Internet DRAFT - draft-ietf-httpbis-p7-auth
draft-ietf-httpbis-p7-auth
HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Adobe
Obsoletes: 2616 (if approved) J. Reschke, Ed.
Updates: 2617 (if approved) greenbytes
Intended status: Standards Track February 6, 2014
Expires: August 10, 2014
Hypertext Transfer Protocol (HTTP/1.1): Authentication
draft-ietf-httpbis-p7-auth-26
Abstract
The Hypertext Transfer Protocol (HTTP) is a stateless application-
level protocol for distributed, collaborative, hypermedia information
systems. This document defines the HTTP Authentication framework.
Editorial Note (To be removed by RFC Editor)
Discussion of this draft takes place on the HTTPBIS working group
mailing list (ietf-http-wg@w3.org), which is archived at
<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
The current issues list is at
<http://tools.ietf.org/wg/httpbis/trac/report/3> and related
documents (including fancy diffs) can be found at
<http://tools.ietf.org/wg/httpbis/>.
The changes in this draft are summarized in Appendix D.2.
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 August 10, 2014.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4
1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 4
2. Access Authentication Framework . . . . . . . . . . . . . . . 4
2.1. Challenge and Response . . . . . . . . . . . . . . . . . . 4
2.2. Protection Space (Realm) . . . . . . . . . . . . . . . . . 6
3. Status Code Definitions . . . . . . . . . . . . . . . . . . . 7
3.1. 401 Unauthorized . . . . . . . . . . . . . . . . . . . . . 7
3.2. 407 Proxy Authentication Required . . . . . . . . . . . . 7
4. Header Field Definitions . . . . . . . . . . . . . . . . . . . 7
4.1. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . . 8
4.2. Authorization . . . . . . . . . . . . . . . . . . . . . . 8
4.3. Proxy-Authenticate . . . . . . . . . . . . . . . . . . . . 9
4.4. Proxy-Authorization . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5.1. Authentication Scheme Registry . . . . . . . . . . . . . . 10
5.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 10
5.1.2. Considerations for New Authentication Schemes . . . . 10
5.2. Status Code Registration . . . . . . . . . . . . . . . . . 12
5.3. Header Field Registration . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6.1. Confidentiality of Credentials . . . . . . . . . . . . . . 13
6.2. Authentication Credentials and Idle Clients . . . . . . . 13
6.3. Protection Spaces . . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Changes from RFCs 2616 and 2617 . . . . . . . . . . . 16
Appendix B. Imported ABNF . . . . . . . . . . . . . . . . . . . . 16
Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 16
Appendix D. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 17
D.1. Since draft-ietf-httpbis-p7-auth-24 . . . . . . . . . . . 17
D.2. Since draft-ietf-httpbis-p7-auth-25 . . . . . . . . . . . 18
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
HTTP provides a general framework for access control and
authentication, via an extensible set of challenge-response
authentication schemes, which can be used by a server to challenge a
client request and by a client to provide authentication information.
This document defines HTTP/1.1 authentication in terms of the
architecture defined in [Part1], including the general framework
previously described in RFC 2617 and the related fields and status
codes previously defined in RFC 2616.
The IANA Authentication Scheme Registry (Section 5.1) lists
registered authentication schemes and their corresponding
specifications, including the "basic" and "digest" authentication
schemes previously defined by 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].
Conformance criteria and considerations regarding error handling are
defined in Section 2.5 of [Part1].
1.2. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234] with a list extension, defined in Section 7 of
[Part1], that allows for compact definition of comma-separated lists
using a '#' operator (similar to how the '*' operator indicates
repetition). Appendix B describes rules imported from other
documents. Appendix C shows the collected grammar with all list
operators expanded to standard ABNF notation.
2. Access Authentication Framework
2.1. Challenge and Response
HTTP provides a simple challenge-response authentication framework
that can be used by a server to challenge a client request and by a
client to provide authentication information. It uses a case-
insensitive token as a means 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.
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Authentication parameters are name=value pairs, where the name token
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 )
token68 = 1*( ALPHA / DIGIT /
"-" / "." / "_" / "~" / "+" / "/" ) *"="
The "token68" 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]).
