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2 HTTPbis Working Group R. Fielding, Ed.
3 Internet-Draft Adobe
4 Obsoletes: 2616 (if approved) Y. Lafon, Ed.
5 Updates: 2617 (if approved) W3C
6 Intended status: Standards Track J. Reschke, Ed.
7 Expires: January 17, 2013 greenbytes
8 July 16, 2012
10 HTTP/1.1, part 7: Authentication
11 draft-ietf-httpbis-p7-auth-20
13 Abstract
15 The Hypertext Transfer Protocol (HTTP) is an application-level
16 protocol for distributed, collaborative, hypermedia information
17 systems. This document defines the HTTP Authentication framework.
19 Editorial Note (To be removed by RFC Editor)
21 Discussion of this draft takes place on the HTTPBIS working group
22 mailing list (ietf-http-wg@w3.org), which is archived at
23 .
25 The current issues list is at
26 and related
27 documents (including fancy diffs) can be found at
28 .
30 The changes in this draft are summarized in Appendix D.1.
32 Status of This Memo
34 This Internet-Draft is submitted in full conformance with the
35 provisions of BCP 78 and BCP 79.
37 Internet-Drafts are working documents of the Internet Engineering
38 Task Force (IETF). Note that other groups may also distribute
39 working documents as Internet-Drafts. The list of current Internet-
40 Drafts is at http://datatracker.ietf.org/drafts/current/.
42 Internet-Drafts are draft documents valid for a maximum of six months
43 and may be updated, replaced, or obsoleted by other documents at any
44 time. It is inappropriate to use Internet-Drafts as reference
45 material or to cite them other than as "work in progress."
47 This Internet-Draft will expire on January 17, 2013.
49 Copyright Notice
51 Copyright (c) 2012 IETF Trust and the persons identified as the
52 document authors. All rights reserved.
54 This document is subject to BCP 78 and the IETF Trust's Legal
55 Provisions Relating to IETF Documents
56 (http://trustee.ietf.org/license-info) in effect on the date of
57 publication of this document. Please review these documents
58 carefully, as they describe your rights and restrictions with respect
59 to this document. Code Components extracted from this document must
60 include Simplified BSD License text as described in Section 4.e of
61 the Trust Legal Provisions and are provided without warranty as
62 described in the Simplified BSD License.
64 This document may contain material from IETF Documents or IETF
65 Contributions published or made publicly available before November
66 10, 2008. The person(s) controlling the copyright in some of this
67 material may not have granted the IETF Trust the right to allow
68 modifications of such material outside the IETF Standards Process.
69 Without obtaining an adequate license from the person(s) controlling
70 the copyright in such materials, this document may not be modified
71 outside the IETF Standards Process, and derivative works of it may
72 not be created outside the IETF Standards Process, except to format
73 it for publication as an RFC or to translate it into languages other
74 than English.
