Registration Protocols Extensions
Internet Engineering Task Force (IETF) M. Loffredo
Internet-Draft
Request for Comments: 9536 M. Martinelli
Intended status:
Category: Standards Track IIT-CNR/Registro.it
Expires: 2 March
ISSN: 2070-1721 April 2024 30 August 2023
Registration Data Access Protocol (RDAP) Reverse Search
draft-ietf-regext-rdap-reverse-search-25
Abstract
The Registration Data Access Protocol (RDAP) does not include query
capabilities for finding the list of domains related to a set of
entities matching a given search pattern. Considering that an RDAP
entity can be associated with any defined object class and other
relationships between RDAP object classes exist, a reverse search can
be applied to other use cases besides the classic domain-entity
scenario. This document describes an RDAP extension that allows
servers to provide a reverse search feature based on the relationship
defined in RDAP between an object class for search and any related
object class. The reverse search based on the domain-entity
relationship is treated as a particular case.
Status of This Memo
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This Internet-Draft will expire on 2 March 2024.
https://www.rfc-editor.org/info/rfc9536.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Conventions Used in This Document . . . . . . . . . . . . 4
2. Reverse Search Path Segment Specification . . . . . . . . . . 4
3. Reverse Search Definition . . . . . . . . . . . . . . . . . . 5
4. Reverse Search Properties Discovery . . . . . . . . . . . . . 5
5. Reverse Search Properties Mapping . . . . . . . . . . . . . . 6
6. Reverse Search Response Specification . . . . . . . . . . . . 7
7. Reverse Search Query Processing . . . . . . . . . . . . . . . 7
8. Reverse Searches Based on Entity Details . . . . . . . . . . 8
9. RDAP Conformance . . . . . . . . . . . . . . . . . . . . . . 10
10. Implementation Considerations . . . . . . . . . . . . . . . . 10
11. Implementation Status . . . . . . . . . . . . . . . . . . . . 10
11.1. IIT-CNR/Registro.it RDAP Server . . . . . . . . . . . . 11
11.2. IIT-CNR/Registro.it RDAP Client . . . . . . . . . . . . 11
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
12.1.
11.1. RDAP Extensions Registry . . . . . . . . . . . . . . . . 12
12.2.
11.2. RDAP Reverse Search Registries . . . . . . . . . . . . . 12
12.2.1.
11.2.1. Creation of the RDAP Reverse Search Registries . . . 12
12.2.2.
11.2.2. Submit Request Requests to IANA . . . . . . . . . . . . . . . 12
12.2.3.
11.2.3. RDAP Reverse Search Registry . . . . . . . . . . . . 13
12.2.3.1.
11.2.3.1. Template . . . . . . . . . . . . . . . . . . . . 13
12.2.3.2.
11.2.3.2. Initial Content . . . . . . . . . . . . . . . . 13
12.2.4.
11.2.4. RDAP Reverse Search Mapping Registry . . . . . . . . 14
12.2.4.1.
11.2.4.1. Template . . . . . . . . . . . . . . . . . . . . 14
12.2.4.2.
11.2.4.2. Initial Content . . . . . . . . . . . . . . . . 15
13.
12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 16
14.
13. Security Considerations . . . . . . . . . . . . . . . . . . . 16
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
16.
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
16.1.
14.1. Normative References . . . . . . . . . . . . . . . . . . 17
16.2.
14.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Paradigms to Enforce Access Control on Reverse Search
in RDAP . . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 21
Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction
The protocol described in this specification aims to extend the RDAP
query capabilities and response to enable reverse search based on the
relationships defined in RDAP between an object class for search and
a related object class. The reverse search based on the domain-
entity relationship is treated as a particular case of such a generic
model.
RDAP providers willing to implement this specification should
carefully consider its implications on the efficiency (see
Section 10), the security (see Section 14) 13), and the compliance with
privacy regulations (see Section 13) 12) of their RDAP service.
1.1. Background
Reverse Whois WHOIS is a service provided by many web applications that
allows users to find domain names owned by an individual or a company
starting from the owner's details, such as name and email. Even if
it has been considered useful for some legal purposes (e.g. (e.g.,
uncovering trademark infringements, infringements and detecting cybercrimes), its
availability as a standardized Whois WHOIS [RFC3912] capability has been
objected to for two main reasons, which now don't seem to conflict
with an RDAP implementation.
The first objection concerns the potential risks of privacy
violation. However, the domain name community is considering a new
generation of Registration Directory Services [ICANN-RDS1]
[ICANN-RDS2] [ICANN-RA], which [ICANN-RDS] [ICANN-RA]
that provide access to sensitive data under some permissible purposes
and in accordance with appropriate policies for requestor
accreditation, authentication authentication, and authorization. RDAP's reliance on
HTTP means that it can make use of common HTTP-
based HTTP-based approaches to
authentication and authorization, making it more useful than Whois WHOIS in
the context of such directory services. Since RDAP consequently
permits a reverse search implementation complying with privacy
protection principles, this first objection is not well-
founded. well-founded.
