draft-ietf-uta-smtp-tlsrpt-01.txt		draft-ietf-uta-smtp-tlsrpt-02.txt
	Using TLS in Applications D. Margolis		Using TLS in Applications D. Margolis
	Internet-Draft Google, Inc		Internet-Draft Google, Inc
	Intended status: Standards Track A. Brotman		Intended status: Standards Track A. Brotman
	Expires: January 9, 2017 Comcast, Inc		Expires: June 18, 2017 Comcast, Inc
	B. Ramakrishnan		B. Ramakrishnan
	Yahoo!, Inc		Yahoo!, Inc
	J. Jones		J. Jones
	Microsoft, Inc		Microsoft, Inc
	M. Risher		M. Risher
	Google, Inc		Google, Inc
	July 8, 2016		December 15, 2016
	SMTP TLS Reporting		SMTP TLS Reporting
	draft-ietf-uta-smtp-tlsrpt-01		draft-ietf-uta-smtp-tlsrpt-02
	Abstract		Abstract
	A number of protocols exist for establishing encrypted channels		A number of protocols exist for establishing encrypted channels
	between SMTP Mail Transfer Agents, including STARTTLS [RFC3207], DANE		between SMTP Mail Transfer Agents, including STARTTLS [RFC3207], DANE
	[RFC6698], and SMTP MTA STS (TODO: Add ref). These protocols can		[RFC6698], and SMTP MTA STS (TODO: Add ref). These protocols can
	fail due to misconfiguration or active attack, leading to undelivered		fail due to misconfiguration or active attack, leading to undelivered
	messages or delivery over unencrypted or unauthenticated channels.		messages or delivery over unencrypted or unauthenticated channels.
	This document describes a reporting mechanism and format by which		This document describes a reporting mechanism and format by which
	sending systems can share statistics and specific information about		sending systems can share statistics and specific information about
	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 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 January 9, 2017.		This Internet-Draft will expire on June 18, 2017.
	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Related Technologies . . . . . . . . . . . . . . . . . . . . 3		2. Related Technologies . . . . . . . . . . . . . . . . . . . . 4
	3. Reporting Policy . . . . . . . . . . . . . . . . . . . . . . 4		3. Reporting Policy . . . . . . . . . . . . . . . . . . . . . . 4
	3.1. Example Reporting Policy . . . . . . . . . . . . . . . . 5		3.1. Example Reporting Policy . . . . . . . . . . . . . . . . 5
	3.1.1. Report using MAILTO . . . . . . . . . . . . . . . . . 5		3.1.1. Report using MAILTO . . . . . . . . . . . . . . . . . 5
	3.1.2. Report using HTTPS . . . . . . . . . . . . . . . . . 5		3.1.2. Report using HTTPS . . . . . . . . . . . . . . . . . 5
	4. Reporting Schema . . . . . . . . . . . . . . . . . . . . . . 5		4. Reporting Schema . . . . . . . . . . . . . . . . . . . . . . 6
	4.1. Result Types . . . . . . . . . . . . . . . . . . . . . . 6		4.1. Report Time-frame . . . . . . . . . . . . . . . . . . . . 6
	4.1.1. Success Type . . . . . . . . . . . . . . . . . . . . 6		4.2. Delivery Summary . . . . . . . . . . . . . . . . . . . . 7
	4.1.2. Routing Failures . . . . . . . . . . . . . . . . . . 6		4.2.1. Success Count . . . . . . . . . . . . . . . . . . . . 7
	4.1.3. Negotiation Failures . . . . . . . . . . . . . . . . 6		4.2.2. Failure Count . . . . . . . . . . . . . . . . . . . . 7
	4.1.4. Policy Failures . . . . . . . . . . . . . . . . . . . 7		4.3. Result Types . . . . . . . . . . . . . . . . . . . . . . 7
	5. Report Delivery . . . . . . . . . . . . . . . . . . . . . . . 7		4.3.1. Routing Failures . . . . . . . . . . . . . . . . . . 7
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7		4.3.2. Negotiation Failures . . . . . . . . . . . . . . . . 7
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 7		4.3.3. Policy Failures . . . . . . . . . . . . . . . . . . . 8
	8. Appendix 1: JSON Report Schema . . . . . . . . . . . . . . . 8		4.3.4. General Failures . . . . . . . . . . . . . . . . . . 8
	9. Appendix 2: Example JSON Report . . . . . . . . . . . . . . . 10		4.3.5. Transient Failures . . . . . . . . . . . . . . . . . 8
	10. Normative References . . . . . . . . . . . . . . . . . . . . 10		5. Report Delivery . . . . . . . . . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11		5.1. Report Filename . . . . . . . . . . . . . . . . . . . . . 9
			5.2. Compression . . . . . . . . . . . . . . . . . . . . . . . 9
			5.3. Email Transport . . . . . . . . . . . . . . . . . . . . . 10
			5.4. HTTPS Transport . . . . . . . . . . . . . . . . . . . . . 10
			5.5. Delivery Retry . . . . . . . . . . . . . . . . . . . . . 11
			6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
			7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
			8. Appendix 1: Example Reporting Policy . . . . . . . . . . . . 12
			8.1. Report using MAILTO . . . . . . . . . . . . . . . . . . . 12
			8.2. Report using HTTPS . . . . . . . . . . . . . . . . . . . 12
			9. Appendix 2: JSON Report Schema . . . . . . . . . . . . . . . 12
			10. Appendix 3: Example JSON Report . . . . . . . . . . . . . . . 15
			11. Normative References . . . . . . . . . . . . . . . . . . . . 16
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	1. Introduction		1. Introduction
	The STARTTLS extension to SMTP [RFC3207] allows SMTP clients and		The STARTTLS extension to SMTP [RFC3207] allows SMTP clients and
	hosts to establish secure SMTP sessions over TLS. The protocol		hosts to establish secure SMTP sessions over TLS. The protocol
	design is based on "Opportunistic Security" (OS) [RFC7435], which		design is based on "Opportunistic Security" (OS) [RFC7435], which
	provides interoperability for clients that do not support STARTTLS		provides interoperability for clients that do not support STARTTLS
	but means that any attacker who can delete parts of the SMTP session		but means that any attacker who can delete parts of the SMTP session
	(such as the "250 STARTTLS" response) or redirect the entire SMTP		(such as the "250 STARTTLS" response) or redirect the entire SMTP
	session (perhaps by overwriting the resolved MX record of the		session (perhaps by overwriting the resolved MX record of the
	skipping to change at page 3, line 18 ¶		skipping to change at page 3, line 31 ¶
	conversation.		conversation.
