< draft-ietf-kitten-sasl-oauth-08.txt		draft-ietf-kitten-sasl-oauth-09.txt >
	KITTEN W. Mills		KITTEN W. Mills
	Internet-Draft Yahoo! Inc.		Internet-Draft Yahoo! Inc.
	Intended status: Standards Track T. Showalter		Intended status: Standards Track T. Showalter
	Expires: March 21, 2013		Expires: June 20, 2013
	H. Tschofenig		H. Tschofenig
	Nokia Siemens Networks		Nokia Siemens Networks
	September 17, 2012		December 17, 2012
	A set of SASL and GSS-API Mechanisms for OAuth		A set of SASL and GSS-API Mechanisms for OAuth
	draft-ietf-kitten-sasl-oauth-08		draft-ietf-kitten-sasl-oauth-09
	Abstract		Abstract
	OAuth enables a third-party application to obtain limited access to a		OAuth enables a third-party application to obtain limited access to a
	protected resource, either on behalf of a resource owner by		protected resource, either on behalf of a resource owner by
	orchestrating an approval interaction, or by allowing the third-party		orchestrating an approval interaction, or by allowing the third-party
	application to obtain access on its own behalf.		application to obtain access on its own behalf.
	This document defines how an application client uses credentials		This document defines how an application client uses credentials
	obtained via OAuth over the Simple Authentication and Security Layer		obtained via OAuth over the Simple Authentication and Security Layer
	(SASL) or the Generic Security Service Application Program Interface		(SASL) or the Generic Security Service Application Program Interface
	(GSS-API) to access a protected resource at a resource serve.		(GSS-API) to access a protected resource at a resource serve.
	Thereby, it enables schemes defined within the OAuth framework for		Thereby, it enables schemes defined within the OAuth framework for
	non-HTTP-based application protocols.		non-HTTP-based application protocols.
	Clients typically store the user's long term credential. This does,		Clients typically store the user's long-term credential. This does,
	however, lead to significant security vulnerabilities, for example,		however, lead to significant security vulnerabilities, for example,
	when such a credential leaks. A significant benefit of OAuth for		when such a credential leaks. A significant benefit of OAuth for
	usage in those clients is that the password is replaced by a token.		usage in those clients is that the password is replaced by a token.
	Tokens typically provided limited access rights and can be managed		Tokens typically provided limited access rights and can be managed
	and revoked separately from the user's long-term credential		and revoked separately from the user's long-term credential
	(password).		(password).
	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
	skipping to change at page 2, line 4 ¶		skipping to change at page 2, line 4 ¶
	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 March 21, 2013.		This Internet-Draft will expire on June 20, 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 3, line 14 ¶		skipping to change at page 3, line 14 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
	3. OAuth SASL Mechanism Specifications . . . . . . . . . . . . . 8		3. OAuth SASL Mechanism Specifications . . . . . . . . . . . . . 8
	3.1. Initial Client Response . . . . . . . . . . . . . . . . . 9		3.1. Initial Client Response . . . . . . . . . . . . . . . . . 9
	3.1.1. Reserved Key/Values . . . . . . . . . . . . . . . . . 10		3.1.1. Reserved Key/Values . . . . . . . . . . . . . . . . . 10
	3.1.2. Use of the gs2-header . . . . . . . . . . . . . . . . 10		3.1.2. Use of the gs2-header . . . . . . . . . . . . . . . . 10
	3.2. Server's Response . . . . . . . . . . . . . . . . . . . . 10		3.2. Server's Response . . . . . . . . . . . . . . . . . . . . 10
	3.2.1. OAuth Identities in the SASL Context . . . . . . . . . 11		3.2.1. OAuth Identifiers in the SASL Context . . . . . . . . 11
	3.2.2. Canonicalization . . . . . . . . . . . . . . . . . . . 11		3.2.2. Server Response to Failed Authentication . . . . . . . 11
	3.2.3. Server response to failed authentication. . . . . . . 11		3.2.3. Completing an Error Message Sequence . . . . . . . . . 12
	3.2.4. Completing an error message sequence. . . . . . . . . 12		3.3. OAuth Access Token Types using Digital Signatures and
	3.3. Use of Signature Type Authorization . . . . . . . . . . . 12		Keyed Message Digests . . . . . . . . . . . . . . . . . . 12
	3.4. Channel Binding . . . . . . . . . . . . . . . . . . . . . 13		3.4. Channel Binding . . . . . . . . . . . . . . . . . . . . . 13
	4. GSS-API OAuth Mechanism Specification . . . . . . . . . . . . 15		4. GSS-API OAuth Mechanism Specification . . . . . . . . . . . . 14
	5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 17		5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
	5.1. Successful Bearer Token Exchange . . . . . . . . . . . . . 17		5.1. Successful Bearer Token Exchange . . . . . . . . . . . . . 16
	5.2. OAuth 1.0a Authorization with Channel Binding . . . . . . 18		5.2. OAuth 1.0a Authorization with Channel Binding . . . . . . 17
	5.3. Failed Exchange . . . . . . . . . . . . . . . . . . . . . 19		5.3. Failed Exchange . . . . . . . . . . . . . . . . . . . . . 18
	5.4. Failed Channel Binding . . . . . . . . . . . . . . . . . . 20		5.4. Failed Channel Binding . . . . . . . . . . . . . . . . . . 19
	5.5. SMTP Example of a failed negotiation. . . . . . . . . . . 20		5.5. SMTP Example of a Failed Negotiation . . . . . . . . . . . 19
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 22		6. Security Considerations . . . . . . . . . . . . . . . . . . . 21
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23		7. Internationalization Considerations . . . . . . . . . . . . . 22
	7.1. SASL Registration . . . . . . . . . . . . . . . . . . . . 23		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
	7.2. GSS-API Registration . . . . . . . . . . . . . . . . . . . 24		8.1. SASL Registration . . . . . . . . . . . . . . . . . . . . 23
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25		8.2. GSS-API Registration . . . . . . . . . . . . . . . . . . . 24
	8.1. Normative References . . . . . . . . . . . . . . . . . . . 25		9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
	8.2. Informative References . . . . . . . . . . . . . . . . . . 26		9.1. Normative References . . . . . . . . . . . . . . . . . . . 25
	Appendix A. Acknowlegements . . . . . . . . . . . . . . . . . . . 27		9.2. Informative References . . . . . . . . . . . . . . . . . . 26
	Appendix B. Document History . . . . . . . . . . . . . . . . . . 28		Appendix A. Acknowlegements . . . . . . . . . . . . . . . . . . . 28
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30		Appendix B. Document History . . . . . . . . . . . . . . . . . . 29
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31
	1. Introduction		1. Introduction
	OAuth [I-D.ietf-oauth-v2] enables a third-party application to obtain		OAuth [RFC6749] enables a third-party application to obtain limited
	limited access to a protected resource, either on behalf of a		access to a protected resource, either on behalf of a resource owner
	resource owner by orchestrating an approval interaction, or by		by orchestrating an approval interaction, or by allowing the third-
	allowing the third-party application to obtain access on its own		party application to obtain access on its own behalf. The core OAuth
	behalf. The core OAuth specification [I-D.ietf-oauth-v2] does not		2.0 specification [RFC6749] does not define the interaction between
	define the interaction between the client and the resource server		the client and the resource server with the access to a protected
	with the access to a protected resource using an Access Token. This		resource using an Access Token. This functionality is described in
	functionality is described in separate specifications, for example		separate specifications, for example bearer tokens [RFC6750], OAuth
	Bearer tokens [I-D.ietf-oauth-v2-bearer], MAC tokens		2.0 MAC tokens [I-D.ietf-oauth-v2-http-mac]. OAuth 1.0a [RFC5849],
	[I-D.ietf-oauth-v2-http-mac], and OAuth 1.0a [RFC5849]. In each of		the predecessor of OAuth 2.0, has a similar design. The main use
	these are defined in an HTTP-based environment only.		cases for OAuth 2.0 and OAuth 1.0 have so far focused on an HTTP-
			based environment only.
