< draft-ietf-httpbis-p7-auth-19.txt   draft-ietf-httpbis-p7-auth-20.txt >
HTTPbis Working Group R. Fielding, Ed. HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Adobe Internet-Draft Adobe
Obsoletes: 2616 (if approved) Y. Lafon, Ed. Obsoletes: 2616 (if approved) Y. Lafon, Ed.
Updates: 2617 (if approved) W3C Updates: 2617 (if approved) W3C
Intended status: Standards Track J. Reschke, Ed. Intended status: Standards Track J. Reschke, Ed.
Expires: September 13, 2012 greenbytes Expires: January 17, 2013 greenbytes
March 12, 2012 July 16, 2012
HTTP/1.1, part 7: Authentication HTTP/1.1, part 7: Authentication
draft-ietf-httpbis-p7-auth-19 draft-ietf-httpbis-p7-auth-20
Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information protocol for distributed, collaborative, hypermedia information
systems. HTTP has been in use by the World Wide Web global systems. This document defines the HTTP Authentication framework.
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) Editorial Note (To be removed by RFC Editor)
Discussion of this draft should take place on the HTTPBIS working Discussion of this draft takes place on the HTTPBIS working group
group mailing list (ietf-http-wg@w3.org), which is archived at mailing list (ietf-http-wg@w3.org), which is archived at
<http://lists.w3.org/Archives/Public/ietf-http-wg/>. <http://lists.w3.org/Archives/Public/ietf-http-wg/>.
The current issues list is at The current issues list is at
<http://tools.ietf.org/wg/httpbis/trac/report/3> and related <http://tools.ietf.org/wg/httpbis/trac/report/3> and related
documents (including fancy diffs) can be found at documents (including fancy diffs) can be found at
<http://tools.ietf.org/wg/httpbis/>. <http://tools.ietf.org/wg/httpbis/>.
The changes in this draft are summarized in Appendix C.20. The changes in this draft are summarized in Appendix D.1.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 13, 2012. This Internet-Draft will expire on January 17, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 40 skipping to change at page 3, line 9
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4 1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4
1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 4 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 5
1.2.1. Core Rules . . . . . . . . . . . . . . . . . . . . . . 5
2. Access Authentication Framework . . . . . . . . . . . . . . . 5 2. Access Authentication Framework . . . . . . . . . . . . . . . 5
2.1. Challenge and Response . . . . . . . . . . . . . . . . . . 5 2.1. Challenge and Response . . . . . . . . . . . . . . . . . . 5
2.2. Protection Space (Realm) . . . . . . . . . . . . . . . . . 7 2.2. Protection Space (Realm) . . . . . . . . . . . . . . . . . 7
2.3. Authentication Scheme Registry . . . . . . . . . . . . . . 7 2.3. Authentication Scheme Registry . . . . . . . . . . . . . . 8
2.3.1. Considerations for New Authentication Schemes . . . . 8 2.3.1. Considerations for New Authentication Schemes . . . . 8
3. Status Code Definitions . . . . . . . . . . . . . . . . . . . 9 3. Status Code Definitions . . . . . . . . . . . . . . . . . . . 9
3.1. 401 Unauthorized . . . . . . . . . . . . . . . . . . . . . 9 3.1. 401 Unauthorized . . . . . . . . . . . . . . . . . . . . . 9
3.2. 407 Proxy Authentication Required . . . . . . . . . . . . 9 3.2. 407 Proxy Authentication Required . . . . . . . . . . . . 10
4. Header Field Definitions . . . . . . . . . . . . . . . . . . . 10 4. Header Field Definitions . . . . . . . . . . . . . . . . . . . 10
4.1. Authorization . . . . . . . . . . . . . . . . . . . . . . 10 4.1. Authorization . . . . . . . . . . . . . . . . . . . . . . 10
4.2. Proxy-Authenticate . . . . . . . . . . . . . . . . . . . . 11 4.2. Proxy-Authenticate . . . . . . . . . . . . . . . . . . . . 11
4.3. Proxy-Authorization . . . . . . . . . . . . . . . . . . . 11 4.3. Proxy-Authorization . . . . . . . . . . . . . . . . . . . 11
4.4. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . . 11 4.4. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . . 12
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
5.1. Authenticaton Scheme Registry . . . . . . . . . . . . . . 12 5.1. Authentication Scheme Registry . . . . . . . . . . . . . . 12
5.2. Status Code Registration . . . . . . . . . . . . . . . . . 12 5.2. Status Code Registration . . . . . . . . . . . . . . . . . 13
5.3. Header Field Registration . . . . . . . . . . . . . . . . 13 5.3. Header Field Registration . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6.1. Authentication Credentials and Idle Clients . . . . . . . 13 6.1. Authentication Credentials and Idle Clients . . . . . . . 13