The second objection to the implementation of a reverse search
capability has been connected with its impact on server processing.
However, the core RDAP specifications already define search queries,
with similar processing requirements, so the basis of this objection
is not clear.
Reverse searches, such as finding the list of domain names associated
with contacts or nameservers, may be useful to registrars as well.
Usually, registries adopt out-of-band solutions to provide results to
registrars asking for reverse searches on their domains. Possible
reasons for such requests are:
* the loss of synchronization between the registrar database and the
registry database; database and
* the need for such data to perform bulk Extensible Provisioning
Protocol (EPP) [RFC5730] updates (e.g. (e.g., changing the contacts of a
set of domains, etc.).
Currently, RDAP does not provide any means for a client to search for
the collection of domains associated with an entity [RFC9082]. A
query (lookup or search) on domains can return the array of entities
related to a domain with different roles (registrant, registrar,
administrative, technical, reseller, etc.), but the reverse operation
is not allowed. Only reverse searches to find the collection of
domains related to a nameserver (ldhName or ip) can be requested.
Since an entity can be in relationship with any RDAP object
[RFC9083], the availability of a reverse search as largely intended
can be common to all the object classes allowed for search. Through
a further step of generalization, the meaning of reverse search in
the RDAP context can be extended to include any query for retrieving
all the objects in relationship with that relates to another query matching a given search
pattern.
1.2. Conventions Used in This Document
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.
2. Reverse Search Path Segment Specification
A generic reverse search path is described by the syntax:
{searchable-resource-type}/reverse_search/{related-resource-
type}?<search-condition>
The path segments are defined as in the following: follows:
"searchable-resource-type": it It MUST be one of the resource types for
search defined in Section 3.2 of [RFC9082] (i.e. (i.e., "domains",
"nameservers"
"nameservers", and "entities") or a resource type extension; extension.
"related-resource-type": it It MUST be one of the resource types for
lookup defined in Section 3.1 of [RFC9082] (i.e. (i.e., "domain",
"nameserver", "entity", "ip" "ip", and "autnum") or a resource type
extension;
extension.
"search-condition": a A sequence of "property=search pattern"
predicates separated by the ampersand character ('&', US-ASCII
value 0x0026).
While related-resource-type is defined as having one of a number of
different values, the only reverse searches defined in this document
are for a related-resource-type of "entity". Reverse searches for
the other resource types specified in [RFC9082] and resource type
extensions may be defined by future documents.
3. Reverse Search Definition
Based on the content of Section 2, defining a reverse search means to
define the triple <searchable resource type, related resource type,
property> and the mapping with the corresponding RDAP object member.
The mapping is done through the use of a JSONPath expression
[I-D.ietf-jsonpath-base].
[RFC9535]. Reverse searches are registered in the "RDAP Reverse Search
Search" registry (see Section 12.2.3), 11.2.3), whereas reverse search
mappings are registered in the "RDAP Reverse Search Mapping Mapping" registry
(see Section 12.2.4). 11.2.4). The reason for having two registries is that
it may be possible for a single type of reverse search to rely on
different members, depending on the server's configuration (see
Section 5).
All of the reverse searches defined by this document (see Section 8)
have property names that are the same as the name of the RDAP object
member that is the subject of the search. For example, the reverse
search with the property name "fn" relies on the value of the "fn"
member inside the jCard of an entity object. However, it is not
necessary that these two names be the same. In particular, remapping
of searches as part of the deprecation of an existing member (see
Section 5) will typically lead to a member with a different name
being used for the search.
Servers MUST NOT provide or implement reverse searches or reverse
search mappings that are not registered with IANA.
4. Reverse Search Properties Discovery
Servers complying with this specification MUST extend the help
response [RFC9083] with the "reverse_search_properties" member which that
contains an array of objects with the following mandatory child
members:
"searchableResourceType": the searchable resource type of the
reverse search query query, as defined in Section 2; 2
"relatedResourceType": the related resource type of the reverse
search query query, as defined in Section 2; 2
"property": the reverse search property used in the predicate of the
reverse search query query, as defined in Section 2; 2
An example of the help response including the
"reverse_search_properties" member is shown in Figure 2. 2
5. Reverse Search Properties Mapping
To permit clients to determine the member used by the server for a
reverse search, servers MUST detail the mapping that is occurring by
adding the "reverse_search_properties_mapping" member to the topmost
object of a reverse search response. This data structure is included
in the search response, rather than in the help response, because it
may differ depending on the query that is sent to the server.
Documents that deprecate or restructure RDAP responses such that a
registered reverse search is no longer able to be used MUST either
note that the relevant reverse search is no longer available (in the
case of deprecation) or describe how to continue supporting the
relevant search by adding another mapping for the reverse search
property (in the case of restructuring).