	Recipient domains may also use the mechanisms defined by MTA-STS		Recipient domains may also use the mechanisms defined by MTA-STS
	(TODO: Add ref) or DANE [RFC6698] to publish additional encryption		(TODO: Add ref) or DANE [RFC6698] to publish additional encryption
	and authentication requirements; this document defines a mechanism		and authentication requirements; this document defines a mechanism
	for sending domains that are compatible with MTA-STS or DANE to share		for sending domains that are compatible with MTA-STS or DANE to share
	success and failure statistics with recipient domains.		success and failure statistics with recipient domains.
	Specifically, this document defines a reporting schema that covers		Specifically, this document defines a reporting schema that covers
	failures in routing, STARTTLS negotiation, and both DANE [RFC6698]		failures in routing, STARTTLS negotiation, and both DANE [RFC6698]
	and MTA-STS (TODO: Add ref) policy validation errors, and standard		and MTA-STS (TODO: Add ref) policy validation errors, and a standard
	TXT record that recipient domains can use to indicate where reports		TXT record that recipient domains can use to indicate where reports
	in this format should be sent.		in this format should be sent.
	This document is intended as a companion to the specification for		This document is intended as a companion to the specification for
	SMTP MTA Strict Transport Security (MTA-STS, TODO: Add ref).		SMTP MTA Strict Transport Security (MTA-STS, TODO: Add ref).
	1.1. Terminology		1.1. Terminology
	The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,		The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
	SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this		SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
	document, are to be interpreted as described in [RFC2119].		document, are to be interpreted as described in [RFC2119].
	We also define the following terms for further use in this document:		We also define the following terms for further use in this document:
	o STS Policy: A definition of the expected TLS availability and		o STS Policy: A definition of the expected TLS availability,
	behavior, as well as the desired actions for a given domain when a		behavior, and desired actions for a given domain when a sending
	sending MTA encounters different results.		MTA encounters problems in negotiating a secure channel. STS is
			defined in [TODO]
	o TLSRPT Policy: A policy detailing the endpoint to which sending		o DANE Policy: A mechanism for enabling the administrators of domain
			names to specify the keys used in that domain's TLS servers. DANE
			is defined in [RFC6698]
			o TLSRPT Policy: A policy specifying the endpoint to which sending
	MTAs should deliver reports.		MTAs should deliver reports.
	o Policy Domain: The domain against which an STS Policy is defined.		o Policy Domain: The domain against which an STS or DANE Policy is
			defined.
	o Sending MTA: The MTA initiating the delivery of an email message.		o Sending MTA: The MTA initiating the delivery of an email message.
	2. Related Technologies		2. Related Technologies
	o This document is intended as a companion to the specification for		o This document is intended as a companion to the specification for
	SMTP MTA Strict Transport Security (MTA-STS, TODO: Add ref).		SMTP MTA Strict Transport Security (MTA-STS, TODO: Add ref).
	o The Public Key Pinning Extension for HTTP [RFC7469] contains a		o The Public Key Pinning Extension for HTTP [RFC7469] contains a
	JSON-based definition for reporting individual pin validation		JSON-based definition for reporting individual pin validation
	failures.		failures.
	o The Domain-based Message Authentication, Reporting, and		o The Domain-based Message Authentication, Reporting, and
	Conformance (DMARC) [RFC7489] contains an XML-based reporting		Conformance (DMARC) [RFC7489] contains an XML-based reporting
	format for aggregate and detailed email delivery errors.		format for aggregate and detailed email delivery errors.
