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Versions: 00 draft-ietf-httpbis-auth-info

Network Working Group                                         J. Reschke
Internet-Draft                                                greenbytes
Intended status: Standards Track                        January 24, 2015
Expires: July 28, 2015


The Hypertext Transfer Protocol (HTTP) Authentication-Info Header Field
                  draft-reschke-httpauth-auth-info-00

Abstract

   This specification defines the "Authentication-Info" and "Proxy-
   Authentication-Info" header fields for use in HTTP authentication
   schemes which need to return additional information during or after
   authentication.

Editorial Note (To be removed by RFC Editor before publication)

   Distribution of this document is unlimited.  Although this is not a
   work item of the HTTPAuth Working Group, comments should be sent to
   the HTTPAuth mailing list (http-auth@ietf.org), which is archived at
   <http://www.ietf.org/mail-archive/web/http-auth/current/
   maillist.html>.

   XML versions and latest edits for this document are available from
   <http://greenbytes.de/tech/webdav/#draft-reschke-httpauth-auth-info>.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on July 28, 2015.

Copyright Notice

   Copyright (c) 2015 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
   (http://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 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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . . . 3
   3.  The Authentication-Info Header Field  . . . . . . . . . . . . . 3
     3.1.  Parameter Value Format  . . . . . . . . . . . . . . . . . . 3
   4.  The Proxy-Authentication-Info Header Field  . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 5





























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1.  Introduction

   This specification defines the "Authentication-Info" and "Proxy-
   Authentication-Info" header fields for use in HTTP authentication
   schemes ([RFC7235]) which need to return additional information
   during or after authentication.

   Both were previously defined in Section 3 of [RFC2617], defining the
   HTTP "Digest" authentication scheme.  This document generalizes the
   description for use not only in "Digest" ([DIGEST]), but also other
   future schemes that might have the same requirements for carrying
   additional information during authentication.

2.  Notational Conventions

   This specification uses the Augmented Backus-Naur Form (ABNF)
   notation of [RFC5234] with a list extension, defined in Section 7 of
   [RFC7230], that allows for compact definition of comma-separated
   lists using a '#' operator (similar to how the '*' operator indicates
   repetition).  The ABNF production for "auth-param" is defined in
   Section 2.1 of [RFC7235].

3.  The Authentication-Info Header Field

   HTTP authentication schemes can use the Authentication-Info response
   header field to return additional information applicable to the
   authentication currently in use.

   The field value is a list of parameters (name/value pairs), using the
   "auth-param" syntax defined in Section 2.1 of [RFC7235].  This
   specification only describes the generic format; authentication
   schemes using "Authentication-Info" will define the individual
   parameters.  The "Digest" Authentication Scheme, for instance,
   defines multiple parameters in Section 3.5.1 of [DIGEST].

     Authentication-Info = #auth-param

   The Authentication-Info header field can be used in any HTTP
   response, independently of request method and status code.  Its
   semantics are defined by the applicable authentication scheme.
   Intermediaries are not allowed to modify the field value in any way.
   Authentication-Info can be used inside trailers ([RFC7230], Section
   4.1.2).

3.1.  Parameter Value Format

   Parameter values can be expressed either as "token" or as "quoted-
   string" (Section 3.2.6 of [RFC7230]).



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   Authentication scheme definitions need to allow both notations, both
   for senders and recipients.  This allows recipients to use generic
   parsing components, independent of the authentication scheme in use.

   For backwards compatibility, authentication scheme definitions can
   restrict the format for senders to one of the two variants.  This can
   be important when it is known that deployed implementations will fail
   when encountering one of the two formats.

4.  The Proxy-Authentication-Info Header Field

   The Proxy-Authentication-Info header field is equivalent to
   Authentication-Info, except that it applies to proxy authentication
   ([RFC7235]):


     Proxy-Authentication-Info = #auth-param

5.  Security Considerations

   Adding information to HTTP responses can affect security and privacy.
   The presence of the header fields alone indicates that HTTP
   authentication is in use.  Additional information could be exposed by
   the contents of the authentication-scheme specific parameters; this
   will have to be considered in the definitions of these schemes.

6.  IANA Considerations

   HTTP header fields are registered within the "Message Headers"
   registry located at
   <http://www.iana.org/assignments/message-headers>, as defined by
   [BCP90].

   This document updates the definitions of the "Authentication-Info"
   and "Proxy-Authentication-Info" header fields, so the "Permanent
   Message Header Field Names" registry shall be updated accordingly:

   +---------------------------+----------+----------+-----------------+
   | Header Field Name         | Protocol | Status   | Reference       |
   +---------------------------+----------+----------+-----------------+
   | Authentication-Info       | http     | standard | Section 3 of    |
   |                           |          |          | this document   |
   | Proxy-Authentication-Info | http     | standard | Section 4 of    |
   |                           |          |          | this document   |
   +---------------------------+----------+----------+-----------------+

7.  References




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7.1.  Normative References

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, June 2014.

   [RFC7235]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Authentication", RFC 7235, June 2014.

7.2.  Informative References

   [BCP90]    Klyne, G., Nottingham, M., and J. Mogul, "Registration
              Procedures for Message Header Fields", BCP 90, RFC 3864,
              September 2004.

   [DIGEST]   Shekh-Yusef, R., Ed., Ahrens, D., and S. Bremer, "HTTP
              Digest Access Authentication",
              draft-ietf-httpauth-digest-12 (work in progress),
              January 2015.

   [RFC2617]  Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
              Leach, P., Luotonen, A., and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",
              RFC 2617, June 1999.

Author's Address

   Julian F. Reschke
   greenbytes GmbH
   Hafenweg 16
   Muenster, NW  48155
   Germany

   EMail: julian.reschke@greenbytes.de
   URI:   http://greenbytes.de/tech/webdav/













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