The "reverse_search_properties_mapping" member contains an array of
objects with the following mandatory child members:
"property": the reverse search property used in the predicate of the
current query query, as defined in Section 2; 2
"propertyPath": the JSONPath expression of the object member (or
members) corresponding to the reverse search property. property
The searchable and the related resource types are derived from the
query, so there is no need to include them in addition to the
property in this member.
This member MUST be included for all properties used in the search,
regardless of whether that property has multiple registered mappings
as at the time of the search, because new mappings may be registered
at any time.
When applied to an object, the JSONPath expression MUST produce a
list of values, each of which is a JSON number or string.
An example of a reverse search response including the
"reverse_search_properties_mapping" member is shown in Figure 3.
6. Reverse Search Response Specification
Reverse search responses use the formats defined in section Section 8 of
[RFC9083], which correspond to the searchable resource types defined
in Section 2.
7. Reverse Search Query Processing
To process a reverse search, the server returns the objects from its
data store that are of type searchable-resource-type and that match
each of the predicates from the search conditions. To determine
whether an object matches a predicate, the server:
* applies the mapping it uses for the reverse search property to the
object in order to generate a list of values, each of which MUST
be a JSON number or string; string and
* checks whether the search pattern matches one or more of those
values.
A search pattern matches a value where it equals the string
representation of the value, value or where it is a match for the value in
accordance with the partial string matching behaviour behavior defined in
section
Section 4.1 of [RFC9082].
Objects are only included in the search results if they satisfy all
included predicates. This includes predicates that are for the same
property: it is necessary
property; in such a case case, it is necessary for the related object to
match against each of those predicates.
Servers MUST return an HTTP 501 (Not Implemented) [RFC9110] response
to inform clients of unsupported reverse searches.
Based on their policy, servers MAY restrict how predicates are used
to make a valid search condition, condition by returning a 400 (Bad Request)
response when a problematic request is received.
A given reverse search or reverse search mapping MAY define
additional or alternative search behaviour behavior past that set out in this
section.
8. Reverse Searches Based on Entity Details
Since in RDAP, an entity can be associated with any other object
class, class in
RDAP, the most common kind of reverse search is one based on an
entity's details. Such reverse searches arise from the query model
by setting the related resource type to "entity".
By selecting a specific searchable resource type, the resulting
reverse search aims at retrieving all the objects (e.g. (e.g., all the
domains) that are related to any entity object matching the search
conditions.
This section defines the reverse search properties servers SHOULD
support for the domain, nameserver, and entity searchable entity-searchable resource
types types,
and the entity related entity-related resource type:
Reverse search property: role
RDAP member path: $.entities[*].roles
Reference: Section 10.2.4 of [RFC9083]
Reverse search property: handle
RDAP member path: $.entities[*].handle
Reference: Section 5.1 of [RFC9083]
Reverse search property: fn
RDAP member path: $.entities[*].vcardArray[1][?(@[0]=='fn')][3]
Reference: Section 6.2.1 of [RFC6350]
Reverse search property: email
RDAP member path: $.entities[*].vcardArray[1][?(@[0]=='email')][3]
Reference: Section 6.4.2 of [RFC6350]
The presence of a predicate on the reverse search property "role"
means that the RDAP response property "roles" MUST contain at least
the specified role.
The last two properties are related to jCard elements [RFC7095], but
the field references are to vCard [RFC6350], since jCard is the JSON
format for vCard.
Examples of reverse search paths based on the domain-entity
relationship are presented in Figure 1.
/domains/reverse_search/entity?handle=CID-40*&role=technical
/domains/reverse_search/entity?fn=Bobby*&role=registrant
/domains/reverse_search/entity?handle=RegistrarX&role=registrar
Figure 1: Examples of reverse search queries Reverse Search Queries
An example of the help response including the supported reverse
search properties supported is shown below. in Figure 2.
{
"rdapConformance": [
"rdap_level_0",
"reverse_search"
],
...
"reverse_search_properties": [
{
"searchableResourceType": "domains",
"relatedResourceType": "entity",
"property": "fn"
},
{
"searchableResourceType": "domains",
"relatedResourceType": "entity",
"property": "handle"
},
{
"searchableResourceType": "domains",
"relatedResourceType": "entity",
"property": "email"
},
{
"searchableResourceType": "domains",
"relatedResourceType": "entity",
"property": "role"
}
],
...
}
Figure 2: An example Example of help response the Help Response including the
"reverse_search_properties_mapping" member
"reverse_search_properties" Member
An example of a response including the mapping that is occurring for
the first reverse search in Figure 1 is shown below.
{
"rdapConformance": [
"rdap_level_0",
"reverse_search"
],
...
"reverse_search_properties_mapping": [
{
"property": "handle",
"propertyPath": "$.entities[*].handle"
},
{
"property": "role",
"propertyPath": "$.entities[*].roles"
}
],
...
