rfc8827xml2.original.xml   rfc8827.xml 
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]>
<?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?> <rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std"
<?rfc toc="yes" ?> number="8827" docName="draft-ietf-rtcweb-security-arch-20"
<?rfc symrefs="yes" ?> ipr="pre5378Trust200902" obsoletes="" updates="" submissionType="IETF"
<?rfc strict="yes" ?> consensus="true" xml:lang="en" tocInclude="true" tocDepth="4"
<?rfc compact="yes" ?> symRefs="true" sortRefs="true" version="3">
<?rfc sortrefs="yes" ?> <!-- xml2rfc v2v3 conversion 2.33.0 -->
<?rfc colonspace="yes" ?>
<?rfc rfcedstyle="no" ?>
<!-- Don't change this. It breaks stuff -->
<?rfc tocdepth="4"?>
<rfc category="std" docName="draft-ietf-rtcweb-security-arch-20"
ipr="pre5378Trust200902">
<front> <front>
<title abbrev="WebRTC Sec. Arch.">WebRTC Security Architecture</title> <title abbrev="WebRTC Sec. Arch.">WebRTC Security Architecture</title>
<seriesInfo name="RFC" value="8827"/>
<author fullname="Eric Rescorla" initials="E.K." surname="Rescorla"> <author fullname="Eric Rescorla" initials="E." surname="Rescorla">
<organization>RTFM, Inc.</organization> <organization>RTFM, Inc.</organization>
<address> <address>
<postal> <postal>
<street>2064 Edgewood Drive</street> <street>2064 Edgewood Drive</street>
<city>Palo Alto</city> <city>Palo Alto</city>
<region>CA</region> <region>CA</region>
<code>94303</code> <code>94303</code>
<country>United States of America</country>
<country>USA</country>
</postal> </postal>
<phone>+1 650 678 2350</phone> <phone>+1 650 678 2350</phone>
<email>ekr@rtfm.com</email> <email>ekr@rtfm.com</email>
</address> </address>
</author> </author>
<date month="June" year="2020"/>
<date/> <!-- [rfced] Please insert any keywords (beyond those that appear in the
title) for use on https://www.rfc-editor.org/search -->
<area>ART</area> <abstract>
<!-- [rfced] In this cluster, we have been expanding WebRTC in the body of the
document (but not the title) as Web Real-Time Communication. Do you want to
include this expansion somewhere, or is not needed with the current
explanatory text?
<workgroup>RTCWEB</workgroup> Original (first occurrence):
This document defines the security architecture for WebRTC, a
protocol suite intended for use with real-time applications that can
be deployed in browsers - "real time communication on the Web".
-->
<abstract>
<t> <t>
This document defines the security architecture for WebRTC, a protocol This document defines the security architecture for WebRTC, a protocol
suite intended for use with real-time applications that can be deployed suite intended for use with real-time applications that can be deployed
in browsers - "real time communication on the Web". in browsers -- "real-time communication on the Web".
</t> </t>
</abstract> </abstract>
</front> </front>
<middle> <middle>
<section anchor="sec.introduction" numbered="true" toc="default">
<section title="Introduction" anchor="sec.introduction"> <name>Introduction</name>
<t> <t>
The Real-Time Communications on the Web (RTCWEB) working group The Real-Time Communications on the Web (RTCWEB) Working Group
standardized protocols for real-time communications between Web standardized protocols for real-time communications between Web
browsers, generally called "WebRTC" <xref target="I-D.ietf-rtcweb-overvi ew"/>. browsers, generally called "WebRTC" <xref target="RFC8825" format="defau lt"/>.
The major use cases for WebRTC technology are real-time audio The major use cases for WebRTC technology are real-time audio
and/or video calls, Web conferencing, and direct data transfer. Unlike and/or video calls, Web conferencing, and direct data transfer. Unlike
most conventional real-time systems, (e.g., SIP-based <xref most conventional real-time systems (e.g., SIP-based <xref target="RFC32
target="RFC3261"></xref> soft phones) WebRTC communications are directly 61" format="default"/> soft phones), WebRTC communications are directly
controlled by some Web server, via a JavaScript (JS) API as shown in controlled by some Web server, via a JavaScript (JS) API as shown in
<xref target="fig.simple"/>. <xref target="fig.simple" format="default"/>.
</t> </t>
<figure title="A simple WebRTC system" anchor="fig.simple"> <figure anchor="fig.simple">
<artwork><![CDATA[ <name>A Simple WebRTC System</name>
+----------------+ <artwork name="" type="" align="left" alt=""><![CDATA[
| | +----------------+
| Web Server | | |
| | | Web Server |
+----------------+ | |
^ ^ +----------------+
/ \ ^ ^
HTTP / \ HTTP / \
/ \ HTTP / \ HTTP
/ \ / \
v v / \
JS API JS API v v
+-----------+ +-----------+ JS API JS API
| | Media | | +-----------+ +-----------+
| Browser |<---------->| Browser | | | Media | |
| | | | | Browser |<---------->| Browser |
+-----------+ +-----------+ | | | |
]]></artwork> +-----------+ +-----------+ ]]></artwork>
</figure> </figure>
<t> <t>
A more complicated system might allow for interdomain calling, as shown A more complicated system might allow for interdomain calling, as shown
in <xref target="fig.multidomain"/>. The protocol to be used between in <xref target="fig.multidomain" format="default"/>. The protocol to b e used between
the domains is not standardized by WebRTC, but given the installed base the domains is not standardized by WebRTC, but given the installed base
and the form of the WebRTC API is likely to be something SDP-based like and the form of the WebRTC API is likely to be something SDP-based like
SIP or something like Extensible Messaging and Presence Protocol (XMPP) SIP or something like the Extensible Messaging and Presence Protocol (XM
<xref target="RFC6120"/>. PP)
<xref target="RFC6120" format="default"/>.
</t> </t>
<figure title="A multidomain WebRTC system" anchor="fig.multidomain"> <figure anchor="fig.multidomain">
<artwork><![CDATA[ <name>A Multidomain WebRTC System</name>
+--------------+ +--------------+ <artwork name="" type="" align="left" alt=""><![CDATA[
| | SIP,XMPP,...| | +--------------+ +--------------+
| Web Server |<----------->| Web Server | | | SIP, XMPP, ... | |
| | | | | Web Server |<-------------->| Web Server |
+--------------+ +--------------+ | | | |
^ ^ +--------------+ +--------------+
| | ^ ^
HTTP | | HTTP | |
| | HTTP | | HTTP
v v | |
JS API JS API v v
+-----------+ +-----------+ JS API JS API
| | Media | | +-----------+ +-----------+
| Browser |<---------------->| Browser | | | Media | |
| | | | | Browser |<------------------->| Browser |
+-----------+ +-----------+ | | | |
]]></artwork> +-----------+ +-----------+ ]]></artwork>
</figure> </figure>
<t> <t>
This system presents a number of new security challenges, which are This system presents a number of new security challenges, which are
analyzed in <xref target="I-D.ietf-rtcweb-security"/>. This document analyzed in <xref target="RFC8826" format="default"/>. This document
describes a security architecture for WebRTC which addresses the threats describes a security architecture for WebRTC which addresses the threats
and requirements described in that document. and requirements described in that document.
</t> </t>
</section> </section>
<section anchor="sec-term" numbered="true" toc="default">
<name>Terminology</name>
<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
"<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
"<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
"<bcp14>SHOULD NOT</bcp14>",
"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are
to be interpreted as described in BCP&nbsp;14 <xref target="RFC2119"/>
<xref target="RFC8174"/> when, and only when, they appear in all capitals,
as shown here.</t>
<section anchor="sec-term" title="Terminology">
<t>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be interpreted as
described in BCP 14 <xref target="RFC2119"/>
<xref target="RFC8174"/> when, and only when, they
appear in all capitals, as shown here.
