HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Adobe
Obsoletes: 2616 (if approved) J. Gettys
Updates: 2617 (if approved) Alcatel-Lucent
Intended status: Standards Track J. Mogul
Expires: July 7, 2012 HP
H. Frystyk
Microsoft
L. Masinter
Adobe
P. Leach
Microsoft
T. Berners-Lee
W3C/MIT
Y. Lafon, Ed.
W3C
J. Reschke, Ed.
greenbytes
January 4, 2012
HTTP/1.1, part 7: Authentication
draft-ietf-httpbis-p7-auth-18
Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information
systems. HTTP has been in use by the World Wide Web global
information initiative since 1990. This document is Part 7 of the
seven-part specification that defines the protocol referred to as
"HTTP/1.1" and, taken together, obsoletes RFC 2616.
Part 7 defines the HTTP Authentication framework.
Editorial Note (To be removed by RFC Editor)
Discussion of this draft should take place on the HTTPBIS working
group mailing list (ietf-http-wg@w3.org), which is archived at
.
The current issues list is at
and related
documents (including fancy diffs) can be found at
.
The changes in this draft are summarized in Appendix C.19.
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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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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 July 7, 2012.
Copyright Notice
Copyright (c) 2012 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
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This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
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material may not have granted the IETF Trust the right to allow
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Without obtaining an adequate license from the person(s) controlling
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than English.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Conformance and Error Handling . . . . . . . . . . . . . . 5
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1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 5
1.2.1. Core Rules . . . . . . . . . . . . . . . . . . . . . . 6
2. Access Authentication Framework . . . . . . . . . . . . . . . 6
2.1. Challenge and Response . . . . . . . . . . . . . . . . . . 6
2.2. Protection Space (Realm) . . . . . . . . . . . . . . . . . 8
2.3. Authentication Scheme Registry . . . . . . . . . . . . . . 8
2.3.1. Considerations for New Authentication Schemes . . . . 9
3. Status Code Definitions . . . . . . . . . . . . . . . . . . . 10
3.1. 401 Unauthorized . . . . . . . . . . . . . . . . . . . . . 10
3.2. 407 Proxy Authentication Required . . . . . . . . . . . . 10
4. Header Field Definitions . . . . . . . . . . . . . . . . . . . 10
4.1. Authorization . . . . . . . . . . . . . . . . . . . . . . 11
4.2. Proxy-Authenticate . . . . . . . . . . . . . . . . . . . . 11
4.3. Proxy-Authorization . . . . . . . . . . . . . . . . . . . 12
4.4. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . . 12
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
5.1. Authenticaton Scheme Registry . . . . . . . . . . . . . . 13
5.2. Status Code Registration . . . . . . . . . . . . . . . . . 13
5.3. Header Field Registration . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
6.1. Authentication Credentials and Idle Clients . . . . . . . 14
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Changes from RFCs 2616 and 2617 . . . . . . . . . . . 16
Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 16
Appendix C. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 17
C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 17
C.2. Since draft-ietf-httpbis-p7-auth-00 . . . . . . . . . . . 17
C.3. Since draft-ietf-httpbis-p7-auth-01 . . . . . . . . . . . 17
C.4. Since draft-ietf-httpbis-p7-auth-02 . . . . . . . . . . . 17
C.5. Since draft-ietf-httpbis-p7-auth-03 . . . . . . . . . . . 17
C.6. Since draft-ietf-httpbis-p7-auth-04 . . . . . . . . . . . 17
C.7. Since draft-ietf-httpbis-p7-auth-05 . . . . . . . . . . . 18
C.8. Since draft-ietf-httpbis-p7-auth-06 . . . . . . . . . . . 18
C.9. Since draft-ietf-httpbis-p7-auth-07 . . . . . . . . . . . 18
C.10. Since draft-ietf-httpbis-p7-auth-08 . . . . . . . . . . . 18
C.11. Since draft-ietf-httpbis-p7-auth-09 . . . . . . . . . . . 18
C.12. Since draft-ietf-httpbis-p7-auth-10 . . . . . . . . . . . 18
C.13. Since draft-ietf-httpbis-p7-auth-11 . . . . . . . . . . . 18
C.14. Since draft-ietf-httpbis-p7-auth-12 . . . . . . . . . . . 19
C.15. Since draft-ietf-httpbis-p7-auth-13 . . . . . . . . . . . 19
C.16. Since draft-ietf-httpbis-p7-auth-14 . . . . . . . . . . . 19
C.17. Since draft-ietf-httpbis-p7-auth-15 . . . . . . . . . . . 19
C.18. Since draft-ietf-httpbis-p7-auth-16 . . . . . . . . . . . 20
C.19. Since draft-ietf-httpbis-p7-auth-17 . . . . . . . . . . . 20
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Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
This document defines HTTP/1.1 access control and authentication. It
includes the relevant parts of RFC 2616 with only minor changes, plus
the general framework for HTTP authentication, as previously defined
in "HTTP Authentication: Basic and Digest Access Authentication"
([RFC2617]).