	Figure 1 shows the abstract message flow as shown in Figure 1 of		Figure 1 shows the abstract message flow as shown in Figure 1 of
	[I-D.ietf-oauth-v2].		OAuth 2.0 [RFC6749].
	+--------+ +---------------+		+--------+ +---------------+
	| |--(A)- Authorization Request ->| Resource |		| |--(A)- Authorization Request ->| Resource |
	| | | Owner |		| | | Owner |
	| |<-(B)-- Authorization Grant ---| |		| |<-(B)-- Authorization Grant ---| |
	| | +---------------+		| | +---------------+
	| |		| |
	| | +---------------+		| | +---------------+
	| |--(C)-- Authorization Grant -->| Authorization |		| |--(C)-- Authorization Grant -->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<-(D)----- Access Token -------| |		| |<-(D)----- Access Token -------| |
	| | +---------------+		| | +---------------+
	| |		| |
	| | +---h------------+		| | +---------------+
	| |--(E)----- Access Token ------>| Resource |		| |--(E)----- Access Token ------>| Resource |
	| | | Server |		| | | Server |
	| |<-(F)--- Protected Resource ---| |		| |<-(F)--- Protected Resource ---| |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 1: Abstract OAuth 2.0 Protocol Flow		Figure 1: Abstract OAuth 2.0 Protocol Flow
	This document takes advantage of the OAuth protocol and its		This document takes advantage of the OAuth protocol and its
	deployment base to provide a way to use SASL [RFC4422] as well as the		deployment base to provide a way to use SASL [RFC4422] as well as the
	GSS-API [RFC2743] to gain access to resources when using non-HTTP-		GSS-API [RFC2743] to gain access to resources when using non-HTTP-
	skipping to change at page 5, line 18 ¶		skipping to change at page 5, line 19 ¶
	protocol exchanges within a data security layer.		protocol exchanges within a data security layer.
	The Generic Security Service Application Program Interface (GSS-API)		The Generic Security Service Application Program Interface (GSS-API)
	[RFC2743] provides a framework for applications to support multiple		[RFC2743] provides a framework for applications to support multiple
	authentication mechanisms through a unified interface.		authentication mechanisms through a unified interface.
	This document defines SASL mechanisms for OAuth, and it conforms to		This document defines SASL mechanisms for OAuth, and it conforms to
	the new bridge between SASL and the GSS-API called GS2 [RFC5801].		the new bridge between SASL and the GSS-API called GS2 [RFC5801].
	This means that this document defines both SASL and GSS-API		This means that this document defines both SASL and GSS-API
	mechanisms. Implementers may be interested in either the SASL, the		mechanisms. Implementers may be interested in either the SASL, the
	GSS-API, or even both mechanisms. To faciliate these two variants,		GSS-API, or even both mechanisms. To facilitate these two variants,
	the description has been split into two parts, one part that provides		the description has been split into two parts, one part that provides
	normative references for those interested in the SASL OAuth mechanism		normative references for those interested in the SASL OAuth mechanism
	(see Section 3), and a second part for those implementers that wish		(see Section 3), and a second part for those implementers that wish
	to implement the GSS-API portion (see Section 4).		to implement the GSS-API portion (see Section 4).
	When OAuth is integrated into SASL and the GSS-API the high-level		When OAuth is integrated into SASL and the GSS-API the high-level
	steps are as follows:		steps are as follows:
	(A) The client requests authorization from the resource owner.		(A) The client requests authorization from the resource owner.
	The authorization request can be made directly to the resource		The authorization request can be made directly to the resource
	skipping to change at page 6, line 5 ¶		skipping to change at page 6, line 5 ¶
	(D) The authorization server authenticates the client and		(D) The authorization server authenticates the client and
	validates the authorization grant, and if valid issues an access		validates the authorization grant, and if valid issues an access
	token.		token.
	(E) The client requests the protected resource from the resource		(E) The client requests the protected resource from the resource
	server and authenticates by presenting the access token.		server and authenticates by presenting the access token.
	(F) The resource server validates the access token, and if valid,		(F) The resource server validates the access token, and if valid,
	indicates a successful authentication.		indicates a successful authentication.
	Steps (E) and (F) are not defined in [I-D.ietf-oauth-v2] and are the		Steps (E) and (F) are not defined in [RFC6749] and are the main
	main functionality specified within this document. Consequently, the		functionality specified within this document. Consequently, the
	message exchange shown in Figure 2 is the result of this		message exchange shown in Figure 2 is the result of this
	specification. The client will genrally need to determine the		specification. The client will generally need to determine the
	authentication endpoints (and perhaps the service endpoints) before		authentication endpoints (and perhaps the service endpoints) before
	the OAuth 2.0 protocol exchange messages in steps (A)-(D) are		the OAuth 2.0 protocol exchange messages in steps (A)-(D) are
	executed. The discovery of the resource owner and authorization		executed. The discovery of the resource owner and authorization
	server endpoints is outside the scope of this specification. The		server endpoints is outside the scope of this specification. The
	client must discover those endpoints using a discovery mechanisms		client must discover those endpoints using a discovery mechanisms
	such as Webfinger using host-meta [I-D.jones-appsawg-webfinger]. In		such as Webfinger using host-meta [I-D.ietf-appsawg-webfinger]. In
	band discovery is not tenable if clients support the OAuth 2.0		band discovery is not tenable if clients support the OAuth 2.0
	password grant. Once credentials are obtained the client proceeds to		password grant. Once credentials are obtained the client proceeds to
	steps (E) and (F) defined in this specification.		steps (E) and (F) defined in this specification.
	----+		----+
	+--------+ +---------------+ |		+--------+ +---------------+ |
	| |--(A)-- Authorization Request --->| Resource | |		| |--(A)-- Authorization Request --->| Resource | |
	| | | Owner | |Plain		| | | Owner | |Plain
	| |<-(B)------ Access Grant ---------| | |OAuth		| |<-(B)------ Access Grant ---------| | |OAuth
	| | +---------------+ |2.0		| | +---------------+ |2.0
	skipping to change at page 7, line 12 ¶		skipping to change at page 7, line 12 ¶
	Figure 2: OAuth SASL Architecture		Figure 2: OAuth SASL Architecture
	2. Terminology		2. Terminology
	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].
	The reader is assumed to be familiar with the terms used in the OAuth		The reader is assumed to be familiar with the terms used in the OAuth
	2.0 specification [I-D.ietf-oauth-v2].		2.0 specification [RFC6749].
	In examples, "C:" and "S:" indicate lines sent by the client and		In examples, "C:" and "S:" indicate lines sent by the client and
	server respectively. Line breaks have been inserted for readability.		server respectively. Line breaks have been inserted for readability.