76 Table of Contents
78 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
79 1.1. Conformance and Error Handling . . . . . . . . . . . . . . 4
80 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 5
81 2. Access Authentication Framework . . . . . . . . . . . . . . . 5
82 2.1. Challenge and Response . . . . . . . . . . . . . . . . . . 5
83 2.2. Protection Space (Realm) . . . . . . . . . . . . . . . . . 7
84 2.3. Authentication Scheme Registry . . . . . . . . . . . . . . 8
85 2.3.1. Considerations for New Authentication Schemes . . . . 8
86 3. Status Code Definitions . . . . . . . . . . . . . . . . . . . 9
87 3.1. 401 Unauthorized . . . . . . . . . . . . . . . . . . . . . 9
88 3.2. 407 Proxy Authentication Required . . . . . . . . . . . . 10
89 4. Header Field Definitions . . . . . . . . . . . . . . . . . . . 10
90 4.1. Authorization . . . . . . . . . . . . . . . . . . . . . . 10
91 4.2. Proxy-Authenticate . . . . . . . . . . . . . . . . . . . . 11
92 4.3. Proxy-Authorization . . . . . . . . . . . . . . . . . . . 11
93 4.4. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . . 12
94 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
95 5.1. Authentication Scheme Registry . . . . . . . . . . . . . . 12
96 5.2. Status Code Registration . . . . . . . . . . . . . . . . . 13
97 5.3. Header Field Registration . . . . . . . . . . . . . . . . 13
98 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
99 6.1. Authentication Credentials and Idle Clients . . . . . . . 13
100 6.2. Protection Spaces . . . . . . . . . . . . . . . . . . . . 14
101 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
102 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
103 8.1. Normative References . . . . . . . . . . . . . . . . . . . 15
104 8.2. Informative References . . . . . . . . . . . . . . . . . . 15
105 Appendix A. Changes from RFCs 2616 and 2617 . . . . . . . . . . . 16
106 Appendix B. Imported ABNF . . . . . . . . . . . . . . . . . . . . 16
107 Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 17
108 Appendix D. Change Log (to be removed by RFC Editor before
109 publication) . . . . . . . . . . . . . . . . . . . . 17
110 D.1. Since draft-ietf-httpbis-p7-auth-19 . . . . . . . . . . . 17
111 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
113 1. Introduction
115 This document defines HTTP/1.1 access control and authentication. It
116 includes the relevant parts of RFC 2616 with only minor changes
117 ([RFC2616]), plus the general framework for HTTP authentication, as
118 previously defined in "HTTP Authentication: Basic and Digest Access
119 Authentication" ([RFC2617]).
121 HTTP provides several OPTIONAL challenge-response authentication
122 mechanisms which can be used by a server to challenge a client
123 request and by a client to provide authentication information. The
124 "basic" and "digest" authentication schemes continue to be specified
125 in RFC 2617.
127 1.1. Conformance and Error Handling
129 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
130 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
131 document are to be interpreted as described in [RFC2119].
133 This specification targets conformance criteria according to the role
134 of a participant in HTTP communication. Hence, HTTP requirements are
135 placed on senders, recipients, clients, servers, user agents,
136 intermediaries, origin servers, proxies, gateways, or caches,
137 depending on what behavior is being constrained by the requirement.
138 See Section 2 of [Part1] for definitions of these terms.
140 The verb "generate" is used instead of "send" where a requirement
141 differentiates between creating a protocol element and merely
142 forwarding a received element downstream.
144 An implementation is considered conformant if it complies with all of
145 the requirements associated with the roles it partakes in HTTP. Note
146 that SHOULD-level requirements are relevant here, unless one of the
147 documented exceptions is applicable.
149 This document also uses ABNF to define valid protocol elements
150 (Section 1.2). In addition to the prose requirements placed upon
151 them, senders MUST NOT generate protocol elements that do not match
152 the grammar defined by the ABNF rules for those protocol elements
153 that are applicable to the sender's role. If a received protocol
154 element is processed, the recipient MUST be able to parse any value
155 that would match the ABNF rules for that protocol element, excluding
156 only those rules not applicable to the recipient's role.
158 Unless noted otherwise, a recipient MAY attempt to recover a usable
159 protocol element from an invalid construct. HTTP does not define
160 specific error handling mechanisms except when they have a direct
161 impact on security, since different applications of the protocol
162 require different error handling strategies. For example, a Web
163 browser might wish to transparently recover from a response where the
164 Location header field doesn't parse according to the ABNF, whereas a
165 systems control client might consider any form of error recovery to
166 be dangerous.
168 1.2. Syntax Notation
170 This specification uses the Augmented Backus-Naur Form (ABNF)
171 notation of [RFC5234] with the list rule extension defined in Section
172 1.2 of [Part1]. Appendix B describes rules imported from other
173 documents. Appendix C shows the collected ABNF with the list rule
174 expanded.
176 2. Access Authentication Framework
178 2.1. Challenge and Response
180 HTTP provides a simple challenge-response authentication mechanism
181 that can be used by a server to challenge a client request and by a
182 client to provide authentication information. It uses an extensible,
183 case-insensitive token to identify the authentication scheme,
184 followed by additional information necessary for achieving
185 authentication via that scheme. The latter can either be a comma-
186 separated list of parameters or a single sequence of characters
187 capable of holding base64-encoded information.
189 Parameters are name-value pairs where the name is matched case-
190 insensitively, and each parameter name MUST only occur once per
191 challenge.
193 auth-scheme = token
195 auth-param = token BWS "=" BWS ( token / quoted-string )
197 b64token = 1*( ALPHA / DIGIT /
198 "-" / "." / "_" / "~" / "+" / "/" ) *"="
200 The "b64token" syntax allows the 66 unreserved URI characters
201 ([RFC3986]), plus a few others, so that it can hold a base64,
202 base64url (URL and filename safe alphabet), base32, or base16 (hex)
203 encoding, with or without padding, but excluding whitespace
204 ([RFC4648]).