	3. Reporting Policy		3. Reporting Policy
	SMTP TLSRPT policies are distributed via DNS from the Policy Domain's		A domain publishes a record to its DNS indicating that it wishes to
	zone, as TXT records (similar to DMARC policies) under the name		receive reports. These SMTP TLSRPT policies are distributed via DNS
	"_smtp_tlsrpt". For example, for the Policy Domain "example.com",		from the Policy Domain's zone, as TXT records (similar to DMARC
	the recipient's SMTP STS policy can be retrieved from		policies) under the name "_smtp-tlsrpt". For example, for the Policy
	"_smtp_tlsrpt.example.com".		Domain "example.com", the recipient's TLSRPT policy can be retrieved
			from "_smtp-tlsrpt.example.com".
	(Future implementations may move to alternate methods of policy
	discovery or distribution. See the section _Future_ _Work_ for more
	discussion.)
	Policies consist of the following directives:		Policies consist of the following directives:
	o "v": This value MUST be equal to "TLSRPTv1".		o "v": This value MUST be equal to "TLSRPTv1".
	o "rua": A URI specifying the endpoint to which aggregate		o "rua": A URI specifying the endpoint to which aggregate
	information about policy failures should be sent (see the section		information about policy failures should be sent (see the section
	_Reporting_ _Schema_ for more information). Two URI schemes are		_Reporting_ _Schema_ for more information). Two URI schemes are
	supported: "mailto" and "https".		supported: "mailto" and "https".
	* In the case of `https`, reports should be submitted via POST		* In the case of "https", reports should be submitted via POST
	([@!RFC2818]) to the specified URI.		([RFC2818]) to the specified URI.
	* In the case of `mailto`, reports should be submitted to the specified
	email address. When sending failure reports via SMTP, sending MTAs		* In the case of "mailto", reports should be submitted to the
	MUST NOT honor SMTP STS or DANE TLSA failures.		specified email address. When sending failure reports via
			SMTP, sending MTAs MUST NOT honor SMTP STS or DANE TLSA
			failures.
	o "ruf": Future use. (There may also be a need for enabling more		o "ruf": Future use. (There may also be a need for enabling more
	detailed "forensic" reporting during initial stages of a		detailed "forensic" reporting during initial stages of a
	deployment. To address this, the authors consider the possibility		deployment. To address this, the authors consider the possibility
	of an optional additional "forensic reporting mode" in which more		of an optional additional "forensic reporting mode" in which more
	details--such as certificate chains and MTA banners--may be		details--such as certificate chains and MTA banners--may be
	reported. See the section _Future_ _Work_ for more details.)		reported.)
	The formal definition of the "_mta_sts" TXT record, defined using		The formal definition of the "_smtp-tlsrpt" TXT record, defined using
	[RFC5234], is as follows:		[RFC5234], is as follows:
	sts-text-record = sts-version *WSP %x3B *WSP sts-id		tlsrpt-record = tlsrpt-version *WSP %x3B tlsrpt-rua
	sts-version = "v" *WSP "=" *WSP %x54 %x4C %x53		tlsrpt-version = "v" *WSP "=" *WSP %x54 %x4C %x53
	%x52 %x50 %x54 %x76 %x31		%x52 %x50 %x54 %x76 %x31
	sts-id = "id" *WSP "=" *WSP 1*32(ALPHA / DIGIT)		tlsrpt-rua = "rua" *WSP "=" *WSP tlsrpt-uri
			tlsrpt-uri = URI
			; "URI" is imported from [@!RFC3986]; commas (ASCII
			; 0x2C) and exclamation points (ASCII 0x21)
			; MUST be encoded; the numeric portion MUST fit
			; within an unsigned 64-bit integer
			If multiple TXT records for "_smtp-tlsrpt" are returned by the
			resolver, records which do not begin with "v=TLSRPTv1;" are
			discarded. If the number of resulting records is not one, senders
			MUST assume the recipient domain does not implement TLSRPT.
	3.1. Example Reporting Policy		3.1. Example Reporting Policy
	3.1.1. Report using MAILTO		3.1.1. Report using MAILTO
	_smtp_tlsrpt.mail.example.com. IN TXT \		_smtp-tlsrpt.example.com. IN TXT \
	"v=TLSRPTv1;rua=mailto:reports@example.com"		"v=TLSRPTv1;rua=mailto:reports@example.com"
	3.1.2. Report using HTTPS		3.1.2. Report using HTTPS
	_smtp_tlsrpt.mail.example.com. IN TXT \		_smtp-tlsrpt.example.com. IN TXT \
	"v=TLSRPTv1; \		"v=TLSRPTv1; \
	rua=https://reporting.example.com/v1/tlsrpt"		rua=https://reporting.example.com/v1/tlsrpt"
	4. Reporting Schema		4. Reporting Schema
			The report is composed as a plain text file encoded in the JSON
			format ([RFC7159]).
	Aggregate reports contain the following fields:		Aggregate reports contain the following fields:
	o Report metadata:		o Report metadata:
	* The organization responsible for the report		* The organization responsible for the report
	+ Contact information for one or more responsible parties for		* Contact information for one or more responsible parties for the
	the contents of the report		contents of the report
	* A unique identifier for the report		* A unique identifier for the report
	* The reporting date range for the report		* The reporting date range for the report
	o Policy, consisting of:		o Policy, consisting of:
	* One of the following policy types:		* One of the following policy types: (1) The SMTP MTA STS policy
			applied (as a string) (2) The DANE TLSA record applied (as a
	+ The SMTP MTA STS policy applied (as a string)		string) (3) The literal string "no-policy-found", if neither a
			TLSA nor MTA-STS policy could be found.