HTTP provides several OPTIONAL challenge-response authentication
mechanisms which can be used by a server to challenge a client
request and by a client to provide authentication information. The
"basic" and "digest" authentication schemes continue to be specified
in RFC 2617.
1.1. Conformance and Error Handling
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].
This document defines conformance criteria for several roles in HTTP
communication, including Senders, Recipients, Clients, Servers, User-
Agents, Origin Servers, Intermediaries, Proxies and Gateways. See
Section 2 of [Part1] for definitions of these terms.
An implementation is considered conformant if it complies with all of
the requirements associated with its role(s). Note that SHOULD-level
requirements are relevant here, unless one of the documented
exceptions is applicable.
This document also uses ABNF to define valid protocol elements
(Section 1.2). In addition to the prose requirements placed upon
them, Senders MUST NOT generate protocol elements that are invalid.
Unless noted otherwise, Recipients MAY take steps to recover a usable
protocol element from an invalid construct. However, HTTP does not
define specific error handling mechanisms, except in cases where it
has direct impact on security. This is because different uses of the
protocol require different error handling strategies; for example, a
Web browser may wish to transparently recover from a response where
the Location header field doesn't parse according to the ABNF,
whereby in a systems control protocol using HTTP, this type of error
recovery could lead to dangerous consequences.
1.2. Syntax Notation
This specification uses the ABNF syntax defined in Section 1.2 of
[Part1] (which extends the syntax defined in [RFC5234] with a list
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rule). Appendix B shows the collected ABNF, with the list rule
expanded.
The following core rules are included by reference, as defined in
[RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF
(CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit
sequence of data), SP (space), and VCHAR (any visible US-ASCII
character).
1.2.1. Core Rules
The core rules below are defined in [Part1]:
BWS =
OWS =
quoted-string =
token =
2. Access Authentication Framework
2.1. Challenge and Response
HTTP provides a simple challenge-response authentication mechanism
that can be used by a server to challenge a client request and by a
client to provide authentication information. It uses an extensible,
case-insensitive token to identify the authentication scheme,
followed by additional information necessary for achieving
authentication via that scheme. The latter can either be a comma-
separated list of parameters or a single sequence of characters
capable of holding base64-encoded information.
Parameters are name-value pairs where the name is matched case-
insensitively, and each parameter name MUST only occur once per
challenge.
auth-scheme = token
auth-param = token BWS "=" BWS ( token / quoted-string )
b64token = 1*( ALPHA / DIGIT /
"-" / "." / "_" / "~" / "+" / "/" ) *"="
The "b64token" syntax allows the 66 unreserved URI characters
([RFC3986]), plus a few others, so that it can hold a base64,
base64url (URL and filename safe alphabet), base32, or base16 (hex)
encoding, with or without padding, but excluding whitespace
([RFC4648]).
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The 401 (Unauthorized) response message is used by an origin server
to challenge the authorization of a user agent. This response MUST
include a WWW-Authenticate header field containing at least one
challenge applicable to the requested resource.