6.2. Protection Spaces . . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14 8.1. Normative References . . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . . 14 8.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. Changes from RFCs 2616 and 2617 . . . . . . . . . . . 15 Appendix A. Changes from RFCs 2616 and 2617 . . . . . . . . . . . 16
Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 16 Appendix B. Imported ABNF . . . . . . . . . . . . . . . . . . . . 16
Appendix C. Change Log (to be removed by RFC Editor before Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 17
publication) . . . . . . . . . . . . . . . . . . . . 16 Appendix D. Change Log (to be removed by RFC Editor before
C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 16 publication) . . . . . . . . . . . . . . . . . . . . 17
C.2. Since draft-ietf-httpbis-p7-auth-00 . . . . . . . . . . . 16 D.1. Since draft-ietf-httpbis-p7-auth-19 . . . . . . . . . . . 17
C.3. Since draft-ietf-httpbis-p7-auth-01 . . . . . . . . . . . 17 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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 . . . . . . . . . . . 17
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 . . . . . . . . . . . 19
C.19. Since draft-ietf-httpbis-p7-auth-17 . . . . . . . . . . . 20
C.20. Since draft-ietf-httpbis-p7-auth-18 . . . . . . . . . . . 20
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
This document defines HTTP/1.1 access control and authentication. It This document defines HTTP/1.1 access control and authentication. It
includes the relevant parts of RFC 2616 with only minor changes, plus includes the relevant parts of RFC 2616 with only minor changes
the general framework for HTTP authentication, as previously defined ([RFC2616]), plus the general framework for HTTP authentication, as
in "HTTP Authentication: Basic and Digest Access Authentication" previously defined in "HTTP Authentication: Basic and Digest Access
([RFC2617]). Authentication" ([RFC2617]).
HTTP provides several OPTIONAL challenge-response authentication HTTP provides several OPTIONAL challenge-response authentication
mechanisms which can be used by a server to challenge a client mechanisms which can be used by a server to challenge a client
request and by a client to provide authentication information. The request and by a client to provide authentication information. The
"basic" and "digest" authentication schemes continue to be specified "basic" and "digest" authentication schemes continue to be specified
in RFC 2617. in RFC 2617.
1.1. Conformance and Error Handling 1.1. Conformance and Error Handling
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
This document defines conformance criteria for several roles in HTTP This specification targets conformance criteria according to the role
communication, including Senders, Recipients, Clients, Servers, User- of a participant in HTTP communication. Hence, HTTP requirements are
Agents, Origin Servers, Intermediaries, Proxies and Gateways. See placed on senders, recipients, clients, servers, user agents,
Section 2 of [Part1] for definitions of these terms. intermediaries, origin servers, proxies, gateways, or caches,
depending on what behavior is being constrained by the requirement.
See Section 2 of [Part1] for definitions of these terms.
The verb "generate" is used instead of "send" where a requirement
differentiates between creating a protocol element and merely
forwarding a received element downstream.
An implementation is considered conformant if it complies with all of An implementation is considered conformant if it complies with all of
the requirements associated with its role(s). Note that SHOULD-level the requirements associated with the roles it partakes in HTTP. Note
requirements are relevant here, unless one of the documented that SHOULD-level requirements are relevant here, unless one of the
exceptions is applicable. documented exceptions is applicable.
This document also uses ABNF to define valid protocol elements This document also uses ABNF to define valid protocol elements
(Section 1.2). In addition to the prose requirements placed upon (Section 1.2). In addition to the prose requirements placed upon
them, Senders MUST NOT generate protocol elements that are invalid. them, senders MUST NOT generate protocol elements that do not match
the grammar defined by the ABNF rules for those protocol elements
that are applicable to the sender's role. If a received protocol
element is processed, the recipient MUST be able to parse any value
that would match the ABNF rules for that protocol element, excluding
only those rules not applicable to the recipient's role.
