Extensible Provisioning Protocol (EPP) Transport over HTTP
draft-loffredo-regext-epp-over-http-03
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Mario Loffredo , Lorenzo Luconi Trombacchi , Maurizio Martinelli , Dan Keathley , James Gould | ||
| Last updated | 2024-02-20 | ||
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draft-loffredo-regext-epp-over-http-03
Internet Engineering Task Force M. Loffredo
Internet-Draft L. Luconi Trombacchi
Intended status: Standards Track M. Martinelli
Expires: 23 August 2024 IIT-CNR/Registro.it
D. Keathley
J. Gould
VeriSign, Inc.
20 February 2024
Extensible Provisioning Protocol (EPP) Transport over HTTP
draft-loffredo-regext-epp-over-http-03
Abstract
This document describes how an Extensible Provisioning Protocol (EPP)
session is mapped onto a Hypertext Transfer Protocol (HTTP)
connection. EPP over HTTP (EoH) requires the use of Transport Layer
Security (TLS) to secure EPP information (i.e. HTTPS).
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
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This Internet-Draft will expire on 23 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Session Management . . . . . . . . . . . . . . . . . . . . . 3
4. Message Exchange . . . . . . . . . . . . . . . . . . . . . . 4
5. Transport Considerations . . . . . . . . . . . . . . . . . . 6
6. Internationalization Considerations . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Change History . . . . . . . . . . . . . . . . . . . 9
A.1. Change from 00 to 01 . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
This document describes how EPP [RFC5730] is mapped onto HTTP
[RFC9110]. Note that there are several versions of HTTP currently in
use, including: HTTP/1.1 [RFC9112], HTTP/2 [RFC9113], and HTTP/3
[RFC9114]. As the differences among such versions do not affect the
EPP mapping described in this document, hereinafter the version
number is omitted except for presenting the special features in the
underlying layers of the HTTP stack.
HTTP represents a higher-level abstraction of a network connection,
removing the need to directly deal with all of the lower-level
details of transport protocols. This makes HTTP much more compatible
with cloud-native infrastructures, and facilitates faster development
times and reduced maintenance costs in such environments.
Security services beyond those defined in EPP are provided by TLS via
HTTPS Section 4.2.2 of [RFC9110].
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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
[BCP14] when, and only when, they appear in all capitals, as shown
here.
3. Session Management
Mapping EPP session management facilities onto HTTP is accomplished
using existing HTTP methods, namely GET and POST. An EPP session
exists between two peers, one that initiates the session request and
one that responds to the session request. The initiating peer is
called the "client", and the responding peer is called the "server".
An EPP server implementing this specification MUST listen for HTTP
session requests on a standard HTTP port assigned by IANA.
Even though HTTP itself is stateless, a stateful EPP session can be
achieved using the mechanism described in [RFC6265]. This mechanism
uses "Set-Cookie" and "Cookie" HTTP headers to facilitate a stateful
HTTP session. Such a session is initiated by the client via sending
a GET request to the sever. The GET request MUST include
"application/epp+xml" (Appendix B of [RFC5730]) in the "Accept" HTTP
header. The server MUST include the EPP Greeting in the response,
and it also MUST use the "Set-Cookie" header to include a token that
represents the identifier of the HTTP session. All subsequent HTTP
requests that include the HTTP session identifier in the "Cookie"
header will be treated as part of the session. The HTTP session
represents an EPP connection, which is initiated by the initial GET
request.
The EPP session begins with a successful EPP <login> command, and can
be referred to as an EPP over HTTP (EoH) session.
An EPP session is normally ended by the client issuing an EPP
<logout> command. A server receiving an EPP <logout> command MUST
end the EPP session. A server MAY also end an EPP session that has
been either active or inactve for longer than a server-defined
period. A server MAY end the HTTP session after ending the EPP
session.
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4. Message Exchange
EPP describes client-server interaction as a command-response
exchange where the client sends one command to the server and the
server returns one response to the client. With the exception of the
EPP Greeting, EPP messages are initiated by the EPP client in the
form of EPP commands. An EPP client MUST send all commands as HTTP
POST requests (Section 6.4 of [RFC9110]). Each POST request MUST
include the HTTP session identifier in the "Cookie" header and
"application/epp+xml" in the "Accept" header. An EPP server MUST
return an EPP response to an EPP command in the HTTP response to the
respective HTTP request.