	+ The DANE TLSA record applied (as a string) * The literal
	string "no-policy-found", if neither a TLSA nor
	MTA-STS policy could be found.
	* The domain for which the policy is applied		* The domain for which the policy is applied
	* The MX host		* The MX host
	* An identifier for the policy (where applicable)		* An identifier for the policy (where applicable)
	o Aggregate counts, comprising result type, sending MTA IP,		o Aggregate counts, comprising result type, sending MTA IP,
	receiving MTA hostname, message count, and an optional additional		receiving MTA hostname, session count, and an optional additional
	information field containing a URI for recipients to review		information field containing a URI for recipients to review
	further information on a failure type.		further information on a failure type.
	Note that the failure types are non-exclusive; an aggregate report		Note that the failure types are non-exclusive; an aggregate report
	MAY contain overlapping "counts" of failure types where a single send		may contain overlapping "counts" of failure types when a single send
	attempt encountered multiple errors.		attempt encountered multiple errors.
	4.1. Result Types		4.1. Report Time-frame
	The list of result types will start with the minimal set below, and		The report SHOULD cover a full day, from 0000-2400 UTC. This should
	is expected to grow over time based on real-world experience. The		allow for easier correlation of failure events.
	initial set is:
	4.1.1. Success Type		4.2. Delivery Summary
	o "success": This indicates that the sending MTA was able to		4.2.1. Success Count
			o "success-count": This indicates that the sending MTA was able to
	successfully negotiate a policy-compliant TLS connection, and		successfully negotiate a policy-compliant TLS connection, and
	serves to provide a "heartbeat" to receiving domains that		serves to provide a "heartbeat" to receiving domains that
	reporting is functional and tabulating correctly.		reporting is functional and tabulating correctly. This field
			contains an aggregate count of successful connections for the
			reporting system.
	4.1.2. Routing Failures		4.2.2. Failure Count
			o "failure-count": This indicates that the sending MTA was unable to
			successfully establish a connection with the receiving platform.
			The "Result Types" section will elaborate on the failed
			negotiation attempts. This field contains an aggregate count of
			failed connections.
			4.3. Result Types
			The list of result types will start with the minimal set below, and
			is expected to grow over time based on real-world experience. The
			initial set is:
			4.3.1. Routing Failures
	o "mx-mismatch": This indicates that the MX resolved for the		o "mx-mismatch": This indicates that the MX resolved for the
	recipient domain did not match the MX constraint specified in the		recipient domain did not match the MX constraint specified in the
	policy.		policy.
	o "certificate-host-mismatch": This indicates that the certificate		4.3.2. Negotiation Failures
	presented by the receiving MX did not match the MX hostname.
	4.1.3. Negotiation Failures
	o "starttls-not-supported": This indicates that the recipient MX did		o "starttls-not-supported": This indicates that the recipient MX did
	not support STARTTLS.		not support STARTTLS.
	o "invalid-certificate": This indicates that the certificate
	presented by the receiving MX did not validate.
	o "certificate-host-mismatch": This indicates that the certificate		o "certificate-host-mismatch": This indicates that the certificate
	presented did not adhere to the constraints specified in the STS		presented did not adhere to the constraints specified in the STS
	or DANE policy, e.g. if the CN field did not match the hostname		or DANE policy, e.g. if the CN field did not match the hostname
	of the MX.		of the MX.
	o "certificate-name-constraints-not-permitted": The certificate		o "certificate-expired": This indicates that the certificate has
	request contains a name that is not listed as permitted in the		expired.
	name constraints extension of the cert issuer.
	o "certificate-name-constraints-excluded": The certificate request		o "certificate-not-trusted": This a label that covers multiple
	contains a name that is listed as excluded in the name constraints		certificate related failures that include, but not limited to
	extension of the issuer.		errors such as untrusted/unknown CAs, certificate name contraints,
			certificate chain errors etc. When using this declaration, the
			reporting MTA SHOULD utilize the "failure-reason" to provide more
			information to the receiving entity.
	o "expired-certificate": This indicates that the certificate has		o "validation-failure": This indicates a general failure for a
	expired.		reason not matching a category above. When using this
			declaration, the reporting MTA SHOULD utilize the "failure-reason"
			to provide more information to the receiving entity.
	4.1.4. Policy Failures		4.3.3. Policy Failures
	4.1.4.1. DANE-specific Policy Failures		4.3.3.1. DANE-specific Policy Failures
	o "tlsa-invalid": This indicates a validation error in the TLSA		o "tlsa-invalid": This indicates a validation error in the TLSA
	record associated with a DANE policy.		record associated with a DANE policy.
	o "dnssec-invalid": This indicates a failure to authenticate DNS		o "dnssec-invalid": This indicates a failure to authenticate DNS
	records for a Policy Domain with a published TLSA record.		records for a Policy Domain with a published TLSA record.
	4.1.4.2. STS-specific Policy Failures		4.3.3.2. STS-specific Policy Failures
	o "sts-invalid": This indicates a validation error for the overall		o "sts-invalid": This indicates a validation error for the overall
	MTA-STS policy.		MTA-STS policy.
	o "webpki-invalid": This indicates that the MTA-STS policy could not		o "webpki-invalid": This indicates that the MTA-STS policy could not
	be authenticated using PKIX validation.		be authenticated using PKIX validation.