Unless noted otherwise, Recipients MAY take steps to recover a usable Unless noted otherwise, a recipient MAY attempt to recover a usable
protocol element from an invalid construct. However, HTTP does not protocol element from an invalid construct. HTTP does not define
define specific error handling mechanisms, except in cases where it specific error handling mechanisms except when they have a direct
has direct impact on security. This is because different uses of the impact on security, since different applications of the protocol
protocol require different error handling strategies; for example, a require different error handling strategies. For example, a Web
Web browser may wish to transparently recover from a response where browser might wish to transparently recover from a response where the
the Location header field doesn't parse according to the ABNF, Location header field doesn't parse according to the ABNF, whereas a
whereby in a systems control protocol using HTTP, this type of error systems control client might consider any form of error recovery to
recovery could lead to dangerous consequences. be dangerous.
1.2. Syntax Notation 1.2. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF) This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234] with the list rule extension defined in Section notation of [RFC5234] with the list rule extension defined in Section
1.2 of [Part1]. Appendix B shows the collected ABNF with the list 1.2 of [Part1]. Appendix B describes rules imported from other
rule expanded. documents. Appendix C 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 = <BWS, defined in [Part1], Section 3.2.1>
OWS = <OWS, defined in [Part1], Section 3.2.1>
quoted-string = <quoted-string, defined in [Part1], Section 3.2.4>
token = <token, defined in [Part1], Section 3.2.4>
2. Access Authentication Framework 2. Access Authentication Framework
2.1. Challenge and Response 2.1. Challenge and Response
HTTP provides a simple challenge-response authentication mechanism HTTP provides a simple challenge-response authentication mechanism
that can be used by a server to challenge a client request and by a that can be used by a server to challenge a client request and by a
client to provide authentication information. It uses an extensible, client to provide authentication information. It uses an extensible,
case-insensitive token to identify the authentication scheme, case-insensitive token to identify the authentication scheme,
followed by additional information necessary for achieving followed by additional information necessary for achieving
skipping to change at page 6, line 24 skipping to change at page 6, line 20
challenge = auth-scheme [ 1*SP ( b64token / #auth-param ) ] challenge = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
Note: User agents will need to take special care in parsing the Note: User agents will need to take special care in parsing the
WWW-Authenticate and Proxy-Authenticate header field values WWW-Authenticate and Proxy-Authenticate header field values
because they can contain more than one challenge, or if more than because they can contain more than one challenge, or if more than
one of each is provided, since the contents of a challenge can one of each is provided, since the contents of a challenge can
itself contain a comma-separated list of authentication itself contain a comma-separated list of authentication
parameters. parameters.
Note: Many browsers fail to parse challenges containing unknown Note: Many clients fail to parse challenges containing unknown
schemes. A workaround for this problem is to list well-supported schemes. A workaround for this problem is to list well-supported
schemes (such as "basic") first. schemes (such as "basic") first.
A user agent that wishes to authenticate itself with an origin server A user agent that wishes to authenticate itself with an origin server
-- usually, but not necessarily, after receiving a 401 (Unauthorized) -- usually, but not necessarily, after receiving a 401 (Unauthorized)
-- MAY do so by including an Authorization header field with the -- can do so by including an Authorization header field with the
request. request.
A client that wishes to authenticate itself with a proxy -- usually, A client that wishes to authenticate itself with a proxy -- usually,
but not necessarily, after receiving a 407 (Proxy Authentication but not necessarily, after receiving a 407 (Proxy Authentication
Required) -- MAY do so by including a Proxy-Authorization header Required) -- can do so by including a Proxy-Authorization header
field with the request. field with the request.
Both the Authorization field value and the Proxy-Authorization field Both the Authorization field value and the Proxy-Authorization field
value consist of credentials containing the authentication value contain the client's credentials for the realm of the resource
information of the client for the realm of the resource being being requested, based upon a challenge received from the server
requested. The user agent MUST choose to use one of the challenges (possibly at some point in the past). When creating their values,
with the strongest auth-scheme it understands and request credentials the user agent ought to do so by selecting the challenge with what it
from the user based upon that challenge. considers to be the most secure auth-scheme that it understands,
obtaining credentials from the user as appropriate.
credentials = auth-scheme [ 1*SP ( b64token / #auth-param ) ] credentials = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
If the origin server does not wish to accept the credentials sent Upon a request for a protected resource that omits credentials,
with a request, it SHOULD return a 401 (Unauthorized) response. The contains invalid credentials (e.g., a bad password) or partial
response MUST include a WWW-Authenticate header field containing at credentials (e.g., when the authentication scheme requires more than
least one (possibly new) challenge applicable to the requested one round trip), an origin server SHOULD return a 401 (Unauthorized)
resource. response. Such responses MUST include a WWW-Authenticate header
field containing at least one (possibly new) challenge applicable to
the requested resource.