</t>
</section> </section>
<section anchor="sec.proposal.trusthierarchy" numbered="true" toc="default">
<section title="Trust Model" anchor="sec.proposal.trusthierarchy"> <name>Trust Model</name>
<t> <t>
The basic assumption of this architecture is that network resources The basic assumption of this architecture is that network resources
exist in a hierarchy of trust, rooted in the browser, which serves as exist in a hierarchy of trust, rooted in the browser, which serves as
the user's Trusted Computing Base (TCB). Any security property which the the user's Trusted Computing Base (TCB). Any security property which the
user wishes to have enforced must be ultimately guaranteed by the user wishes to have enforced must be ultimately guaranteed by the
browser (or transitively by some property the browser browser (or transitively by some property the browser
verifies). Conversely, if the browser is compromised, then no security verifies). Conversely, if the browser is compromised, then no security
guarantees are possible. Note that there are cases (e.g., Internet guarantees are possible. Note that there are cases (e.g., Internet
kiosks) where the user can't really trust the browser that much. In kiosks) where the user can't really trust the browser that much. In
these cases, the level of security provided is limited by how much they these cases, the level of security provided is limited by how much they
trust the browser. trust the browser.
</t> </t>
<t> <t>
Optimally, we would not rely on trust in any entities other than the Optimally, we would not rely on trust in any entities other than the
browser. However, this is unfortunately not possible if we wish to have browser. However, this is unfortunately not possible if we wish to have
a functional system. Other network elements fall into two categories: a functional system. Other network elements fall into two categories:
those which can be authenticated by the browser and thus can be granted those which can be authenticated by the browser and thus can be granted
permissions to access sensitive resources, and those which cannot be permissions to access sensitive resources, and those which cannot be
authenticated and thus are untrusted. authenticated and thus are untrusted.
</t> </t>
<section anchor="sec.proposal.authenticated" numbered="true" toc="default"
<section title="Authenticated Entities" anchor="sec.proposal.authenticated >
"> <name>Authenticated Entities</name>
<t> <t>
There are two major classes of authenticated entities in the system: There are two major classes of authenticated entities in the system:
</t> </t>
<t> <dl newline="false" spacing="normal">
<list style="symbols"> <dt>Calling services:</dt>
<t> <dd>Web sites whose origin we can verify (optimally
Calling services: Web sites whose origin we can verify (optimally
via HTTPS, but in some cases because we are on a topologically via HTTPS, but in some cases because we are on a topologically
restricted network, such as behind a firewall, and can infer restricted network, such as behind a firewall, and can infer
authentication from firewall behavior). authentication from firewall behavior).</dd>
</t> <dt>Other users:</dt>
<t> <dd>WebRTC peers whose origin we can verify
Other users: WebRTC peers whose origin we can verify cryptographically (optimally via DTLS-SRTP).</dd>
cryptographically (optimally via DTLS-SRTP). </dl>
</t>
</list>
</t>
<t> <t>
Note that merely being authenticated does not make these entities Note that merely being authenticated does not make these entities
trusted. For instance, just because we can verify that trusted. For instance, just because we can verify that
https://www.example.org/ is owned by Dr. Evil does not mean that we ca n &lt;https://www.example.org/&gt; is owned by Dr. Evil does not mean th at we can
trust Dr. Evil to access our camera and microphone. However, it gives trust Dr. Evil to access our camera and microphone. However, it gives
the user an opportunity to determine whether he wishes to trust the user an opportunity to determine whether he wishes to trust
Dr. Evil or not; after all, if he desires to contact Dr. Evil (perhaps Dr. Evil or not; after all, if he desires to contact Dr. Evil (perhaps
to arrange for ransom payment), it's safe to temporarily give him to arrange for ransom payment), it's safe to temporarily give him
access to the camera and microphone for the purpose of the call, but access to the camera and microphone for the purpose of the call, but
he doesn't want Dr. Evil to be able to access his camera and he doesn't want Dr. Evil to be able to access his camera and
microphone other than during the call. The point here is that we must microphone other than during the call. The point here is that we must
first identify other elements before we can determine whether and how first identify other elements before we can determine whether and how
much to trust them. Additionally, sometimes we need to identify the much to trust them. Additionally, sometimes we need to identify the
communicating peer before we know what policies to apply. communicating peer before we know what policies to apply.
</t>
</section> <!-- [rfced] Sections 3.1 and subsequent: Per the "Gender-Specific
Language" section of <https://www.rfc-editor.org/styleguide/part2/>,
please let us know if we may change these instances of "he," "him,"
and "his" to "they," "them," and "their."
<section title="Unauthenticated Entities" anchor="sec.proposal.unauthentic Original:
ated"> However, it
gives the user an opportunity to determine whether he wishes to trust
Dr. Evil or not; after all, if he desires to contact Dr. Evil
(perhaps to arrange for ransom payment), it's safe to temporarily
give him access to the camera and microphone for the purpose of the
call, but he doesn't want Dr. Evil to be able to access his camera
and microphone other than during the call.
...
The
idea behind this type of permissions is that a user might have a
fairly narrow list of peers he is willing to communicate with, e.g.,
"my mother" rather than "anyone on Facebook".
...
Note that this
does not mean that the IdP might not lie, but that is a
trustworthiness judgement that the user can make at the time he looks
at the identity.
...
Note that
this requires user consent in many cases but because the data channel
does not need consent, he can use that directly.
...
Fundamentally, the IdP proxy is just a piece of HTML and JS loaded by
the browser, so nothing stops a Web attacker from creating their own
IFRAME, loading the IdP proxy HTML/JS, and requesting a signature
over his own keys rather than those generated in the browser. -->
</t>
</section>
<section anchor="sec.proposal.unauthenticated" numbered="true" toc="defaul
t">
<name>Unauthenticated Entities</name>
<t> <t>
Other than the above entities, we are not generally able to identify Other than the above entities, we are not generally able to identify
other network elements, thus we cannot trust them. This does not mean other network elements; thus, we cannot trust them. This does not mea n
that it is not possible to have any interaction with them, but it that it is not possible to have any interaction with them, but it
means that we must assume that they will behave maliciously and design means that we must assume that they will behave maliciously and design
a system which is secure even if they do so. a system which is secure even if they do so.
</t> </t>
</section> </section>
</section> </section>
<!-- Not layered ? --> <section anchor="sec.proposal.overview" numbered="true" toc="default">
<name>Overview</name>
<!-- [rfced] Section 4: We found these comments in the original
approved XML file. Were these items resolved?
Original:
</section>
<!- - Not layered ? - ->
<section title="Overview" anchor="sec.proposal.overview"> <section title="Overview" anchor="sec.proposal.overview">
<!-- TODO: Federated --> <!- - TODO: Federated - -> -->
<t> <t>
This section describes a typical WebRTC session and shows how the This section describes a typical WebRTC session and shows how the
various security elements interact and what guarantees are provided to various security elements interact and what guarantees are provided to
the user. The example in this section is a "best case" scenario in which the user. The example in this section is a "best case" scenario in which
we provide the maximal amount of user authentication and media privacy we provide the maximal amount of user authentication and media privacy
with the minimal level of trust in the calling service. Simpler versions with the minimal level of trust in the calling service. Simpler versions
with lower levels of security are also possible and are noted in the with lower levels of security are also possible and are noted in the
text where applicable. It's also important to recognize the tension text where applicable. It's also important to recognize the tension
between security (or performance) and privacy. The example shown here is between security (or performance) and privacy. The example shown here is
aimed towards settings where we are more concerned about secure calling aimed towards settings where we are more concerned about secure calling
than about privacy, but as we shall see, there are settings where one than about privacy, but as we shall see, there are settings where one
might wish to make different tradeoffs--this architecture is still might wish to make different trade&nbhy;offs -- this architecture is sti ll
compatible with those settings. compatible with those settings.
</t> </t>
<t> <t>
For the purposes of this example, we assume the topology shown in the For the purposes of this example, we assume the topology shown in the
figures below. This topology is derived from the topology shown in <xref figures below. This topology is derived from the topology shown in <xref
target="fig.simple"/>, but separates Alice and Bob's identities from the target="fig.simple" format="default"/>, but separates Alice's and Bob's identit
ies from the
process of signaling. Specifically, Alice and Bob have relationships process of signaling. Specifically, Alice and Bob have relationships
with some Identity Provider (IdP) that supports a protocol (such as with some Identity Provider (IdP) that supports a protocol (such as
OpenID Connect) that can be used to demonstrate their identity to OpenID Connect) that can be used to demonstrate their identity to
other parties. For instance, Alice might have an account with a social other parties. For instance, Alice might have an account with a social
network which she can then use to authenticate to other web sites network which she can then use to authenticate to other Web sites
without explicitly having an account with those sites; this is a fairly without explicitly having an account with those sites; this is a fairly
conventional pattern on the Web. <xref conventional pattern on the Web. &nbsp;<xref target="sec.trust-relations
target="sec.trust-relationships"/> provides an overview of Identity hips" format="default"/> provides an overview of Identity
Providers and the relevant terminology. Alice and Bob might have Providers and the relevant terminology. Alice and Bob might have
relationships with different IdPs as well. relationships with different IdPs as well.