			4.3.4. General Failures
			When a negotiation failure can not be categorized into one of the
			"Negotiation Failures" stated above, the reporter SHOULD use the
			"validation-failure" category. As TLS grows and becomes more
			complex, new mechanisms may not be easily categorized. This allows
			for a generic feedback category. When this category is used, the
			reporter SHOULD also use the "failure-reason-code" to give some
			feedback to the receiving entity. This is intended to be a short
			text field, and the contents of the field should be an error code or
			error text, such as "X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION".
			4.3.5. Transient Failures
			Transient errors due to too-busy network, TCP timeouts, etc. are not
			required to be reported.
	5. Report Delivery		5. Report Delivery
			Reports can be delivered either as an email message via SMTP or via
			HTTP POST.
			5.1. Report Filename
			The filename is typically constructed using the following ABNF:
			filename = sender "!" policy-domain "!" begin-timestamp
			"!" end-timestamp [ "!" unique-id ] "." extension
			unique-id = 1*(ALPHA / DIGIT)
			sender = domain ; imported from [@!RFC5322]
			policy-domain = domain
			begin-timestamp = 1*DIGIT
			; seconds since 00:00:00 UTC January 1, 1970
			; indicating start of the time range contained
			; in the report
			end-timestamp = 1*DIGIT
			; seconds since 00:00:00 UTC January 1, 1970
			; indicating end of the time range contained
			; in the report
			extension = "json" / "json.gz"
			The extension MUST be "json" for a plain JSON file, or "json.gz" for
			a JSON file compressed using GZIP.
			"unique-id" allows an optional unique ID generated by the Sending MTA
			to distinguish among multiple reports generated simultaneously by
			different sources within the same Policy Domain. For example, this
			is a possible filename for the gzip file of a report to the Policy
			Domain "example.net" from the Sending MTA "mail.sender.example.com":
			`mail.sender.example.com!example.net!1470013207!1470186007!001.json.gz`
			5.2. Compression
			The report SHOULD be subjected to GZIP compression for both email and
			HTTPS transport. Declining to apply compression can cause the report
			to be too large for a receiver to process (a commonly observed
			receiver limit is ten megabytes); compressing the file increases the
			chances of acceptance of the report at some compute cost.
			5.3. Email Transport
			The report MAY be delivered by email. No specific MIME message
			structure is required. It is presumed that the aggregate reporting
			address will be equipped to extract MIME parts with the prescribed
			media type and filename and ignore the rest.
			If compressed, the report should use the media type "application/
			gzip" if compressed (see [RFC6713]), and "text/json" otherwise.
			The [RFC5322].Subject field for individual report submissions SHOULD
			conform to the following ABNF:
			tlsrpt-subject = %x52.65.70.6f.72.74 1*FWS ; "Report"
			%x44.6f.6d.61.69.6e.3a 1*FWS ; "Domain:"
			domain-name 1*FWS ; from RFC 6376
			%x53.75.62.6d.69.74.74.65.72.3a ; "Submitter:"
			1*FWS domain-name 1*FWS
			%x52.65.70.6f.72.74.2d.49.44.3a ; "Report-ID:"
			msg-id ; from RFC 5322
			The first domain-name indicates the DNS domain name about which the
			report was generated. The second domain-name indicates the DNS
			domain name representing the Sending MTA generating the report. The
			purpose of the Report-ID: portion of the field is to enable the
			Policy Domain to identify and ignore duplicate reports that might be
			sent by a Sending MTA.
			For instance, this is a possible Subject field for a report to the
			Policy Domain "example.net" from the Sending MTA
			"mail.sender.example.com". It is line-wrapped as allowed by
			[RFC5322]:
			Subject: Report Domain: example.net
			Submitter: mail.sender.example.com
			Report-ID: <735ff.e317+bf22029@mailexample.net>
	Note that, when sending failure reports via SMTP, sending MTAs MUST		Note that, when sending failure reports via SMTP, sending MTAs MUST
	NOT honor SMTP STS or DANE TLSA failures.		NOT honor SMTP STS or DANE TLSA failures.
			5.4. HTTPS Transport
			The report MAY be delivered by POST to HTTPS. If compressed, the
			report should use the media type "application/gzip" (see [RFC6713]),
			and "text/json" otherwise.
			5.5. Delivery Retry
			In the event of a delivery failure, regardless of the delivery
			method, a sender SHOULD attempt redelivery for up to 24hrs after the
			initial attempt. As previously stated the reports are optional, so
			while it is ideal to attempt redelivery, it is not required. If
			multiple retries are attempted, they should be on a logarithmic
			scale.
	6. IANA Considerations		6. IANA Considerations
	There are no IANA considerations at this time.		There are no IANA considerations at this time.
