draft-ietf-httpbis-expect-ct-07.txt		draft-ietf-httpbis-expect-ct-latest.txt
	HTTP Working Group E. Stark		HTTP Working Group E. Stark
	Internet-Draft Google		Internet-Draft Google
	Intended status: Experimental July 16, 2018		Intended status: Experimental August 8, 2018
	Expires: January 17, 2019		Expires: February 9, 2019
	Expect-CT Extension for HTTP		Expect-CT Extension for HTTP
	draft-ietf-httpbis-expect-ct-07		draft-ietf-httpbis-expect-ct-latest
	Abstract		Abstract
	This document defines a new HTTP header field, named Expect-CT, that		This document defines a new HTTP header field, named Expect-CT, that
	allows web host operators to instruct user agents to expect valid		allows web host operators to instruct user agents to expect valid
	Signed Certificate Timestamps (SCTs) to be served on connections to		Signed Certificate Timestamps (SCTs) to be served on connections to
	these hosts. Expect-CT allows web host operators to discover		these hosts. Expect-CT allows web host operators to discover
	misconfigurations in their Certificate Transparency deployments and		misconfigurations in their Certificate Transparency deployments and
	ensure that misissued certificates accepted by UAs are discoverable		ensure that misissued certificates accepted by UAs are discoverable
	in Certificate Transparency logs.		in Certificate Transparency logs.
	skipping to change at page 1, line 46 ¶		skipping to change at page 1, line 46 ¶
	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 https://datatracker.ietf.org/drafts/current/.		Drafts is at https://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 January 17, 2019.		This Internet-Draft will expire on February 9, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 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
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 27 ¶		skipping to change at page 2, line 27 ¶
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4		1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Server and Client Behavior . . . . . . . . . . . . . . . . . 5		2. Server and Client Behavior . . . . . . . . . . . . . . . . . 5
	2.1. Response Header Field Syntax . . . . . . . . . . . . . . 5		2.1. Response Header Field Syntax . . . . . . . . . . . . . . 5
	2.1.1. The report-uri Directive . . . . . . . . . . . . . . 6		2.1.1. The report-uri Directive . . . . . . . . . . . . . . 5
	2.1.2. The enforce Directive . . . . . . . . . . . . . . . . 6		2.1.2. The enforce Directive . . . . . . . . . . . . . . . . 6
	2.1.3. The max-age Directive . . . . . . . . . . . . . . . . 7		2.1.3. The max-age Directive . . . . . . . . . . . . . . . . 7
	2.1.4. Examples . . . . . . . . . . . . . . . . . . . . . . 7		2.1.4. Examples . . . . . . . . . . . . . . . . . . . . . . 7
	2.2. Server Processing Model . . . . . . . . . . . . . . . . . 7		2.2. Server Processing Model . . . . . . . . . . . . . . . . . 7
	2.2.1. HTTP-over-Secure-Transport Request Type . . . . . . . 8		2.2.1. HTTP-over-Secure-Transport Request Type . . . . . . . 7
	2.2.2. HTTP Request Type . . . . . . . . . . . . . . . . . . 8		2.2.2. HTTP Request Type . . . . . . . . . . . . . . . . . . 8
	2.3. User Agent Processing Model . . . . . . . . . . . . . . . 8		2.3. User Agent Processing Model . . . . . . . . . . . . . . . 8
	2.3.1. Missing or Malformed Expect-CT Header Fields . . . . 8		2.3.1. Missing or Malformed Expect-CT Header Fields . . . . 8
	2.3.2. Expect-CT Header Field Processing . . . . . . . . . . 8		2.3.2. Expect-CT Header Field Processing . . . . . . . . . . 8
	2.3.3. Reporting . . . . . . . . . . . . . . . . . . . . . . 10		2.3.3. Reporting . . . . . . . . . . . . . . . . . . . . . . 10
	2.4. Evaluating Expect-CT Connections for CT Compliance . . . 10		2.4. Evaluating Expect-CT Connections for CT Compliance . . . 10
	2.4.1. Skipping CT compliance checks . . . . . . . . . . . . 11		2.4.1. Skipping CT compliance checks . . . . . . . . . . . . 11
	3. Reporting Expect-CT Failure . . . . . . . . . . . . . . . . . 11		3. Reporting Expect-CT Failure . . . . . . . . . . . . . . . . . 11