</t> </t>
<t> <t>
This separation of identity provision and signaling isn't particularly This separation of identity provision and signaling isn't particularly
important in "closed world" cases where Alice and Bob are users on the important in "closed world" cases where Alice and Bob are users on the
same social network and have identities based on that domain (<xref same social network and have identities based on that domain (<xref targ
target="fig.proposal.idp"/>). However, there are important settings wher et="fig.proposal.idp" format="default"/>). However, there are important settings
e where
that is not the case, such as federation (calls from one domain to that is not the case, such as federation (calls from one domain to
another; <xref target="fig.proposal-federated.idp"/>) and calling on another; see <xref target="fig.proposal-federated.idp" format="default"/ >) and calling on
untrusted sites, such as where two users who have a relationship via a untrusted sites, such as where two users who have a relationship via a
given social network want to call each other on another, untrusted, given social network want to call each other on another, untrusted,
site, such as a poker site. site, such as a poker site.
</t> </t>
<t> <t>
Note that the servers themselves are also authenticated by an external Note that the servers themselves are also authenticated by an external
identity service, the SSL/TLS certificate infrastructure (not shown). identity service, the SSL/TLS certificate infrastructure (not shown).
As is conventional in the Web, all identities are ultimately rooted in As is conventional in the Web, all identities are ultimately rooted in
that system. For instance, when an IdP makes an identity assertion, the that system. For instance, when an IdP makes an identity assertion, the
Relying Party consuming that assertion is able to verify because it is Relying Party consuming that assertion is able to verify because it is
able to connect to the IdP via HTTPS. able to connect to the IdP via HTTPS.
</t> </t>
<figure title="A call with IdP-based identity" anchor="fig.proposal.idp"> <figure anchor="fig.proposal.idp">
<artwork><![CDATA[ <name>A Call with IdP-Based Identity</name>
<artwork name="" type="" align="left" alt=""><![CDATA[
+----------------+ +----------------+
| | | |
| Signaling | | Signaling |
| Server | | Server |
| | | |
+----------------+ +----------------+
^ ^ ^ ^
/ \ / \
HTTPS / \ HTTPS HTTPS / \ HTTPS
/ \ / \
skipping to change at line 325 skipping to change at line 317
Alice | Browser |<---------->| Browser | Bob Alice | Browser |<---------->| Browser | Bob
| | (DTLS+SRTP)| | | | (DTLS+SRTP)| |
+-----------+ +-----------+ +-----------+ +-----------+
^ ^--+ +--^ ^ ^ ^--+ +--^ ^
| | | | | | | |
v | | v v | | v
+-----------+ | | +-----------+ +-----------+ | | +-----------+
| |<--------+ | | | |<--------+ | |
| IdP1 | | | IdP2 | | IdP1 | | | IdP2 |
| | +------->| | | | +------->| |
+-----------+ +-----------+ +-----------+ +-----------+ ]]></artwork>
]]></artwork>
</figure> </figure>
<t> <t>
<xref target="fig.proposal-federated.idp"/> shows essentially the same <xref target="fig.proposal-federated.idp" format="default"/> shows essen tially the same
calling scenario but with a call between two separate domains (i.e., a calling scenario but with a call between two separate domains (i.e., a
federated case), as in <xref target="fig.multidomain"/>. As mentioned federated case), as in <xref target="fig.multidomain" format="default"/>
above, the domains communicate by some unspecified protocol and . As mentioned
above, the domains communicate by some unspecified protocol, and
providing separate signaling and identity allows for calls to be providing separate signaling and identity allows for calls to be
authenticated regardless of the details of the inter-domain protocol. authenticated regardless of the details of the inter-domain protocol.
</t> </t>
<figure title="A federated call with IdP-based identity" anchor="fig.propo <figure anchor="fig.proposal-federated.idp">
sal-federated.idp"> <name>A Federated Call with IdP-Based Identity</name>
<artwork><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
+----------------+ Unspecified +----------------+ +----------------+ Unspecified +----------------+
| | protocol | | | | protocol | |
| Signaling |<----------------->| Signaling | | Signaling |<----------------->| Signaling |
| Server | (SIP, XMPP, ...) | Server | | Server | (SIP, XMPP, ...) | Server |
| | | | | | | |
+----------------+ +----------------+ +----------------+ +----------------+
^ ^ ^ ^
| | | |
HTTPS | | HTTPS HTTPS | | HTTPS
| | | |
skipping to change at line 363 skipping to change at line 355
Alice | Browser |<--------------------------->| Browser | Bob Alice | Browser |<--------------------------->| Browser | Bob
| | DTLS+SRTP | | | | DTLS+SRTP | |
+-----------+ +-----------+ +-----------+ +-----------+
^ ^--+ +--^ ^ ^ ^--+ +--^ ^
| | | | | | | |
v | | v v | | v
+-----------+ | | +-----------+ +-----------+ | | +-----------+
| |<-------------------------+ | | | |<-------------------------+ | |
| IdP1 | | | IdP2 | | IdP1 | | | IdP2 |
| | +------------------------>| | | | +------------------------>| |
+-----------+ +-----------+ +-----------+ +-----------+ ]]></artwork>
]]></artwork>
</figure> </figure>
<section numbered="true" toc="default">
<section title="Initial Signaling"> <name>Initial Signaling</name>
<t> <t>
For simplicity, assume the topology in <xref For simplicity, assume the topology in <xref target="fig.proposal.idp"
target="fig.proposal.idp"/>. Alice and Bob are both users of a common format="default"/>. Alice and Bob are both users of a common
calling service; they both have approved the calling service to make calling service; they both have approved the calling service to make
calls (we defer the discussion of device access permissions until calls (we defer the discussion of device access permissions until
later). They are both connected to the calling service via HTTPS and later). They are both connected to the calling service via HTTPS and
so know the origin with some level of confidence. They also have so know the origin with some level of confidence. They also have
accounts with some identity provider. This sort of identity service accounts with some identity provider. This sort of identity service
is becoming increasingly common in the Web environment (with technolog ies is becoming increasingly common in the Web environment (with technolog ies
such as Federated Google Login, Facebook Connect, OAuth, such as Federated Google Login, Facebook Connect, OAuth,
OpenID, WebFinger), and is often provided as a side effect service of OpenID, WebFinger), and is often provided as a side effect service of
a user's ordinary accounts with some service. In this example, we show a user's ordinary accounts with some service. In this example, we show
Alice and Bob using a separate identity service, though the identity Alice and Bob using a separate identity service, though the identity
service may be the same entity as the calling service or there may be service may be the same entity as the calling service or there may be
no identity service at all. no identity service at all.
</t> </t>
<t> <t>
Alice is logged onto the calling service and decides to call Bob. She Alice is logged onto the calling service and decides to call Bob. &nbs p;She
can see from the calling service that he is online and the calling can see from the calling service that he is online and the calling
service presents a JS UI in the form of a button next to Bob's name service presents a JS UI in the form of a button next to Bob's name
which says "Call". Alice clicks the button, which initiates a JS which says "Call". Alice clicks the button, which initiates a JS
callback that instantiates a PeerConnection object. This does not callback that instantiates a PeerConnection object. This does not
require a security check: JS from any origin is allowed to get this require a security check: JS from any origin is allowed to get this
far. far.
</t> </t>
<t> <t>
Once the PeerConnection is created, the calling service JS needs to Once the PeerConnection is created, the calling service JS needs to
set up some media. Because this is an audio/video call, it creates a set up some media. Because this is an audio/video call, it creates a
MediaStream with two MediaStreamTracks, one connected to an audio MediaStream with two MediaStreamTracks, one connected to an audio
input and one connected to a video input. At this point the first input and one connected to a video input. At this point, the first
security check is required: untrusted origins are not allowed to security check is required: untrusted origins are not allowed to
access the camera and microphone, so the browser prompts Alice for access the camera and microphone, so the browser prompts Alice for
permission. permission.