	Note that the IMAP SASL specification requires base64 encoding		Note that the IMAP SASL specification requires base64 encoding, see
	message, not this memo.		Section 4 of [RFC4648], not this memo.
	3. OAuth SASL Mechanism Specifications		3. OAuth SASL Mechanism Specifications
	SASL is used as a generalized authentication method in a variety of		SASL is used as an authentication framework in a variety of
	application layer protocols. This document defines the following		application layer protocols. This document defines the following
	SASL mechanisms for usage with OAuth:		SASL mechanisms for usage with OAuth:
	OAUTHBEARER Authorization using Bearer tokens.		OAUTHBEARER: Authorization using OAuth 2.0 bearer tokens as
			described in [RFC6750].
	OAUTH10A Authorization using OAuth 1.0a tokens.		OAUTH10A: Authorization using OAuth 1.0a MAC tokens (using the
			HMAC-SHA1 keyed message digest) as described in Section 3.4.2
			of [RFC5849].
	OAUTH10A-PLUS Adds channel binding [RFC5056] capability to		OAUTH10A-PLUS: Adds channel binding [RFC5056] capability to
	OAUTH10A for additional security guarantees.		OAUTH10A for protection against man-in-the-middle attacks.
	Any new OAuth token scheme MAY define a new SASL mechanism compatible		New extensions may be defined to add additional OAuth Access Token
	with the mechanisms defined here by simply registering the new		Types. Such a new SASL OAuth mechanism can be added by simply
	name(s) and citing this specification for the further definition.		registering the new name(s) and citing this specification for the
	New channel binding enabled "-PLUS" mechanisms defined in this way		further definition. New channel binding enabled "-PLUS" mechanisms
	MUST include message integrity protection. A newly defined mechanism		defined in this way MUST include message integrity protection. A
	would also need to register a new GS2 OID.		newly defined mechanism would also need to register a new GS2 OID.
	These mechanisms are client initiated and lock-step, the server		These mechanisms are client initiated and lock-step, the server
	always replying to a client message. In the case where the client		always replying to a client message. In the case where the client
	has and correctly uses a valid token the flow is:		has and correctly uses a valid token the flow is:
	o Client sends a valid and correct initial client response.		o Client sends a valid and correct initial client response.
	o Server responds with a successful authentication.		o Server responds with a successful authentication.
	In the case where authorization fails the server sends an error		In the case where authorization fails the server sends an error
	skipping to change at page 8, line 45 ¶		skipping to change at page 8, line 48 ¶
	server in order to allow the server to finish the exchange. Some		server in order to allow the server to finish the exchange. Some
	protocols and common SASL implementations do not support both sending		protocols and common SASL implementations do not support both sending
	a SASL message and finalizing a SASL negotiation, the additional		a SASL message and finalizing a SASL negotiation, the additional
	client message in the error case deals with this problem. This		client message in the error case deals with this problem. This
	exchange is:		exchange is:
	o Client sends an invalid initial client response.		o Client sends an invalid initial client response.
	o Server responds with an error message.		o Server responds with an error message.
	o Client sends a dummy client reponse.		o Client sends a dummy client response.
	o Server fails the authentication.		o Server fails the authentication.
	3.1. Initial Client Response		3.1. Initial Client Response
	Client responses are a key/value pair sequence. The initial client		Client responses are a key/value pair sequence. The initial client
	response includes a gs2-header as defined in GS2 [RFC5801], which		response includes a gs2-header as defined in GS2 [RFC5801], which
	carries the authorization ID. These key/value pairs carry the		carries the authorization ID. These key/value pairs carry the
	equivalent values from an HTTP context in order to be able to		equivalent values from an HTTP context in order to be able to
	complete an OAuth style HTTP authorization. The ABNF [RFC5234]		complete an OAuth style HTTP authorization. Unknown key/value pairs
	syntax is:		MUST be ignored by the server. The ABNF [RFC5234] syntax is:
	kvsep = %x01		kvsep = %x01
	key = 1*ALPHA		key = 1*ALPHA
	value = *(VCHAR | SP | HTAB | CR | LF )		value = *(VCHAR / SP / HTAB / CR / LF )
	kvpair = key "=" value kvsep		kvpair = key "=" value kvsep
	client_resp = 0*kvpair kvsep		client_resp = 0*kvpair kvsep
	;; gs2-header = As defined in GSS-API		;; gs2-header = As defined in GSS-API
	initial_client_resp = gs2-header kvsep client_resp		initial_client_resp = gs2-header kvsep client_resp
	The following key/value pairs are defined in the client response:		The following key/value pairs are defined in the client response:
	auth (REQUIRED): The payload of the HTTP Authorization header for		auth (REQUIRED): The payload of the HTTP Authorization header for
	an equivalent HTTP OAuth authroization.		an equivalent HTTP OAuth authorization.
	host: Contains the host name to which the client connected.		host: Contains the host name to which the client connected.
	port: Contains the port number represented as a decimal positive		port: Contains the port number represented as a decimal positive
	integer string without leading zeros to which the client		integer string without leading zeros to which the client
	connected.		connected.
	qs: The HTTP query string. In non-channel binding mechanisms		qs: The HTTP query string. In non-channel binding mechanisms
	this is reserved, the client SHOUD NOT send it, and has the		this is reserved, the client SHOUD NOT send it, and has the
	default value of "". In "-PLUS" variants this carries a single		default value of "". In "-PLUS" variants this carries a single
	key value pair "cbdata" for the channel binding data payload		key value pair "cbdata" for the channel binding data payload
	formatted as an HTTP query string.		formatted as an HTTP query string.
	In authorization schemes that use signatures, the client MUST send		For OAuth Access Token Types that use digital signatures or keyed
	host and port number key/values, and the server MUST fail an		message digests the client MUST send host and port number key/values,
	authorization request requiring signatures that does not have host		and the server MUST fail an authorization request requiring
	and port values. For authorization schemes that require a URI scheme		signatures or keyed message digests that do not have host and port
	as part of the data being signed "http" is always used. In OAuth		values. For authorization schemes that require a URI scheme as part
	1.0a for example, the signature base string includes the		of the data being signed "http" is always used. In OAuth 1.0a for
			example, the so-called signature base string calculation includes the
	reconstructed HTTP URL.		reconstructed HTTP URL.
	3.1.1. Reserved Key/Values		3.1.1. Reserved Key/Values
	In these mechanisms values for path, query string and post body are		In these mechanisms values for path, query string and post body are
	assigned default values. OAuth authorization schemes MAY define		assigned default values. OAuth authorization schemes MAY define
	usage of these in the SASL context and extend this specification.		usage of these in the SASL context and extend this specification.
	For OAuth schemes that use request signatures the default values MUST		For OAuth Access Token Types that use request signatures the default
	be used unless explict values are provided in the client response.		values MUST be used unless explicit values are provided in the client
	The following key values are reserved for future use:		response. The following key values are reserved for future use:
	mthd (RESERVED): HTTP method for use in signatures, the default		mthd (RESERVED): HTTP method for use in signatures, the default
	value is "POST".		value is "POST".
	path (RESERVED): HTTP path data, the default value is "/".		path (RESERVED): HTTP path data, the default value is "/".
	post (RESERVED): HTTP post data, the default value is "".		post (RESERVED): HTTP post data, the default value is "".