	3.1. Generating a violation report . . . . . . . . . . . . . . 12		3.1. Generating a violation report . . . . . . . . . . . . . . 12
	3.2. Sending a violation report . . . . . . . . . . . . . . . 13		3.2. Sending a violation report . . . . . . . . . . . . . . . 13
	skipping to change at page 3, line 9 ¶		skipping to change at page 3, line 9 ¶
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
	6.1. Header Field Registry . . . . . . . . . . . . . . . . . . 16		6.1. Header Field Registry . . . . . . . . . . . . . . . . . . 16
	6.2. Media Types Registry . . . . . . . . . . . . . . . . . . 16		6.2. Media Types Registry . . . . . . . . . . . . . . . . . . 16
	7. Usability Considerations . . . . . . . . . . . . . . . . . . 17		7. Usability Considerations . . . . . . . . . . . . . . . . . . 17
	8. Authoring Considerations . . . . . . . . . . . . . . . . . . 17		8. Authoring Considerations . . . . . . . . . . . . . . . . . . 17
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
	9.1. Normative References . . . . . . . . . . . . . . . . . . 18		9.1. Normative References . . . . . . . . . . . . . . . . . . 18
	9.2. Informative References . . . . . . . . . . . . . . . . . 19		9.2. Informative References . . . . . . . . . . . . . . . . . 19
	9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 19		9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 19
	Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . 20		Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . 20
	A.1. Since -06 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.1. Since -07 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.2. Since -05 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.2. Since -06 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.3. Since -04 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.3. Since -05 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.4. Since -03 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.4. Since -04 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.5. Since -02 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.5. Since -03 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.6. Since -01 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.6. Since -02 . . . . . . . . . . . . . . . . . . . . . . . . 20
	A.7. Since -00 . . . . . . . . . . . . . . . . . . . . . . . . 20		A.7. Since -01 . . . . . . . . . . . . . . . . . . . . . . . . 20
			A.8. Since -00 . . . . . . . . . . . . . . . . . . . . . . . . 20
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 21		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 21
	1. Introduction		1. Introduction
	This document defines a new HTTP header field that enables UAs to		This document defines a new HTTP header field that enables UAs to
	identify web hosts that expect the presence of Signed Certificate		identify web hosts that expect the presence of Signed Certificate
	Timestamps (SCTs) [I-D.ietf-trans-rfc6962-bis] in future Transport		Timestamps (SCTs) [I-D.ietf-trans-rfc6962-bis] in future Transport
	Layer Security (TLS) [RFC5246] connections.		Layer Security (TLS) [RFC5246] connections.
	Web hosts that serve the Expect-CT HTTP header field are noted by the		Web hosts that serve the Expect-CT HTTP header field are noted by the
	skipping to change at page 5, line 25 ¶		skipping to change at page 5, line 25 ¶
	header field, using the grammar defined in [RFC5234] and the rules		header field, using the grammar defined in [RFC5234] and the rules
	defined in Section 3.2 of [RFC7230].		defined in Section 3.2 of [RFC7230].
	Expect-CT = #expect-ct-directive		Expect-CT = #expect-ct-directive
	expect-ct-directive = directive-name [ "=" directive-value ]		expect-ct-directive = directive-name [ "=" directive-value ]
	directive-name = token		directive-name = token
	directive-value = token / quoted-string		directive-value = token / quoted-string
	Figure 1: Syntax of the Expect-CT header field		Figure 1: Syntax of the Expect-CT header field
	Optional white space ("OWS") is used as defined in Section 3.2.3 of
	[RFC7230]. "token" and "quoted-string" are used as defined in
	Section 3.2.6 of [RFC7230].
