draft-ietf-rtcweb-stun-consent-freshness-06.txt		draft-ietf-rtcweb-stun-consent-freshness-07.txt
	RTCWEB M. Perumal		RTCWEB M. Perumal
	Internet-Draft Ericsson		Internet-Draft Ericsson
	Intended status: Standards Track D. Wing		Intended status: Standards Track D. Wing
	Expires: February 13, 2015 R. Ravindranath		Expires: March 19, 2015 R. Ravindranath
	T. Reddy		T. Reddy
	Cisco Systems		Cisco Systems
	M. Thomson		M. Thomson
	Mozilla		Mozilla
	August 12, 2014		September 15, 2014
	STUN Usage for Consent Freshness		STUN Usage for Consent Freshness
	draft-ietf-rtcweb-stun-consent-freshness-06		draft-ietf-rtcweb-stun-consent-freshness-07
	Abstract		Abstract
	To prevent sending excessive traffic to an endpoint, periodic consent		To prevent sending excessive traffic to an endpoint, periodic consent
	needs to be obtained from that remote endpoint.		needs to be obtained from that remote endpoint.
	This document describes a consent mechanism using a new STUN usage.		This document describes a consent mechanism using a new Session
	This same mechanism can also determine connection loss ("liveness")		Traversal Utilities for NAT (STUN) usage. This same mechanism can
	with a remote peer.		also determine connection loss ("liveness") with a remote peer.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on February 13, 2015.		This Internet-Draft will expire on March 19, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 34		skipping to change at page 2, line 34
	10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7		10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	11.1. Normative References . . . . . . . . . . . . . . . . . . 7		11.1. Normative References . . . . . . . . . . . . . . . . . . 7
	11.2. Informative References . . . . . . . . . . . . . . . . . 7		11.2. Informative References . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	To prevent attacks on peers, RTP endpoints have to ensure the remote		To prevent attacks on peers, RTP endpoints have to ensure the remote
	peer wants to receive traffic. This is performed both when the		peer wants to receive traffic. This is performed both when the
	session is first established to the remote peer using ICE		session is first established to the remote peer using Interactive
	connectivity checks, and periodically for the duration of the session		Connectivity Establishment ICE [RFC5245] connectivity checks, and
	using the procedures defined in this document.		periodically for the duration of the session using the procedures
			defined in this document.
	When a session is first established, WebRTC implementations are		When a session is first established, ICE implementations obtain
	required to perform STUN connectivity checks as part of ICE		initial consent by performing STUN connectivity checks as part of
	[RFC5245]. That initial consent is not described further in this		ICE. That initial consent is not described further in this document
	document and it is assumed that ICE is being used for that initial		and it is assumed that ICE is being used for that initial consent.
	consent.
	Related to consent is loss of connectivity ("liveness"). Many		Related to consent is loss of connectivity ("liveness"). Many
	applications want notification of connection loss to take appropriate		applications want notification of connection loss to take appropriate
	actions (e.g., alert the user, try switching to a different		actions (e.g., alert the user, try switching to a different
	interface).		interface).
	This document describes a new STUN usage with exchange of request and		This document describes a new STUN usage with exchange of request and
	response messages to verify the remote peer's consent to receive		response messages to verify the remote peer's consent to receive
	traffic, and the absence of which for a period of time indicates a		traffic, and the absence of which for a period of time indicates a
	loss of liveness.		loss of liveness.
	WebRTC endpoints are required to support full ICE as specified in		When a (full) ICE implementation interworks with an ICE-lite
	section 3.4 of [I-D.ietf-rtcweb-transports]. However, when WebRTC		implementation the ICE-lite implementation will not generate consent
	endpoints interwork with other endpoints that support only ICE-lite		checks, but will just just respond to consent checks it receives.
	(e.g., gateways) those endpoints will not generate consent checks,
	but just respond to consent checks they receive.
	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].
	Consent: It is the mechanism of obtaining permission to send traffic		Consent: It is the mechanism of obtaining permission to send traffic
	to a certain transport address. This is the initial consent to		to a certain transport address. This is the initial consent to
	send traffic, which is obtained by ICE or a TCP handshake.		send traffic, which is obtained by ICE or a TCP handshake.
	skipping to change at page 3, line 42		skipping to change at page 3, line 40
	port number.		port number.