	3.1.2. Use of the gs2-header		3.1.2. Use of the gs2-header
	skipping to change at page 10, line 41 ¶		skipping to change at page 10, line 41 ¶
	credential, if it does not the server MUST fail the negotiation.		credential, if it does not the server MUST fail the negotiation.
	In the non "-PLUS" mechanisms the "gs2-cb-flag" MUST be set to "n"		In the non "-PLUS" mechanisms the "gs2-cb-flag" MUST be set to "n"
	because channel-binding [RFC5056] data is not expected. In the		because channel-binding [RFC5056] data is not expected. In the
	OAUTH10A-PLUS mechanism (or other -PLUS variants based on this		OAUTH10A-PLUS mechanism (or other -PLUS variants based on this
	specification) the "gs2-cb-flag" MUST be set appropriately by the		specification) the "gs2-cb-flag" MUST be set appropriately by the
	client.		client.
	3.2. Server's Response		3.2. Server's Response
	The server validates the response per the specification for the		The server validates the response per the specification for the OAuth
	authorization scheme used. If the authorization scheme used includes		Access Token Types used. If the OAuth Access Token Type utilizes a
	signing of the request parameters the client must provide a client		digital signature or a keyed message digest of the request parameters
	response that satisfies the data requirements for the scheme in use.		then the client must provide a client response that satisfies the
			data requirements for the scheme in use.
	In a "-PLUS" mechanism the server examines the channel binding data,		In a "-PLUS" mechanism the server examines the channel binding data,
	extracts the channel binding unique prefix, and extracts the raw		extracts the channel binding unique prefix, and extracts the raw
	channel biding data based on the channel binding type used. It then		channel biding data based on the channel binding type used. It then
	computes it's own copy of the channel binding payload and compares		computes it's own copy of the channel binding payload and compares
	that to the payload sent by the client in the cbdata key/value.		that to the payload sent by the client in the cbdata key/value.
	Those two must be equal for channel binding to succeed.		Those two must be equal for channel binding to succeed.
	The server responds to a successfully verified client message by		The server responds to a successfully verified client message by
	completing the SASL negotiation. The authenticated identity reported		completing the SASL negotiation. The authenticated identity reported
	by the SASL mechanism is the identity securely established for the		by the SASL mechanism is the identity securely established for the
	client with the OAuth credential. The application, not the SASL		client with the OAuth credential. The application, not the SASL
	mechanism, based on local access policy determines whether the		mechanism, based on local access policy determines whether the
	identity reported by the mechanism is allowed access to the requested		identity reported by the mechanism is allowed access to the requested
	resource. Note that the semantics of the authz-id is specified by		resource. Note that the semantics of the authz-id is specified by
	the SASL framework [RFC4422].		the SASL framework [RFC4422].
	3.2.1. OAuth Identities in the SASL Context		3.2.1. OAuth Identifiers in the SASL Context
	Some OAuth schemes can carry both an owner or resource identity and a		OAuth access tokens may carry the authenticated identifier of the
	"proxy" identity, for example an OAuth 1.0a [RFC5849] mechanism where		resource owner and client authentication provides the authenticated
	the consumer key (oauth_consumer_key) identifies the entity using the		identity of the client issuing the request to the resource server.
	token and the token itself identifies the owner or resouce. If both
	identities are needed by an application the developer will need to		If both identities are needed by an application the developer will
	provide a way to communicate that from the SASL mechanism back to the		need to provide a way to communicate that from the SASL mechanism
	application such as a GSS-API [RFC2473] named type like		back to the application such as a GSS-API [RFC2743] named type like
	GSS_C_NT_USER_NAME or a comparable newly defined GSS-API name type or		GSS_C_NT_USER_NAME or a comparable newly defined GSS-API name type or
	name attribute [RFC6680].		name attribute [RFC6680].
	3.2.2. Canonicalization		3.2.2. Server Response to Failed Authentication
	The identity asserted by the OAuth authorization server is canonical
	for display. The server MAY provide a different canonical form based
	on local data.
	3.2.3. Server response to failed authentication.
	For a failed authentication the server returns a JSON [RFC4627]		For a failed authentication the server returns a JSON [RFC4627]
	formatted error result, and fails the authentication. The error		formatted error result, and fails the authentication. The error
	result consists of the following values:		result consists of the following values:
	status (REQUIRED): The authorization error code. Valid error		status (REQUIRED): The authorization error code. Valid error
	codes are defined in the IANA [[need registry name]] registry		codes are defined in the IANA [[need registry name]] registry
	specified in the OAuth 2 core specification.		specified in the OAuth 2 core specification.
	scope (OPTIONAL): An OAuth scope which is valid to access the		scope (OPTIONAL): An OAuth scope which is valid to access the
	service. This may be empty which implies that unscoped tokens		service. This may be empty which implies that unscoped tokens
	are required, or a space separated list. Use of a space		are required, or a space separated list. Use of a space
	separated list is NOT RECOMMENDED.		separated list is NOT RECOMMENDED.
	If the resource server provides a scope the client SHOULD always		If the resource server provides a scope then the client MUST always
	request scoped tokens from the token endpoint. The client MAY use a		request scoped tokens from the token endpoint. If the resource
	scope other than the one provided by the resource server. Scopes		server provides no scope to the client then the client SHOULD presume
	other than those advertised by the resource server are be defined by		an empty scope (unscoped token) is needed.
	the resource owner and provided in service documentation or discovery
	information (which is beyond the scope of this memo). If not present
	then the client SHOULD presume an empty scope (unscoped token) is
	needed.
	If channel binding is in use and the channel binding fails the server		If channel binding is in use and the channel binding fails the server
	responds with a status code set to 412 to indicate that the channel		responds with a status code set to 412 to indicate that the channel
	binding precondition failed. If the authentication scheme in use		binding precondition failed. If the authentication scheme in use
	does not include signing the server SHOULD revoke the presented		does not include signing the server SHOULD revoke the presented
	credential and the client SHOULD discard that credential.		credential and the client SHOULD discard that credential.
	3.2.4. Completing an error message sequence.		3.2.3. Completing an Error Message Sequence
	Section 3.6 of [RFC4422] explicitly prohibits additional information		Section 3.6 of [RFC4422] explicitly prohibits additional information
	in an unsuccessful authentication outcome. Therefor, the error		in an unsuccessful authentication outcome. Therefore, the error
	message is sent in a normal message. The client MUST then send an		message is sent in a normal message. The client MUST then send an
	additional client response consisting of a single %x01 (control A)		additional client response consisting of a single %x01 (control A)
	character to the server in order to allow the server to finish the		character to the server in order to allow the server to finish the
	exchange.		exchange.
	3.3. Use of Signature Type Authorization		3.3. OAuth Access Token Types using Digital Signatures and Keyed
			Message Digests
	Some OAuth mechanisms support authorization using signatures, which		OAuth Access Token Types may use digital signatures or keyed message
	requires that both client and server construct the string to be		digests. The client and the resource server need to perform a
	signed. OAuth 2 is designed for authentication/authorization to		cryptographic computation for integrity protection and data origin
	access specific URIs. SASL is designed for user authentication, and		authentication.
	has no facility for being more specific. In this mechanism we
	require or define default values for the data elements from an HTTP		OAuth is designed for access to resources identified by URIs. SASL
	request which allow the signature base string to be constructed		is designed for user authentication, and has no facility for more
	properly. The default HTTP path is "/" and the default post body is		fine-grained access control. In this specification we require or
	empty. These atoms are defined as extension points so that no		define default values for the data elements from an HTTP request
	changes are needed if there is a revision of SASL which supports more		which allow the signature base string to be constructed properly.
	specific resource authorization, e.g. IMAP access to a specific		The default HTTP path is "/" and the default post body is empty.
	folder or FTP access limited to a specific directory.		These atoms are defined as extension points so that no changes are
			needed if there is a revision of SASL which supports more specific
			resource authorization, e.g., IMAP access to a specific folder or FTP
			access limited to a specific directory.