A 401 (Unauthorized) response message is used by an origin server to
challenge the authorization of a user agent, including a WWW-
Authenticate header field containing at least one challenge
applicable to the requested resource.
A 407 (Proxy Authentication Required) response message is used by a
proxy to challenge the authorization of a client, including a Proxy-
Authenticate header field containing at least one challenge
applicable to the proxy for the requested resource.
challenge = auth-scheme [ 1*SP ( token68 / #auth-param ) ]
Note: Many clients fail to parse a challenge that contains an
unknown scheme. 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)
-- can 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) -- can do so by including a Proxy-Authorization header
field with the request.
Both the Authorization field value and the Proxy-Authorization field
value contain the client's credentials for the realm of the resource
being requested, based upon a challenge received in a response
(possibly at some point in the past). When creating their values,
the user agent ought to do so by selecting the challenge with what it
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considers to be the most secure auth-scheme that it understands,
obtaining credentials from the user as appropriate. Transmission of
credentials within header field values implies significant security
considerations regarding the confidentiality of the underlying
connection, as described in Section 6.1.
credentials = auth-scheme [ 1*SP ( token68 / #auth-param ) ]
Upon receipt of a request for a protected resource that omits
credentials, contains invalid credentials (e.g., a bad password) or
partial credentials (e.g., when the authentication scheme requires
more than one round trip), an origin server SHOULD send a 401
(Unauthorized) response that contains a WWW-Authenticate header field
with at least one (possibly new) challenge applicable to the
requested resource.
Likewise, upon receipt of a request that omits proxy credentials or
contains invalid or partial proxy credentials, a proxy that requires
authentication SHOULD generate a 407 (Proxy Authentication Required)
response that contains a Proxy-Authenticate header field with at
least one (possibly new) challenge applicable to the proxy.
A server that receives valid credentials which are not adequate to
gain access ought to respond with the 403 (Forbidden) status code
(Section 6.5.3 of [Part2]).
HTTP does not restrict applications to this simple challenge-response
framework for access authentication. Additional mechanisms can be
used, such as authentication 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.
2.2. Protection Space (Realm)
The "realm" authentication parameter is reserved for use by
authentication schemes that wish to indicate a 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
5.5 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 a response can have multiple challenges with the
same auth-scheme but different realms.
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The protection space determines the domain over which credentials can
be automatically applied. If a prior request has been authorized,
the user agent MAY reuse the same credentials for all other requests
within that protection space for a period of time determined by the
authentication scheme, parameters, and/or user preferences (such as a
configurable inactivity timeout). Unless specifically allowed by the
authentication scheme, a single protection space cannot extend
outside the scope of its server.
For historical reasons, a sender MUST only generate 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.
3. Status Code Definitions
3.1. 401 Unauthorized
The 401 (Unauthorized) status code indicates that the request has not
been applied because it lacks valid authentication credentials for
the target resource. The server generating a 401 response MUST send
a WWW-Authenticate header field (Section 4.1) containing at least one
challenge applicable to the target resource.
If the request included authentication credentials, then the 401
response indicates that authorization has been refused for those
credentials. The user agent MAY repeat the request with a new or
replaced Authorization header field (Section 4.2). 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 agent SHOULD present the enclosed representation to the
user, since it usually contains relevant diagnostic information.
3.2. 407 Proxy Authentication Required
The 407 (Proxy Authentication Required) status code is similar to 401
(Unauthorized), but indicates that the client needs to authenticate
itself in order to use a proxy. The proxy MUST send a Proxy-
Authenticate header field (Section 4.3) containing a challenge
applicable to that proxy for the target resource. The client MAY
repeat the request with a new or replaced Proxy-Authorization header
field (Section 4.4).
4. Header Field Definitions
This section defines the syntax and semantics of header fields
related to the HTTP authentication framework.
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4.1. WWW-Authenticate
The "WWW-Authenticate" header field indicates the authentication
scheme(s) and parameters applicable to the target resource.