HTTP does not guarantee that POST requests are idempotent. However,
the semantics of EPP do require EPP commands to be idempotent, so
processing a command more than once will produce the same net effect
on the repository as successfully processing the command once.
The EPP command XML is framed by the content of the HTTP POST
request, and the EPP response XML is framed by the content of the
HTTP response. Each HTTP request MUST contain a single EPP message,
and each HTTP response MUST contain a single EPP response. Commands
MUST be processed independently and in the same order as received
from the client.
Servers MUST NOT use HTTP return codes to signal clients about the
failure of the EPP commands. The HTTP code 200 MUST be used for both
successful and unsuccessful EPP requests. Servers MUST use HTTP
codes to signal clients about the failure of the HTTP requests.
Servers MUST return an EPP 2002 response (i.e. Command use error) if
the client issues an EPP command with either an empty or an invalid
session ID.
A server SHOULD impose a limit on the amount of time required for a
client to issue a well-formed EPP command. A server SHOULD end an
EPP session if a well-formed command is not received within the time
limit.
HTTP/2 and HTTP/3 support a multiplexing feature that was introduced
to address head-of-line blocking issues in previous HTTP versions.
In the context of multiple requests being sent on a single HTTP
connection, multiplexing allows the delivery of responses in a
different order from how the requests were made. Due to this
behavior, pipelining MUST NOT be used by EoH clients. EoH clients
MUST wait for a server response to a command before sending a
subsequent command.
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A general state machine for an EPP server is described in Section 2
of [RFC5730]. A general client-server message exchange using HTTP is
illustrated in Figure 1.
Client Server
| |
| GET Server URL |
| >>------------------------------->> |
| |
| Send Greeting |
| <<-------------------------------<< |
| |
| POST <login> |
| >>------------------------------->> |
| |
| Send Response |
| <<-------------------------------<< |
| |
| POST Command X |
| >>------------------------------->> |
| |
| Send Response X |
| <<-------------------------------<< |
| |
| POST Command Y |
| >>------------------------------->> |
| |
| Send Response Y |
| <<-------------------------------<< |
| . |
.
.
| POST <logout> |
| >>------------------------------->> |
| |
| Send Response |
| <<-------------------------------<< |
Figure 1: HTTP Client-Server Message Exchange
The EPP server MUST follow the "EPP Server State Machine" procedure
described in [RFC5730].
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5. Transport Considerations
Section 2.1 of [RFC5730] describes considerations to be addressed by
protocol transport mappings. This document addresses each of those
considerations using a combination of features of the HTTP protocol
itself and features of this document.
* Command Order: Section 4 includes a requirement for ordered
message delivery.
* Session Mapping: EPP session management is described in Section 3
of this document.
* Stateful Nature: Achieving the stateful nature of EPP is described
in Section 3.
* Frame Data Units: Section 4 of this document describes how each
EPP command is framed within the content of HTTP requests and
responses.
* Congestion Avoidance: Section 3.9.3 of [RFC8095] confirms
congestion avoidance as a feature of HTTP.
* Reliability: Section 3.9.3 of [RFC8095] confirms reliable message
delivery as a feature of HTTP.
* Pipelining: Section 4 of this document stipulates that command
pipelining must not be used in EoH.
6. Internationalization Considerations
Servers MUST use the "charset" attribute in the HTTP "Content-Type"
response header field to specify the character encoding (e.g.
Content-Type: application/epp+xml; charset=UTF-8).
7. IANA Considerations
This specification does not request any actions by IANA.
8. Security Considerations
Since client credentials are included in the EPP <login> command,
HTTPS (Section 4.2.2 of [RFC9110]) MUST be used to protect them from
disclosure while in transit. HTTPS indicates that TLS is being used
to secure the HTTP connection between the client and server.
Transferring over TLS also prevents sniffing the session ID and,
consequently, impersonating a client to perform actions on
registrars' objects. Servers are REQUIRED to support TLS 1.2
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[RFC8446][RFC9155] or higher.