	The directives defined in this specification are described below.		The directives defined in this specification are described below.
	The overall requirements for directives are:		The overall requirements for directives are:
	1. The order of appearance of directives is not significant.		1. The order of appearance of directives is not significant.
	2. A given directive MUST NOT appear more than once in a given		2. A given directive MUST NOT appear more than once in a given
	header field. Directives are either optional or required, as		header field. Directives are either optional or required, as
	stipulated in their definitions.		stipulated in their definitions.
	3. Directive names are case insensitive.		3. Directive names are case insensitive.
	skipping to change at page 6, line 23 ¶		skipping to change at page 6, line 17 ¶
	report-uri-value = absolute-URI		report-uri-value = absolute-URI
	Figure 2: Syntax of the report-uri directive value		Figure 2: Syntax of the report-uri directive value
	"absolute-URI" is defined in Section 4.3 of [RFC3986].		"absolute-URI" is defined in Section 4.3 of [RFC3986].
	Hosts may set "report-uri"s that use HTTP or HTTPS. If the scheme in		Hosts may set "report-uri"s that use HTTP or HTTPS. If the scheme in
	the "report-uri" is one that uses TLS (e.g., HTTPS), UAs MUST check		the "report-uri" is one that uses TLS (e.g., HTTPS), UAs MUST check
	Expect-CT compliance when the host in the "report-uri" is a Known		Expect-CT compliance when the host in the "report-uri" is a Known
	Expect-CT Host; similarly, UAs MUST apply HSTS if the host in the		Expect-CT Host; similarly, UAs MUST apply HSTS [RFC6797] if the host
	"report-uri" is a Known HSTS Host.		in the "report-uri" is a Known HSTS Host.
	Note that the report-uri need not necessarily be in the same Internet		Note that the report-uri need not necessarily be in the same Internet
	domain or web origin as the host being reported about.		domain or web origin as the host being reported about.
	UAs SHOULD make their best effort to report Expect-CT failures to the		UAs SHOULD make their best effort to report Expect-CT failures to the
	"report-uri", but they may fail to report in exceptional conditions.		"report-uri", but they may fail to report in exceptional conditions.
	For example, if connecting to the "report-uri" itself incurs an		For example, if connecting to the "report-uri" itself incurs an
	Expect-CT failure or other certificate validation failure, the UA		Expect-CT failure or other certificate validation failure, the UA
	MUST cancel the connection. Similarly, if Expect-CT Host A sets a		MUST cancel the connection. Similarly, if Expect-CT Host A sets a
	"report-uri" referring to Expect-CT Host B, and if B sets a "report-		"report-uri" referring to Expect-CT Host B, and if B sets a "report-
	uri" referring to A, and if both hosts fail to comply to the UA's CT		uri" referring to A, and if both hosts fail to comply to the UA's CT
	Policy, the UA SHOULD detect and break the loop by failing to send		Policy, the UA SHOULD detect and break the loop by failing to send
	reports to and about those hosts.		reports to and about those hosts.
	UAs SHOULD limit the rate at which they send reports. For example,		UAs SHOULD limit the rate at which they send reports. For example,
	it is unnecessary to send the same report to the same "report-uri"		it is unnecessary to send the same report to the same "report-uri"
	more than once.		more than once in the same web browsing session.