If a proxy does not accept the credentials sent with a request, it Likewise, upon a request that requires authentication by proxies that
SHOULD return a 407 (Proxy Authentication Required). The response omit credentials or contain invalid or partial credentials, a proxy
MUST include a Proxy-Authenticate header field containing a (possibly SHOULD return a 407 (Proxy Authentication Required) response. Such
new) challenge applicable to the proxy for the requested resource. responses MUST include a Proxy-Authenticate header field containing a
(possibly new) challenge applicable to the proxy.
A server receiving credentials that are valid, but not adequate to
gain access, ought to respond with the 403 (Forbidden) status code
(Section 4.6.3 of [Part2]).
The HTTP protocol does not restrict applications to this simple The HTTP protocol does not restrict applications to this simple
challenge-response mechanism for access authentication. Additional challenge-response mechanism for access authentication. Additional
mechanisms MAY be used, such as encryption at the transport level or mechanisms MAY be used, such as encryption at the transport level or
via message encapsulation, and with additional header fields via message encapsulation, and with additional header fields
specifying authentication information. However, such additional specifying authentication information. However, such additional
mechanisms are not defined by this specification. mechanisms are not defined by this specification.
Proxies MUST forward the WWW-Authenticate and Authorization headers Proxies MUST forward the WWW-Authenticate and Authorization header
unmodified and follow the rules found in Section 4.1. fields unmodified and follow the rules found in Section 4.1.
2.2. Protection Space (Realm) 2.2. Protection Space (Realm)
The authentication parameter realm is reserved for use by The authentication parameter realm is reserved for use by
authentication schemes that wish to indicate the scope of protection. authentication schemes that wish to indicate the scope of protection.
A protection space is defined by the canonical root URI (the scheme A protection space is defined by the canonical root URI (the scheme
and authority components of the effective request URI; see Section and authority components of the effective request URI; see Section
5.5 of [Part1]) of the server being accessed, in combination with the 5.5 of [Part1]) of the server being accessed, in combination with the
realm value if present. These realms allow the protected resources realm value if present. These realms allow the protected resources
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There are certain aspects of the HTTP Authentication Framework that There are certain aspects of the HTTP Authentication Framework that
put constraints on how new authentication schemes can work: put constraints on how new authentication schemes can work:
o HTTP authentication is presumed to be stateless: all of the o HTTP authentication is presumed to be stateless: all of the
information necessary to authenticate a request MUST be provided information necessary to authenticate a request MUST be provided
in the request, rather than be dependent on the server remembering in the request, rather than be dependent on the server remembering
prior requests. Authentication based on, or bound to, the prior requests. Authentication based on, or bound to, the
underlying connection is outside the scope of this specification underlying connection is outside the scope of this specification
and inherently flawed unless steps are taken to ensure that the and inherently flawed unless steps are taken to ensure that the
connection cannot be used by any party other than the connection cannot be used by any party other than the
authenticated user (see Section 2.3 of [Part1]). authenticated user (see Section 2.4 of [Part1]).
o The authentication parameter "realm" is reserved for defining o The authentication parameter "realm" is reserved for defining
Protection Spaces as defined in Section 2.2. New schemes MUST NOT Protection Spaces as defined in Section 2.2. New schemes MUST NOT
use it in a way incompatible with that definition. use it in a way incompatible with that definition.
o The "b64token" notation was introduced for compatibility with o The "b64token" notation was introduced for compatibility with
existing authentication schemes and can only be used once per existing authentication schemes and can only be used once per
challenge/credentials. New schemes thus ought to use the "auth- challenge/credentials. New schemes thus ought to use the "auth-
param" syntax instead, because otherwise future extensions will be param" syntax instead, because otherwise future extensions will be
impossible. impossible.
o The parsing of challenges and credentials is defined by this o The parsing of challenges and credentials is defined by this
specification, and cannot be modified by new authentication specification, and cannot be modified by new authentication
schemes. When the auth-param syntax is used, all parameters ought schemes. When the auth-param syntax is used, all parameters ought
to support both token and quoted-string syntax, and syntactical to support both token and quoted-string syntax, and syntactical
constraints ought to be defined on the field value after parsing constraints ought to be defined on the field value after parsing
(i.e., quoted-string processing). This is necessary so that (i.e., quoted-string processing). This is necessary so that
recipients can use a generic parser that applies to all recipients can use a generic parser that applies to all
authentication schemes. authentication schemes.