As a further measure to enforce client identification, servers SHOULD
require clients to present a digital certificate. Clients who
possess and present a valid X.509 digital certificate, issued by a
recognized Certification Authority (CA), could be identified and
authenticated by a server who trusts the corresponding CA. This
certificate-based mechanism is supported by HTTPS and can be used
with EPP over HTTP.
Servers are RECOMMENDED to implement additional measures to verify
the client. These measures include IP allow-listing, identifying the
client by its IP address and locking the session ID to the client's
IP address.
Session IDs SHOULD be randomly generated to mitigate the risk of
obtaining a valid one through a brute-force search. A session ID
SHOULD be at least 128 bits or 16 bytes long. An example of a
reliable session ID is the Universally Unique Identifier (UUID).
Servers MAY limit the lifetime of active sessions to avoid them being
exchanged for a long time.
The following measures MAY also be taken to control cookies usage:
* Restricting their scope through the "Domain" and "Path" attributes
* Limiting their lifetime through the "Max-Age" and "Expire"
attributes
Other attributes that are normally used to secure the cookies and
prevent them to be accessed by unintended parties or scripts, such as
"HttpOnly" and "Secure", are meaningless in this context. Finally,
servers are RECOMMENDED to perform additional checks to limit the
rate of open EPP sessions and HTTP connections to mitigate the risk
of congestion of requests. Here again, IP allow-listing could also
be implemented to prevent DDoS attacks.
If the EPP server is configured as a load balancer routing the
requests to a pool of backend servers, some of the aforementioned
checks SHOULD be implemented on the load balancer side.
9. Acknowledgements
The authors wish to acknowledge the input from the .IT technical
team.
10. References
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10.1. Normative References
[BCP14] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017.
<https://www.rfc-editor.org/info/bcp14>
[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
<https://www.rfc-editor.org/info/rfc5730>.
[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265,
DOI 10.17487/RFC6265, April 2011,
<https://www.rfc-editor.org/info/rfc6265>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[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>.
[RFC9112] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP/1.1", STD 99, RFC 9112, DOI 10.17487/RFC9112,
June 2022, <https://www.rfc-editor.org/info/rfc9112>.
[RFC9113] Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
DOI 10.17487/RFC9113, June 2022,
<https://www.rfc-editor.org/info/rfc9113>.
[RFC9114] Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114,
June 2022, <https://www.rfc-editor.org/info/rfc9114>.
[RFC9155] Velvindron, L., Moriarty, K., and A. Ghedini, "Deprecating
MD5 and SHA-1 Signature Hashes in TLS 1.2 and DTLS 1.2",
RFC 9155, DOI 10.17487/RFC9155, December 2021,
<https://www.rfc-editor.org/info/rfc9155>.
10.2. Informative References
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[RFC8095] Fairhurst, G., Ed., Trammell, B., Ed., and M. Kuehlewind,
Ed., "Services Provided by IETF Transport Protocols and
Congestion Control Mechanisms", RFC 8095,
DOI 10.17487/RFC8095, March 2017,
<https://www.rfc-editor.org/info/rfc8095>.
Appendix A. Change History
A.1. Change from 00 to 01
1. Added Dan Keathley and James Gould as co-authors.
Authors' Addresses
Mario Loffredo
IIT-CNR/Registro.it
Via Moruzzi,1
56124 Pisa
Italy
Email: mario.loffredo@iit.cnr.it
URI: https://www.iit.cnr.it
Lorenzo Luconi Trombacchi
IIT-CNR/Registro.it
Via Moruzzi,1
56124 Pisa
Italy
Email: lorenzo.luconi@iit.cnr.it
URI: https://www.iit.cnr.it
Maurizio Martinelli
IIT-CNR/Registro.it
Via Moruzzi,1
56124 Pisa
Italy
Email: maurizio.martinelli@iit.cnr.it
URI: https://www.iit.cnr.it
Daniel Keathley
VeriSign, Inc.
12061 Bluemont Way
Reston, VA 20190
United States of America
Email: dkeathley@verisign.com
URI: http://www.verisigninc.com
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James Gould
VeriSign, Inc.
12061 Bluemont Way
Reston, VA 20190
United States of America
Email: jgould@verisign.com
URI: http://www.verisigninc.com
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