}
Figure 3: An example Example of an RDAP response Response including the
"reverse_search_properties" member
"reverse_search_properties_mapping" Member
9. RDAP Conformance
Servers complying with this specification MUST include the value
"reverse_search" in the rdapConformance property of the help response
[RFC9083] and any other response including the
"reverse_search_properties_mapping" member. The information needed
to register this value in the "RDAP Extensions" registry is described
in Section 12.1. 11.1.
10. Implementation Considerations
To limit the impact of processing the search predicates, servers are
RECOMMENDED to make use of techniques to speed up the data retrieval
in their underlying data store store, such as indexes or similar. In
addition, risks with respect to performance degradation or result set
generation can be mitigated by adopting practices used for standard
searches, e.g. e.g., restricting the search functionality, limiting the
rate of search requests according to the user's authorization,
truncating and paging the results [RFC8977], and returning partial
responses [RFC8982].
11. Implementation Status
NOTE: Please remove this section and the reference to RFC 7942 prior
to publication 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 [RFC7942].
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".
11.1. IIT-CNR/Registro.it RDAP Server
* Responsible Organization: Institute of Informatics and Telematics
of National Research Council (IIT-CNR)/Registro.it
* Location: https://rdap.pubtest.nic.it/
* Description: This implementation includes support for RDAP queries
using data from the public test environment of .it ccTLD. Reverse
search is allowed to authenticated users. Registrar users are
allowed to perform reverse searches on their own domains and
contacts. This is achieved by adding an implicit predicate to the
search condition.
* Level of Maturity: This is an "alpha" test implementation.
* Coverage: This implementation includes all of the features
described in this specification.
* Contact Information: Mario Loffredo, mario.loffredo@iit.cnr.it
11.2. IIT-CNR/Registro.it RDAP Client
* Responsible Organization: Institute of Informatics and Telematics
of National Research Council (IIT-CNR)/Registro.it
* Location: https://web-rdap.pubtest.nic.it/
* Description: This is a Javascript web-based RDAP client. RDAP
responses are retrieved from RDAP servers by the browser, parsed
into an HTML representation, and displayed in a format improving
the user experience. Reverse search is allowed to authenticated
users.
* Level of Maturity: This is an "alpha" test implementation.
* Coverage: This implementation includes all of the features
described in this specification.
* Contact Information: Francesco Donini, francesco.donini@iit.cnr.it
12. IANA Considerations
12.1.
11.1. RDAP Extensions Registry
IANA is requested to register has registered the following value in the "RDAP Extensions"
registry:
*
Extension identifier: Identifier: reverse_search
*
Registry operator: Operator: Any
* Published specification: This document.
*
Specification: RFC 9536
Contact: IETF <iesg@ietf.org>
*
Intended usage: Usage: This extension identifier is used for both URI path
segments and response extensions related to the reverse search in
RDAP.
12.2.
11.2. RDAP Reverse Search Registries
12.2.1.
11.2.1. Creation of the RDAP Reverse Search Registries
IANA is requested to create has created the "RDAP Reverse Search" and "RDAP Reverse Search
Mapping" registries within the group "Registration Data Access Protocol (RDAP)".
(RDAP)" category in the protocol registries.
These registries follow the Specification Required process registration
policy, as defined in Section 4.5 4.6 of [RFC8126].
The designated expert should prevent collisions and confirm that
suitable documentation, as described in Section 4.6 4.5 of [RFC8126], is
available to ensure interoperability.
Creators of either new RDAP reverse searches or new mappings for
registered reverse searches SHOULD NOT replicate functionality
already available by way of other documents referenced in these
registries. Creators MAY register additional reverse search mappings
for existing properties, but they SHOULD NOT map a registered reverse
search property to a response field with a meaning other than that of
the response fields referenced by the mappings already registered for
that property. In other words, all the mappings for a reverse search
property MUST point to response fields with the same meaning.
12.2.2.
11.2.2. Submit Request Requests to IANA
Registration requests can be sent to <iana@iana.org>.
12.2.3.
11.2.3. RDAP Reverse Search Registry
12.2.3.1.
11.2.3.1. Template
"Searchable
Property: The name of the reverse search property.
Description: A brief human-readable text describing the reverse
search property.
Searchable Resource Type": Type: The searchable resource type of the
reverse search query (Section 2) including the reverse search
property. Multiple reverse search properties differing only by
this field can be grouped together by listing all the searchable
resource types separated by comma (see Section 12.2.3.2).
"Related 11.2.3.2).
Related Resource Type": Type: The related resource type of the reverse
search query (Section 2) including the reverse search property.
"Property": The name of the reverse search property.
"Description": A brief human-readable text describing the reverse
search property.
"Registrant Name":
Registrant: The name of the person registering the reverse search
property.
"Registrant
Contact Information": Information: An email address, postal address, or some other
information to be used to contact the registrant.
"Reference":
Reference: Document (e.g. (e.g., the RFC number) and section reference
where the reverse search property is specified.