	Using the example in the OAuth 1.0a specification as a starting		Using the example in the OAuth 1.0a specification as a starting
	point, on an IMAP server running on port 143 and given the OAuth 1.0a		point, on an IMAP server running on port 143 and given the OAuth 1.0a
	style authorization request (with %x01 shown as ^A and line breaks		style authorization request (with %x01 shown as ^A and line breaks
	added for readability) below:		added for readability) below:
	n,a=user@example.com^A		n,a=user@example.com^A
	host=example.com^A		host=example.com^A
	user=user@example.com^A		user=user@example.com^A
	port=143^A		port=143^A
	skipping to change at page 13, line 42 ¶		skipping to change at page 13, line 31 ¶
	POST&http%3A%2F%2Fexample.com:143%2F&oauth_consumer_key%3D9djdj82h4		POST&http%3A%2F%2Fexample.com:143%2F&oauth_consumer_key%3D9djdj82h4
	8djs9d2%26oauth_nonce%3D7d8f3e4a%26oauth_signature_method%3DHMAC-SH		8djs9d2%26oauth_nonce%3D7d8f3e4a%26oauth_signature_method%3DHMAC-SH
	A1%26oauth_timestamp%3D137131201%26oauth_token%3Dkkk9d7dh3k39sjv7		A1%26oauth_timestamp%3D137131201%26oauth_token%3Dkkk9d7dh3k39sjv7
	3.4. Channel Binding		3.4. Channel Binding
	The channel binding data is carried in the "qs" (query string) key		The channel binding data is carried in the "qs" (query string) key
	value pair formatted as a standard HTTP query parameter with the name		value pair formatted as a standard HTTP query parameter with the name
	"cbdata". Channel binding requires that the channel binding data be		"cbdata". Channel binding requires that the channel binding data be
	integrity protected end-to-end in order to protect against man-in-		integrity protected end-to-end in order to protect against man-in-
	the-middle attacks. All authorization schemes offered with "-PLUS"		the-middle attacks. All SASL OAuth mechanisms with a "-PLUS" postfix
	mechanisms MUST provide integrity protection. It should be noted		MUST provide integrity protection. It should be noted that while the
	that while the Bearer token scheme specifies SSL for normal usage it		Bearer Access Token Type mandates TLS it does not create keying
	offers no integrity protection and is not suitable for use with		material at the application layer and is not suitable for use with
	channel binding.		channel bindings.
	The channel binding data is computed by the client based on it's		The channel binding data is computed by the client based on it's
	choice of preferred channel binding type. As specified in [RFC5056],		choice of preferred channel binding type. As specified in [RFC5056],
	the channel binding information MUST start with the channel binding		the channel binding information MUST start with the channel binding
	unique prefix, followed by a colon (ASCII 0x3A), followed by a base64		unique prefix, followed by a colon (ASCII 0x3A), followed by a base64
	encoded channel binding payload. The channel binding payload is the		encoded channel binding payload. The channel binding payload is the
	raw data from the channel binding type. For example, if the client		raw data from the channel binding type. For example, if the client
	is using tls-unique for channel binding then the raw channel binding		is using tls-unique for channel binding then the raw channel binding
	data is the TLS finished message as specified in section 3.1 of		data is the TLS finished message as specified in Section 3.1 of
	[RFC5929].		[RFC5929].
	4. GSS-API OAuth Mechanism Specification		4. GSS-API OAuth Mechanism Specification
	Note: The normative references in this section are informational for		Note: The normative references in this section are informational for
	SASL implementers, but they are normative for GSS-API implementers.		SASL implementers, but they are normative for GSS-API implementers.
	A SASL OAuth mechanism is also a GSS-API mechanism and the messages		A SASL OAuth mechanism is also a GSS-API mechanism and the messages
	described in Section 3 are the same with the following changes to the		described in Section 3 are the same with the following changes to the
	GS2 related elements:		GS2 related elements:
	skipping to change at page 15, line 38 ¶		skipping to change at page 14, line 38 ¶
	(GSS_C_MUTUAL_FLAG) set to TRUE. OAuth supports credential		(GSS_C_MUTUAL_FLAG) set to TRUE. OAuth supports credential
	delegation, therefore security contexts may have the deleg_state flag		delegation, therefore security contexts may have the deleg_state flag
	(GSS_C_DELEG_FLAG) set to either TRUE or FALSE.		(GSS_C_DELEG_FLAG) set to either TRUE or FALSE.
	The mutual authentication property of this mechanism relies on		The mutual authentication property of this mechanism relies on
	successfully comparing the TLS server identity with the negotiated		successfully comparing the TLS server identity with the negotiated
	target name. Since the TLS channel is managed by the application		target name. Since the TLS channel is managed by the application
	outside of the GSS-API mechanism, the mechanism itself is unable to		outside of the GSS-API mechanism, the mechanism itself is unable to
	confirm the name while the application is able to perform this		confirm the name while the application is able to perform this
	comparison for the mechanism. For this reason, applications MUST		comparison for the mechanism. For this reason, applications MUST
	match the TLS server identity with the target name, as discussed in		match the TLS server identity with the target name using the
	[RFC6125].		appropriate application profile, as discussed in [RFC6125]. For
			example, when SASL OAuth is run over IMAP then the IMAP profile of
			RFC 6125 is used.
	OAuth mechanisms do not support per-message tokens or		OAuth mechanisms do not support per-message tokens or
	GSS_Pseudo_random.		GSS_Pseudo_random.
	OAuth supports a standard generic name syntax for acceptors, such as		OAuth supports a standard generic name syntax for acceptors, such as
	GSS_C_NT_HOSTBASED_SERVICE (see [RFC2743], Section 4.1). These		GSS_C_NT_HOSTBASED_SERVICE (see [RFC2743], Section 4.1). These
	service names MUST be associated with the "entityID" claimed by the		service names MUST be associated with the "entityID" claimed by the
	RP. OAuth mechanisms support only a single name type for initiators:		RP. OAuth mechanisms support only a single name type for initiators:
	GSS_C_NT_USER_NAME. GSS_C_NT_USER_NAME is the default name type.		GSS_C_NT_USER_NAME. GSS_C_NT_USER_NAME is the default name type.
	The query, display, and exported name syntaxes for OAuth principal		The query, display, and exported name syntaxes for OAuth principal
	skipping to change at page 17, line 10 ¶		skipping to change at page 16, line 10 ¶
	Section 4). The exported name token does, of course, conform to		Section 4). The exported name token does, of course, conform to
	[RFC2743], Section 3.2, but the "NAME" part of the token should be		[RFC2743], Section 3.2, but the "NAME" part of the token should be
	treated as a potential input string to the OAuth name normalization		treated as a potential input string to the OAuth name normalization
	rules.		rules.