Note: the fact that the value syntax for the "realm" parameter is Note: The fact that the value syntax for the "realm" parameter is
restricted to quoted-string was a bad design choice not to be restricted to quoted-string was a bad design choice not to be
repeated for new parameters. repeated for new parameters.
o Definitions of new schemes ought to define the treatment of o Definitions of new schemes ought to define the treatment of
unknown extension parameters. In general, a "must-ignore" rule is unknown extension parameters. In general, a "must-ignore" rule is
preferable over "must-understand", because otherwise it will be preferable over "must-understand", because otherwise it will be
hard to introduce new parameters in the presence of legacy hard to introduce new parameters in the presence of legacy
recipients. Furthermore, it's good to describe the policy for recipients. Furthermore, it's good to describe the policy for
defining new parameters (such as "update the specification", or defining new parameters (such as "update the specification", or
"use this registry"). "use this registry").
skipping to change at page 9, line 25 skipping to change at page 9, line 30
o Authentication schemes need to document whether they are usable in o Authentication schemes need to document whether they are usable in
origin-server authentication (i.e., using WWW-Authenticate), origin-server authentication (i.e., using WWW-Authenticate),
and/or proxy authentication (i.e., using Proxy-Authenticate). and/or proxy authentication (i.e., using Proxy-Authenticate).
o The credentials carried in an Authorization header field are o The credentials carried in an Authorization header field are
specific to the User Agent, and therefore have the same effect on specific to the User Agent, and therefore have the same effect on
HTTP caches as the "private" Cache-Control response directive, HTTP caches as the "private" Cache-Control response directive,
within the scope of the request they appear in. within the scope of the request they appear in.
Therefore, new authentication schemes which choose not to carry Therefore, new authentication schemes which choose not to carry
credentials in the Authorization header (e.g., using a newly credentials in the Authorization header field (e.g., using a newly
defined header) will need to explicitly disallow caching, by defined header field) will need to explicitly disallow caching, by
mandating the use of either Cache-Control request directives mandating the use of either Cache-Control request directives
(e.g., "no-store") or response directives (e.g., "private"). (e.g., "no-store") or response directives (e.g., "private").
3. Status Code Definitions 3. Status Code Definitions
3.1. 401 Unauthorized 3.1. 401 Unauthorized
The request requires user authentication. The response MUST include The request requires user authentication. The response MUST include
a WWW-Authenticate header field (Section 4.4) containing a challenge a WWW-Authenticate header field (Section 4.4) containing a challenge
applicable to the target resource. The client MAY repeat the request applicable to the target resource. The client MAY repeat the request
skipping to change at page 11, line 7 skipping to change at page 11, line 12
subsequent request. But if the response is stale, all caches subsequent request. But if the response is stale, all caches
MUST first revalidate it with the origin server, using the header MUST first revalidate it with the origin server, using the header
fields from the new request to allow the origin server to fields from the new request to allow the origin server to
authenticate the new request. authenticate the new request.
3. If the response includes the "public" cache-control directive, it 3. If the response includes the "public" cache-control directive, it
MAY be returned in reply to any subsequent request. MAY be returned in reply to any subsequent request.
4.2. Proxy-Authenticate 4.2. Proxy-Authenticate
The "Proxy-Authenticate" header field consists of a challenge that The "Proxy-Authenticate" header field consists of at least one
indicates the authentication scheme and parameters applicable to the challenge that indicates the authentication scheme(s) and parameters
proxy for this effective request URI (Section 5.5 of [Part1]). It applicable to the proxy for this effective request URI (Section 5.5
MUST be included as part of a 407 (Proxy Authentication Required) of [Part1]). It MUST be included as part of a 407 (Proxy
response. Authentication Required) response.