The combination of "Searchable Searchable Resource Type", "Related Type, Related Resource
Type" Type,
and "Property" Property MUST be unique across the registry entries.
12.2.3.2.
11.2.3.2. Initial Content
IANA is requested to register has registered the following entries in the "RDAP Reverse
Search" registry. For all entries, the common values are shown in
Table 1 1, whereas the specific values are shown in Table 2.
+================================+================================+
+==========================+================================+
| Registry Property | Value |
+================================+================================+
+==========================+================================+
| Searchable Resource Type | domains, nameservers, entities |
+--------------------------------+--------------------------------+
+--------------------------+--------------------------------+
| Related Resource Type | entity |
+--------------------------------+--------------------------------+
+--------------------------+--------------------------------+
| Registrant Name | IETF |
+--------------------------------+--------------------------------+
+--------------------------+--------------------------------+
| Registrant Contact Information | iesg@ietf.org |
+--------------------------------+--------------------------------+
+--------------------------+--------------------------------+
| Reference | This document, Section 8 RFC 9536 |
+--------------------------------+--------------------------------+
+--------------------------+--------------------------------+
Table 1: Common values Values for all entries All Entries in the "RDAP RDAP
Reverse
Search" registry Search Registry
+==========+==============================================+
| Property | Description |
+==========+==============================================+
| fn | The server supports the domain/nameserver/ |
| | entity search based on the full name (a.k.a. |
| | formatted name) of an associated entity |
+----------+----------------------------------------------+
| handle | The server supports the domain/nameserver/ |
| | entity search based on the handle of an |
| | associated entity |
+----------+----------------------------------------------+
| email | The server supports the domain/nameserver/ |
| | entity search based on the email address of |
| | an associated entity |
+----------+----------------------------------------------+
| role | The server supports the domain/nameserver/ |
| | entity search based on the role of an |
| | associated entity |
+----------+----------------------------------------------+
Table 2: Specific values Values for all entries Entries in the "RDAP RDAP
Reverse Search" registry
12.2.4. Search Registry
11.2.4. RDAP Reverse Search Mapping Registry
12.2.4.1.
11.2.4.1. Template
"Searchable Resource Type":
Property: The same as defined in the "Reverse
Search Registry".
"Related "RDAP Reverse Search" registry.
Property Path: The JSONPath of the RDAP property this reverse search
property maps to.
Searchable Resource Type": Type: The same as defined in the "Reverse Search
Registry".
"Property": "RDAP Reverse
Search" registry.
Related Resource Type: The same as defined in the "Reverse Search Registry".
"Property Path": The JSONPath of the RDAP property this reverse
search property maps to.
"Description": A brief human-readable text describing this reverse
search property mapping.
"Registrant Name": "RDAP Reverse
Search" registry.
Registrant: The name of the person registering this reverse search
property mapping.
"Registrant
Contact Information": Information: The same as defined in the
"Reverse Search Registry".
"Reference": "RDAP Reverse
Search" registry.
Reference: Document (e.g. (e.g., the RFC number) and section reference
where this reverse search property mapping is specified.
The combination of "Searchable Searchable Resource Type", "Related Type, Related Resource
Type", "Property" Type,
Property, and "Property Path" Property Path MUST be unique across the registry
entries.
12.2.4.2.
11.2.4.2. Initial Content
IANA is requested to register has registered the following entries in the "RDAP Reverse Search
Mapping" registry. For all entries, the common values are the same
as defined in the "RDAP Reverse Search" registry (see Table 1) 1),
whereas the specific values are shown in below (see Table 3. 3).
+==========+==================================================+
| Property | Property Path |
+==========+==================================================+
| fn | $.entities[*].vcardArray[1][?(@[0]=='fn')][3] |
+----------+--------------------------------------------------+
| handle | $.entities[*].handle |
+----------+--------------------------------------------------+
| email | $.entities[*].vcardArray[1][?(@[0]=='email')][3] |
+----------+--------------------------------------------------+
| role | $.entities[*].roles |
+----------+--------------------------------------------------+
Table 3: Specific values Values for all entries Entries in the "RDAP RDAP Reverse
Search Mapping" registry
13. Mapping Registry
12. Privacy Considerations
The search functionality defined in this document may affect the
privacy of entities in the registry (and elsewhere) in various ways: ways;
see [RFC6973] for a general treatment of privacy in protocol
specifications. Registry operators should be aware of the tradeoffs trade-offs
that result from implementation of implementing this functionality.
Many jurisdictions have laws or regulations that restrict the use of
"Personal Data",
"personal data", per the definition in [RFC6973]. Given that,
registry operators should ascertain whether the regulatory
environment in which they operate permits implementation of the
functionality defined in this document.
In those cases where this functionality makes use of sensitive
information, it the information MUST only be accessible to authorized
users supported
by under a lawful basis.
Since reverse search requests and responses could contain Personally
Identifiable Information (PII), reverse search functionality MUST be
available over HTTPS only.