The 407 (Proxy Authentication Required) response message is used by a
proxy to challenge the authorization of a client and MUST include a
Proxy-Authenticate header field containing at least one challenge
applicable to the proxy for the requested resource.
challenge = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
Note: User agents will need to take special care in parsing the
WWW-Authenticate and Proxy-Authenticate header field values
because they can contain more than one challenge, or if more than
one of each is provided, since the contents of a challenge can
itself contain a comma-separated list of authentication
parameters.
Note: Many browsers fail to parse challenges containing unknown
schemes. A workaround for this problem is to list well-supported
schemes (such as "basic") first.
A user agent that wishes to authenticate itself with an origin server
-- usually, but not necessarily, after receiving a 401 (Unauthorized)
-- MAY do so by including an Authorization header field with the
request.
A client that wishes to authenticate itself with a proxy -- usually,
but not necessarily, after receiving a 407 (Proxy Authentication
Required) -- MAY do so by including a Proxy-Authorization header
field with the request.
Both the Authorization field value and the Proxy-Authorization field
value consist of credentials containing the authentication
information of the client for the realm of the resource being
requested. The user agent MUST choose to use one of the challenges
with the strongest auth-scheme it understands and request credentials
from the user based upon that challenge.
credentials = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
If the origin server does not wish to accept the credentials sent
with a request, it SHOULD return a 401 (Unauthorized) response. The
response MUST include a WWW-Authenticate header field containing at
least one (possibly new) challenge applicable to the requested
resource.
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If a proxy does not accept the credentials sent with a request, it
SHOULD return a 407 (Proxy Authentication Required). The response
MUST include a Proxy-Authenticate header field containing a (possibly
new) challenge applicable to the proxy for the requested resource.
The HTTP protocol does not restrict applications to this simple
challenge-response mechanism for access authentication. Additional
mechanisms MAY be used, such as encryption at the transport level or
via message encapsulation, and with additional header fields
specifying authentication information. However, such additional
mechanisms are not defined by this specification.
Proxies MUST forward the WWW-Authenticate and Authorization headers
unmodified and follow the rules found in Section 4.1.
2.2. Protection Space (Realm)
The authentication parameter realm is reserved for use by
authentication schemes that wish to indicate the scope of protection.
A protection space is defined by the canonical root URI (the scheme
and authority components of the effective request URI; see Section
4.3 of [Part1]) of the server being accessed, in combination with the
realm value if present. These realms allow the protected resources
on a server to be partitioned into a set of protection spaces, each
with its own authentication scheme and/or authorization database.
The realm value is a string, generally assigned by the origin server,
which can have additional semantics specific to the authentication
scheme. Note that there can be multiple challenges with the same
auth-scheme but different realms.
The protection space determines the domain over which credentials can
be automatically applied. If a prior request has been authorized,
the same credentials MAY be reused for all other requests within that
protection space for a period of time determined by the
authentication scheme, parameters, and/or user preference. Unless
otherwise defined by the authentication scheme, a single protection
space cannot extend outside the scope of its server.
For historical reasons, senders MUST only use the quoted-string
syntax. Recipients might have to support both token and quoted-
string syntax for maximum interoperability with existing clients that
have been accepting both notations for a long time.
2.3. Authentication Scheme Registry
The HTTP Authentication Scheme Registry defines the name space for
the authentication schemes in challenges and credentials.
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Registrations MUST include the following fields:
o Authentication Scheme Name
o Pointer to specification text
o Notes (optional)
Values to be added to this name space are subject to IETF review
([RFC5226], Section 4.1).
The registry itself is maintained at
.