206 The 401 (Unauthorized) response message is used by an origin server
207 to challenge the authorization of a user agent. This response MUST
208 include a WWW-Authenticate header field containing at least one
209 challenge applicable to the requested resource.
211 The 407 (Proxy Authentication Required) response message is used by a
212 proxy to challenge the authorization of a client and MUST include a
213 Proxy-Authenticate header field containing at least one challenge
214 applicable to the proxy for the requested resource.
216 challenge = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
218 Note: User agents will need to take special care in parsing the
219 WWW-Authenticate and Proxy-Authenticate header field values
220 because they can contain more than one challenge, or if more than
221 one of each is provided, since the contents of a challenge can
222 itself contain a comma-separated list of authentication
223 parameters.
225 Note: Many clients fail to parse challenges containing unknown
226 schemes. A workaround for this problem is to list well-supported
227 schemes (such as "basic") first.
229 A user agent that wishes to authenticate itself with an origin server
230 -- usually, but not necessarily, after receiving a 401 (Unauthorized)
231 -- can do so by including an Authorization header field with the
232 request.
234 A client that wishes to authenticate itself with a proxy -- usually,
235 but not necessarily, after receiving a 407 (Proxy Authentication
236 Required) -- can do so by including a Proxy-Authorization header
237 field with the request.
239 Both the Authorization field value and the Proxy-Authorization field
240 value contain the client's credentials for the realm of the resource
241 being requested, based upon a challenge received from the server
242 (possibly at some point in the past). When creating their values,
243 the user agent ought to do so by selecting the challenge with what it
244 considers to be the most secure auth-scheme that it understands,
245 obtaining credentials from the user as appropriate.
247 credentials = auth-scheme [ 1*SP ( b64token / #auth-param ) ]
249 Upon a request for a protected resource that omits credentials,
250 contains invalid credentials (e.g., a bad password) or partial
251 credentials (e.g., when the authentication scheme requires more than
252 one round trip), an origin server SHOULD return a 401 (Unauthorized)
253 response. Such responses MUST include a WWW-Authenticate header
254 field containing at least one (possibly new) challenge applicable to
255 the requested resource.
257 Likewise, upon a request that requires authentication by proxies that
258 omit credentials or contain invalid or partial credentials, a proxy
259 SHOULD return a 407 (Proxy Authentication Required) response. Such
260 responses MUST include a Proxy-Authenticate header field containing a
261 (possibly new) challenge applicable to the proxy.
263 A server receiving credentials that are valid, but not adequate to
264 gain access, ought to respond with the 403 (Forbidden) status code
265 (Section 4.6.3 of [Part2]).
267 The HTTP protocol does not restrict applications to this simple
268 challenge-response mechanism for access authentication. Additional
269 mechanisms MAY be used, such as encryption at the transport level or
270 via message encapsulation, and with additional header fields
271 specifying authentication information. However, such additional
272 mechanisms are not defined by this specification.
274 Proxies MUST forward the WWW-Authenticate and Authorization header
275 fields unmodified and follow the rules found in Section 4.1.
277 2.2. Protection Space (Realm)
279 The authentication parameter realm is reserved for use by
280 authentication schemes that wish to indicate the scope of protection.
282 A protection space is defined by the canonical root URI (the scheme
283 and authority components of the effective request URI; see Section
284 5.5 of [Part1]) of the server being accessed, in combination with the
285 realm value if present. These realms allow the protected resources
286 on a server to be partitioned into a set of protection spaces, each
287 with its own authentication scheme and/or authorization database.
288 The realm value is a string, generally assigned by the origin server,
289 which can have additional semantics specific to the authentication
290 scheme. Note that there can be multiple challenges with the same
291 auth-scheme but different realms.
293 The protection space determines the domain over which credentials can
294 be automatically applied. If a prior request has been authorized,
295 the same credentials MAY be reused for all other requests within that
296 protection space for a period of time determined by the
297 authentication scheme, parameters, and/or user preference. Unless
298 otherwise defined by the authentication scheme, a single protection
299 space cannot extend outside the scope of its server.
301 For historical reasons, senders MUST only use the quoted-string
302 syntax. Recipients might have to support both token and quoted-
303 string syntax for maximum interoperability with existing clients that
304 have been accepting both notations for a long time.