WWW-Authenticate = 1#challenge
A server generating a 401 (Unauthorized) response MUST send a WWW-
Authenticate header field containing at least one challenge. A
server MAY generate a WWW-Authenticate header field in other response
messages to indicate that supplying credentials (or different
credentials) might affect the response.
A proxy forwarding a response MUST NOT modify any WWW-Authenticate
fields in that response.
User agents are advised to take special care in parsing the field
value, as it might contain more than one challenge, and each
challenge can contain a comma-separated list of authentication
parameters. Furthermore, the header field itself can occur multiple
times.
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".
Note: The challenge grammar production uses the list syntax as
well. Therefore, a sequence of comma, whitespace, and comma can
be considered either as applying to the preceding challenge, or to
be an empty entry in the list of challenges. In practice, this
ambiguity does not affect the semantics of the header field value
and thus is harmless.
4.2. Authorization
The "Authorization" header field allows a user agent to authenticate
itself with an origin server -- usually, but not necessarily, after
receiving a 401 (Unauthorized) response. Its value consists of
credentials containing the authentication information of the user
agent for the realm of the resource being requested.
Authorization = credentials
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If a request is authenticated and a realm specified, the same
credentials are presumed to 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).
A proxy forwarding a request MUST NOT modify any Authorization fields
in that request. See Section 3.2 of [Part6] for details of and
requirements pertaining to handling of the Authorization field by
HTTP caches.
4.3. Proxy-Authenticate
The "Proxy-Authenticate" header field consists of at least one
challenge that indicates the authentication scheme(s) and parameters
applicable to the proxy for this effective request URI (Section 5.5
of [Part1]). A proxy MUST send at least one Proxy-Authenticate
header field in each 407 (Proxy Authentication Required) response
that it generates.
Proxy-Authenticate = 1#challenge
Unlike WWW-Authenticate, the Proxy-Authenticate header field applies
only to the next outbound client on the response chain. This is
because only the client that chose a given proxy is likely to have
the credentials necessary for authentication. However, when multiple
proxies are used within the same administrative domain, such as
office and regional caching proxies within a large corporate network,
it is common for credentials to be generated by the user agent and
passed through the hierarchy until consumed. Hence, in such a
configuration, it will appear as if Proxy-Authenticate is being
forwarded because each proxy will send the same challenge set.
Note that the parsing considerations for WWW-Authenticate apply to
this header field as well; see Section 4.1 for details.
4.4. Proxy-Authorization
The "Proxy-Authorization" header field allows the client to identify
itself (or its user) to a proxy that requires authentication. Its
value consists of credentials containing the authentication
information of the client 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 inbound proxy that demanded authentication using the
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Proxy-Authenticate field. When multiple proxies are used in a chain,
the Proxy-Authorization header field is consumed by the first inbound
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.
5. IANA Considerations
5.1. Authentication Scheme Registry
The HTTP Authentication Scheme Registry defines the name space for
the authentication schemes in challenges and credentials. It will be
created and maintained at (the suggested URI)
<http://www.iana.org/assignments/http-authschemes>.
5.1.1. Procedure
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 require IETF Review (see
[RFC5226], Section 4.1).
5.1.2. 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 HTTP authentication is presumed to be stateless: all of the
information necessary to authenticate a request MUST be provided
in the request, rather than be dependent on the server remembering
prior requests. Authentication based on, or bound to, the
underlying connection is outside the scope of this specification
and inherently flawed unless steps are taken to ensure that the
connection cannot be used by any party other than the
authenticated user (see Section 2.3 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.
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o The "token68" notation was introduced for compatibility with
existing authentication schemes and can only be used once per
challenge or credential. 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.
o Definitions of new schemes ought to define the treatment of
unknown extension parameters. In general, a "must-ignore" rule is
preferable over "must-understand", because otherwise it will be
hard to introduce new parameters in the presence of legacy
recipients. Furthermore, it's good to describe the policy for
defining new parameters (such as "update the specification", or
"use this registry").
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
(Section 5.2.2.6 of [Part6]), within the scope of the request they
appear in.