	7. Security Considerations		7. Security Considerations
	SMTP TLS Reporting provides transparency into misconfigurations or		SMTP TLS Reporting provides transparency into misconfigurations or
	attempts to intercept or tamper with mail between hosts who support		attempts to intercept or tamper with mail between hosts who support
	STARTTLS. There are several security risks presented by the		STARTTLS. There are several security risks presented by the
	existence of this reporting channel:		existence of this reporting channel:
	skipping to change at page 8, line 14 ¶		skipping to change at page 11, line 40 ¶
	o Untrusted content: An attacker could inject malicious code into		o Untrusted content: An attacker could inject malicious code into
	the report, opening a vulnerability in the receiving domain.		the report, opening a vulnerability in the receiving domain.
	Implementers are advised to take precautions against evaluating		Implementers are advised to take precautions against evaluating
	the contents of the report.		the contents of the report.
	o Report snooping: An attacker could create a bogus TLSRPT record to		o Report snooping: An attacker could create a bogus TLSRPT record to
	receive statistics about a domain the attacker does not own.		receive statistics about a domain the attacker does not own.
	Since an attacker able to poison DNS is already able to receive		Since an attacker able to poison DNS is already able to receive
	counts of SMTP connections (and, absent DANE or MTA-STS policies,		counts of SMTP connections (and, absent DANE or MTA-STS policies,
	actual SMTP message payloads) today, this does not present a		actual SMTP message payloads), this does not present a significant
	significant new vulnerability.		new vulnerability.
	8. Appendix 1: JSON Report Schema		o Reports as DDoS: TLSRPT allows specifying destinations for the
			reports that are outside the authority of the Policy Domain, which
			allows domains to delegate processing of reports to a partner
			organization. However, an attacker who controls the Policy Domain
			DNS could also use this mechanism to direct the reports to an
			unwitting victim, flooding that victim with excessive reports.
			DMARC [RFC7489] defines an elegant solution for verifying
			delegation; however, since the attacker had less ability to
			generate large reports than with DMARC failures, and since the
			reports are generated by the sending MTA, such a delegation
			mechanism is left for a future version of this specification.
			8. Appendix 1: Example Reporting Policy
			8.1. Report using MAILTO
			_smtp-tlsrpt.mail.example.com. IN TXT \
			"v=TLSRPTv1;rua=mailto:reports@example.com"
			8.2. Report using HTTPS
			_smtp-tlsrpt.mail.example.com. IN TXT \
			"v=TLSRPTv1; \
			rua=https://reporting.example.com/v1/tlsrpt"
			9. Appendix 2: JSON Report Schema
	The JSON schema is derived from the HPKP JSON schema [RFC7469] (cf.		The JSON schema is derived from the HPKP JSON schema [RFC7469] (cf.
	Section 3)		Section 3)
			{
	{		"organization-name": organization-name,
	"organization-name": organization-name,		"date-range": {
	"date-range": {		"start-datetime": date-time,
	"start-datetime": date-time,		"end-datetime": date-time
	"end-datetime": date-time		},
	},		"contact-info": email-address,
	"contact-info": email-address,		"report-id": report-id,
	"report-id": report-id,		"policy": {
	"policy": {		"policy-type": policy-type,
	"policy-type": policy-type,		"policy-string": policy-string,
	"policy-string": policy-string,		"policy-domain": domain,
	"policy-domain": domain,		"mx-host": mx-host-pattern
	"mx-host": mx-host-pattern		},
	},		"summary": {
	"report-items": [		"success-aggregate": total-successful-session-count,
	{		"failure-aggregate:" total-failure-session-count
	"result-type": result-type,
	"sending-mta-ip": ip-address,
	"receiving-mx-hostname": receiving-mx-hostname,
	"message-count": message-count,
	"additional-information": additional-info-uri
	}
	]
	}		}
			"failure-details": [
			{
			"result-type": result-type,
			"sending-mta-ip": ip-address,
			"receiving-mx-hostname": receiving-mx-hostname,
			"receiving-mx-helo": receiving-mx-helo,
			"session-count": failed-session-count,
			"additional-information": additional-info-uri,
			"failure-reason-code": "Text body"
			}
			]
			}
	JSON Report Format		Figure: JSON Report Format
	o "organization-name": The name of the organization responsible for		o "organization-name": The name of the organization responsible for
	the report. It is provided as a string.		the report. It is provided as a string.
	o "date-time": The date-time indicates the start- and end-times for		o "date-time": The date-time indicates the start- and end-times for
	the report range. It is provided as a string formatted according		the report range. It is provided as a string formatted according
	to Section 5.6, "Internet Date/Time Format", of [RFC3339].		to Section 5.6, "Internet Date/Time Format", of [RFC3339]. The
			report should be for a full UTC day, 0000-2400.
	o "email-address": The contact information for a responsible party		o "email-address": The contact information for a responsible party
	of the report. It is provided as a string formatted according to		of the report. It is provided as a string formatted according to
	Section 3.4.1, "Addr-Spec", of [RFC5322].		Section 3.4.1, "Addr-Spec", of [RFC5322].
	o "report-id": A unique identifier for the report. Report authors		o "report-id": A unique identifier for the report. Report authors
	may use whatever scheme they prefer to generate a unique		may use whatever scheme they prefer to generate a unique
	identifier. It is provided as a string.		identifier. It is provided as a string.
	o "policy-type": The type of policy that was applied by the sending		o "policy-type": The type of policy that was applied by the sending
	domain. Presently, the only two valid choices are "tlsa" and		domain. Presently, the only three valid choices are "tlsa",
	"sts". It is provided as a string.		"sts", and the literal string "no-policy-found". It is provided
			as a string.
	o "policy-string": The string serialization of the policy, whether		o "policy-string": The string serialization of the policy, whether
	TLSA record or STS policy. Any linefeeds from the original policy		TLSA record or STS policy. Any linefeeds from the original policy
	MUST be replaced with [SP]. TODO: Help with specifics.		MUST be replaced with [SP]. TODO: Help with specifics.
	o "domain": The Policy Domain upon which the policy was applied.		o "domain": The Policy Domain upon which the policy was applied.