	5. Examples		5. Examples
	These examples illustrate exchanges between an IMAP and SMTP clients		These examples illustrate exchanges between an IMAP and SMTP clients
	and servers.		and servers.
	Note to implementers: Authorization scheme names are case		Note to implementers: The SASL OAuth method names are case
	insensitive. One example uses "Bearer" but that could as easily be		insensitive. One example uses "Bearer" but that could as easily be
	"bearer", "BEARER", or "BeArEr".		"bearer", "BEARER", or "BeArEr".
	5.1. Successful Bearer Token Exchange		5.1. Successful Bearer Token Exchange
	This example shows a successful OAuth 2.0 bearer token exchange.		This example shows a successful OAuth 2.0 bearer token exchange.
	Note that line breaks are inserted for readability.		Note that line breaks are inserted for readability.
	S: * IMAP4rev1 Server Ready		S: * OK IMAP4rev1 Server Ready
	C: t0 CAPABILITY		C: t0 CAPABILITY
	S: * CAPABILITY IMAP4rev1 AUTH=OAUTHBEARER		S: * CAPABILITY IMAP4rev1 AUTH=OAUTHBEARER SASL-IR
	S: t0 OK Completed		S: t0 OK Completed
	C: t1 AUTHENTICATE OAUTHBEARER bixhPXVzZXJAZXhhbXBsZS5jb20BaG9zdD1zZX		C: t1 AUTHENTICATE OAUTHBEARER bixhPXVzZXJAZXhhbXBsZS5jb20BaG9zdD1zZX
	J2ZXIuZXhhbXBsZS5jb20BcG9ydD0xNDMBYXV0aD1CZWFyZXIgdkY5ZGZ0NHFtV		J2ZXIuZXhhbXBsZS5jb20BcG9ydD0xNDMBYXV0aD1CZWFyZXIgdkY5ZGZ0NHFtV
	GMyTnZiM1JsY2tCaGJIUmhkbWx6ZEdFdVkyOXRDZz09AQE=		GMyTnZiM1JsY2tCaGJIUmhkbWx6ZEdFdVkyOXRDZz09AQE=
	S: t1 OK SASL authentication succeeded		S: t1 OK SASL authentication succeeded
	As required by IMAP [RFC3501], the payloads are base64-encoded. The		As required by IMAP [RFC3501], the payloads are base64-encoded. The
	decoded initial client response (with %x01 represented as ^A and long		decoded initial client response (with %x01 represented as ^A and long
	lines wrapped for readability) is:		lines wrapped for readability) is:
	skipping to change at page 18, line 13 ¶		skipping to change at page 17, line 13 ¶
	0x0D and 0x0A), these are not displayed explicitly in the example.		0x0D and 0x0A), these are not displayed explicitly in the example.
	[connection begins]		[connection begins]
	S: 220 mx.example.com ESMTP 12sm2095603fks.9		S: 220 mx.example.com ESMTP 12sm2095603fks.9
	C: EHLO sender.example.com		C: EHLO sender.example.com
	S: 250-mx.example.com at your service,[172.31.135.47]		S: 250-mx.example.com at your service,[172.31.135.47]
	S: 250-SIZE 35651584		S: 250-SIZE 35651584
	S: 250-8BITMIME		S: 250-8BITMIME
	S: 250-AUTH LOGIN PLAIN OAUTHBEARER		S: 250-AUTH LOGIN PLAIN OAUTHBEARER
	S: 250-ENHANCEDSTATUSCODES		S: 250-ENHANCEDSTATUSCODES
	S: 250-PIPELINING		S: 250 PIPELINING
	C: t1 AUTHENTICATE OAUTHBEARER bixhPXVzZXJAZXhhbXBsZS5jb20BaG9zdD1zZX		C: t1 AUTHENTICATE OAUTHBEARER bixhPXVzZXJAZXhhbXBsZS5jb20BaG9zdD1zZX
	J2ZXIuZXhhbXBsZS5jb20BcG9ydD0xNDMBYXV0aD1CZWFyZXIgdkY5ZGZ0NHFtV		J2ZXIuZXhhbXBsZS5jb20BcG9ydD0xNDMBYXV0aD1CZWFyZXIgdkY5ZGZ0NHFtV
	GMyTnZiM1JsY2tCaGJIUmhkbWx6ZEdFdVkyOXRDZz09AQE=		GMyTnZiM1JsY2tCaGJIUmhkbWx6ZEdFdVkyOXRDZz09AQE=
	S: 235 Authentication successful.		S: 235 Authentication successful.
	[connection continues...]		[connection continues...]
	5.2. OAuth 1.0a Authorization with Channel Binding		5.2. OAuth 1.0a Authorization with Channel Binding
	This example shows channel binding in the context of an OAuth 1.0a		This example shows channel binding in the context of an OAuth 1.0a
	signed authorization request. Note that line breaks are inserted for		request using a keyed message digest. Note that line breaks are
	readability.		inserted for readability.
	S: * CAPABILITY IMAP4rev1 AUTH=OAUTH10A-PLUS SASL-IR IMAP4rev1 Server		S: * OK [CAPABILITY IMAP4rev1 AUTH=OAUTH10A-PLUS SASL-IR]
	Ready		IMAP4rev1 Server Ready
	S: t0 OK Completed
	C: t1 AUTHENTICATE OAUTH10A-PLUS cD10bHMtdW5pcXVlLGE9dXNlckBleGFtcGxlL		C: t1 AUTHENTICATE OAUTH10A-PLUS cD10bHMtdW5pcXVlLGE9dXNlckBleGFtcGxlL
	mNvbQFob3N0PXNlcnZlci5leGFtcGxlLmNvbQFwb3J0PTE0MwFhdXRoPU9BdXRoI		mNvbQFob3N0PXNlcnZlci5leGFtcGxlLmNvbQFwb3J0PTE0MwFhdXRoPU9BdXRoI
	HJlYWxtPSJFeGFtcGxlIixvYXV0aF9jb25zdW1lcl9rZXk9IjlkamRqODJoNDhka		HJlYWxtPSJFeGFtcGxlIixvYXV0aF9jb25zdW1lcl9rZXk9IjlkamRqODJoNDhka
	nM5ZDIiLG9hdXRoX3Rva2VuPSJra2s5ZDdkaDNrMzlzanY3IixvYXV0aF9zaWduY		nM5ZDIiLG9hdXRoX3Rva2VuPSJra2s5ZDdkaDNrMzlzanY3IixvYXV0aF9zaWduY
	XR1cmVfbWV0aG9kPSJITUFDLVNIQTEiLG9hdXRoX3RpbWVzdGFtcD0iMTM3MTMxM		XR1cmVfbWV0aG9kPSJITUFDLVNIQTEiLG9hdXRoX3RpbWVzdGFtcD0iMTM3MTMxM
	jAxIixvYXV0aF9ub25jZT0iN2Q4ZjNlNGEiLG9hdXRoX3NpZ25hdHVyZT0iU1Nkd		jAxIixvYXV0aF9ub25jZT0iN2Q4ZjNlNGEiLG9hdXRoX3NpZ25hdHVyZT0iU1Nkd
	ElHRWdiR2wwZEd4bElIUmxZU0J3YjNRdSIBcXM9Y2JkYXRhPXRscy11bmlxdWU6U		ElHRWdiR2wwZEd4bElIUmxZU0J3YjNRdSIBcXM9Y2JkYXRhPXRscy11bmlxdWU6U
	0c5M0lHSnBaeUJwY3lCaElGUk1VeUJtYVc1aGJDQnRaWE56WVdkbFB3bz0BAQ==		0c5M0lHSnBaeUJwY3lCaElGUk1VeUJtYVc1aGJDQnRaWE56WVdkbFB3bz0BAQ==
	S: t1 OK SASL authentication succeeded		S: t1 OK SASL authentication succeeded
	skipping to change at page 20, line 41 ¶		skipping to change at page 19, line 41 ¶
	The decoded server response is:		The decoded server response is:
	{		{
	"status":"412",		"status":"412",
	"scope":"example_scope"		"scope":"example_scope"
	}		}
	The client responds with the required dummy response.		The client responds with the required dummy response.