	3. Design Considerations		3. Design Considerations
	Although ICE requires periodic keepalive traffic to keep NAT bindings		Although ICE requires periodic keepalive traffic to keep NAT bindings
	alive (Section 10 of [RFC5245], [RFC6263]), those keepalives are sent		alive (Section 10 of [RFC5245], [RFC6263]), those keepalives are sent
	as STUN Indications which are send-and-forget, and do not evoke a		as STUN Indications which are send-and-forget, and do not evoke a
	response. A response is necessary both for consent to continue		response. A response is necessary both for consent to continue
	sending traffic, as well as to verify session liveness. Thus, we		sending traffic, as well as to verify session liveness. Thus, we
	need a request/response mechanism for consent freshness. ICE can be		need a request/response mechanism for consent freshness. ICE can be
	used for that mechanism because ICE already requires ICE agents		used for that mechanism because ICE implementations are already
	continue listening for ICE messages, as described in section 10 of		required to continue listening for ICE messages, as described in
	[RFC5245].		section 10 of [RFC5245].
	4. Solution		4. Solution
	There are two ways consent to send traffic is revoked: expiration of		There are two ways consent to send traffic is revoked: expiration of
	consent and immediate revocation of consent, which are discussed in		consent and immediate revocation of consent, which are discussed in
	the following sections.		the following sections.
	4.1. Expiration of Consent		4.1. Expiration of Consent
	A WebRTC browser performs a combined consent freshness and session		A WebRTC implementation [I-D.ietf-rtcweb-overview], which implements
	liveness test using STUN request/response as described below:		ICE, MUST perform a combined consent freshness and session liveness
			test using STUN request/response as described below:
	An endpoint MUST NOT send application data (e.g., RTP, RTCP, SCTP,		An endpoint MUST NOT send application data (e.g., RTP, RTCP, SCTP,
	DTLS), over any transport protocol (e.g., UDP, TCP) on an ICE-		DTLS), over any transport protocol (e.g., UDP, TCP) on an ICE-
	initiated connection unless the receiving endpoint consents to		initiated connection unless the receiving endpoint consents to
	receive the data. After a successful ICE connectivity check on a		receive the data. After a successful ICE connectivity check on a
	particular transport address, subsequent consent MUST be obtained		particular transport address, subsequent consent MUST be obtained
	following the procedure described in this document. The consent		following the procedure described in this document. The consent
	expires after a fixed amount of time. During ICE restart consent		expires after a fixed amount of time. During ICE restart consent
	checks MUST continue to be sent on previously validated pair, and		checks MUST continue to be sent on previously validated pair, and
	MUST be responded to on the previously validated pair, until ICE		MUST be responded to on the previously validated pair, until ICE
	skipping to change at page 5, line 8		skipping to change at page 5, line 8
	endpoint MUST cease transmission on that 5-tuple.		endpoint MUST cease transmission on that 5-tuple.
	To meet the security needs of consent, an untrusted application		To meet the security needs of consent, an untrusted application
	(e.g., JavaScript) MUST NOT be able to obtain or control the STUN		(e.g., JavaScript) MUST NOT be able to obtain or control the STUN
	transaction ID, because that enables spoofing STUN responses,		transaction ID, because that enables spoofing STUN responses,
	falsifying consent.		falsifying consent.
	While TCP affords some protection from off-path attackers ([RFC5961],		While TCP affords some protection from off-path attackers ([RFC5961],
	[RFC4953]), there is still a risk an attacker could cause a TCP		[RFC4953]), there is still a risk an attacker could cause a TCP
	sender to send packets forever by spoofing ACKs. To prevent such an		sender to send packets forever by spoofing ACKs. To prevent such an
	attack, consent checks MUST be performed over all WebRTC-initiated		attack, consent checks MUST be performed over all transport
	transport connections, including TCP. In this way, an off-path		connections, including TCP. In this way, an off-path attacker
	attacker spoofing TCP segments can not cause a TCP sender to send		spoofing TCP segments can not cause a TCP sender to send packets
	packets longer than the consent timer (30 seconds).		longer than the consent timer (30 seconds).