2.3.1. Considerations for New Authentication Schemes
There are certain aspects of the HTTP Authentication Framework that
put constraints on how new authentication schemes can work:
o Authentication schemes need to be compatible with the inherent
constraints of HTTP; for instance, that messages need to keep
their semantics when inspected in isolation, thus an
authentication scheme can not bind information to the TCP session
over which the message was received (see Section 2.2 of [Part1]).
o The authentication parameter "realm" is reserved for defining
Protection Spaces as defined in Section 2.2. New schemes MUST NOT
use it in a way incompatible with that definition.
o The "b64token" notation was introduced for compatibility with
existing authentication schemes and can only be used once per
challenge/credentials. New schemes thus ought to use the "auth-
param" syntax instead, because otherwise future extensions will be
impossible.
o The parsing of challenges and credentials is defined by this
specification, and cannot be modified by new authentication
schemes. When the auth-param syntax is used, all parameters ought
to support both token and quoted-string syntax, and syntactical
constraints ought to be defined on the field value after parsing
(i.e., quoted-string processing). This is necessary so that
recipients can use a generic parser that applies to all
authentication schemes.
Note: the fact that the value syntax for the "realm" parameter is
restricted to quoted-string was a bad design choice not to be
repeated for new parameters.
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o Authentication schemes need to document whether they are usable in
origin-server authentication (i.e., using WWW-Authenticate),
and/or proxy authentication (i.e., using Proxy-Authenticate).
o The credentials carried in an Authorization header field are
specific to the User Agent, and therefore have the same effect on
HTTP caches as the "private" Cache-Control response directive,
within the scope of the request they appear in.
Therefore, new authentication schemes which choose not to carry
credentials in the Authorization header (e.g., using a newly
defined header) will need to explicitly disallow caching, by
mandating the use of either Cache-Control request directives
(e.g., "no-store") or response directives (e.g., "private").
3. Status Code Definitions
3.1. 401 Unauthorized
The request requires user authentication. The response MUST include
a WWW-Authenticate header field (Section 4.4) containing a challenge
applicable to the target resource. The client MAY repeat the request
with a suitable Authorization header field (Section 4.1). If the
request already included Authorization credentials, then the 401
response indicates that authorization has been refused for those
credentials. If the 401 response contains the same challenge as the
prior response, and the user agent has already attempted
authentication at least once, then the user SHOULD be presented the
representation that was given in the response, since that
representation might include relevant diagnostic information.
3.2. 407 Proxy Authentication Required
This code is similar to 401 (Unauthorized), but indicates that the
client ought to first authenticate itself with the proxy. The proxy
MUST return a Proxy-Authenticate header field (Section 4.2)
containing a challenge applicable to the proxy for the target
resource. The client MAY repeat the request with a suitable Proxy-
Authorization header field (Section 4.3).
4. Header Field Definitions
This section defines the syntax and semantics of HTTP/1.1 header
fields related to authentication.
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4.1. Authorization
The "Authorization" header field allows a user agent to authenticate
itself with a server -- usually, but not necessarily, after receiving
a 401 (Unauthorized) response. Its value consists of credentials
containing information of the user agent for the realm of the
resource being requested.
Authorization = credentials
If a request is authenticated and a realm specified, the same
credentials SHOULD be valid for all other requests within this realm
(assuming that the authentication scheme itself does not require
otherwise, such as credentials that vary according to a challenge
value or using synchronized clocks).
When a shared cache (see Section 1.2 of [Part6]) receives a request
containing an Authorization field, it MUST NOT return the
corresponding response as a reply to any other request, unless one of
the following specific exceptions holds:
1. If the response includes the "s-maxage" cache-control directive,
the cache MAY use that response in replying to a subsequent
request. But (if the specified maximum age has passed) a proxy
cache MUST first revalidate it with the origin server, using the
header fields from the new request to allow the origin server to
authenticate the new request. (This is the defined behavior for
s-maxage.) If the response includes "s-maxage=0", the proxy MUST
always revalidate it before re-using it.
2. If the response includes the "must-revalidate" cache-control
directive, the cache MAY use that response in replying to a
subsequent request. But if the response is stale, all caches
MUST first revalidate it with the origin server, using the header
fields from the new request to allow the origin server to
authenticate the new request.
3. If the response includes the "public" cache-control directive, it
MAY be returned in reply to any subsequent request.
4.2. Proxy-Authenticate
The "Proxy-Authenticate" header field consists of a challenge that
indicates the authentication scheme and parameters applicable to the
proxy for this effective request URI (Section 4.3 of [Part1]). It
MUST be included as part of a 407 (Proxy Authentication Required)
response.