306 2.3. Authentication Scheme Registry
308 The HTTP Authentication Scheme Registry defines the name space for
309 the authentication schemes in challenges and credentials.
311 Registrations MUST include the following fields:
313 o Authentication Scheme Name
315 o Pointer to specification text
317 o Notes (optional)
319 Values to be added to this name space require IETF Review (see
320 [RFC5226], Section 4.1).
322 The registry itself is maintained at
323 .
325 2.3.1. Considerations for New Authentication Schemes
327 There are certain aspects of the HTTP Authentication Framework that
328 put constraints on how new authentication schemes can work:
330 o HTTP authentication is presumed to be stateless: all of the
331 information necessary to authenticate a request MUST be provided
332 in the request, rather than be dependent on the server remembering
333 prior requests. Authentication based on, or bound to, the
334 underlying connection is outside the scope of this specification
335 and inherently flawed unless steps are taken to ensure that the
336 connection cannot be used by any party other than the
337 authenticated user (see Section 2.4 of [Part1]).
339 o The authentication parameter "realm" is reserved for defining
340 Protection Spaces as defined in Section 2.2. New schemes MUST NOT
341 use it in a way incompatible with that definition.
343 o The "b64token" notation was introduced for compatibility with
344 existing authentication schemes and can only be used once per
345 challenge/credentials. New schemes thus ought to use the "auth-
346 param" syntax instead, because otherwise future extensions will be
347 impossible.
349 o The parsing of challenges and credentials is defined by this
350 specification, and cannot be modified by new authentication
351 schemes. When the auth-param syntax is used, all parameters ought
352 to support both token and quoted-string syntax, and syntactical
353 constraints ought to be defined on the field value after parsing
354 (i.e., quoted-string processing). This is necessary so that
355 recipients can use a generic parser that applies to all
356 authentication schemes.
358 Note: The fact that the value syntax for the "realm" parameter is
359 restricted to quoted-string was a bad design choice not to be
360 repeated for new parameters.
362 o Definitions of new schemes ought to define the treatment of
363 unknown extension parameters. In general, a "must-ignore" rule is
364 preferable over "must-understand", because otherwise it will be
365 hard to introduce new parameters in the presence of legacy
366 recipients. Furthermore, it's good to describe the policy for
367 defining new parameters (such as "update the specification", or
368 "use this registry").
370 o Authentication schemes need to document whether they are usable in
371 origin-server authentication (i.e., using WWW-Authenticate),
372 and/or proxy authentication (i.e., using Proxy-Authenticate).
374 o The credentials carried in an Authorization header field are
375 specific to the User Agent, and therefore have the same effect on
376 HTTP caches as the "private" Cache-Control response directive,
377 within the scope of the request they appear in.
379 Therefore, new authentication schemes which choose not to carry
380 credentials in the Authorization header field (e.g., using a newly
381 defined header field) will need to explicitly disallow caching, by
382 mandating the use of either Cache-Control request directives
383 (e.g., "no-store") or response directives (e.g., "private").
385 3. Status Code Definitions
387 3.1. 401 Unauthorized
389 The request requires user authentication. The response MUST include
390 a WWW-Authenticate header field (Section 4.4) containing a challenge
391 applicable to the target resource. The client MAY repeat the request
392 with a suitable Authorization header field (Section 4.1). If the
393 request already included Authorization credentials, then the 401
394 response indicates that authorization has been refused for those
395 credentials. If the 401 response contains the same challenge as the
396 prior response, and the user agent has already attempted
397 authentication at least once, then the user SHOULD be presented the
398 representation that was given in the response, since that
399 representation might include relevant diagnostic information.
401 3.2. 407 Proxy Authentication Required
403 This code is similar to 401 (Unauthorized), but indicates that the
404 client ought to first authenticate itself with the proxy. The proxy
405 MUST return a Proxy-Authenticate header field (Section 4.2)
406 containing a challenge applicable to the proxy for the target
407 resource. The client MAY repeat the request with a suitable Proxy-
408 Authorization header field (Section 4.3).
410 4. Header Field Definitions
412 This section defines the syntax and semantics of HTTP/1.1 header
413 fields related to authentication.
415 4.1. Authorization
417 The "Authorization" header field allows a user agent to authenticate
418 itself with a server -- usually, but not necessarily, after receiving
419 a 401 (Unauthorized) response. Its value consists of credentials
420 containing information of the user agent for the realm of the
421 resource being requested.
