi ADDRESSES &Addresses } AddressFamilySet ADDRESS-FAMILY ::= { addressFamilyIPv4 | addressFamilyIPv6 } addressFamilyIPv4 ADDRESS-FAMILY ::= { AFI afi-IPv4 ADDRESSES ROAAddressesIPv4 } addressFamilyIPv6 ADDRESS-FAMILY ::= { AFI afi-IPv6 ADDRESSES ROAAddressesIPv6 } afi-IPv4 OCTET STRING ::= '0001'H afi-IPv6 OCTET STRING ::= '0002'H ROAAddressesIPv4 ::= SEQUENCE (SIZE(1..MAX)) OF ROAIPAddress{ub-IPv4} ROAAddressesIPv6 ::= SEQUENCE (SIZE(1..MAX)) OF ROAIPAddress{ub-IPv6} ub-IPv4 INTEGER ::= 32 ub-IPv6 INTEGER ::= 128 ROAIPAddress {INTEGER: ub} ::= SEQUENCE { address BIT STRING (SIZE(0..ub)), maxLength INTEGER (0..ub) OPTIONAL } END

The version Element The version number of the RouteOriginAttestation entry MUST be 0.

The asID Element The asID element contains the AS number that is authorized to originate routes to the given IP address prefixes.

The ipAddrBlocks Element The ipAddrBlocks element encodes the set of IP address prefixes to which the AS is authorized to originate routes. Note that the syntax here is more restrictive than that used in the IP address delegation extension defined in . That extension can represent arbitrary address ranges, whereas ROAs need to represent only IP prefixes.

Type ROAIPAddressFamily Within the ROAIPAddressFamily structure, the addressFamily element contains the Address Family Identifier (AFI) of an IP address family. This specification only supports IPv4 and IPv6; therefore, addressFamily MUST be either 0001 or 0002. IPv4 prefixes MUST NOT appear as IPv4-mapped IPv6 addresses (). There MUST be only one instance of ROAIPAddressFamily per unique AFI in the ROA. Thus, the ROAIPAddressFamily structure MUST NOT appear more than twice. The addresses field contains IP prefixes as a sequence of type ROAIPAddress.

Type ROAIPAddress A ROAIPAddress structure is a sequence containing an address element of type BIT STRING and an optional maxLength element of type INTEGER.

The address Element The address element is of type BIT STRING and represents a single IP address prefix. This field uses the same representation of an IP address prefix as a BIT STRING as the IPAddress type defined in .

The maxLength Element When present, the maxLength element specifies the maximum length of the IP address prefix that the AS is authorized to advertise. The maxLength element SHOULD NOT be encoded if the maximum length is equal to the prefix length. Certification Authorities SHOULD anticipate that future Relying Parties will become increasingly stringent in considering the presence of superfluous maxLength elements an encoding error. If present, the maxLength element MUST be:

• an integer greater than or equal to the length of the accompanying prefix, and
• less than or equal to the maximum length (in bits) of an IP address in the applicable address family: 32 in the case of IPv4 and 128 in the case of IPv6.

For example, if the IP address prefix is 203.0.113.0/24 and maxLength is 26, the AS is authorized to advertise any more-specific prefix with a maximum length of 26. In this example, the AS would be authorized to advertise 203.0.113.0/24, 203.0.113.128/25, or 203.0.113.192/26, but not 203.0.113.0/27. See for more information on the use of maxLength. When the maxLength element is not present, the AS is only authorized to advertise the exact prefix specified in the ROAIPAddress structure's address element.

Note on Overlapping or Superfluous Information Encoding Note that a valid ROA may contain an IP address prefix (within a ROAIPAddress element) that is encompassed by another IP address prefix (within a separate ROAIPAddress element). For example, a ROA may contain the prefix 203.0.113.0/24 with maxLength 26, as well as the prefix 203.0.113.0/28 with maxLength 28. This ROA would authorize the indicated AS to advertise any prefix beginning with 203.0.113 with a minimum length of 24 and a maximum length of 26, as well as the specific prefix 203.0.113.0/28. Additionally, a ROA MAY contain two ROAIPAddress elements, where the IP address prefix is identical in both cases. However, this is NOT RECOMMENDED, because in such a case, the ROAIPAddress element with the shorter maxLength grants no additional privileges to the indicated AS and thus can be omitted without changing the meaning of the ROA.

Canonical Form for ipAddrBlocks As the data structure described by the ROA ASN.1 module allows for many different ways to represent the same set of IP address information, a canonical form is defined such that every set of IP address information has a unique representation. In order to produce and verify this canonical form, the process described in this section SHOULD be used to ensure that information elements are unique with respect to one another and sorted in ascending order. Certification Authorities SHOULD anticipate that future Relying Parties will impose a strict requirement for the ipAddrBlocks field to be in this canonical form. This canonicalization procedure builds upon the canonicalization procedure specified in . In order to semantically compare, sort, and deduplicate the contents of the ipAddrBlocks field, each ROAIPAddress element is mapped to an abstract data element composed of four integer values:

afi

The AFI value appearing in the addressFamily field of the containing ROAIPAddressFamily as an integer.

addr

The first IP address of the IP prefix appearing in the ROAIPAddress address field, as a 32-bit (IPv4) or 128-bit (IPv6) integer value.

plen

The length of the IP prefix appearing in the ROAIPAddress address field as an integer value.

mlen

The value appearing in the maxLength field of the ROAIPAddress element, if present; otherwise, the above prefix length value.