Providing reverse search in RDAP carries the following threats as
described in [RFC6973]:
* Correlation
* Disclosure
* Misuse of information data
Therefore, RDAP providers need to mitigate the risk of those threats
by implementing appropriate measures supported by security services
(see Section 14).
14. 13).
13. Security Considerations
Security services that are required to provide controlled access to
the operations specified in this document are described in [RFC7481].
A non-exhaustive list of access control paradigms an RDAP provider
can implement is presented in Appendix A.
As an additional measure to enforce security by preventing reverse
searches to be accessed from unauthorized users, the RDAP providers
may consider to physically separate separating the reverse search endpoints from
the other ones by configuring a proxy routing the reverse searches to
a dedicated backend server and leveraging further security services
offered by other protocol layers layers, such as digital certificates and IP
whitelisting.
allow-listing.
Finally, the specification of the relationship within the reverse
search path allows the RDAP servers to implement different
authorization policies on a per-relationship basis.
15. Acknowledgements
The authors would like to acknowledge the following individuals for
their contributions to this document: Francesco Donini, Scott
Hollenbeck, Francisco Arias, Gustavo Lozano, Eduardo Alvarez, Ulrich
Wisser, James Gould and Pawel Kowalik.
Tom Harrison and Jasdip Singh provided relevant feedback and constant
support to the implementation of this proposal. Their contributions
have been greatly appreciated.
16.
14. References
16.1.
14.1. Normative References
[I-D.ietf-jsonpath-base]
Gössner, S., Normington, G., and C. Bormann, "JSONPath:
Query expressions for JSON", Work in Progress, Internet-
Draft, draft-ietf-jsonpath-base-20, 25 August 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-
jsonpath-base-20>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6350] Perreault, S., "vCard Format Specification", RFC 6350,
DOI 10.17487/RFC6350, August 2011,
<https://www.rfc-editor.org/info/rfc6350>.
[RFC7095] Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095,
DOI 10.17487/RFC7095, January 2014,
<https://www.rfc-editor.org/info/rfc7095>.
[RFC7481] Hollenbeck, S. and N. Kong, "Security Services for the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 7481, DOI 10.17487/RFC7481, March 2015,
<https://www.rfc-editor.org/info/rfc7481>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access
Protocol (RDAP) Query Format", STD 95, RFC 9082,
DOI 10.17487/RFC9082, June 2021,
<https://www.rfc-editor.org/info/rfc9082>.
[RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 9083, DOI 10.17487/RFC9083, June 2021,
<https://www.rfc-editor.org/info/rfc9083>.
[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/info/rfc9110>.
16.2.
[RFC9535] Gössner, S., Ed., Normington, G., Ed., and C. Bormann,
Ed., "JSONPath: Query Expressions for JSON", RFC 9535,
DOI 10.17487/RFC9535, February 2024,
<https://www.rfc-editor.org/info/rfc9535>.
14.2. Informative References
[ICANN-RA] Internet Corporation For Assigned Names and Numbers,
"Registry ICANN, "Base Registry Agreement", July 2017,
<https://newgtlds.icann.org/sites/default/files/
agreements/agreement-approved-31jul17-en.pdf>.
[ICANN-RDS1]
Internet Corporation For Assigned Names and Numbers, January 2024,
<https://www.icann.org/en/registry-agreements/base-
agreement>.
[ICANN-RDS]
ICANN, "Final Report from the Expert Working Group on gTLD
Directory Services: A Next-Generation Registration
Directory Service (RDS)", June 2014,
<https://www.icann.org/en/system/files/files/final-report-
06jun14-en.pdf>.
[ICANN-RDS2]
Internet Corporation For Assigned Names and Numbers,
"Final Issue Report on a Next-Generation gTLD RDS to
Replace WHOIS", October 2015,
<http://whois.icann.org/sites/default/files/files/final-
issue-report-next-generation-rds-07oct15-en.pdf>.
[OIDCC] OpenID Foundation, Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 1", November 2014, 2", December 2023,
<http://openid.net/specs/openid-connect-core-1_0.html>.
[RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
DOI 10.17487/RFC3912, September 2004,
<https://www.rfc-editor.org/info/rfc3912>.
[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
<https://www.rfc-editor.org/info/rfc5730>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013,
<https://www.rfc-editor.org/info/rfc6973>.
[RFC8977] Loffredo, M., Martinelli, M., and S. Hollenbeck,
"Registration Data Access Protocol (RDAP) Query Parameters
for Result Sorting and Paging", RFC 8977,
DOI 10.17487/RFC8977, January 2021,
<https://www.rfc-editor.org/info/rfc8977>.
[RFC8982] Loffredo, M. and M. Martinelli, "Registration Data Access
Protocol (RDAP) Partial Response", RFC 8982,
DOI 10.17487/RFC8982, February 2021,
<https://www.rfc-editor.org/info/rfc8982>.