</t> </t>
<t> <t>
In the current W3C API, once some streams have been added, Alice's In the current W3C API, once some streams have been added, Alice's
browser + JS generates a signaling message <xref browser + JS generates a signaling message <xref target="RFC8829" form
target="I-D.ietf-rtcweb-jsep"/> containing: at="default"/> containing:
</t> </t>
<t> <ul spacing="normal">
<list style="symbols"> <li>
<t>
Media channel information Media channel information
</t> </li>
<t> <li>
Interactive Connectivity Establishment (ICE) <xref Interactive Connectivity Establishment (ICE) <xref target="RFC8445
target="RFC8445"/> candidates " format="default"/> candidates
</t> </li>
<t> <li>
A fingerprint attribute binding the communication to a key pair A "fingerprint" attribute binding the communication to a key pair
<xref target="RFC5763"/>. Note that this key may simply be <xref target="RFC5763" format="default"/>. Note that this key may
simply be
ephemerally generated for this call or specific to this domain, ephemerally generated for this call or specific to this domain,
and Alice may have a large number of such keys. and Alice may have a large number of such keys.
</t> </li>
</list> </ul>
</t>
<t> <t>
Prior to sending out the signaling message, the PeerConnection code Prior to sending out the signaling message, the PeerConnection code
contacts the identity service and obtains an assertion binding Alice's contacts the identity service and obtains an assertion binding Alice's
identity to her fingerprint. The exact details depend on the identity identity to her fingerprint. The exact details depend on the identity
service (though as discussed in <xref target="sec.generic.idp"/> service (though as discussed in <xref target="sec.generic.idp" format= "default"/>
PeerConnection can be agnostic to them), but for now it's easiest to PeerConnection can be agnostic to them), but for now it's easiest to
think of as an OAuth token. The assertion may bind other think of as an OAuth token. The assertion may bind other
information to the identity besides the fingerprint, but at minimum it information to the identity besides the fingerprint, but at minimum it
needs to bind the fingerprint. needs to bind the fingerprint.
</t> </t>
<t> <t>
This message is sent to the signaling server, e.g., by XMLHttpRequest This message is sent to the signaling server, e.g., by XMLHttpRequest
<xref target="XmlHttpRequest"/> or by WebSockets <xref <xref target="XmlHttpRequest" format="default"/> or by WebSockets
target="RFC6455"/>, over TLS <xref target="RFC5246"/>. <xref target="RFC6455" format="default"/>, over TLS <xref
target="RFC5246" format="default"/>.
<!-- [rfced] Section 4.1: Because RFC 5246 has been obsoleted by
RFC 8446, would you like to (1) cite and list RFC 8446 instead,
(2) list both documents, or (3) leave the obsolete citation in place
(i.e., no changes)?
Original:
This message is sent to the signaling server, e.g., by XMLHttpRequest
[XmlHttpRequest] or by WebSockets [RFC6455], over TLS [RFC5246]. -->
The signaling server processes the message from Alice's browser, The signaling server processes the message from Alice's browser,
determines that this is a call to Bob and sends a signaling message to determines that this is a call to Bob, and sends a signaling message t o
Bob's browser (again, the format is currently undefined). The JS on Bob's browser (again, the format is currently undefined). The JS on
Bob's browser processes it, and alerts Bob to the incoming call and to Bob's browser processes it, and alerts Bob to the incoming call and to
Alice's identity. In this case, Alice has provided an identity Alice's identity. In this case, Alice has provided an identity
assertion and so Bob's browser contacts Alice's identity provider assertion and so Bob's browser contacts Alice's identity provider
(again, this is done in a generic way so the browser has no specific (again, this is done in a generic way so the browser has no specific
knowledge of the IdP) to verify the assertion. It is also possible knowledge of the IdP) to verify the assertion. It is also possible
to have IdPs with which the browser has a specific trustrelationship, to have IdPs with which the browser has a specific trust relationship,
as described in <xref target="sec.trust-relationships"/>. as described in <xref target="sec.trust-relationships" format="default
"/>.
This allows the browser This allows the browser
to display a trusted element in the browser chrome indicating that a to display a trusted element in the browser chrome indicating that a
call is coming in from Alice. If Alice is in Bob's address book, then call is coming in from Alice. If Alice is in Bob's address book, then
this interface might also include her real name, a picture, etc. The this interface might also include her real name, a picture, etc. The
calling site will also provide some user interface element (e.g., a calling site will also provide some user interface element (e.g., a
button) to allow Bob to answer the call, though this is most likely button) to allow Bob to answer the call, though this is most likely
not part of the trusted UI. not part of the trusted UI.
</t> </t>
<t> <t>
If Bob agrees a PeerConnection is instantiated with the message from If Bob agrees, a PeerConnection is instantiated with the message from
Alice's side. Then, a similar process occurs as on Alice's browser: Alice's side. Then, a similar process occurs as on Alice's browser:
Bob's browser prompts him for device permission, the media streams are Bob's browser prompts him for device permission, the media streams are
created, and a return signaling message containing media information, created, and a return signaling message containing media information,
ICE candidates, and a fingerprint is sent back to Alice via the ICE candidates, and a fingerprint is sent back to Alice via the
signaling service. If Bob has a relationship with an IdP, the message signaling service. If Bob has a relationship with an IdP, the message
will also come with an identity assertion. will also come with an identity assertion.
</t> </t>
<t> <t>
At this point, Alice and Bob each know that the other party wants to At this point, Alice and Bob each know that the other party wants to
have a secure call with them. Based purely on the interface provided have a secure call with them. Based purely on the interface provided
by the signaling server, they know that the signaling server claims by the signaling server, they know that the signaling server claims
that the call is from Alice to Bob. This level of security is provided that the call is from Alice to Bob. &nbsp;This level of security is pr ovided
merely by having the fingerprint in the message and having that merely by having the fingerprint in the message and having that
message received securely from the signaling server. Because the far message received securely from the signaling server. Because the far
end sent an identity assertion along with their message, they know end sent an identity assertion along with their message, they know
that this is verifiable from the IdP as well. Note that if the call is that this is verifiable from the IdP as well. Note that if the call is
federated, as shown in <xref target="fig.proposal-federated.idp"/> federated, as shown in <xref target="fig.proposal-federated.idp" forma t="default"/>,
then Alice is able to verify Bob's identity in a way that is not then Alice is able to verify Bob's identity in a way that is not
mediated by either her signaling server or Bob's. Rather, she verifies mediated by either her signaling server or Bob's. Rather, she verifies
it directly with Bob's IdP. it directly with Bob's IdP.
</t> </t>
<t> <t>
Of course, the call works perfectly well if either Alice or Bob Of course, the call works perfectly well if either Alice or Bob
doesn't have a relationship with an IdP; they just get a lower level doesn't have a relationship with an IdP; they just get a lower level
of assurance. I.e., they simply have whatever information their of assurance. That is, they simply have whatever information their
calling site claims about the caller/callee's identity. Moreover, calling site claims about the caller/callee's identity. Moreover,
Alice might wish to make an anonymous call through an anonymous Alice might wish to make an anonymous call through an anonymous
calling site, in which case she would of course just not provide any calling site, in which case she would of course just not provide any
identity assertion and the calling site would mask her identity from identity assertion and the calling site would mask her identity from
Bob. Bob.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="Media Consent Verification"> <name>Media Consent Verification</name>
<t> <t>
As described in (<xref target="I-D.ietf-rtcweb-security"/>; Section As described in <xref target="RFC8826" sectionFormat="comma"
4.2) media consent verification is provided via ICE. Thus, Alice and section="4.2"/>, media consent verification is provided via ICE.
Thus, Alice and
Bob perform ICE checks with each other. At the completion of these Bob perform ICE checks with each other. At the completion of these
checks, they are ready to send non-ICE data. checks, they are ready to send non-ICE data.