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Proxy-Authenticate = 1#challenge
Unlike WWW-Authenticate, the Proxy-Authenticate header field applies
only to the current connection and SHOULD NOT be passed on to
downstream clients. However, an intermediate proxy might need to
obtain its own credentials by requesting them from the downstream
client, which in some circumstances will appear as if the proxy is
forwarding the Proxy-Authenticate header field.
4.3. Proxy-Authorization
The "Proxy-Authorization" header field allows the client to identify
itself (or its user) to a proxy which requires authentication. Its
value consists of credentials containing the authentication
information of the user agent for the proxy and/or realm of the
resource being requested.
Proxy-Authorization = credentials
Unlike Authorization, the Proxy-Authorization header field applies
only to the next outbound proxy that demanded authentication using
the Proxy-Authenticate field. When multiple proxies are used in a
chain, the Proxy-Authorization header field is consumed by the first
outbound proxy that was expecting to receive credentials. A proxy
MAY relay the credentials from the client request to the next proxy
if that is the mechanism by which the proxies cooperatively
authenticate a given request.
4.4. WWW-Authenticate
The "WWW-Authenticate" header field consists of at least one
challenge that indicates the authentication scheme(s) and parameters
applicable to the effective request URI (Section 4.3 of [Part1]).
It MUST be included in 401 (Unauthorized) response messages and MAY
be included in other response messages to indicate that supplying
credentials (or different credentials) might affect the response.
WWW-Authenticate = 1#challenge
User agents are advised to take special care in parsing the WWW-
Authenticate field value as it might contain more than one challenge,
or if more than one WWW-Authenticate header field is provided, the
contents of a challenge itself can contain a comma-separated list of
authentication parameters.
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For instance:
WWW-Authenticate: Newauth realm="apps", type=1,
title="Login to \"apps\"", Basic realm="simple"
This header field contains two challenges; one for the "Newauth"
scheme with a realm value of "apps", and two additional parameters
"type" and "title", and another one for the "Basic" scheme with a
realm value of "simple".
5. IANA Considerations
5.1. Authenticaton Scheme Registry
The registration procedure for HTTP Authentication Schemes is defined
by Section 2.3 of this document.
The HTTP Method Authentication Scheme shall be created at
.
5.2. Status Code Registration
The HTTP Status Code Registry located at
shall be updated
with the registrations below:
+-------+-------------------------------+-------------+
| Value | Description | Reference |
+-------+-------------------------------+-------------+
| 401 | Unauthorized | Section 3.1 |
| 407 | Proxy Authentication Required | Section 3.2 |
+-------+-------------------------------+-------------+
5.3. Header Field Registration
The Message Header Field Registry located at shall be
updated with the permanent registrations below (see [RFC3864]):
+---------------------+----------+----------+-------------+
| Header Field Name | Protocol | Status | Reference |
+---------------------+----------+----------+-------------+
| Authorization | http | standard | Section 4.1 |
| Proxy-Authenticate | http | standard | Section 4.2 |
| Proxy-Authorization | http | standard | Section 4.3 |
| WWW-Authenticate | http | standard | Section 4.4 |
+---------------------+----------+----------+-------------+
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The change controller is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force".
6. Security Considerations
This section is meant to inform application developers, information
providers, and users of the security limitations in HTTP/1.1 as
described by this document. The discussion does not include
definitive solutions to the problems revealed, though it does make
some suggestions for reducing security risks.
6.1. Authentication Credentials and Idle Clients
Existing HTTP clients and user agents typically retain authentication
information indefinitely. HTTP/1.1 does not provide a method for a
server to direct clients to discard these cached credentials. This
is a significant defect that requires further extensions to HTTP.
Circumstances under which credential caching can interfere with the
application's security model include but are not limited to:
o Clients which have been idle for an extended period following
which the server might wish to cause the client to reprompt the
user for credentials.
o Applications which include a session termination indication (such
as a "logout" or "commit" button on a page) after which the server
side of the application "knows" that there is no further reason
for the client to retain the credentials.