	5.5. SMTP Example of a failed negotiation.		5.5. SMTP Example of a Failed Negotiation
	This example shows an authorization failure in an SMTP exchange.		This example shows an authorization failure in an SMTP exchange.
	Note that line breaks are inserted for readability, and that the SMTP		Note that line breaks are inserted for readability, and that the SMTP
	protocol terminates lines with CR and LF characters (ASCII values		protocol terminates lines with CR and LF characters (ASCII values
	0x0D and 0x0A), these are not displayed explicitly in the example.		0x0D and 0x0A), these are not displayed explicitly in the example.
	[connection begins]		[connection begins]
	S: 220 mx.example.com ESMTP 12sm2095603fks.9		S: 220 mx.example.com ESMTP 12sm2095603fks.9
	C: EHLO sender.example.com		C: EHLO sender.example.com
	S: 250-mx.example.com at your service,[172.31.135.47]		S: 250-mx.example.com at your service,[172.31.135.47]
	S: 250-SIZE 35651584		S: 250-SIZE 35651584
	S: 250-8BITMIME		S: 250-8BITMIME
	S: 250-AUTH LOGIN PLAIN OAUTHBEARER		S: 250-AUTH LOGIN PLAIN OAUTHBEARER
	S: 250-ENHANCEDSTATUSCODES		S: 250-ENHANCEDSTATUSCODES
	S: 250-PIPELINING		S: 250 PIPELINING
	C: AUTH OAUTHBEARER bixhPT1zb21ldXNlckBleGFtcGxlLmNvbQFhdXRoPUJlYXJlciB2		C: AUTH OAUTHBEARER bixhPT1zb21ldXNlckBleGFtcGxlLmNvbQFhdXRoPUJlYXJlciB2
	RjlkZnQ0cW1UYzJOdmIzUmxja0JoZEhSaGRtbHpkR0V1WTI5dENnPT0BAQ==		RjlkZnQ0cW1UYzJOdmIzUmxja0JoZEhSaGRtbHpkR0V1WTI5dENnPT0BAQ==
	S: 334 eyJzdGF0dXMiOiI0MDEiLCJzY2hlbWVzIjoiYmVhcmVyIG1hYyIsInNjb3BlIjoia		S: 334 eyJzdGF0dXMiOiI0MDEiLCJzY2hlbWVzIjoiYmVhcmVyIG1hYyIsInNjb3BlIjoia
	HR0cHM6Ly9tYWlsLmdvb2dsZS5jb20vIn0K		HR0cHM6Ly9tYWlsLmdvb2dsZS5jb20vIn0K
	C: AQ==		C: AQ==
	S: 535-5.7.1 Username and Password not accepted. Learn more at		S: 535-5.7.1 Username and Password not accepted. Learn more at
	S: 535 5.7.1 http://support.example.com/mail/oauth		S: 535 5.7.1 http://support.example.com/mail/oauth
	[connection continues...]		[connection continues...]
	The server returned an error message in the 334 SASL message, the		The server returned an error message in the 334 SASL message, the
	client responds with the required dummy response, and the server		client responds with the required dummy response, and the server
	finalizes the negotiation.		finalizes the negotiation.
	6. Security Considerations		6. Security Considerations
	This mechanism does not provide a security layer, but does provide a		OAuth 1.0a and OAuth 2 allows for a variety of deployment scenarios,
	provision for channel binding. The OAuth 2 specification		and the security properties of these profiles vary. Application
	[I-D.ietf-oauth-v2] allows for a variety of usages, and the security		developers therefore need to understand the needs of their
	properties of these profiles vary. The usage of bearer tokens, for		applications before selecting a specific SASL OAuth mechanism.
	example, provide security features similar to cookies. Applications
	using this mechanism SHOULD exercise the same level of care using
	this mechanism as they would in using the SASL PLAIN mechanism. In
	particular, TLS 1.2 or an equivalent secure channel MUST be
	implemented and its usage is RECOMMENDED.
	The channel binding in this mechanism has different properties based		The channel binding in this mechanism has different properties based
	on the authentication scheme used. The integrity guarantee for		on the Access Token Type used.
	channel binding depends on the quality of the guarantee in the the
	authorization scheme.
	It is possible that SASL will be authenticating a connection and the		It is possible that SASL will be authenticating a connection and the
	life of that connection may outlast the life of the token used to		life of that connection may outlast the life of the access token used
	authenticate it. This is a common problem in application protocols		to establish it. This is a common problem in application protocols
	where connections are long-lived, and not a problem with this		where connections are long-lived, and not a problem with this
	mechanism per se. Servers MAY unilaterally disconnect clients in		mechanism per se. Servers MAY unilaterally disconnect clients in
	accordance with the application protocol.		accordance with the application protocol.
	An OAuth credential is not equivalent to the password or primary		The OAuth access token (and related keying material) is not
	account credential. There are protocols like XMPP that allow actions		equivalent to the user's long term password. As such, care has to be
	like change password. The server SHOULD ensure that actions taken in		taken when these OAuth credentials are used for actions like changing
	the authenticated channel are appropriate to the strength of the		passwords (as it is possible with some protocols, e.g., XMPP). The
	presented credential.		server SHOULD ensure that actions taken in the authenticated channel
			are appropriate to the strength of the presented credential.
	Tokens have a lifetime associated with them. Reducing the lifetime		Access tokens have a lifetime. Reducing the lifetime of an access
	of a token provides security benefits in the case that tokens leak.		token provides security benefits, as described in
	In addition a previously obtained token MAY be revoked or rendered		[I-D.ietf-oauth-v2-threatmodel], and OAuth 2.0 introduces refresh
	invalid at any time. The client MAY request a new access token for		tokens to obtain new access token on the fly. Additionally, a
	each connection to a resource server, but it SHOULD cache and re-use		previously obtained access token MAY be revoked or rendered invalid
			at any time. The client MAY request a new access token for each
			connection to a resource server, but it SHOULD cache and re-use
	access credentials that appear to be valid.		access credentials that appear to be valid.
	7. IANA Considerations		7. Internationalization Considerations
	7.1. SASL Registration		The identifer asserted by the OAuth authorization server about the
			resource owner inside the access token may be displayed to a human.
			For example, when SASL is used in the context of IMAP the resource
			server may assert the resource owner's email address to the IMAP
			server for usage in an email-based application. The identifier may
			therefore contain internationalized characters and an application
			needs to ensure that the mapping between the identifier provided by
			OAuth is suitable for use with the application layer protocol SASL is
			incorporated into.