</t> </t>
<t> <t>
At this point, Alice knows that (a) Bob (assuming he is verified via At this point, Alice knows that (a) Bob (assuming he is verified via
his IdP) or someone else who the signaling service is claiming is Bob his IdP) or someone else who the signaling service is claiming is Bob
is willing to exchange traffic with her and (b) that either Bob is at is willing to exchange traffic with her and (b) either Bob is at
the IP address which she has verified via ICE or there is an attacker the IP address which she has verified via ICE or there is an attacker
who is on-path to that IP address detouring the traffic. Note that it who is on-path to that IP address detouring the traffic. Note that it
is not possible for an attacker who is on-path between Alice and Bob is not possible for an attacker who is on-path between Alice and Bob
but not attached to the signaling service to spoof these checks but not attached to the signaling service to spoof these checks
because they do not have the ICE credentials. Bob has the same because they do not have the ICE credentials. Bob has the same
security guarantees with respect to Alice. security guarantees with respect to Alice.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="DTLS Handshake"> <name>DTLS Handshake</name>
<t> <t>
Once the requisite ICE checks have completed, Alice and Bob can set Once the requisite ICE checks have completed, Alice and Bob can set
up a secure channel or channels. This is performed via DTLS <xref targ up a secure channel or channels. This is performed via DTLS <xref targ
et="RFC6347"/> et="RFC6347" format="default"/>
and DTLS-SRTP <xref target="RFC5763"/> keying for SRTP and DTLS-SRTP <xref target="RFC5763" format="default"/> keying for SRT
<xref target="RFC3711"/> for the media channel and SCTP over DTLS P
<xref target="RFC8261"/> for data <xref target="RFC3711" format="default"/> for the media channel and
the Stream Control Transmission Protocol (SCTP) over DTLS
<xref target="RFC8261" format="default"/> for data
channels. Specifically, Alice and Bob perform a DTLS handshake on channels. Specifically, Alice and Bob perform a DTLS handshake on
every component which has been established by ICE. The total number of every component which has been established by ICE. The total number of
channels depends on the amount of muxing; in the most likely case we channels depends on the amount of muxing; in the most likely case, we
are using both RTP/RTCP mux and muxing multiple media streams on the are using both RTP/RTCP mux and muxing multiple media streams on the
same channel, in which case there is only one DTLS handshake. Once the same channel, in which case there is only one DTLS handshake. Once the
DTLS handshake has completed, the keys are exported <xref DTLS handshake has completed, the keys are exported <xref target="RFC5
target="RFC5705"/> and used to key SRTP for the media channels. 705" format="default"/> and used to key SRTP for the media channels.
</t> </t>
<t> <t>
At this point, Alice and Bob know that they share a set of secure data At this point, Alice and Bob know that they share a set of secure data
and/or media channels with keys which are not known to any third-party and/or media channels with keys which are not known to any third-party
attacker. If Alice and Bob authenticated via their IdPs, then they attacker. If Alice and Bob authenticated via their IdPs, then they
also know that the signaling service is not mounting a also know that the signaling service is not mounting a
man-in-the-middle attack on their traffic. Even if they do not use an man-in-the-middle attack on their traffic. Even if they do not use an
IdP, as long as they have minimal trust in the signaling service not IdP, as long as they have minimal trust in the signaling service not
to perform a man-in-the-middle attack, they know that their to perform a man-in-the-middle attack, they know that their
communications are secure against the signaling service as well (i.e., communications are secure against the signaling service as well (i.e.,
skipping to change at line 539 skipping to change at line 536
and/or media channels with keys which are not known to any third-party and/or media channels with keys which are not known to any third-party
attacker. If Alice and Bob authenticated via their IdPs, then they attacker. If Alice and Bob authenticated via their IdPs, then they
also know that the signaling service is not mounting a also know that the signaling service is not mounting a
man-in-the-middle attack on their traffic. Even if they do not use an man-in-the-middle attack on their traffic. Even if they do not use an
IdP, as long as they have minimal trust in the signaling service not IdP, as long as they have minimal trust in the signaling service not
to perform a man-in-the-middle attack, they know that their to perform a man-in-the-middle attack, they know that their
communications are secure against the signaling service as well (i.e., communications are secure against the signaling service as well (i.e.,
that the signaling service cannot mount a passive attack on the that the signaling service cannot mount a passive attack on the
communications). communications).
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="Communications and Consent Freshness"> <name>Communications and Consent Freshness</name>
<t> <t>
From a security perspective, everything from here on in is a little From a security perspective, everything from here on in is a little
anticlimactic: Alice and Bob exchange data protected by the keys anticlimactic: Alice and Bob exchange data protected by the keys
negotiated by DTLS. Because of the security guarantees discussed in negotiated by DTLS. Because of the security guarantees discussed in
the previous sections, they know that the communications are encrypted the previous sections, they know that the communications are encrypted
and authenticated. and authenticated.
</t> </t>
<t> <t>
The one remaining security property we need to establish is "consent The one remaining security property we need to establish is "consent
freshness", i.e., allowing Alice to verify that Bob is still prepared freshness", i.e., allowing Alice to verify that Bob is still prepared
to receive her communications so that Alice does not continue to send to receive her communications so that Alice does not continue to send
large traffic volumes to entities which went abruptly offline. ICE large traffic volumes to entities which went abruptly offline. ICE
specifies periodic STUN keepalives but only if media is not flowing. specifies periodic Session Traversal Utilities for NAT (STUN) keepaliv es but only if media is not flowing.
Because the consent issue is more difficult here, we require WebRTC Because the consent issue is more difficult here, we require WebRTC
implementations to periodically send keepalives. As described in implementations to periodically send keepalives. As described in
Section 5.3, these keepalives MUST be based on the consent freshness Section 5.3, these keepalives <bcp14>MUST</bcp14> be based on the cons
mechanism specified in <xref target="RFC7675"/>. If a ent freshness
mechanism specified in <xref target="RFC7675" format="default"/>.
<!-- [rfced] Section 4.4: This document does not have a Section 5.3.
Please let us know which section should be cited here.
Original:
As described in
Section 5.3, these keepalives MUST be based on the consent freshness
mechanism specified in [RFC7675]. -->
If a
keepalive fails and no new ICE channels can be established, then the keepalive fails and no new ICE channels can be established, then the
session is terminated. session is terminated.
</t> </t>
</section> </section>
</section> </section>
<section anchor="sec.sdp-id-attr" numbered="true" toc="default">
<section title="SDP Identity Attribute" anchor="sec.sdp-id-attr"> <name>SDP Identity Attribute</name>
<t> <t>
The SDP 'identity' attribute is a session-level attribute that The SDP "identity" attribute is a session-level attribute that
is used by an endpoint to convey its identity assertion to its is used by an endpoint to convey its identity assertion to its
peer. The identity assertion value is encoded as Base-64, as described peer. The identity-assertion value is encoded as base64, as described
in Section 4 of <xref target="RFC4648"/>. in <xref target="RFC4648" sectionFormat="of" section="4"/>.
</t> </t>
<t> <t>
The procedures in this section are based on the assumption The procedures in this section are based on the assumption
that the identity assertion of an endpoint is bound to the that the identity assertion of an endpoint is bound to the
fingerprints of the endpoint. This does not preclude the definition of fingerprints of the endpoint. This does not preclude the definition of
alternative means of binding an assertion to the endpoint, but such alternative means of binding an assertion to the endpoint, but such
means are outside the scope of this specification. means are outside the scope of this specification.
</t> </t>
<t> <t>
The semantics of multiple 'identity' attributes within an The semantics of multiple "identity" attributes within an
offer or answer are undefined. Implementations SHOULD only include a offer or answer are undefined. Implementations <bcp14>SHOULD</bcp14> on
single 'identity' attribute in an offer or answer and relying parties ly include a
MAY elect to ignore all but the first 'identity' attribute. single "identity" attribute in an offer or answer, and relying parties
</t> <bcp14>MAY</bcp14> elect to ignore all but the first "identity" attribut
<t> e.
<list style="hanging">
<t hangText="Name:">identity</t>
<t hangText="Value:">identity-assertion</t>
<t hangText="Usage Level:">session</t>
<t hangText="Charset Dependent:">no</t>
<t hangText="Default Value:">N/A</t>
<t hangText="Name:">identity</t>
</list>
</t> </t>
<figure> <dl newline="false" spacing="normal">
<dt>Name:</dt>
<dd>identity</dd>
<dt>Value:</dt>
<dd>identity-assertion</dd>
<dt>Usage Level:</dt>
<dd>session</dd>
<dt>Charset Dependent:</dt>
<dd>no</dd>
<dt>Default Value:</dt>
<dd>N/A</dd>
<dt>Name:</dt>
<dd>identity</dd>
</dl>
<!-- [rfced] Section 5: Are both "Name: identity" entries needed in
this list?