	For messages sent to "user@example.com" this field would contain		For messages sent to "user@example.com" this field would contain
	"example.com". It is provided as a string.		"example.com". It is provided as a string.
	o "mx-host-pattern": The pattern of MX hostnames from the applied		o "mx-host-pattern": The pattern of MX hostnames from the applied
	skipping to change at page 9, line 45 ¶		skipping to change at page 14, line 34 ¶
	o "ip-address": The IP address of the sending MTA that attempted the		o "ip-address": The IP address of the sending MTA that attempted the
	STARTTLS connection. It is provided as a string representation of		STARTTLS connection. It is provided as a string representation of
	an IPv4 or IPv6 address in dot-decimal or colon-hexadecimal		an IPv4 or IPv6 address in dot-decimal or colon-hexadecimal
	notation.		notation.
	o "receiving-mx-hostname": The hostname of the receiving MTA MX		o "receiving-mx-hostname": The hostname of the receiving MTA MX
	record with which the sending MTA attempted to negotiate a		record with which the sending MTA attempted to negotiate a
	STARTTLS connection.		STARTTLS connection.
	o "message-count": The number of (attempted) messages that match the		o "receiving-mx-helo": (optional) The HELO or EHLO string from the
			banner announced during the reported session.
			o "success-aggregate": The aggregate number (integer) of
			successfully negotiated SSL-enabled connections to the receiving
			site.
			o "failure-aggregate": The aggregate number (integer) of failures to
			negotiate an SSL-enabled connection to the receiving site.
			o "session-count": The number of (attempted) sessions that match the
	relevant "result-type" for this section.		relevant "result-type" for this section.
	o "additional-info-uri": An optional URI pointing to additional		o "additional-info-uri": An optional URI pointing to additional
	information around the relevant "result-type". For example, this		information around the relevant "result-type". For example, this
	URI might host the complete certificate chain presented during an		URI might host the complete certificate chain presented during an
	attempted STARTTLS session.		attempted STARTTLS session.
	9. Appendix 2: Example JSON Report		o "failure-reason-code": A text field to include an SSL-related
			error code or error message.
			10. Appendix 3: Example JSON Report
	{		{
	"organization-name": "Company-X",		"organization-name": "Company-X",
	"date-range": {		"date-range": {
	"start-datetime": "2016-04-01T00:00:00Z",		"start-datetime": "2016-04-01T00:00:00Z",
	"end-datetime": "2016-04-01T23:59:59Z"		"end-datetime": "2016-04-01T23:59:59Z"
	},		},
	"contact-info": "sts-reporting@company-x.com",		"contact-info": "sts-reporting@company-x.com",
	"report-id": "5065427c-23d3-47ca-b6e0-946ea0e8c4be",		"report-id": "5065427c-23d3-47ca-b6e0-946ea0e8c4be",
	"policy": {		"policy": {
	"policy-type": "sts",		"policy-type": "sts",
	"policy-string": "TODO: Add me",		"policy-string": "{ \"version\": \"STSv1\",\"mode\": \"report\", \"mx\": [\"*.mail.company-y.com\"], \"max_age\": 86400 }",
	"policy-domain": "company-y.com",		"policy-domain": "company-y.com",
	"mx-host": "*.mail.company-y.com"		"mx-host": "*.mail.company-y.com"
	},		},
	"report-items": [{		"summary": {
	"result-type": "ExpiredCertificate",		"success-aggregate": 5326,
	"sending-mta-ip": "98.136.216.25",		"failure-aggregate": 303
	"receiving-mx-hostname": "mx1.mail.company-y.com",		}
	"message-count": 100		"failure-details": [{
	}, {		"result-type": "certificate-expired",
	"result-type": "StarttlsNotSupported",		"sending-mta-ip": "98.136.216.25",
	"sending-mta-ip": "98.22.33.99",		"receiving-mx-hostname": "mx1.mail.company-y.com",
	"receiving-mx-hostname": "mx2.mail.company-y.com",		"session-count": 100
	"message-count": 200,		}, {
	"additional-information": "hxxps://reports.company-x.com/		"result-type": "starttls-not-supported",
	report_info?id=5065427c-23d3#StarttlsNotSupported"		"sending-mta-ip": "98.22.33.99",
	}]		"receiving-mx-hostname": "mx2.mail.company-y.com",
			"session-count": 200,
			"additional-information": "hxxps://reports.company-x.com/
			report_info?id=5065427c-23d3#StarttlsNotSupported"
			}, {
			"result-type: "validation-failure",
			"sending-mta-ip": "47.97.15.2",
			"receiving-mx-hostname: "mx-backup.mail.company-y.com",
			"session-count": 3,
			"failure-error-code": "X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED"
			}]
	}		}
	Example JSON report for a messages from Company-X to Company-Y, where		Figure: Example JSON report for a messages from Company-X to
	100 messages were attempted to Company Y servers with an expired		Company-Y, where 100 sessions were attempted to Company Y servers
	certificate and 200 messages were attempted to Company Y servers that		with an expired certificate and 200 sessions were attempted to
	did not successfully respond to the STARTTLS command.		Company Y servers that did not successfully respond to the "STARTTLS"
			command. Additionally 3 sessions failed due to
			"X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED".