	An endpoint that is not sending any application traffic does not need		An endpoint that is not sending any application traffic does not need
	to obtain consent which can slightly conserve its resources.		to obtain consent which can slightly conserve its resources.
	However, the endpoint needs to ensure its NAT or firewall mappings		However, the endpoint needs to ensure its NAT or firewall mappings
	persist which can be done using keepalive or other techniques (see		persist which can be done using keepalive or other techniques (see
	Section 10 of [RFC5245] and see [RFC6263]). If the endpoint wants to		Section 10 of [RFC5245] and see [RFC6263]). If the endpoint wants to
	send application traffic, it needs to first obtain consent if its		send application traffic, it needs to first obtain consent if its
	consent has expired.		consent has expired.
	4.2. Immediate Revocation of Consent		4.2. Immediate Revocation of Consent
	skipping to change at page 7, line 48		skipping to change at page 7, line 48
	Keeping Alive the NAT Mappings Associated with RTP / RTP		Keeping Alive the NAT Mappings Associated with RTP / RTP
	Control Protocol (RTCP) Flows", RFC 6263, June 2011.		Control Protocol (RTCP) Flows", RFC 6263, June 2011.
	11.2. Informative References		11.2. Informative References
	[I-D.ietf-avtcore-srtp-ekt]		[I-D.ietf-avtcore-srtp-ekt]
	McGrew, D. and D. Wing, "Encrypted Key Transport for		McGrew, D. and D. Wing, "Encrypted Key Transport for
	Secure RTP", draft-ietf-avtcore-srtp-ekt-02 (work in		Secure RTP", draft-ietf-avtcore-srtp-ekt-02 (work in
	progress), February 2014.		progress), February 2014.
	[I-D.ietf-rtcweb-transports]		[I-D.ietf-rtcweb-overview]
	Alvestrand, H., "Transports for RTCWEB", draft-ietf-		Alvestrand, H., "Overview: Real Time Protocols for
	rtcweb-transports-05 (work in progress), June 2014.		Browser-based Applications", draft-ietf-rtcweb-overview-11
			(work in progress), August 2014.
	[I-D.ietf-tsvwg-rtcweb-qos]		[I-D.ietf-tsvwg-rtcweb-qos]
	Dhesikan, S., Jennings, C., Druta, D., Jones, P., and J.		Dhesikan, S., Jennings, C., Druta, D., Jones, P., and J.
	Polk, "DSCP and other packet markings for RTCWeb QoS",		Polk, "DSCP and other packet markings for RTCWeb QoS",
	draft-ietf-tsvwg-rtcweb-qos-02 (work in progress), June		draft-ietf-tsvwg-rtcweb-qos-02 (work in progress), June
	2014.		2014.
	[RFC3830] Arkko, J., Carrara, E., Lindholm, F., Naslund, M., and K.		[RFC3830] Arkko, J., Carrara, E., Lindholm, F., Naslund, M., and K.
	Norrman, "MIKEY: Multimedia Internet KEYing", RFC 3830,		Norrman, "MIKEY: Multimedia Internet KEYing", RFC 3830,
	August 2004.		August 2004.
	skipping to change at page 8, line 34		skipping to change at page 8, line 34
	2010.		2010.
	[RFC6062] Perreault, S. and J. Rosenberg, "Traversal Using Relays		[RFC6062] Perreault, S. and J. Rosenberg, "Traversal Using Relays
	around NAT (TURN) Extensions for TCP Allocations", RFC		around NAT (TURN) Extensions for TCP Allocations", RFC
	6062, November 2010.		6062, November 2010.
	Authors' Addresses		Authors' Addresses
	Muthu Arul Mozhi Perumal		Muthu Arul Mozhi Perumal
	Ericsson		Ericsson
	Mahadevapura		Ferns Icon
	Bangalore, Karnataka 560048		Doddanekundi, Mahadevapura
			Bangalore, Karnataka 560037
	India		India
	Email: muthu.arul@gmail.com		Email: muthu.arul@gmail.com
	Dan Wing		Dan Wing
	Cisco Systems		Cisco Systems
	821 Alder Drive		821 Alder Drive
	Milpitas, California 95035		Milpitas, California 95035
	USA		USA
End of changes. 13 change blocks.
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