Therefore, new authentication schemes that choose not to carry
credentials in the Authorization header field (e.g., using a newly
defined header field) will need to explicitly disallow caching, by
mandating the use of either Cache-Control request directives
(e.g., "no-store", Section 5.2.1.5 of [Part6]) or response
directives (e.g., "private").
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5.2. Status Code Registration
The HTTP Status Code Registry located at
<http://www.iana.org/assignments/http-status-codes> 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
HTTP header fields are registered within the Message Header Field
Registry maintained at <http://www.iana.org/assignments/
message-headers/message-header-index.html>.
This document defines the following HTTP header fields, so their
associated registry entries shall be updated according to the
permanent registrations below (see [BCP90]):
+---------------------+----------+----------+-------------+
| Header Field Name | Protocol | Status | Reference |
+---------------------+----------+----------+-------------+
| Authorization | http | standard | Section 4.2 |
| Proxy-Authenticate | http | standard | Section 4.3 |
| Proxy-Authorization | http | standard | Section 4.4 |
| WWW-Authenticate | http | standard | Section 4.1 |
+---------------------+----------+----------+-------------+
The change controller is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force".
6. Security Considerations
This section is meant to inform developers, information providers,
and users of known security concerns specific to HTTP authentication.
More general security considerations are addressed in HTTP messaging
[Part1] and semantics [Part2].
Everything about the topic of HTTP authentication is a security
consideration, so the list of considerations below is not exhaustive.
Furthermore, it is limited to security considerations regarding the
authentication framework, in general, rather than discussing all of
the potential considerations for specific authentication schemes
(which ought to be documented in the specifications that define those
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schemes). Various organizations maintain topical information and
links to current research on Web application security (e.g.,
[OWASP]), including common pitfalls for implementing and using the
authentication schemes found in practice.
6.1. Confidentiality of Credentials
The HTTP authentication framework does not define a single mechanism
for maintaining the confidentiality of credentials; instead, each
authentication scheme defines how the credentials are encoded prior
to transmission. While this provides flexibility for the development
of future authentication schemes, it is inadequate for the protection
of existing schemes that provide no confidentiality on their own, or
that do not sufficiently protect against replay attacks.
Furthermore, if the server expects credentials that are specific to
each individual user, the exchange of those credentials will have the
effect of identifying that user even if the content within
credentials remains confidential.
HTTP depends on the security properties of the underlying transport
or session-level connection to provide confidential transmission of
header fields. In other words, if a server limits access to
authenticated users using this framework, the server needs to ensure
that the connection is properly secured in accordance with the nature
of the authentication scheme used. For example, services that depend
on individual user authentication often require a connection to be
secured with TLS ("Transport Layer Security", [RFC5246]) prior to
exchanging any credentials.
6.2. Authentication Credentials and Idle Clients
Existing HTTP clients and user agents typically retain authentication
information indefinitely. HTTP does not provide a mechanism for the
origin server to direct clients to discard these cached credentials,
since the protocol has no awareness of how credentials are obtained
or managed by the user agent. The mechanisms for expiring or
revoking credentials can be specified as part of an authentication
scheme definition.
Circumstances under which credential caching can interfere with the
application's security model include but are not limited to:
o Clients that have been idle for an extended period, following
which the server might wish to cause the client to re-prompt the
user for credentials.
o Applications that include a session termination indication (such
as a "logout" or "commit" button on a page) after which the server
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side of the application "knows" that there is no further reason
for the client to retain the credentials.
User agents that cache credentials are encouraged to provide a
readily accessible mechanism for discarding cached credentials under
user control.
6.3. Protection Spaces
Authentication schemes that solely rely on the "realm" mechanism for
establishing a protection space will expose credentials to all
resources on an origin server. Clients that have successfully made
authenticated requests with a resource can use the same
authentication credentials for other resources on the same origin
server. This makes it possible for a different resource to harvest
authentication credentials for other resources.
This is of particular concern when an origin server hosts resources
for multiple parties under the same canonical root URI (Section 2.2).
Possible mitigation strategies include restricting direct access to
authentication credentials (i.e., not making the content of the
Authorization request header field available), and separating
protection spaces by using a different host name (or port number) for
each party.