This is currently under separate study. There are a number of work-
arounds to parts of this problem, and we encourage the use of
password protection in screen savers, idle time-outs, and other
methods which mitigate the security problems inherent in this
problem. In particular, user agents which cache credentials are
encouraged to provide a readily accessible mechanism for discarding
cached credentials under user control.
7. Acknowledgments
This specification takes over the definition of the HTTP
Authentication Framework, previously defined in RFC 2617. We thank
John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D.
Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for
their work on that specification. See Section 6 of [RFC2617] for
further acknowledgements.
See Section 11 of [Part1] for the Acknowledgments related to this
document revision.
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8. References
8.1. Normative References
[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,
and Message Parsing", draft-ietf-httpbis-p1-messaging-18
(work in progress), January 2012.
[Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
Nottingham, M., Ed., and J. Reschke, Ed., "HTTP/1.1, part
6: Caching", draft-ietf-httpbis-p6-cache-18 (work in
progress), January 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
8.2. Informative References
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[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.
[RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration
Procedures for Message Header Fields", BCP 90, RFC 3864,
September 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
Fielding, et al. Expires July 7, 2012 [Page 15]
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Appendix A. Changes from RFCs 2616 and 2617
The "realm" parameter isn't required anymore in general;
consequently, the ABNF allows challenges without any auth parameters.
(Section 2)
The "b64token" alternative to auth-param lists has been added for
consistency with legacy authentication schemes such as "Basic".
(Section 2)
Change ABNF productions for header fields to only define the field
value. (Section 4)
Appendix B. Collected ABNF
Authorization = credentials
BWS =
OWS =
Proxy-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS
challenge ] )
Proxy-Authorization = credentials
WWW-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS challenge
] )
auth-param = token BWS "=" BWS ( token / quoted-string )
auth-scheme = token
b64token = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
*"="
challenge = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *(
OWS "," [ OWS auth-param ] ) ] ) ]
credentials = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param )
*( OWS "," [ OWS auth-param ] ) ] ) ]
quoted-string =
token =
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ABNF diagnostics:
; Authorization defined but not used
; Proxy-Authenticate defined but not used
; Proxy-Authorization defined but not used
; WWW-Authenticate defined but not used
Appendix C. Change Log (to be removed by RFC Editor before publication)
C.1. Since RFC 2616
Extracted relevant partitions from [RFC2616].
C.2. Since draft-ietf-httpbis-p7-auth-00
Closed issues:
o : "Normative and
Informative references"
C.3. Since draft-ietf-httpbis-p7-auth-01
Ongoing work on ABNF conversion
():
o Explicitly import BNF rules for "challenge" and "credentials" from
RFC2617.
o Add explicit references to BNF syntax and rules imported from
other parts of the specification.
C.4. Since draft-ietf-httpbis-p7-auth-02
Ongoing work on IANA Message Header Field Registration
():
o Reference RFC 3984, and update header field registrations for
header fields defined in this document.
C.5. Since draft-ietf-httpbis-p7-auth-03
None.
C.6. Since draft-ietf-httpbis-p7-auth-04
Ongoing work on ABNF conversion
():
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o Use "/" instead of "|" for alternatives.
o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
whitespace ("OWS") and required whitespace ("RWS").
o Rewrite ABNFs to spell out whitespace rules, factor out header
field value format definitions.
C.7. Since draft-ietf-httpbis-p7-auth-05
Final work on ABNF conversion
():
o Add appendix containing collected and expanded ABNF, reorganize
ABNF introduction.
C.8. Since draft-ietf-httpbis-p7-auth-06
None.
C.9. Since draft-ietf-httpbis-p7-auth-07
Closed issues:
o : "move IANA
registrations for optional status codes"
C.10. Since draft-ietf-httpbis-p7-auth-08
No significant changes.
C.11. Since draft-ietf-httpbis-p7-auth-09
Partly resolved issues:
o : "Term for the
requested resource's URI"
C.12. Since draft-ietf-httpbis-p7-auth-10
None.