Thus, the equality or relative order of two ROAIPAddress elements can be tested by comparing their abstract representations.

Comparator The set of ipAddrBlocks is totally ordered. The order of two ipAddrBlocks is determined by the first non-equal comparison in the following list.

1. Data elements with a lower afi value precede data elements with a higher afi value.
2. Data elements with a lower addr value precede data elements with a higher addr value.
3. Data elements with a lower plen value precede data elements with a higher plen value.
4. Data elements with a lower mlen value precede data elements with a higher mlen value.

Data elements for which all four values compare equal are duplicates of one another.

Example Implementations

• A sorting implementation in ISO/IEC 9899:1999 ("ANSI C99").
• A sorting implementation in the Rust 2021 Edition.

ROA Validation Before a Relying Party can use a ROA to validate a routing announcement, the Relying Party MUST first validate the ROA. To validate a ROA, the Relying Party MUST perform all the validation checks specified in as well as the following additional ROA-specific validation steps:

• The IP address delegation extension is present in the end-entity (EE) certificate (contained within the ROA), and every IP address prefix in the ROA payload is contained within the set of IP addresses specified by the EE certificate's IP address delegation extension.
• The EE certificate's IP address delegation extension MUST NOT contain "inherit" elements as described in .
• The Autonomous System identifier delegation extension described in is not used in ROAs and MUST NOT be present in the EE certificate.
• The ROA content fully conforms with all requirements specified in Sections  and .

If any of the above checks fail, the ROA in its entirety MUST be considered invalid and an error SHOULD be logged.

Security Considerations There is no assumption of confidentiality for the data in a ROA; it is anticipated that ROAs will be stored in repositories that are accessible to all ISPs, and perhaps to all Internet users. There is no explicit authentication associated with a ROA, since the PKI used for ROA validation provides authorization but not authentication. Although the ROA is a signed, application-layer object, there is no intent to convey non-repudiation via a ROA. The purpose of a ROA is to convey authorization for an AS to originate a route to the prefix or prefixes in the ROA. Thus, the integrity of a ROA MUST be established. This ROA specification makes use of the RPKI signed object format; thus, all security considerations discussed in also apply to ROAs. Additionally, the signed object profile uses the CMS signed message format for integrity; thus, ROAs inherit all security considerations associated with that data structure. The right of the ROA signer to authorize the target AS to originate routes to the prefix or prefixes is established through the use of the address space and AS number PKI as described in . Specifically, one MUST verify the signature on the ROA using an X.509 certificate issued under this PKI and check that the prefix or prefixes in the ROA are contained within those in the certificate's IP address delegation extension.

IANA Considerations

SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1) IANA has updated the id-ct-routeOriginAuthz entry in the "SMI Security for S&wj;/MIME CMS Content Type (1.2.840.113549.1.9.16.1)" registry as follows:

Decimal	Description	References
24	id-ct-routeOriginAuthz	RFC 9582

RPKI Signed Objects Registry IANA has updated the Route Origination Authorization entry in the "RPKI Signed Objects" registry created by as follows:

Name	OID	Reference
Route Origination Authorization	1.2.840.113549.1.9.16.1.24	RFC 9582

File Extension IANA has updated the entry for the ROA file extension in the "RPKI Repository Name Schemes" registry created by as follows:

Filename Extension	RPKI Object	Reference
.roa	Route Origination Authorization	RFC 9582

SMI Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0) IANA has allocated the following entry in the "SMI Security for S&wj;/MIME Module Identifier (1.2.840.113549.1.9.16.0)" registry:

Decimal	Description	References
75	id-mod-rpkiROA-2023	RFC 9582

Media Type IANA has updated the media type application/rpki-roa in the "Media Types" registry as follows:

Type name:

application

Subtype name:

rpki-roa

Required parameters:

N/A

Optional parameters:

N/A

Encoding considerations:

binary

Security considerations:

Carries an RPKI ROA (RFC 9582). This media type contains no active content. See Section 6 of RFC 9582 for further information.

Interoperability considerations:

None

Published specification:

RFC 9582

Applications that use this media type:

RPKI operators

Additional information:

Content:

This media type is a signed object, as defined in , which contains a payload of a list of prefixes and an AS identifier as defined in RFC 9582.

Magic number(s):

None

File extension(s):

.roa

Macintosh file type code(s):

None

Person & email address to contact for further information:

Job Snijders <job@fastly.com>

Intended usage:

COMMON

Restrictions on usage:

None

Change controller:

IETF

References Normative References ITU-T Informative References commit 68969ea commit 023e756

Example ROA eContent Payload An example of a DER-encoded ROA eContent is provided below, with annotation following the "#" character. Below is a complete RPKI ROA signed object, Base64 encoded per. The object in this appendix has the following properties:

Acknowledgements The authors wish to thank , , , , , , , and for their help and contributions. Additionally, the authors thank , , , , , , , , and for their careful reviews and helpful comments.