423 Authorization = credentials
425 If a request is authenticated and a realm specified, the same
426 credentials SHOULD be valid for all other requests within this realm
427 (assuming that the authentication scheme itself does not require
428 otherwise, such as credentials that vary according to a challenge
429 value or using synchronized clocks).
431 When a shared cache (see Section 1.2 of [Part6]) receives a request
432 containing an Authorization field, it MUST NOT return the
433 corresponding response as a reply to any other request, unless one of
434 the following specific exceptions holds:
436 1. If the response includes the "s-maxage" cache-control directive,
437 the cache MAY use that response in replying to a subsequent
438 request. But (if the specified maximum age has passed) a proxy
439 cache MUST first revalidate it with the origin server, using the
440 header fields from the new request to allow the origin server to
441 authenticate the new request. (This is the defined behavior for
442 s-maxage.) If the response includes "s-maxage=0", the proxy MUST
443 always revalidate it before re-using it.
445 2. If the response includes the "must-revalidate" cache-control
446 directive, the cache MAY use that response in replying to a
447 subsequent request. But if the response is stale, all caches
448 MUST first revalidate it with the origin server, using the header
449 fields from the new request to allow the origin server to
450 authenticate the new request.
452 3. If the response includes the "public" cache-control directive, it
453 MAY be returned in reply to any subsequent request.
455 4.2. Proxy-Authenticate
457 The "Proxy-Authenticate" header field consists of at least one
458 challenge that indicates the authentication scheme(s) and parameters
459 applicable to the proxy for this effective request URI (Section 5.5
460 of [Part1]). It MUST be included as part of a 407 (Proxy
461 Authentication Required) response.
463 Proxy-Authenticate = 1#challenge
465 Unlike WWW-Authenticate, the Proxy-Authenticate header field applies
466 only to the current connection, and intermediaries SHOULD NOT forward
467 it to downstream clients. However, an intermediate proxy might need
468 to obtain its own credentials by requesting them from the downstream
469 client, which in some circumstances will appear as if the proxy is
470 forwarding the Proxy-Authenticate header field.
472 Note that the parsing considerations for WWW-Authenticate apply to
473 this header field as well; see Section 4.4 for details.
475 4.3. Proxy-Authorization
477 The "Proxy-Authorization" header field allows the client to identify
478 itself (or its user) to a proxy which requires authentication. Its
479 value consists of credentials containing the authentication
480 information of the user agent for the proxy and/or realm of the
481 resource being requested.
483 Proxy-Authorization = credentials
485 Unlike Authorization, the Proxy-Authorization header field applies
486 only to the next outbound proxy that demanded authentication using
487 the Proxy-Authenticate field. When multiple proxies are used in a
488 chain, the Proxy-Authorization header field is consumed by the first
489 outbound proxy that was expecting to receive credentials. A proxy
490 MAY relay the credentials from the client request to the next proxy
491 if that is the mechanism by which the proxies cooperatively
492 authenticate a given request.
494 4.4. WWW-Authenticate
496 The "WWW-Authenticate" header field consists of at least one
497 challenge that indicates the authentication scheme(s) and parameters
498 applicable to the effective request URI (Section 5.5 of [Part1]).
500 It MUST be included in 401 (Unauthorized) response messages and MAY
501 be included in other response messages to indicate that supplying
502 credentials (or different credentials) might affect the response.
504 WWW-Authenticate = 1#challenge
506 User agents are advised to take special care in parsing the WWW-
507 Authenticate field value as it might contain more than one challenge,
508 or if more than one WWW-Authenticate header field is provided, the
509 contents of a challenge itself can contain a comma-separated list of
510 authentication parameters.
512 For instance:
514 WWW-Authenticate: Newauth realm="apps", type=1,
515 title="Login to \"apps\"", Basic realm="simple"
517 This header field contains two challenges; one for the "Newauth"
518 scheme with a realm value of "apps", and two additional parameters
519 "type" and "title", and another one for the "Basic" scheme with a
520 realm value of "simple".
522 Note: The challenge grammar production uses the list syntax as
523 well. Therefore, a sequence of comma, whitespace, and comma can
524 be considered both as applying to the preceding challenge, or to
525 be an empty entry in the list of challenges. In practice, this
526 ambiguity does not affect the semantics of the header field value
527 and thus is harmless.