Proxy-Authenticate = 1#challenge Proxy-Authenticate = 1#challenge
Unlike WWW-Authenticate, the Proxy-Authenticate header field applies Unlike WWW-Authenticate, the Proxy-Authenticate header field applies
only to the current connection and SHOULD NOT be passed on to only to the current connection, and intermediaries SHOULD NOT forward
downstream clients. However, an intermediate proxy might need to it to downstream clients. However, an intermediate proxy might need
obtain its own credentials by requesting them from the downstream to obtain its own credentials by requesting them from the downstream
client, which in some circumstances will appear as if the proxy is client, which in some circumstances will appear as if the proxy is
forwarding the Proxy-Authenticate header field. forwarding the Proxy-Authenticate header field.
Note that the parsing considerations for WWW-Authenticate apply to Note that the parsing considerations for WWW-Authenticate apply to
this header field as well; see Section 4.4 for details. this header field as well; see Section 4.4 for details.
4.3. Proxy-Authorization 4.3. Proxy-Authorization
The "Proxy-Authorization" header field allows the client to identify The "Proxy-Authorization" header field allows the client to identify
itself (or its user) to a proxy which requires authentication. Its itself (or its user) to a proxy which requires authentication. Its
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Note: The challenge grammar production uses the list syntax as Note: The challenge grammar production uses the list syntax as
well. Therefore, a sequence of comma, whitespace, and comma can well. Therefore, a sequence of comma, whitespace, and comma can
be considered both as applying to the preceding challenge, or to be considered both as applying to the preceding challenge, or to
be an empty entry in the list of challenges. In practice, this be an empty entry in the list of challenges. In practice, this
ambiguity does not affect the semantics of the header field value ambiguity does not affect the semantics of the header field value
and thus is harmless. and thus is harmless.
5. IANA Considerations 5. IANA Considerations
5.1. Authenticaton Scheme Registry 5.1. Authentication Scheme Registry
The registration procedure for HTTP Authentication Schemes is defined The registration procedure for HTTP Authentication Schemes is defined
by Section 2.3 of this document. by Section 2.3 of this document.
The HTTP Method Authentication Scheme shall be created at The HTTP Method Authentication Scheme shall be created at
<http://www.iana.org/assignments/http-authschemes>. <http://www.iana.org/assignments/http-authschemes>.
5.2. Status Code Registration 5.2. Status Code Registration
The HTTP Status Code Registry located at The HTTP Status Code Registry located at
skipping to change at page 14, line 8 skipping to change at page 14, line 22
for the client to retain the credentials. for the client to retain the credentials.
This is currently under separate study. There are a number of work- This is currently under separate study. There are a number of work-
arounds to parts of this problem, and we encourage the use of arounds to parts of this problem, and we encourage the use of
password protection in screen savers, idle time-outs, and other password protection in screen savers, idle time-outs, and other
methods which mitigate the security problems inherent in this methods which mitigate the security problems inherent in this
problem. In particular, user agents which cache credentials are problem. In particular, user agents which cache credentials are
encouraged to provide a readily accessible mechanism for discarding encouraged to provide a readily accessible mechanism for discarding
cached credentials under user control. cached credentials under user control.
6.2. Protection Spaces
Authentication schemes that solely rely on the "realm" mechanism for
establishing a protection space will expose credentials to all
resources on a server. Clients that have successfully made
authenticated requests with a resource can use the same
authentication credentials for other resources on the same server.
This makes it possible for a different resource to harvest
authentication credentials for other resources.
This is of particular concern when a 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 for each party.
7. Acknowledgments 7. Acknowledgments
This specification takes over the definition of the HTTP This specification takes over the definition of the HTTP
Authentication Framework, previously defined in RFC 2617. We thank Authentication Framework, previously defined in RFC 2617. We thank
John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D.
Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for
their work on that specification. See Section 6 of [RFC2617] for their work on that specification. See Section 6 of [RFC2617] for
further acknowledgements. further acknowledgements.
See Section 9 of [Part1] for the Acknowledgments related to this See Section 9 of [Part1] for the Acknowledgments related to this
skipping to change at page 14, line 21 skipping to change at page 15, line 4
Authentication Framework, previously defined in RFC 2617. We thank Authentication Framework, previously defined in RFC 2617. We thank
John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D. John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D.
Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for
their work on that specification. See Section 6 of [RFC2617] for their work on that specification. See Section 6 of [RFC2617] for
further acknowledgements. further acknowledgements.