C.13. Since draft-ietf-httpbis-p7-auth-11
Closed issues:
o : "introduction
to part 7 is work-in-progress"
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o : "auth-param
syntax"
o : "Header
Classification"
o : "absorbing the
auth framework from 2617"
Partly resolved issues:
o : "should we
have an auth scheme registry"
C.14. Since draft-ietf-httpbis-p7-auth-12
None.
C.15. Since draft-ietf-httpbis-p7-auth-13
Closed issues:
o : "untangle
ABNFs for header fields"
C.16. Since draft-ietf-httpbis-p7-auth-14
None.
C.17. Since draft-ietf-httpbis-p7-auth-15
Closed issues:
o : "Relationship
between 401, Authorization and WWW-Authenticate"
o : "Realm
required on challenges"
o : "auth-param
syntax"
o :
"Considerations for new authentications schemes"
o : "LWS in auth-
param ABNF"
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o : "credentials
ABNF missing SP (still using implied LWS?)"
C.18. Since draft-ietf-httpbis-p7-auth-16
Closed issues:
o : "Document
HTTP's error-handling philosophy"
o : "add advice on
defining auth scheme parameters"
C.19. Since draft-ietf-httpbis-p7-auth-17
Closed issues:
o : "allow
unquoted realm parameters"
o : "Repeating
auth-params"
Index
4
401 Unauthorized (status code) 10
407 Proxy Authentication Required (status code) 10
A
auth-param 6
auth-scheme 6
Authorization header field 11
B
b64token 6
C
challenge 7
credentials 7
G
Grammar
auth-param 6
auth-scheme 6
Authorization 11
b64token 6
challenge 7
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credentials 7
Proxy-Authenticate 11
Proxy-Authorization 12
WWW-Authenticate 12
H
Header Fields
Authorization 11
Proxy-Authenticate 11
Proxy-Authorization 12
WWW-Authenticate 12
P
Protection Space 8
Proxy-Authenticate header field 11
Proxy-Authorization header field 12
R
Realm 8
S
Status Codes
401 Unauthorized 10
407 Proxy Authentication Required 10
W
WWW-Authenticate header field 12
Authors' Addresses
Roy T. Fielding (editor)
Adobe Systems Incorporated
345 Park Ave
San Jose, CA 95110
USA
EMail: fielding@gbiv.com
URI: http://roy.gbiv.com/
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Jim Gettys
Alcatel-Lucent Bell Labs
21 Oak Knoll Road
Carlisle, MA 01741
USA
EMail: jg@freedesktop.org
URI: http://gettys.wordpress.com/
Jeffrey C. Mogul
Hewlett-Packard Company
HP Labs, Large Scale Systems Group
1501 Page Mill Road, MS 1177
Palo Alto, CA 94304
USA
EMail: JeffMogul@acm.org
Henrik Frystyk Nielsen
Microsoft Corporation
1 Microsoft Way
Redmond, WA 98052
USA
EMail: henrikn@microsoft.com
Larry Masinter
Adobe Systems Incorporated
345 Park Ave
San Jose, CA 95110
USA
EMail: LMM@acm.org
URI: http://larry.masinter.net/
Paul J. Leach
Microsoft Corporation
1 Microsoft Way
Redmond, WA 98052
EMail: paulle@microsoft.com
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Tim Berners-Lee
World Wide Web Consortium
MIT Computer Science and Artificial Intelligence Laboratory
The Stata Center, Building 32
32 Vassar Street
Cambridge, MA 02139
USA
EMail: timbl@w3.org
URI: http://www.w3.org/People/Berners-Lee/
Yves Lafon (editor)
World Wide Web Consortium
W3C / ERCIM
2004, rte des Lucioles
Sophia-Antipolis, AM 06902
France
EMail: ylafon@w3.org
URI: http://www.raubacapeu.net/people/yves/
Julian F. Reschke (editor)
greenbytes GmbH
Hafenweg 16
Muenster, NW 48155
Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
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