Extensible Provisioning Protocol (EPP) Transport over HTTPS
draft-loffredo-regext-epp-over-http-05
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| Document | Type | Active Internet-Draft (regext WG) | |
|---|---|---|---|
| Authors | Mario Loffredo , Lorenzo Luconi Trombacchi , Maurizio Martinelli , Dan Keathley , James Gould | ||
| Last updated | 2024-12-02 (Latest revision 2024-09-24) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Candidate for WG Adoption | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-loffredo-regext-epp-over-http-05
Internet Engineering Task Force M. Loffredo
Internet-Draft L. Luconi Trombacchi
Intended status: Standards Track M. Martinelli
Expires: 28 March 2025 IIT-CNR/Registro.it
D. Keathley
J. Gould
VeriSign, Inc.
24 September 2024
Extensible Provisioning Protocol (EPP) Transport over HTTPS
draft-loffredo-regext-epp-over-http-05
Abstract
This document describes how an Extensible Provisioning Protocol (EPP)
connection is mapped onto a Hypertext Transfer Protocol (HTTP)
session. 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
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 March 2025.
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. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Implementation Status . . . . . . . . . . . . . . . . . . . . 6
7.1. Verisign EPP SDK . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
10. Normative References . . . . . . . . . . . . . . . . . . . . 9
Appendix A. Change History . . . . . . . . . . . . . . . . . . . 10
A.1. Change from 02 to 03 . . . . . . . . . . . . . . . . . . 10
A.2. Change from 03 to 04 . . . . . . . . . . . . . . . . . . 10
A.3. Change from 04 to 05 . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
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 on top of an EPP connection between two peers, one that
initiates the connection request and one that responds to the
connection 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.
The EPP Greeting must include "application/epp+xml" in the "Content-
Type" header with the character encoding of the EPP XML (e.g.,
"application/epp+xml;charset=UTF-8") and MUST include ""no-cache" in
the "Cache-Control" header and include "0" in the "Expires" header to
disable caching. The server 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, referred to as an EPP over
HTTP (EoH) connection, which is initiated by the initial GET request.
The EPP session begins with a successful EPP <login> command on the
EoH connection 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. The EPP command and the EPP response MUST
include "application/epp+xml" in the "Content-Type" header with the
character encoding of the EPP XML (e.g., "application/
epp+xml;charset=UTF-8"). The EPP response MUST include "no-cache" in
the "Cache-Control" header and include "0" in the "Expires" header to
disable caching.
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
HTTP session identifier.
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
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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.
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. IANA Considerations
This specification does not request any actions by IANA.
7. Implementation Status
Note to RFC Editor: Please remove this section and the reference to
[RFC7942] before publication.
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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 [RFC7942], "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".
7.1. Verisign EPP SDK
Organization: Verisign Inc.
Name: Verisign EPP SDK
Description: The Verisign EPP SDK includes both a full client
implementation and a full server stub implementation of draft-
loffredo-regext-epp-over-http. Both HTTP/1.1 and HTTP/2 were
implemented, but HTTP/3 was not due to the lack of support of the
underlying library.
Level of maturity: Development
Coverage: All aspects of the protocol are implemented with HTTP/1.1
and HTTP/2.
Licensing: GNU Lesser General Public License
Contact: jgould@verisign.com
URL: https://www.verisign.com/en_US/channel-resources/domain-
registry-products/epp-sdks
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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 HTTP session
identifier and, consequently, impersonating a client to perform
actions on registrars' objects. Servers are REQUIRED to support TLS
1.2 [RFC8446][RFC9155] or higher.
Servers are RECOMMENDED to implement additional measures to verify
the client. These measures include IP allow-listing and locking the
HTTP session identifier to the client's IP address.
HTTP session identifiers SHOULD be randomly generated to mitigate the
risk of obtaining a valid one through a brute-force search. A HTTP
session identifier SHOULD be at least 128 bits or 16 bytes long. An
example of a reliable HTTP session identifier 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.
As a further measure to enforce the security, servers MUST 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.
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.
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9. Acknowledgements
The authors wish to acknowledge the input from the .IT technical
team.
10. Normative References
[BCP14] Best Current Practice 14,
<https://www.rfc-editor.org/info/bcp14>.
At the time of writing, this BCP comprises the following:
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>.
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>.
[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>.
[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>.
[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>.
[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>.
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[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>.
Appendix A. Change History
A.1. Change from 02 to 03
1. Added Dan Keathley and James Gould as co-authors.
A.2. Change from 03 to 04
1. Clarified the difference between an EoH connection and an EPP
session.
2. Added inclusion of the "Content-Type" header in every request and
response except for the initial GET establishing the EoH
connection.
3. Revised the Security Considerations section.
A.3. Change from 04 to 05
1. Added the Implementation Status section with the Verisign EPP SDK
implementation.
2. Removed the "Internationalization Considerations" section and
added the EoH character encoding matching the EPP XML character
encoding for the EPP Greeting, the EPP commands, and the EPP
responses.
3. Added inclusion of the "Cache-Control" and "Expires" headers for
the the EPP Greeting, the EPP commands, and the EPP responses.
Authors' Addresses
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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
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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