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 10 of [Part1] for the Acknowledgments related to this
document revision.
8. References
8.1. Normative References
[Part1] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
draft-ietf-httpbis-p1-messaging-26 (work in progress),
February 2014.
[Part2] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content",
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draft-ietf-httpbis-p2-semantics-26 (work in progress),
February 2014.
[Part6] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
draft-ietf-httpbis-p6-cache-26 (work in progress),
February 2014.
[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
[BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration
Procedures for Message Header Fields", BCP 90, RFC 3864,
September 2004.
[OWASP] van der Stock, A., Ed., "A Guide to Building Secure Web
Applications and Web Services", The Open Web Application
Security Project (OWASP) 2.0.1, July 2005,
<https://www.owasp.org/>.
[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.
[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.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
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Appendix A. Changes from RFCs 2616 and 2617
The framework for HTTP Authentication is now defined by this
document, rather than RFC 2617.
The "realm" parameter is no longer always required on challenges;
consequently, the ABNF allows challenges without any auth parameters.
(Section 2)
The "token68" alternative to auth-param lists has been added for
consistency with legacy authentication schemes such as "Basic".
(Section 2)
This specification introduces the Authentication Scheme Registry,
along with considerations for new authentication schemes.
(Section 5.1)
Appendix B. Imported ABNF
The following core rules are included by reference, as defined in
Appendix B.1 of [RFC5234]: 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).
The rules below are defined in [Part1]:
BWS = <BWS, defined in [Part1], Section 3.2.3>
OWS = <OWS, defined in [Part1], Section 3.2.3>
quoted-string = <quoted-string, defined in [Part1], Section 3.2.6>
token = <token, defined in [Part1], Section 3.2.6>
Appendix C. Collected ABNF
In the collected ABNF below, list rules are expanded as per Section
1.2 of [Part1].
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Authorization = credentials
BWS = <BWS, defined in [Part1], Section 3.2.3>
OWS = <OWS, defined in [Part1], Section 3.2.3>
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
challenge = auth-scheme [ 1*SP ( token68 / [ ( "," / auth-param ) *(
OWS "," [ OWS auth-param ] ) ] ) ]
credentials = auth-scheme [ 1*SP ( token68 / [ ( "," / auth-param )
*( OWS "," [ OWS auth-param ] ) ] ) ]
quoted-string = <quoted-string, defined in [Part1], Section 3.2.6>
token = <token, defined in [Part1], Section 3.2.6>
token68 = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
*"="
Appendix D. Change Log (to be removed by RFC Editor before publication)
Changes up to the IETF Last Call draft are summarized in <http://
trac.tools.ietf.org/html/draft-ietf-httpbis-p7-auth-24#appendix-D>.
D.1. Since draft-ietf-httpbis-p7-auth-24
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/510>: "SECDIR review
of draft-ietf-httpbis-p7-auth-24"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/513>: "APPSDIR
review of draft-ietf-httpbis-p7-auth-24"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/516>: "note about
WWW-A parsing potentially misleading"
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D.2. Since draft-ietf-httpbis-p7-auth-25
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/522>: "Gen-art
review of draft-ietf-httpbis-p7-auth-25"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/536>: "IESG ballot
on draft-ietf-httpbis-p7-auth-25"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/538>: "add
'stateless' to Abstract"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/539>: "mention TLS
vs plain text passwords or dict attacks?"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/542>: "improve
introduction of list rule"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/549>: "augment
security considerations with pointers to current research"
Index
4
401 Unauthorized (status code) 7
407 Proxy Authentication Required (status code) 7
A
Authorization header field 8
C
Canonical Root URI 6
G
Grammar
auth-param 5
auth-scheme 5
Authorization 8
challenge 5
credentials 6
Proxy-Authenticate 9
Proxy-Authorization 9
token68 5
WWW-Authenticate 8
P
Protection Space 6
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Proxy-Authenticate header field 9
Proxy-Authorization header field 9
R
Realm 6
W
WWW-Authenticate header field 8
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/
Julian F. Reschke (editor)
greenbytes GmbH
Hafenweg 16
Muenster, NW 48155
Germany
EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/
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