Original:
Name: identity
Value: identity-assertion
Usage Level: session
Charset Dependent: no
Default Value: N/A
Name: identity -->
<t>Syntax:</t>
<sourcecode name="abnf-1" type="abnf" ><![CDATA[
identity-assertion = identity-assertion-value
*(SP identity-extension)
identity-assertion-value = base64
identity-extension = extension-name [ "=" extension-value ]
extension-name = token
extension-value = 1*(%x01-09 / %x0b-0c / %x0e-3a / %x3c-ff)
; byte-string from [RFC4566]
<ALPHA and DIGIT as defined in [RFC4566]>
<base64 as defined in [RFC4566]>
]]></sourcecode>
<t>Example:</t>
<!-- [rfced] Section 5: We have split the <artwork> into 2 pieces: the
first has been tagged as <sourcecode type="abnf"> and the second as
<sourcecode type="sdp" >. See
<https://www.rfc-editor.org/materials/sourcecode-types.txt> for the preferred
list of "type" attributes. Please review and let us know if ay updates are
needed.
For the definitions of ALPHA and DIGIT, RFC 4566 refers to RFC 4234, which has
been obsoleted by RFC 5234. Should this document reference RFC 5234 for ALPHA
and DIGIT? Also, RFC 4566 will soon be obsoleted by RFC-to-be 8866
<draft-ietf-mmusic-rfc4566bis-37>; should this document be updated to point to
RFC 8866?
Original:
<artwork type="inline"><![CDATA[ <artwork type="inline"><![CDATA[
Syntax: Syntax:
identity-assertion = identity-assertion-value identity-assertion = identity-assertion-value
*(SP identity-extension) *(SP identity-extension)
identity-assertion-value = base64 identity-assertion-value = base64
identity-extension = extension-name [ "=" extension-value ] identity-extension = extension-name [ "=" extension-value ]
extension-name = token extension-name = token
extension-value = 1*(%x01-09 / %x0b-0c / %x0e-3a / %x3c-ff) extension-value = 1*(%x01-09 / %x0b-0c / %x0e-3a / %x3c-ff)
; byte-string from [RFC4566] ; byte-string from [RFC4566]
skipping to change at line 618 skipping to change at line 674
<ALPHA and DIGIT as defined in [RFC4566]> <ALPHA and DIGIT as defined in [RFC4566]>
<base64 as defined in [RFC4566]> <base64 as defined in [RFC4566]>
Example: Example:
a=identity:\ a=identity:\
eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\ eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\
In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\ In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\
IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\ IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\
aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9 aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9
-->
Note that long lines in the example are folded to meet the column <sourcecode name="sdp-1" type="sdp" ><![CDATA[
width constraints of this document; the backslash ("\") at the end of a=identity:\
a line, the carriage return that follows, and whitespace shall be ignored. eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\
In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\
IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\
aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9 ]]></sourcecode>
]]></artwork> <aside><t>Note that long lines in the example are folded to meet the column
</figure> width constraints of this document; the backslash ("\") at the end of
<t> a line, the carriage return that follows, and whitespace shall be ignored.</t>
</aside>
<t>
This specification does not define any extensions for the attribute. This specification does not define any extensions for the attribute.
</t> </t>
<t> <t>
The identity-assertion value is a JSON <xref target="RFC8259"/> encoded The identity-assertion value is a JSON encoded string
string. The JSON object <xref target="RFC8259" format="default"/>. The JSON object
contains two keys: "assertion" and "idp". The <spanx style="verb">asser contains two keys: "assertion" and "idp". The "assertion" key value con
tion</spanx> key value contains tains
an opaque string that is consumed by the IdP. The <spanx style="verb">i an opaque string that is consumed by the IdP. The "idp" key value conta
dp</spanx> key value contains a ins a
dictionary with one or two further values that identify the IdP. See dictionary with one or two further values that identify the IdP. See
<xref target="sec.request-assert"/> for more details. <xref target="sec.request-assert" format="default"/> for more details.
</t> </t>
<section title="Offer/Answer Considerations" anchor="sec.sdp-id-attr-oa"> <section anchor="sec.sdp-id-attr-oa" numbered="true" toc="default">
<t> <name>Offer/Answer Considerations</name>
This section defines the SDP Offer/Answer <xref target="RFC3264"/> co
nsiderations for the SDP <t>
'identity' attribute. This section defines the SDP offer/answer <xref target="RFC3264" form
</t> at="default"/> considerations for the SDP
<t> "identity" attribute.
</t>
<t>
Within this section, 'initial offer' refers to the first offer in the Within this section, 'initial offer' refers to the first offer in the
SDP session that contains an SDP <spanx style="verb">identity</spanx> SDP session that contains an SDP "identity" attribute.
attribute. </t>
</t> <section anchor="sec.sdp-id-attr-oa-inio" numbered="true" toc="default">
<section title="Generating the Initial SDP Offer" anchor="sec.sdp-id-at <name>Generating the Initial SDP Offer</name>
tr-oa-inio"> <t>
<t>
When an offerer sends an offer, in order to provide its When an offerer sends an offer, in order to provide its
identity assertion to the peer, it includes an 'identity' attribute i n identity assertion to the peer, it includes an "identity" attribute i n
the offer. In addition, the offerer includes one or more SDP the offer. In addition, the offerer includes one or more SDP
'fingerprint' attributes. The 'identity' attribute MUST be bound to "fingerprint" attributes. The "identity" attribute <bcp14>MUST</bcp1
all the 'fingerprint' attributes in the session 4> be bound to
all the "fingerprint" attributes in the session
description. description.
</t> </t>
</section> </section>
<section title="Generating of SDP Answer" anchor="sec.sdp-id-attr-oa-an <section anchor="sec.sdp-id-attr-oa-ansa" numbered="true" toc="default">
sa"> <name>Generating an SDP Answer</name>
<t> <t>
If the answerer elects to include an 'identity' attribute, it follo If the answerer elects to include an "identity" attribute, it follo
ws ws
the same steps as those in <xref target="sec.sdp-id-attr-oa-inio"/> the same steps as those in <xref target="sec.sdp-id-attr-oa-inio" f
. ormat="default"/>.
The answerer can choose to include or omit an 'identity' attribute The answerer can choose to include or omit an "identity" attribute
independently, independently,
regardless of whether the offerer did so. regardless of whether the offerer did so.
</t> </t>
</section> </section>
<section title="Processing an SDP Offer or Answer" anchor="sec.sdp-id-a <section anchor="sec.sdp-id-attr-oa-offa" numbered="true" toc="default">
ttr-oa-offa"> <name>Processing an SDP Offer or Answer</name>
<t> <t>
When an endpoint receives an offer or answer that contains an 'iden When an endpoint receives an offer or answer that contains an "iden
tity' tity"
attribute, the answerer can use the the attribute information to attribute, the answerer can use the attribute information to
contact the IdP and verify the identity of the peer. If the identit y contact the IdP and verify the identity of the peer. If the identit y
requires a third-party IdP as described in <xref target="sec.trust- relationships"/> requires a third-party IdP as described in <xref target="sec.trust- relationships" format="default"/>,
then that IdP will need to have been specifically configured. then that IdP will need to have been specifically configured.
If the identity verification fails, the answerer MUST discard the If the identity verification fails, the answerer <bcp14>MUST</bcp14 > discard the
offer or answer as malformed. offer or answer as malformed.
</t> </t>
</section> </section>
<section title="Modifying the Session" anchor="sec.sdp-id-attr-oa-modi" <section anchor="sec.sdp-id-attr-oa-modi" numbered="true" toc="default">
> <name>Modifying the Session</name>
<t> <t>
When modifying a session, if the set of fingerprints is When modifying a session, if the set of fingerprints is
unchanged, then the sender MAY send the same 'identity' attribute. unchanged, then the sender <bcp14>MAY</bcp14> send the same "identi
In ty" attribute. In
this case, the established identity MUST be applied to existing DTL this case, the established identity <bcp14>MUST</bcp14> be applied
S to existing DTLS
connections as well as new connections established using one of tho se connections as well as new connections established using one of tho se
fingerprints. Note that <xref target="I-D.ietf-rtcweb-jsep"/>, Sect fingerprints. Note that <xref target="RFC8829" sectionFormat="comma
ion " section="5.2.1"/> requires that each media section use the same set of
5.2.1 requires that each media section use the same set of
fingerprints for every media section. fingerprints for every media section.
