An HTTP Status Code to Report Requester Impairment
draft-richardroda-420requesterimpaired-04

HTTP                                                        R. Roda, Ed.
Internet-Draft                                          12 December 2023
Intended status: Informational                                          
Expires: 14 June 2024

           An HTTP Status Code to Report Requester Impairment
               draft-richardroda-420requesterimpaired-04

Abstract

   This document specifies a Hypertext Transfer Protocol (HTTP) status
   code for use when an operation or resource is denied due to requester
   impairment.

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   This Internet-Draft will expire on 14 June 2024.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  420 Requester Impaired  . . . . . . . . . . . . . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   This document specifies a Hypertext Transfer Protocol (HTTP) status
   code for use when a request is denied because the requester is
   impaired.

1.1.  Requirements Language

   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.  420 Requester Impaired

   The status code 420 indicates that the server is denying the request
   as a consequence of evidence of requester impairment.

   The server in question might not be an origin server.  An
   intermediate proxy closer to the requester may be in a better
   position to assess potential requester impairment.  Such a proxy may
   refuse to forward the request and respond with this error code.

   There is no requirement that the requester be human.  Certain AI
   systems can exhibit behaviors such as giving hallucinated, incorrect,
   and differing answers for a given input.

   420 responses MUST include a Link header [RFC8288] with a relation
   type of "status".  This link is used by the remediated requester to
   obtain information about the server state and to signal to the server
   that the requester is remediated.  Requesters SHOULD use this link
   when remediated before making subsequent requests unless a bearer
   token is used as described under Section 4 and the server does not
   require usage of the link.

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   A 420 response is non-cacheable by default, i.e., unless otherwise
   indicated by the method definition or explicit cache controls; see
   [RFC9111].

   AI
      An artificial intelligence system that is capable of making
      independent decisions without direct human control.

   proxy
      A server with a primary purpose of forwarding requests to other
      servers to process.

   HTTP/1.1 420 Requester Impaired
   Link: <https://example.com/impaired/remediated>; rel="status"
   Content-Type: application/problem+json
   Content-Language: en
   {
       "type": "https://example.com/erratic-requests",
       "title": "Requester Impaired: Erratic Behavior Detected.",
       "detail": "Erratic requests detected."
   }

       Figure 1: Example Response in [RFC9457] Problem Details Format

3.  IANA Considerations

   IANA is asked to update the HTTP Status Codes Registry with the
   following entry:

   *  Code: 420

   *  Description: Requester Impaired

   *  Specification: This RFC

4.  Security Considerations

   The usage of the link resource provided by the Link header to assert
   requester remediation assumes a requester or proxy that is
   trustworthy enough to halt requests and only access the link resource
   after requester remediation.  If greater security is required,
   perhaps to enable an external system to remediate and validate the
   requester, a server MAY require an OAuth authorization [RFC7523]
   bearer token [RFC6750] to signal remediation of the requester.

   If a valid bearer token is required and missing, further requests
   SHOULD be rejected with a 403 Forbidden response code with the
   insufficient_scope error code and scope attribute naming the

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   authorization token required as described in [RFC6750] section 3.1.
   Once this authorization bearer token is validated the server MAY
   allow requests without using the Link provided in the 420 response,
   but MUST NOT respond to usage of the link as an error.

5.  References

5.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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>.

   [RFC9111]  Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Caching", STD 98, RFC 9111,
              DOI 10.17487/RFC9111, June 2022,
              <https://www.rfc-editor.org/info/rfc9111>.

   [RFC9457]  Nottingham, M., Wilde, E., and S. Dalal, "Problem Details
              for HTTP APIs", RFC 9457, DOI 10.17487/RFC9457, July 2023,
              <https://www.rfc-editor.org/info/rfc9457>.

   [RFC8288]  Nottingham, M., "Web Linking", RFC 8288,
              DOI 10.17487/RFC8288, October 2017,
              <https://www.rfc-editor.org/info/rfc8288>.

   [RFC7523]  Jones, M., Campbell, B., and C. Mortimore, "JSON Web Token
              (JWT) Profile for OAuth 2.0 Client Authentication and
              Authorization Grants", RFC 7523, DOI 10.17487/RFC7523, May
              2015, <https://www.rfc-editor.org/info/rfc7523>.

   [RFC6750]  Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
              Framework: Bearer Token Usage", RFC 6750,
              DOI 10.17487/RFC6750, October 2012,
              <https://www.rfc-editor.org/info/rfc6750>.

Author's Address

   Richard Roda (editor)
   Email: richard_roda@hotmail.com
   URI:   https://www.linkedin.com/in/richardroda/

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