Internet DRAFT - draft-ietf-httpbis-legally-restricted-status
draft-ietf-httpbis-legally-restricted-status
HTTP Working Group T. Bray
Internet-Draft Textuality
Intended status: Standards Track November 10, 2015
Expires: May 13, 2016
An HTTP Status Code to Report Legal Obstacles
draft-ietf-httpbis-legally-restricted-status-04
Abstract
This document specifies a Hypertext Transfer Protocol (HTTP) status
code for use when resource access is denied as a consequence of legal
demands.
Editorial Note (To be removed by RFC Editor before publication)
Discussion of this draft takes place on the HTTPBIS working group
mailing list (ietf-http-wg@w3.org), which is archived at [1].
Working Group information can be found at [2] and [3]; source code
and issues list for this draft can be found at [4].
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 May 13, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 2
3. 451 Unavailable For Legal Reasons . . . . . . . . . . . . . . 3
4. Identifying Blocking Entities . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
This document specifies a Hypertext Transfer Protocol (HTTP) status
code for use when a server operator has received a legal demand to
deny access to a resource or to a set of resources which includes the
requested resource.
This status code can be used to provide transparency in circumstances
where issues of law or public policy affect server operations. This
transparency may be beneficial both to these operators and to end
users.
[RFC4924] discusses the forces working against transparent operation
of the Internet; these clearly include legal interventions to
restrict access to content. As that document notes, and as Section 4
of [RFC4084] states, such restrictions should be made explicit.
Feedback should occur on the ietf-http-wg@w3.org mailing list.
2. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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3. 451 Unavailable For Legal Reasons
This status code indicates that the server is denying access to the
resource as a consequence of a legal demand.
The server in question might not be an origin server. This type of
legal demand typically most directly affects the operations of ISPs
and search engines.
Responses using this status code SHOULD include an explanation, in
the response body, of the details of the legal demand: the party
making it, the applicable legislation or regulation, and what classes
of person and resource it applies to. For example:
HTTP/1.1 451 Unavailable For Legal Reasons
Link: <https://spqr.example.org/legislatione>; rel="blocked-by"
Content-Type: text/html
<html>
<head><title>Unavailable For Legal Reasons</title></head>
<body>
<h1>Unavailable For Legal Reasons</h1>
<p>This request may not be serviced in the Roman Province
of Judea due to the Lex Julia Majestatis, which disallows
access to resources hosted on servers deemed to be
operated by the People's Front of Judea.</p>
</body>
</html>
The use of the 451 status code implies neither the existence nor non-
existence of the resource named in the request. That is to say, it
is possible that if the legal demands were removed, a request for the
resource still might not succeed.
Note that in many cases clients can still access the denied resource
by using technical countermeasures such as a VPN or the Tor network.
A 451 response is cacheable by default; i.e., unless otherwise
indicated by the method definition or explicit cache controls; see
[RFC7234].
4. Identifying Blocking Entities
As noted above, when an attempt to access a resource fails with
status 451, the entity blocking access might or might not be the
origin server. There are a variety of entities in the resource-
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access path which could choose to deny access, for example ISPs,
cache providers, and DNS servers.
It is useful, when legal blockages occur, to be able to identify the
entities actually implementing the blocking.
When an entity blocks access to a resource and returns status 451, it
SHOULD include a "Link" HTTP header field [RFC5988] whose value is a
URI reference [RFC3986] identifying itself. When used for this
purpose, the "Link" header field MUST have a "rel" parameter whose
value is "blocked-by".
The intent is that the header be used to identify the entity actually
implementing blockage, not any other entity mandating it. A human
readable response body, as discussed above, is the appropriate
location for discussion of administrative and policy issues.
5. Security Considerations
Clients cannot rely upon the use of the 451 status code. It is
possible that certain legal authorities might wish to avoid
transparency, and not only demand the restriction of access to
certain resources, but also avoid disclosing that the demand was
made.
6. IANA Considerations
The HTTP Status Codes Registry should be updated with the following
entry:
o Code: 451
o Description: Unavailable for Legal Reasons
o Specification: [ this document ]
The Link Relation Type Registry should updated with the following
entry:
o Relation Name: blocked-by
o Description: Identifies the entity blocking access to a resource
folllowing on receipt of a legal demand.
o Reference: This document
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7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC5988] Nottingham, M., "Web Linking", RFC 5988, DOI 10.17487/
RFC5988, October 2010,
<http://www.rfc-editor.org/info/rfc5988>.
[RFC7234] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
RFC 7234, DOI 10.17487/RFC7234, June 2014,
<http://www.rfc-editor.org/info/rfc7234>.
7.2. Informative References
[RFC4084] Klensin, J., "Terminology for Describing Internet
Connectivity", BCP 104, RFC 4084, DOI 10.17487/RFC4084,
May 2005, <http://www.rfc-editor.org/info/rfc4084>.
[RFC4924] Aboba, B., Ed. and E. Davies, "Reflections on Internet
Transparency", RFC 4924, DOI 10.17487/RFC4924, July 2007,
<http://www.rfc-editor.org/info/rfc4924>.
Appendix A. Acknowledgements
Thanks to Terence Eden, who observed that the existing status code
403 was not really suitable for this situation, and suggested the
creation of a new status code.
Thanks also to Ray Bradbury.
Author's Address
Tim Bray
Textuality
Email: tbray@textuality.com
URI: http://www.tbray.org/ongoing/
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