	2.1.2. The enforce Directive		2.1.2. The enforce Directive
	The OPTIONAL "enforce" directive is a valueless directive that, if		The OPTIONAL "enforce" directive is a valueless directive that, if
	present (i.e., it is "asserted"), signals to the UA that compliance		present (i.e., it is "asserted"), signals to the UA that compliance
	to the CT Policy should be enforced (rather than report-only) and		to the CT Policy should be enforced (rather than report-only) and
	that the UA should refuse future connections that violate its CT		that the UA should refuse future connections that violate its CT
	Policy. When both the "enforce" directive and "report-uri" directive		Policy. When both the "enforce" directive and "report-uri" directive
	(as defined in Figure 2) are present, the configuration is referred		(as defined in Figure 2) are present, the configuration is referred
	to as an "enforce-and-report" configuration, signalling to the UA		to as an "enforce-and-report" configuration, signalling to the UA
	skipping to change at page 16, line 32 ¶		skipping to change at page 16, line 32 ¶
	6.1. Header Field Registry		6.1. Header Field Registry
	This document registers the "Expect-CT" header field in the		This document registers the "Expect-CT" header field in the
	"Permanent Message Header Field Names" registry located at		"Permanent Message Header Field Names" registry located at
	https://www.iana.org/assignments/message-headers [4].		https://www.iana.org/assignments/message-headers [4].
	Header field name: Expect-CT		Header field name: Expect-CT
	Applicable protocol: http		Applicable protocol: http
	Status: standard		Status: experimental
	Author/Change controller: IETF		Author/Change controller: IETF
	Specification document(s): This document		Specification document(s): This document
	Related information: (empty)		Related information: (empty)
	6.2. Media Types Registry		6.2. Media Types Registry
	The MIME media type for Expect-CT violation reports is "application/		The MIME media type for Expect-CT violation reports is "application/
	skipping to change at page 20, line 7 ¶		skipping to change at page 20, line 7 ¶
	[1] https://lists.w3.org/Archives/Public/ietf-http-wg/		[1] https://lists.w3.org/Archives/Public/ietf-http-wg/
	[2] http://httpwg.github.io/		[2] http://httpwg.github.io/
	[3] https://github.com/httpwg/http-extensions/labels/expect-ct		[3] https://github.com/httpwg/http-extensions/labels/expect-ct
	[4] https://www.iana.org/assignments/message-headers		[4] https://www.iana.org/assignments/message-headers
	Appendix A. Changes		Appendix A. Changes
	A.1. Since -06		A.1. Since -07
	o Editorial changes		o Editorial changes
	A.2. Since -05		A.2. Since -06
			o Editorial changes
			A.3. Since -05
	o Remove SHOULD requirement that UAs disallow certificate error		o Remove SHOULD requirement that UAs disallow certificate error
	overrides for Known Expect-CT Hosts.		overrides for Known Expect-CT Hosts.
	o Remove restriction that Expect-CT Hosts cannot be IP addresses.		o Remove restriction that Expect-CT Hosts cannot be IP addresses.
	o Editorial changes		o Editorial changes
	A.3. Since -04		A.4. Since -04
	o Editorial changes		o Editorial changes
	A.4. Since -03		A.5. Since -03
	o Editorial changes		o Editorial changes
	A.5. Since -02		A.6. Since -02
	o Add concept of test reports and specify that servers must respond		o Add concept of test reports and specify that servers must respond
	with 2xx status codes to valid reports.		with 2xx status codes to valid reports.
	o Add "failure-mode" key to reports to allow report servers to		o Add "failure-mode" key to reports to allow report servers to
	distinguish report-only from enforced failures.		distinguish report-only from enforced failures.
	A.6. Since -01		A.7. Since -01
	o Change SCT reporting format to support both RFC 6962 and 6962-bis		o Change SCT reporting format to support both RFC 6962 and 6962-bis
	SCTs.		SCTs.
	A.7. Since -00		A.8. Since -00
	o Editorial changes		o Editorial changes
	o Change Content-Type header of reports to 'application/expect-ct-		o Change Content-Type header of reports to 'application/expect-ct-
	report+json'		report+json'
	o Update header field syntax to match convention (issue #327)		o Update header field syntax to match convention (issue #327)
	o Reference RFC 6962-bis instead of RFC 6962		o Reference RFC 6962-bis instead of RFC 6962
	Author's Address		Author's Address
	Emily Stark		Emily Stark
	Google		Google
	Email: estark@google.com		Email: estark@google.com
End of changes. 18 change blocks.
	29 lines changed or deleted		29 lines changed or added
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