3. The ROA Content Type
The content-type for a ROA is defined as id
This OID MUST appear within both the eContentType in the encap
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.¶
This is an Internet Standards Track document.¶
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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 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.¶
It is assumed that the reader is familiar with the terms and concepts described in "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile" [RFC5280] and "X.509 Extensions for IP Addresses and AS Identifiers" [RFC3779].¶
Additionally, this document makes use of the RPKI signed object profile [RFC6488]; 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 [RFC6487]; thus, familiarity with that profile is also assumed.¶
The content-type for a ROA is defined as id
This OID MUST appear within both the eContentType in the encap
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:¶
The version number of the Route
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 ROAIPAddress
There MUST be only one instance of ROAIPAddress
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:¶
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
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 canonicalizatio
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:¶
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 for which all four values compare equal are duplicates of one another.¶
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:¶
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
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.¶
IANA has updated the id
IANA has updated the Route Origination Authorization entry in the "RPKI Signed Objects" registry created by [RFC6488] as follows:¶
IANA has updated the entry for the ROA file extension in the "RPKI Repository Name Schemes" registry created by [RFC6481] as follows:¶
IANA has allocated the following entry in the "SMI Security for S/MIME Module Identifier
IANA has updated the media type application
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 [RFC4648].¶
The object in this appendix has the following properties:¶
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.¶