Appendix A. Paradigms to Enforce Access Control on Reverse Search in
RDAP
Access control can be implemented according to different paradigms
introducing increasingly stringent rules. The paradigms reported
here in the following listed below
leverage the capabilities that are either built-in built in or provided as
extensions by the OpenID Connect [OIDCC]:
*
Role-Based Access Control (RBAC): access Access rights are granted
depending on roles. Generally, this is done by grouping users
into fixed categories and assigning static grants to each
category. A more dynamic approach can be implemented by using the
OpenID Connect "scope" claim;
* claim.
Purpose-Based Access Control (PBAC): access Access rules are based on the
notion of purpose, being the intended use of some data by a user.
It can be implemented by tagging a request with the usage purpose
and making the RDAP server check the compliance between the given
purpose and the control rules applied to the data to be returned;
* returned.
Attribute-Based Access Control (ABAC): rules Rules to manage access rights
are evaluated and applied according to specific attributes
describing the context within which data are requested. It can be
implemented by setting within an out-of-band process by setting additional
OpenID Connect claims describing that describe the request context and making make
the RDAP server check the for compliance between the given context and
the control rules that are applied to the data to be returned;
* returned.
Time-Based Access Control (TBAC): data Data access is allowed for a
limited time only. It can be implemented by assigning the users
with
temporary credentials linked to access grants whose scope is
limited. with limited scopes.
With regard to the privacy threats reported in Section 13, 12,
correlation and disclosure can be mitigated by minimizing both the
request features and the response data based on user roles (i.e. (i.e.,
RBAC). Misuse can be mitigated by checking for the purpose of the
request (i.e. (i.e., PBAC). It can be accomplished according to the
following approaches:
*
Full Trust: the The registry trusts the fairness of an accredited user.
The requestor is always legitimized to submit his their requests under
a lawful basis. Additionally, he they can be required to specify the
purpose as either a claim of his their account or a query parameter.
In the former case, the purpose is assumed to be the same for
every request. In the latter case, the purpose must be one of
those associated to the user;
* user.
Zero Trust: the The registry requires documents assessing that assess whether the
requestor is legitimized to submit a given request. It can be
implemented by assigning the requestor with a temporary OpenID account
linked to the given request (i.e. (i.e., TBAC) and describing the
request through a set of claims (i.e. (i.e., ABAC). The association
between the temporary account and the claims about the request is
made by an out-of-band application. In so doing, the RDAP server
is able to check that the incoming request is consistent with the
request claims linked to the temporary account.
The two approaches can be used together:
* The former is suitable for users carrying out a task in the public
interest,
interest or exercising their official authority (e.g. (e.g., an officer
of a cybercrime agency). Similarly, registrars can submit reverse
searches on their domains and contacts based on their contractual
relationship with the domain holders. In this case, the query
results can be restricted to those pertaining to a registrar by
adding an implicit predicate to the search condition.
* The latter can be taken to allow domain name dispute resolution
service providers to request information in defense of the
legitimate interests of complainants.
Appendix B. Change Log
00: Initial working group version ported from draft-loffredo-regext-
rdap-reverse-search-04
01: Updated "Privacy Considerations" section.
02: Revised the text.
03: Refactored the query model.
04: Keepalive refresh.
05: Reorganized "Abstract". Corrected "Conventions Used in This
Document" section. Added "RDAP Conformance" section. Changed
"IANA Considerations" section. Added references to RFC7095 and
RFC8174. Other minor edits.
06: Updated "Privacy Considerations", "Security Considerations" and
"Acknowledgements" sections. Added some normative and informative
references. Added Appendix A.
07: Updated normative references.
08: Changed "Implementation Status" section. Updated informative
references.
09: Extended the query model to represent a reverse search based on
any relationship between the RDAP object classes. Changed the
path segment "role" into a query parameter.
10: Updated "Reverse Searches Based on Entity Details" section to
consider the use of JSContact format instead of jCard. Added
references
Acknowledgements
The authors would like to JSContact documents.
11: Updated acknowledge the document based on Tom Harrison and James Gould
feedback:
* Updated section "RDAP Path Segment Specification":
- Clarified how servers must evaluate a reverse search
including predicates that are following individuals for the same property.
- Specified the error response servers must return when
receiving a wrong reverse search request according to
their
policy.
- Clarified that searchs for the related-resource-type values
other than "entity" may be defined in future documents.
* Reviewed text in section "Reverse Searches Based on Entity
Details" about reverse searches based on custom response
extensions.
* Removed references to JSContact documents in section "Reverse
Searches Based on Entity Details". Moved the mapping between
jCard properties used in the RDAP response and JSContact
counterparts to draft-ietf-regext-rdap-jscontact.
* Added section "RDAP Response Specification".
* Changed the text to present reverse search as a single
extension with multiple features.
* Changed the definition of searchable-resource-type and related-
resource-type to consider also the resource type extensions.