See Section 9 of [Part1] for the Acknowledgments related to this See Section 9 of [Part1] for the Acknowledgments related to this
document revision. document revision.
8. References 8. References
8.1. Normative References 8.1. Normative References
[Part1] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., [Part1] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 1: URIs, Connections, and Message "HTTP/1.1, part 1: Message Routing and Syntax"",
Parsing", draft-ietf-httpbis-p1-messaging-19 (work in draft-ietf-httpbis-p1-messaging-20 (work in progress),
progress), March 2012. July 2012.
[Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 2: Semantics and Payloads",
draft-ietf-httpbis-p2-semantics-20 (work in progress),
July 2012.
[Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed., [Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
draft-ietf-httpbis-p6-cache-19 (work in progress), draft-ietf-httpbis-p6-cache-20 (work in progress),
March 2012. July 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008. Specifications: ABNF", STD 68, RFC 5234, January 2008.
8.2. Informative References 8.2. Informative References
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
skipping to change at page 15, line 28 skipping to change at page 16, line 15
Appendix A. Changes from RFCs 2616 and 2617 Appendix A. Changes from RFCs 2616 and 2617
The "realm" parameter isn't required anymore in general; The "realm" parameter isn't required anymore in general;
consequently, the ABNF allows challenges without any auth parameters. consequently, the ABNF allows challenges without any auth parameters.
(Section 2) (Section 2)
The "b64token" alternative to auth-param lists has been added for The "b64token" alternative to auth-param lists has been added for
consistency with legacy authentication schemes such as "Basic". consistency with legacy authentication schemes such as "Basic".
(Section 2) (Section 2)
Introduce Authentication Scheme Registry. (Section 2.3)
Change ABNF productions for header fields to only define the field Change ABNF productions for header fields to only define the field
value. (Section 4) value. (Section 4)
Appendix B. Collected ABNF 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 3.2.1>
OWS = <OWS, defined in [Part1], Section 3.2.1>
quoted-string = <quoted-string, defined in [Part1], Section 3.2.4>
token = <token, defined in [Part1], Section 3.2.4>
Appendix C. Collected ABNF
Authorization = credentials Authorization = credentials
BWS = <BWS, defined in [Part1], Section 3.2.1> BWS = <BWS, defined in [Part1], Section 3.2.1>
OWS = <OWS, defined in [Part1], Section 3.2.1> OWS = <OWS, defined in [Part1], Section 3.2.1>
Proxy-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS Proxy-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS
challenge ] ) challenge ] )
Proxy-Authorization = credentials Proxy-Authorization = credentials
skipping to change at page 16, line 35 skipping to change at page 17, line 35
challenge = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *( challenge = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *(
OWS "," [ OWS auth-param ] ) ] ) ] OWS "," [ OWS auth-param ] ) ] ) ]
credentials = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) credentials = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param )
*( OWS "," [ OWS auth-param ] ) ] ) ] *( OWS "," [ OWS auth-param ] ) ] ) ]
quoted-string = <quoted-string, defined in [Part1], Section 3.2.4> quoted-string = <quoted-string, defined in [Part1], Section 3.2.4>
token = <token, defined in [Part1], Section 3.2.4> token = <token, defined in [Part1], Section 3.2.4>
ABNF diagnostics: Appendix D. Change Log (to be removed by RFC Editor before publication)
; 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 <http://tools.ietf.org/wg/httpbis/trac/ticket/35>: "Normative and
Informative references"
C.3. Since draft-ietf-httpbis-p7-auth-01
Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
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
(<http://tools.ietf.org/wg/httpbis/trac/ticket/40>):
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
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
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
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
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 <http://tools.ietf.org/wg/httpbis/trac/ticket/198>: "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 <http://tools.ietf.org/wg/httpbis/trac/ticket/196>: "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 <http://tools.ietf.org/wg/httpbis/trac/ticket/130>: "introduction
to part 7 is work-in-progress"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/195>: "auth-param
syntax"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/224>: "Header
Classification"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/237>: "absorbing the
auth framework from 2617"
Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/141>: "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 <http://tools.ietf.org/wg/httpbis/trac/ticket/276>: "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 <http://tools.ietf.org/wg/httpbis/trac/ticket/78>: "Relationship
between 401, Authorization and WWW-Authenticate"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/177>: "Realm
required on challenges"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/195>: "auth-param
syntax"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/257>:
"Considerations for new authentications schemes"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/287>: "LWS in auth-
param ABNF"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/309>: "credentials
ABNF missing SP (still using implied LWS?)"