			At the time of writing the standardization of the assertion format
			(in JSON format) is still ongoing, see
			[I-D.ietf-oauth-json-web-token].
			8. IANA Considerations
			8.1. SASL Registration
	The IANA is requested to register the following SASL profile:		The IANA is requested to register the following SASL profile:
	SASL mechanism profile: OAUTHBEARER		SASL mechanism profile: OAUTHBEARER
	Security Considerations: See this document		Security Considerations: See this document
	Published Specification: See this document		Published Specification: See this document
	For further information: Contact the authors of this document.		For further information: Contact the authors of this document.
	skipping to change at page 24, line 5 ¶		skipping to change at page 24, line 5 ¶
	Security Considerations: See this document		Security Considerations: See this document
	Published Specification: See this document		Published Specification: See this document
	For further information: Contact the authors of this document.		For further information: Contact the authors of this document.
	Owner/Change controller: the IETF		Owner/Change controller: the IETF
	Note: None		Note: None
	7.2. GSS-API Registration		8.2. GSS-API Registration
	IANA is further requested to assign an OID for thESE GSS mechanismS		IANA is further requested to assign an OID for these GSS mechanisms
	in the SMI numbers registry, with the prefix of		in the SMI numbers registry, with the prefix of
	iso.org.dod.internet.security.mechanisms (1.3.6.1.5.5) and to		iso.org.dod.internet.security.mechanisms (1.3.6.1.5.5) and to
	reference this specification in the registry.		reference this specification in the registry.
	8. References		9. References
	8.1. Normative References
	[I-D.ietf-oauth-v2]
	Hardt, D., "The OAuth 2.0 Authorization Framework",
	draft-ietf-oauth-v2-31 (work in progress), August 2012.
	[I-D.ietf-oauth-v2-bearer]		9.1. Normative References
	Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
	Framework: Bearer Token Usage",
	draft-ietf-oauth-v2-bearer-23 (work in progress),
	August 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.
	[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in		[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
	IPv6 Specification", RFC 2473, December 1998.		IPv6 Specification", RFC 2473, December 1998.
	[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,		[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext		Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
	Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.		Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
	skipping to change at page 25, line 46 ¶		skipping to change at page 25, line 36 ¶
	[RFC3174] Eastlake, D. and P. Jones, "US Secure Hash Algorithm 1		[RFC3174] Eastlake, D. and P. Jones, "US Secure Hash Algorithm 1
	(SHA1)", RFC 3174, September 2001.		(SHA1)", RFC 3174, September 2001.
	[RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and		[RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and
	Security Layer (SASL)", RFC 4422, June 2006.		Security Layer (SASL)", RFC 4422, June 2006.
	[RFC4627] Crockford, D., "The application/json Media Type for		[RFC4627] Crockford, D., "The application/json Media Type for
	JavaScript Object Notation (JSON)", RFC 4627, July 2006.		JavaScript Object Notation (JSON)", RFC 4627, July 2006.
			[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
			Encodings", RFC 4648, October 2006.
	[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure		[RFC5056] Williams, N., "On the Use of Channel Bindings to Secure
	Channels", RFC 5056, November 2007.		Channels", RFC 5056, November 2007.
	[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234, January 2008.		Specifications: ABNF", STD 68, RFC 5234, January 2008.
	[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security		[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246, August 2008.		(TLS) Protocol Version 1.2", RFC 5246, August 2008.
	[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,		[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
	skipping to change at page 26, line 33 ¶		skipping to change at page 26, line 26 ¶
	Verification of Domain-Based Application Service Identity		Verification of Domain-Based Application Service Identity
	within Internet Public Key Infrastructure Using X.509		within Internet Public Key Infrastructure Using X.509
	(PKIX) Certificates in the Context of Transport Layer		(PKIX) Certificates in the Context of Transport Layer
	Security (TLS)", RFC 6125, March 2011.		Security (TLS)", RFC 6125, March 2011.
	[RFC6680] Williams, N., Johansson, L., Hartman, S., and S.		[RFC6680] Williams, N., Johansson, L., Hartman, S., and S.
	Josefsson, "Generic Security Service Application		Josefsson, "Generic Security Service Application
	Programming Interface (GSS-API) Naming Extensions",		Programming Interface (GSS-API) Naming Extensions",
	RFC 6680, August 2012.		RFC 6680, August 2012.
	8.2. Informative References		[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework",
			RFC 6749, October 2012.
	[I-D.ietf-oauth-v2-http-mac]		[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
	Hammer-Lahav, E., "HTTP Authentication: MAC Access		Framework: Bearer Token Usage", RFC 6750, October 2012.
	Authentication", draft-ietf-oauth-v2-http-mac-01 (work in
	progress), February 2012.
	[I-D.jones-appsawg-webfinger]		9.2. Informative References
			[I-D.ietf-appsawg-webfinger]
	Jones, P., Salgueiro, G., and J. Smarr, "WebFinger",		Jones, P., Salgueiro, G., and J. Smarr, "WebFinger",
	draft-jones-appsawg-webfinger-06 (work in progress),		draft-ietf-appsawg-webfinger-07 (work in progress),
	June 2012.		December 2012.
			[I-D.ietf-oauth-json-web-token]
			Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
			(JWT)", draft-ietf-oauth-json-web-token-05 (work in
			progress), November 2012.
			[I-D.ietf-oauth-v2-http-mac]
			Richer, J., Mills, W., and H. Tschofenig, "OAuth 2.0
			Message Authentication Code (MAC) Tokens",
			draft-ietf-oauth-v2-http-mac-02 (work in progress),
			November 2012.
			[I-D.ietf-oauth-v2-threatmodel]
			Lodderstedt, T., McGloin, M., and P. Hunt, "OAuth 2.0
			Threat Model and Security Considerations",
			draft-ietf-oauth-v2-threatmodel-08 (work in progress),
			October 2012.
	[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION		[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
	4rev1", RFC 3501, March 2003.		4rev1", RFC 3501, March 2003.
	Appendix A. Acknowlegements		Appendix A. Acknowlegements
	The authors would like to thank the members of the Kitten working		The authors would like to thank the members of the Kitten working
	group, and in addition and specifically: Simon Josefson, Torsten		group, and in addition and specifically: Simon Josefson, Torsten
	Lodderstadt, Ryan Troll, and Nico Williams.		Lodderstadt, Ryan Troll, Alexey Melnikov, and Nico Williams.
			This document was produced under the chairmanship of Alexey Melnikov,
			Tom Yu, Shawn Emery, Josh Howlett, Sam Hartman. The area directors
			included Stephen Farrell.
	Appendix B. Document History		Appendix B. Document History
	[[ to be removed by RFC editor before publication as an RFC ]]		[[ to be removed by RFC editor before publication as an RFC ]]
			-09
			o Incorporated review by Alexey and Hannes.
			o Clarified the three OAuth SASL mechanisms.
			o Updated references
			o Extended acknowledgements
	-08		-08
	o Fixed the channel binding examples for p=$cbtype		o Fixed the channel binding examples for p=$cbtype
	o More tuning of the authcid language and edited and renamed 3.2.1.		o More tuning of the authcid language and edited and renamed 3.2.1.
	-07		-07
	o Struck the MUST langiage from authzid.		o Struck the MUST langiage from authzid.
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