529 5. IANA Considerations
531 5.1. Authentication Scheme Registry
533 The registration procedure for HTTP Authentication Schemes is defined
534 by Section 2.3 of this document.
536 The HTTP Method Authentication Scheme shall be created at
537 .
539 5.2. Status Code Registration
541 The HTTP Status Code Registry located at
542 shall be updated
543 with the registrations below:
545 +-------+-------------------------------+-------------+
546 | Value | Description | Reference |
547 +-------+-------------------------------+-------------+
548 | 401 | Unauthorized | Section 3.1 |
549 | 407 | Proxy Authentication Required | Section 3.2 |
550 +-------+-------------------------------+-------------+
552 5.3. Header Field Registration
554 The Message Header Field Registry located at shall be
556 updated with the permanent registrations below (see [RFC3864]):
558 +---------------------+----------+----------+-------------+
559 | Header Field Name | Protocol | Status | Reference |
560 +---------------------+----------+----------+-------------+
561 | Authorization | http | standard | Section 4.1 |
562 | Proxy-Authenticate | http | standard | Section 4.2 |
563 | Proxy-Authorization | http | standard | Section 4.3 |
564 | WWW-Authenticate | http | standard | Section 4.4 |
565 +---------------------+----------+----------+-------------+
567 The change controller is: "IETF (iesg@ietf.org) - Internet
568 Engineering Task Force".
570 6. Security Considerations
572 This section is meant to inform application developers, information
573 providers, and users of the security limitations in HTTP/1.1 as
574 described by this document. The discussion does not include
575 definitive solutions to the problems revealed, though it does make
576 some suggestions for reducing security risks.
578 6.1. Authentication Credentials and Idle Clients
580 Existing HTTP clients and user agents typically retain authentication
581 information indefinitely. HTTP/1.1 does not provide a method for a
582 server to direct clients to discard these cached credentials. This
583 is a significant defect that requires further extensions to HTTP.
584 Circumstances under which credential caching can interfere with the
585 application's security model include but are not limited to:
587 o Clients which have been idle for an extended period following
588 which the server might wish to cause the client to reprompt the
589 user for credentials.
591 o Applications which include a session termination indication (such
592 as a "logout" or "commit" button on a page) after which the server
593 side of the application "knows" that there is no further reason
594 for the client to retain the credentials.
596 This is currently under separate study. There are a number of work-
597 arounds to parts of this problem, and we encourage the use of
598 password protection in screen savers, idle time-outs, and other
599 methods which mitigate the security problems inherent in this
600 problem. In particular, user agents which cache credentials are
601 encouraged to provide a readily accessible mechanism for discarding
602 cached credentials under user control.
604 6.2. Protection Spaces
606 Authentication schemes that solely rely on the "realm" mechanism for
607 establishing a protection space will expose credentials to all
608 resources on a server. Clients that have successfully made
609 authenticated requests with a resource can use the same
610 authentication credentials for other resources on the same server.
611 This makes it possible for a different resource to harvest
612 authentication credentials for other resources.
614 This is of particular concern when a server hosts resources for
615 multiple parties under the same canonical root URI (Section 2.2).
616 Possible mitigation strategies include restricting direct access to
617 authentication credentials (i.e., not making the content of the
618 Authorization request header field available), and separating
619 protection spaces by using a different host name for each party.
621 7. Acknowledgments
623 This specification takes over the definition of the HTTP
624 Authentication Framework, previously defined in RFC 2617. We thank
625 John Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D.
626 Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for
627 their work on that specification. See Section 6 of [RFC2617] for
628 further acknowledgements.
630 See Section 9 of [Part1] for the Acknowledgments related to this
631 document revision.