* Replaced "reverse" with "reverse_search_0" in the generic
reverse search path. Updated Figure 1 accordingly.
* Removed the phrase "but with a special focus on its privacy
implications" from both the "Abstract" and the "Introduction".
Moved the mapping between jCard properties used in the RDAP
response and JSContact counterparts contributions to draft-ietf-regext-rdap-
jscontact.
* Reviewed the text of "Privacy Considerations" section.
* Text cleaning.
12: Replaced "reverse_search_0" with "reverse_search" as both URI
path segment, extension identifier this document: Francesco Donini, Scott
Hollenbeck, Francisco Arias, Gustavo Lozano, Eduardo Alvarez, Ulrich
Wisser, James Gould, and rdapConformance tag to
match the working group consensus.
13: Done some minor text changes.
14: Revised text of first sentence Pawel Kowalik.
Tom Harrison and added references to RFC8977 Jasdip Singh provided relevant feedback and RFC8982 in the "Implementation Considerations" section.
15: Moved RFC6973 from Normative References to Informative
References. Remnoved informative reference to draft-ietf-regext-
rdap-openid. Rephrased text in Appendix A accordingly.
16: Moved OIDC from Normative References to Informative References.
Added the "Reverse Search Properties Discovery" section. Added
"RDAP JSON Values Registry" as a subsection of the "IANA
Considerations" section. Rephrased the "Reverse Searches Based on
Entity Details" section to refer to the "Reverse Search Properties
Discovery" section. Updated the "Acknowledgements" section.
Minor text edits.
17: Revised the "Reverse Search Properties Discovery" section.
Replaced "RDAP JSON Values Registry" section with the "RDAP
Reverse Search Properties Registry" section.
18: Changed "Expert Review" with "Specification Required" in the
"Creation of the RDAP Reverse Search Properties Registry" section.
Renamed the "RDAP Reverse Search Properties Registry" into "RDAP
Reverse Search Registry". Aligned the RDAP Reverse Search
Registry template with the initial content. Introduced the
"reverse_search_properties_mapping" response extension. Added the
"RDAP Reverse Search Mapping Registry". Reorganized the document constant
support to separate the implementation of a generic reverse search from
that based on domain-entity relationship.
19: Added the "Reverse Search Query Processing" section. Changed
the definition of search-condition in Section 2. Moved the
"Reverse Search Response Specification" section. Corrected
Figure 3.
20:
* Changed document title.
* Changed "Servers MUST NOT provide or implement unregistered
reverse searches or unregistered reverse search mappings." to
"Servers MUST NOT provide or implement reverse searches or
reverse search mappings that are not registered with IANA." in
Section 3.
* Changed "...that the RDAP response property "roles" must
contain at least the specified role" to "...that the RDAP
response property "roles" MUST contain at least the specified
role" in Section 8.
* Changed the value of the "Intended usage" property of the "RDAP
Extensions Registry" entry in Section 12.1.
* Changed "..., reverse search functionality SHOULD be available
over HTTPS only." to "..., reverse search functionality MUST be
available over HTTPS only." in Section 13.
21:
* Added a sentence about servers signaling the unsupported
reverse searches to Section 7.
* Replaced "$.." with "$." in JSONPath expressions.
* Clarified that the registry group the new registries must be
added to is "Registration Data Access Protocol (RDAP)".
* Removed unused normative reference to RFC7480.
22:
* Expanded EPP acronym in Section 1.
* Moved RFC3912 and RFC5730 from normative to informative
references.
23:
* Replaced IESG with IETF as the Registrant Name for each entry
in the IANA registries.
* Rearranged the layout of the initial content for the IANA
registries.
* Added titles to figures.
* Repalced "RDAP providers are REQUIRED to" with "RDAP providers
need to" in Section 14.
* Text cleaning.
24:
* Added text to Section 12.2.1 to make the term "collisions"
clear enough for future DEs.
* Added titles to tables.
25:
* Added text to Section 1 to reference the implications of this
specification on efficiency, security and compliance with
privacy regulations.
* Changed text in Privacy Considerations to clarify that in those
cases where sensitive information are used, this feature MUST
be accessble to authorized users only.
* Added text to Section 14 to describe additional measures to
enforce the security.
* Added text to Appendix A to clarify how the proposed access
control paradigms can contribute to mitigate the threats listed
in Section 13.
* Moved the reference to RFC3912.
* Moved reference to draft-ietf-jsonpath-based to Normative
References.
* Text cleaning. proposal. Their contributions
have been greatly appreciated.
Authors' Addresses
Mario Loffredo
IIT-CNR/Registro.it
Via Moruzzi,1
56124 Pisa
Italy
Email: mario.loffredo@iit.cnr.it
URI: http://www.iit.cnr.it
Maurizio Martinelli
IIT-CNR/Registro.it
Via Moruzzi,1
56124 Pisa
Italy
Email: maurizio.martinelli@iit.cnr.it
URI: http://www.iit.cnr.it