If a new identity attribute is received, then the receiver MUST If a new "identity" attribute is received, then the receiver <bcp14 >MUST</bcp14>
apply that identity to all existing connections. apply that identity to all existing connections.
</t> </t>
<t> <t>
If the set of fingerprints changes, then the sender MUST If the set of fingerprints changes, then the sender <bcp14>MUST</bc
either send a new 'identity' attribute or none at all. p14>
either send a new "identity" attribute or none at all.
Because a change in fingerprints also causes a new DTLS Because a change in fingerprints also causes a new DTLS
connection to be established, the receiver MUST discard connection to be established, the receiver <bcp14>MUST</bcp14> disc ard
all previously established identities. all previously established identities.
</t> </t>
</section>
</section> </section>
</section>
</section> </section>
<section anchor="sec.proposal.detailed" numbered="true" toc="default">
<section title="Detailed Technical Description" anchor="sec.proposal.detaile <name>Detailed Technical Description</name>
d"> <section anchor="sec.proposal.origin" numbered="true" toc="default">
<name>Origin and Web Security Issues</name>
<section title="Origin and Web Security Issues" anchor="sec.proposal.origi
n">
<t> <t>
The basic unit of permissions for WebRTC is the origin <xref The basic unit of permissions for WebRTC is the origin <xref target="R
target="RFC6454"/>. Because the security of the origin depends on FC6454" format="default"/>. Because the security of the origin depends on
being able to authenticate content from that origin, the origin can being able to authenticate content from that origin, the origin can
only be securely established if data is transferred over HTTPS <xref only be securely established if data is transferred over HTTPS <xref t
target="RFC2818"/>. Thus, clients MUST treat HTTP and HTTPS origins as arget="RFC2818" format="default"/>. Thus, clients <bcp14>MUST</bcp14> treat HTTP
different permissions domains. Note: this follows directly from the and HTTPS origins as
different permissions domains. Note: This follows directly from the
origin security model and is stated here merely for clarity. origin security model and is stated here merely for clarity.
</t> </t>
<t> <t>
Many web browsers currently forbid by default any active mixed content Many Web browsers currently forbid by default any active mixed content
on HTTPS pages. That is, when JavaScript is loaded from an HTTP origin on HTTPS pages. That is, when JavaScript is loaded from an HTTP origin
onto an HTTPS page, an error is displayed and the HTTP content is not onto an HTTPS page, an error is displayed and the HTTP content is not
executed unless the user overrides the error. Any browser which executed unless the user overrides the error. Any browser which
enforces such a policy will also not permit access to WebRTC enforces such a policy will also not permit access to WebRTC
functionality from mixed content pages (because they never display functionality from mixed content pages (because they never display
mixed content). Browsers which allow active mixed content MUST mixed content). Browsers which allow active mixed content <bcp14>MUST </bcp14>
nevertheless disable WebRTC functionality in mixed content settings. nevertheless disable WebRTC functionality in mixed content settings.
</t> </t>
<t> <t>
Note that it is possible for a page which was not mixed content to Note that it is possible for a page that was not mixed content to
become mixed content during the duration of the call. The major risk become mixed content during the duration of the call. The major risk
here is that the newly arrived insecure JS might redirect media to a here is that the newly arrived insecure JS might redirect media to a
location controlled by the attacker. Implementations MUST either location controlled by the attacker. Implementations <bcp14>MUST</bcp 14> either
choose to terminate the call or display a warning at that point. choose to terminate the call or display a warning at that point.
</t> </t>
<t> <t>
Also note that the security architecture depends on the keying materia l Also note that the security architecture depends on the keying materia l
not being available to move between origins. But, it is assumed that not being available to move between origins. But it is assumed that
the identity assertion can be passed to anyone that the page cares to. the identity assertion can be passed to anyone that the page cares to.
</t> </t>
</section> </section>
<section anchor="sec.proposal.device.permissions" numbered="true" toc="def
<section title="Device Permissions Model" anchor="sec.proposal.device.perm ault">
issions"> <name>Device Permissions Model</name>
<t> <t>
Implementations MUST obtain explicit user consent prior to providing Implementations <bcp14>MUST</bcp14> obtain explicit user consent prior
access to the camera and/or microphone. Implementations MUST at to providing
access to the camera and/or microphone. Implementations <bcp14>MUST</b
cp14> at
minimum support the following two permissions models for HTTPS minimum support the following two permissions models for HTTPS
origins. origins.
</t> </t>
<t> <ul spacing="normal">
<list style="symbols"> <li>
<t>
Requests for one-time camera/microphone access. Requests for one-time camera/microphone access.
</t> </li>
<t> <li>
Requests for permanent access. Requests for permanent access.
</t> </li>
</list> </ul>
</t>
<t> <t>
Because HTTP origins cannot be securely established against network Because HTTP origins cannot be securely established against network
attackers, implementations MUST refuse all permissions grants for attackers, implementations <bcp14>MUST</bcp14> refuse all permissions grants for
HTTP origins. HTTP origins.
</t> </t>
<t> <t>
In addition, they SHOULD support requests for access that promise that In addition, they <bcp14>SHOULD</bcp14> support requests for access th at promise that
media from this grant will be sent to a single communicating peer media from this grant will be sent to a single communicating peer
(obviously there could be other requests for other peers), eE.g., (obviously there could be other requests for other peers), e.g.,
"Call customerservice@example.org". The semantics of this request are "Call customerservice@example.org". The semantics of this request are
that the media stream from the camera and microphone will only be that the media stream from the camera and microphone will only be
routed through a connection which has been cryptographically verified routed through a connection which has been cryptographically verified
(through the IdP mechanism or an X.509 certificate in the DTLS-SRTP (through the IdP mechanism or an X.509 certificate in the DTLS-SRTP
handshake) as being associated with the stated identity. Note that it handshake) as being associated with the stated identity. Note that it
is unlikely that browsers would have X.509 certificates, but servers is unlikely that browsers would have X.509 certificates, but servers
might. Browsers servicing such requests SHOULD clearly indicate that might. Browsers servicing such requests <bcp14>SHOULD</bcp14> clearly indicate that
identity to the user when asking for permission. The idea behind this identity to the user when asking for permission. The idea behind this
type of permissions is that a user might have a fairly narrow list of type of permissions is that a user might have a fairly narrow list of
peers he is willing to communicate with, e.g., "my mother" rather than peers he is willing to communicate with, e.g., "my mother" rather than
"anyone on Facebook". Narrow permissions grants allow the browser to "anyone on Facebook". Narrow permissions grants allow the browser to
do that enforcement. do that enforcement.
</t> </t>
<dl newline="false" spacing="normal">
<t> <dt>API Requirement:</dt>
<list style="hanging"> <dd>
<t hangText="API Requirement:"> The API <bcp14>MUST</bcp14> provide a mechanism for the requesting
The API MUST provide a mechanism for the requesting JS to JS to
relinquish the ability to see or modify the media (e.g., via relinquish the ability to see or modify the media (e.g., via
MediaStream.record()). Combined with secure authentication of the MediaStream.record()). Combined with secure authentication of the
communicating peer, this allows a user to be sure that the calling communicating peer, this allows a user to be sure that the calling
site is not accessing or modifying their conversion. site is not accessing or modifying their conversion.
</t> </dd>
</list> </dl>
</t> <dl newline="false" spacing="normal">
<dt>UI Requirement:</dt>
<t> <dd>
<list style="hanging"> The UI <bcp14>MUST</bcp14> clearly indicate when the user's camera
<t hangText="UI Requirement:"> and microphone
The UI MUST clearly indicate when the user's camera and microphone are in use. This indication <bcp14>MUST NOT</bcp14> be suppressib
are in use. This indication MUST NOT be suppressable by the JS le by the JS
and MUST clearly indicate how to terminate device access, and and <bcp14>MUST</bcp14> clearly indicate how to terminate device a
ccess, and
provide a UI means to immediately stop camera/microphone input provide a UI means to immediately stop camera/microphone input
without the JS being able to prevent it. without the JS being able to prevent it.