633 8. References
634 8.1. Normative References
636 [Part1] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
637 "HTTP/1.1, part 1: Message Routing and Syntax"",
638 draft-ietf-httpbis-p1-messaging-20 (work in progress),
639 July 2012.
641 [Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
642 "HTTP/1.1, part 2: Semantics and Payloads",
643 draft-ietf-httpbis-p2-semantics-20 (work in progress),
644 July 2012.
646 [Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed.,
647 and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
648 draft-ietf-httpbis-p6-cache-20 (work in progress),
649 July 2012.
651 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
652 Requirement Levels", BCP 14, RFC 2119, March 1997.
654 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
655 Specifications: ABNF", STD 68, RFC 5234, January 2008.
657 8.2. Informative References
659 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
660 Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
661 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
663 [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
664 Leach, P., Luotonen, A., and L. Stewart, "HTTP
665 Authentication: Basic and Digest Access Authentication",
666 RFC 2617, June 1999.
668 [RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration
669 Procedures for Message Header Fields", BCP 90, RFC 3864,
670 September 2004.
672 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
673 Resource Identifier (URI): Generic Syntax", STD 66,
674 RFC 3986, January 2005.
676 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
677 Encodings", RFC 4648, October 2006.
679 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
680 IANA Considerations Section in RFCs", BCP 26, RFC 5226,
681 May 2008.
683 Appendix A. Changes from RFCs 2616 and 2617
685 The "realm" parameter isn't required anymore in general;
686 consequently, the ABNF allows challenges without any auth parameters.
687 (Section 2)
689 The "b64token" alternative to auth-param lists has been added for
690 consistency with legacy authentication schemes such as "Basic".
691 (Section 2)
693 Introduce Authentication Scheme Registry. (Section 2.3)
695 Change ABNF productions for header fields to only define the field
696 value. (Section 4)
698 Appendix B. Imported ABNF
700 The following core rules are included by reference, as defined in
701 Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),
702 CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double
703 quote), HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any
704 8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII
705 character).
707 The rules below are defined in [Part1]:
709 BWS =
710 OWS =
711 quoted-string =
712 token =
714 Appendix C. Collected ABNF
716 Authorization = credentials
718 BWS =
720 OWS =
722 Proxy-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS
723 challenge ] )
724 Proxy-Authorization = credentials
726 WWW-Authenticate = *( "," OWS ) challenge *( OWS "," [ OWS challenge
727 ] )
729 auth-param = token BWS "=" BWS ( token / quoted-string )
730 auth-scheme = token
732 b64token = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" )
733 *"="
735 challenge = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param ) *(
736 OWS "," [ OWS auth-param ] ) ] ) ]
737 credentials = auth-scheme [ 1*SP ( b64token / [ ( "," / auth-param )
738 *( OWS "," [ OWS auth-param ] ) ] ) ]
740 quoted-string =
742 token =
744 Appendix D. Change Log (to be removed by RFC Editor before publication)
746 Changes up to the first Working Group Last Call draft are summarized
747 in .
750 D.1. Since draft-ietf-httpbis-p7-auth-19
752 Closed issues:
754 o : "Realms and
755 scope"
757 o : "Strength"
759 o :
760 "Authentication exchanges"
762 o : "ABNF
763 requirements for recipients"
765 o : "note
766 introduction of new IANA registries as normative changes"
768 Index
770 4
771 401 Unauthorized (status code) 9
772 407 Proxy Authentication Required (status code) 10
774 A
775 auth-param 5
776 auth-scheme 5
777 Authorization header field 10
779 B
780 b64token 5
782 C
783 Canonical Root URI 7
784 challenge 6
785 credentials 6
787 G
788 Grammar
789 auth-param 5
790 auth-scheme 5
791 Authorization 10
792 b64token 5
793 challenge 6
794 credentials 6
795 Proxy-Authenticate 11
796 Proxy-Authorization 11
797 WWW-Authenticate 12
799 H
800 Header Fields
801 Authorization 10
802 Proxy-Authenticate 11
803 Proxy-Authorization 11
804 WWW-Authenticate 12
806 P
807 Protection Space 7
808 Proxy-Authenticate header field 11
809 Proxy-Authorization header field 11
811 R
812 Realm 7
814 S
815 Status Codes
816 401 Unauthorized 9
817 407 Proxy Authentication Required 10
819 W
820 WWW-Authenticate header field 12
822 Authors' Addresses
824 Roy T. Fielding (editor)
825 Adobe Systems Incorporated
826 345 Park Ave
827 San Jose, CA 95110
828 USA
830 EMail: fielding@gbiv.com
831 URI: http://roy.gbiv.com/
833 Yves Lafon (editor)
834 World Wide Web Consortium
835 W3C / ERCIM
836 2004, rte des Lucioles
837 Sophia-Antipolis, AM 06902
838 France
840 EMail: ylafon@w3.org
841 URI: http://www.raubacapeu.net/people/yves/
843 Julian F. Reschke (editor)
844 greenbytes GmbH
845 Hafenweg 16
846 Muenster, NW 48155
847 Germany
849 EMail: julian.reschke@greenbytes.de
850 URI: http://greenbytes.de/tech/webdav/