	10. Normative References		11. Normative References
	[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,		Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
	DOI 10.17487/RFC2119, March 1997,		RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
			[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, DOI 10.17487/
			RFC2818, May 2000,
			<http://www.rfc-editor.org/info/rfc2818>.
	[RFC3207] Hoffman, P., "SMTP Service Extension for Secure SMTP over		[RFC3207] Hoffman, P., "SMTP Service Extension for Secure SMTP over
	Transport Layer Security", RFC 3207, DOI 10.17487/RFC3207,		Transport Layer Security", RFC 3207, DOI 10.17487/RFC3207,
	February 2002, <http://www.rfc-editor.org/info/rfc3207>.		February 2002, <http://www.rfc-editor.org/info/rfc3207>.
	[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:		[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
	Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,		Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
	<http://www.rfc-editor.org/info/rfc3339>.		<http://www.rfc-editor.org/info/rfc3339>.
	[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234,		Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/
	DOI 10.17487/RFC5234, January 2008,		RFC5234, January 2008,
	<http://www.rfc-editor.org/info/rfc5234>.		<http://www.rfc-editor.org/info/rfc5234>.
	[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,		[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, DOI
	DOI 10.17487/RFC5322, October 2008,		10.17487/RFC5322, October 2008,
	<http://www.rfc-editor.org/info/rfc5322>.		<http://www.rfc-editor.org/info/rfc5322>.
	[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and		[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
	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, DOI 10.17487/RFC6125, March		Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
	2011, <http://www.rfc-editor.org/info/rfc6125>.		2011, <http://www.rfc-editor.org/info/rfc6125>.
	[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication		[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
	of Named Entities (DANE) Transport Layer Security (TLS)		of Named Entities (DANE) Transport Layer Security (TLS)
	Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August		Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
	2012, <http://www.rfc-editor.org/info/rfc6698>.		2012, <http://www.rfc-editor.org/info/rfc6698>.
			[RFC6713] Levine, J., "The 'application/zlib' and 'application/gzip'
			Media Types", RFC 6713, DOI 10.17487/RFC6713, August 2012,
			<http://www.rfc-editor.org/info/rfc6713>.
			[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
			Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
			2014, <http://www.rfc-editor.org/info/rfc7159>.
	[RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection		[RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection
	Most of the Time", RFC 7435, DOI 10.17487/RFC7435,		Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
	December 2014, <http://www.rfc-editor.org/info/rfc7435>.		December 2014, <http://www.rfc-editor.org/info/rfc7435>.
	[RFC7469] Evans, C., Palmer, C., and R. Sleevi, "Public Key Pinning		[RFC7469] Evans, C., Palmer, C., and R. Sleevi, "Public Key Pinning
	Extension for HTTP", RFC 7469, DOI 10.17487/RFC7469, April		Extension for HTTP", RFC 7469, DOI 10.17487/RFC7469, April
	2015, <http://www.rfc-editor.org/info/rfc7469>.		2015, <http://www.rfc-editor.org/info/rfc7469>.
	[RFC7489] Kucherawy, M., Ed. and E. Zwicky, Ed., "Domain-based		[RFC7489] Kucherawy, M., Ed. and E. Zwicky, Ed., "Domain-based
	Message Authentication, Reporting, and Conformance		Message Authentication, Reporting, and Conformance
	skipping to change at page 12, line 4 ¶		skipping to change at page 17, line 28 ¶
	Message Authentication, Reporting, and Conformance		Message Authentication, Reporting, and Conformance
	(DMARC)", RFC 7489, DOI 10.17487/RFC7489, March 2015,		(DMARC)", RFC 7489, DOI 10.17487/RFC7489, March 2015,
	<http://www.rfc-editor.org/info/rfc7489>.		<http://www.rfc-editor.org/info/rfc7489>.
	Authors' Addresses		Authors' Addresses
	Daniel Margolis		Daniel Margolis
	Google, Inc		Google, Inc
	Email: dmargolis (at) google.com		Email: dmargolis (at) google.com
	Alexander Brotman		Alexander Brotman
	Comcast, Inc		Comcast, Inc
	Email: alexander_brotman (at) cable.comcast (dot com)		Email: alex_brotman (at) comcast.com
	Binu Ramakrishnan		Binu Ramakrishnan
	Yahoo!, Inc		Yahoo!, Inc
	Email: rbinu (at) yahoo-inc (dot com)		Email: rbinu (at) yahoo-inc (dot com)
	Janet Jones		Janet Jones
	Microsoft, Inc		Microsoft, Inc
	Email: janet.jones (at) microsoft (dot com)		Email: janet.jones (at) microsoft (dot com)
End of changes. 61 change blocks.
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