This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by
the Internet Engineering Steering Group (IESG). Further
information on Internet Standards is available in Section 2 of
RFC 7841.¶
Information about the current status of this document, any
errata, and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9582.¶
The primary purpose of the Resource Public Key Infrastructure (RPKI) is to improve routing security.
(See [RFC6480] 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 [RFC6488], which defines a Cryptographic Message Syntax (CMS) wrapper [RFC5652] for the ROA content as well as a generic validation procedure for RPKI signed objects.
Therefore, to complete the specification of the ROA (see Section 4 of [RFC6488]), 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) [X.690].¶
-
Additional steps required to validate ROAs (in addition to the validation steps specified in [RFC6488]).¶
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.¶
This section summarizes the significant changes between [RFC6482] 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.¶
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 [RFC6488]).¶
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 number of the RouteOriginAttestation entry MUST be 0.¶
The asID element contains the AS number that is authorized to originate routes to the given IP address prefixes.¶
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 [RFC3779].
That extension can represent arbitrary address ranges, whereas ROAs need to represent only IP prefixes.¶
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 (Section 2.5.5.2 of [RFC4291]).¶
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.¶
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 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 Section 2.2.3.8 of [RFC3779].¶
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 [RFC9319] 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 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.¶
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 Section 2.2.3.6 of [RFC3779].¶
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.¶
The set of ipAddrBlocks is totally ordered.
The order of two ipAddrBlocks is determined by the first non-equal comparison in the following list.¶
-
Data elements with a lower afi value precede data elements with a higher afi value.¶
-
Data elements with a lower addr value precede data elements with a higher addr value.¶
-
Data elements with a lower plen value precede data elements with a higher plen value.¶
-
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.¶
- A sorting implementation [roasort-c] in ISO/IEC 9899:1999 ("ANSI C99").¶
- A sorting implementation [roasort-rs] in the Rust 2021 Edition.¶
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 [RFC6488] as well as the following additional ROA-specific validation steps:¶
-
The IP address delegation extension [RFC3779] 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 [RFC3779].¶
-
The Autonomous System identifier delegation extension described in [RFC3779] 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 3 and 4.¶
If any of the above checks fail, the ROA in its entirety MUST be considered invalid and an error SHOULD be logged.¶
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 [RFC6488] 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 [RFC6480].
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.¶
The authors wish to thank Theo Buehler, Ties de Kock, Martin Hoffmann, Charles Gardiner, Russ Housley, Jeffrey Haas, Bob Beck, and Tom Harrison for their help and contributions.
Additionally, the authors thank Jim Fenton, Vijay Gurbani, Haoyu Song, Rob Austein, Roque Gagliano, Danny McPherson, Sam Weiler, Jasdip Singh, and Murray S. Kucherawy for their careful reviews and helpful comments.¶