C.18. Since draft-ietf-httpbis-p7-auth-16
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/186>: "Document
HTTP's error-handling philosophy"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/320>: "add advice on Changes up to the first Working Group Last Call draft are summarized
defining auth scheme parameters" in <http://trac.tools.ietf.org/html/
draft-ietf-httpbis-p7-auth-19#appendix-C>.
C.19. Since draft-ietf-httpbis-p7-auth-17 D.1. Since draft-ietf-httpbis-p7-auth-19
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/314>: "allow o <http://tools.ietf.org/wg/httpbis/trac/ticket/348>: "Realms and
unquoted realm parameters" scope"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/321>: "Repeating
auth-params"
C.20. Since draft-ietf-httpbis-p7-auth-18 o <http://tools.ietf.org/wg/httpbis/trac/ticket/349>: "Strength"
Closed issues: o <http://tools.ietf.org/wg/httpbis/trac/ticket/357>:
"Authentication exchanges"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/334>: "recipient o <http://tools.ietf.org/wg/httpbis/trac/ticket/361>: "ABNF
behavior for new auth parameters" requirements for recipients"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/342>: "WWW- o <http://tools.ietf.org/wg/httpbis/trac/ticket/368>: "note
Authenticate ABNF slightly ambiguous" introduction of new IANA registries as normative changes"
Index Index
4 4
401 Unauthorized (status code) 9 401 Unauthorized (status code) 9
407 Proxy Authentication Required (status code) 9 407 Proxy Authentication Required (status code) 10
A A
auth-param 5 auth-param 5
auth-scheme 5 auth-scheme 5
Authorization header field 10 Authorization header field 10
B B
b64token 5 b64token 5
C C
Canonical Root URI 7
challenge 6 challenge 6
credentials 6 credentials 6
G G
Grammar Grammar
auth-param 5 auth-param 5
auth-scheme 5 auth-scheme 5
Authorization 10 Authorization 10
b64token 5 b64token 5
challenge 6 challenge 6
credentials 6 credentials 6
Proxy-Authenticate 11 Proxy-Authenticate 11
Proxy-Authorization 11 Proxy-Authorization 11
WWW-Authenticate 12 WWW-Authenticate 12
H H
Header Fields Header Fields
Authorization 10 Authorization 10
Proxy-Authenticate 11 Proxy-Authenticate 11
Proxy-Authorization 11 Proxy-Authorization 11
WWW-Authenticate 11 WWW-Authenticate 12
P P
Protection Space 7 Protection Space 7
Proxy-Authenticate header field 11 Proxy-Authenticate header field 11
Proxy-Authorization header field 11 Proxy-Authorization header field 11
R R
Realm 7 Realm 7
S S
Status Codes Status Codes
401 Unauthorized 9 401 Unauthorized 9
407 Proxy Authentication Required 9 407 Proxy Authentication Required 10
W W
WWW-Authenticate header field 11 WWW-Authenticate header field 12
Authors' Addresses Authors' Addresses
Roy T. Fielding (editor) Roy T. Fielding (editor)
Adobe Systems Incorporated Adobe Systems Incorporated
345 Park Ave 345 Park Ave
San Jose, CA 95110 San Jose, CA 95110
USA USA
EMail: fielding@gbiv.com EMail: fielding@gbiv.com
skipping to change at page 22, line 4 skipping to change at page 19, line 36
Yves Lafon (editor) Yves Lafon (editor)
World Wide Web Consortium World Wide Web Consortium
W3C / ERCIM W3C / ERCIM
2004, rte des Lucioles 2004, rte des Lucioles
Sophia-Antipolis, AM 06902 Sophia-Antipolis, AM 06902
France France
EMail: ylafon@w3.org EMail: ylafon@w3.org
URI: http://www.raubacapeu.net/people/yves/ URI: http://www.raubacapeu.net/people/yves/
Julian F. Reschke (editor) Julian F. Reschke (editor)
greenbytes GmbH greenbytes GmbH
Hafenweg 16 Hafenweg 16
Muenster, NW 48155 Muenster, NW 48155
Germany Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: julian.reschke@greenbytes.de EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/ URI: http://greenbytes.de/tech/webdav/
 End of changes. 53 change blocks. 
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