</t> </dd>
</list> </dl>
</t> <dl newline="false" spacing="normal">
<dt>UI Requirement:</dt>
<t> <dd>
<list style="hanging"> If the UI indication of camera/microphone use is displayed in the
<t hangText="UI Requirement:">
If the UI indication of camera/microphone use are displayed in the
browser such that minimizing the browser window would hide the browser such that minimizing the browser window would hide the
indication, or the JS creating an overlapping window would hide indication, or the JS creating an overlapping window would hide
the indication, then the browser SHOULD stop camera and microphone the indication, then the browser <bcp14>SHOULD</bcp14> stop camera
input when the indication is hidden. [Note: this may not be and microphone
input when the indication is hidden. (Note: This may not be
necessary in systems that are non-windows-based but that have good necessary in systems that are non-windows-based but that have good
notifications support, such as phones.] notifications support, such as phones.)
</t> </dd>
</list> </dl>
</t>
<t> <!-- [rfced] Section 6.2: Is the bullet list after this "UI
<list style="symbols"> Requirement:" list item supposed to be a "sub-list" (as was done,
<t> for example, after the "UI Requirements:" list item in Section 6.5),
Browsers MUST NOT permit permanent screen or application sharing or should it remain as a separate list?
Original:
UI Requirement: If the UI indication of camera/microphone use are
displayed in the browser such that minimizing the browser window
would hide the indication, or the JS creating an overlapping
window would hide the indication, then the browser SHOULD stop
camera and microphone input when the indication is hidden. [Note:
this may not be necessary in systems that are non-windows-based
but that have good notifications support, such as phones.]
o Browsers MUST NOT permit permanent screen or application sharing
permissions to be installed as a response to a JS request for
permissions. Instead, they must require some other user action
such as a permissions setting or an application install experience
to grant permission to a site.
... -->
<ul spacing="normal">
<li>
Browsers <bcp14>MUST NOT</bcp14> permit permanent screen or applic
ation sharing
permissions to be installed as a response to a JS request for permissions to be installed as a response to a JS request for
permissions. Instead, they must require some other user action permissions. Instead, they must require some other user action
such as a permissions setting or an application install experience such as a permissions setting or an application install experience
to grant permission to a site. to grant permission to a site.
</t> </li>
<t> <li>
Browsers MUST provide a separate dialog request for Browsers <bcp14>MUST</bcp14> provide a separate dialog request for
screen/application sharing permissions even if the media request screen/application sharing permissions even if the media request
is made at the same time as camera and microphone. is made at the same time as camera and microphone.
</t>
<t> <!-- [rfced] Section 6.2: Please clarify the meaning of "as camera
The browser MUST indicate any windows which are currently being and microphone."
shared in some unambiguous way. Windows which are not visible MUST
NOT be shared even if the application is being shared. If the
screen is being shared, then that MUST be indicated.
</t>
</list>
</t>
Original:
o Browsers MUST provide a separate dialog request for screen/
application sharing permissions even if the media request is made
at the same time as camera and microphone. -->
</li>
<li>
The browser <bcp14>MUST</bcp14> indicate any windows which are cur
rently being
shared in some unambiguous way. Windows which are not visible <bcp
14>MUST
NOT</bcp14> be shared even if the application is being shared. If
the
screen is being shared, then that <bcp14>MUST</bcp14> be indicated
.
</li>
</ul>
<t> <t>
Browsers MAY permit the formation of data channels without any direct Browsers <bcp14>MAY</bcp14> permit the formation of data channels with out any direct
user approval. Because sites can always tunnel data through the user approval. Because sites can always tunnel data through the
server, further restrictions on the data channel do not provide any server, further restrictions on the data channel do not provide any
additional security. (See <xref additional security. (See <xref target="sec.proposal.communications.c
target="sec.proposal.communications.consent"/> for a related issue). onsent" format="default"/> for a related issue.)
</t> </t>
<t> <t>
Implementations which support some form of direct user authentication Implementations which support some form of direct user authentication
SHOULD also provide a policy by which a user can authorize calls only <bcp14>SHOULD</bcp14> also provide a policy by which a user can author ize calls only
to specific communicating peers. Specifically, the implementation to specific communicating peers. Specifically, the implementation
SHOULD provide the following interfaces/controls: <bcp14>SHOULD</bcp14> provide the following interfaces/controls:
</t> </t>
<t> <ul spacing="normal">
<list style="symbols"> <li>
<t>
Allow future calls to this verified user. Allow future calls to this verified user.
</t> </li>
<t> <li>
Allow future calls to any verified user who is in my system Allow future calls to any verified user who is in my system
address book (this only works with address book integration, of address book (this only works with address book integration, of
course). course).
</t> </li>
</list> </ul>
</t>
<t> <t>
Implementations SHOULD also provide a different user interface Implementations <bcp14>SHOULD</bcp14> also provide a different user in terface
indication when calls are in progress to users whose identities are indication when calls are in progress to users whose identities are
directly verifiable. <xref target="sec.proposal.comsec"/> provides directly verifiable. <xref target="sec.proposal.comsec" format="defau lt"/> provides
more on this. more on this.
</t> </t>
</section> </section>
<section anchor="sec.proposal.communications.consent" numbered="true" toc=
<section title="Communications Consent" anchor="sec.proposal.communication "default">
s.consent"> <name>Communications Consent</name>
<t> <t>
Browser client implementations of WebRTC MUST implement ICE. Server Browser client implementations of WebRTC <bcp14>MUST</bcp14> implement
gateway implementations which operate only at public IP addresses MUST ICE. Server
implement either full ICE or ICE-Lite <xref target="RFC8445"/>. gateway implementations which operate only at public IP addresses <bcp
14>MUST</bcp14>
implement either full ICE or ICE-Lite <xref target="RFC8445" format="d
efault"/>.
</t> </t>
<t> <t>
Browser implementations MUST verify reachability via ICE prior to Browser implementations <bcp14>MUST</bcp14> verify reachability via IC E prior to
sending any non-ICE packets to a given destination. Implementations sending any non-ICE packets to a given destination. Implementations
MUST NOT provide the ICE transaction ID to JavaScript during the <bcp14>MUST NOT</bcp14> provide the ICE transaction ID to JavaScript d uring the
lifetime of the transaction (i.e., during the period when the ICE lifetime of the transaction (i.e., during the period when the ICE
stack would accept a new response for that transaction). The JS MUST stack would accept a new response for that transaction). The JS <bcp1
NOT be permitted to control the local ufrag and password, though it of 4>MUST
NOT</bcp14> be permitted to control the local ufrag and password, thou
gh it of
course knows it. course knows it.
</t> </t>
<t> <!-- FIXME: phrasing of first sentence still awkward --> <t>
While continuing consent is required, the ICE <xref While continuing consent is required, the ICE <xref target="RFC8445" s
target="RFC8445"/>; Section 10 keepalives use STUN Binding Indications ectionFormat="comma" section="10"/> keepalives use STUN Binding Indications whic
which are h are
one-way and therefore not sufficient. The current WG consensus is to one-way and therefore not sufficient.
<!-- [rfced] Section 6.3: Please advise regarding the following:
1. We do not see the word "keepalive" in Section 10 of RFC 8445, but
we do see it in 8445's Section 11. Please confirm that "Section 10"
is correct here and will be clear to readers.
2. We found the use of "which" confusing here. Are all STUN Binding
Indications one-way and therefore not sufficient (in which case "STUN
Binding Indications, which are" would be correct), or only some (in
which case "STUN Binding Indications that are" would be correct)?
3. We found this comment, in the XML file, just prior to this
sentence: "FIXME: phrasing of first sentence still awkward."
Please let us know how/if you want to fix the phrasing.
Original:
While continuing consent is required, the ICE [RFC8445]; Section 10
keepalives use STUN Binding Indications which are one-way and
therefore not sufficient. -->
The current WG consensus is to
use ICE Binding Requests for continuing consent freshness. ICE already use ICE Binding Requests for continuing consent freshness. ICE already
requires that implementations respond to such requests, so this requires that implementations respond to such requests, so this
approach is maximally compatible. A separate document will profile the approach is maximally compatible. A separate document will profile the
ICE timers to be used; see <xref target="RFC7675"/>. ICE timers to be used; see <xref target="RFC7675" format="default"/>.
</t> </t>
</section> </section>
<section anchor="sec.proposal.ip.location.privacy" numbered="true" toc="de
<section title="IP Location Privacy" anchor="sec.proposal.ip.location.priv fault">
acy"> <name>IP Location Privacy</name>
<t> <t>
A side effect of the default ICE behavior is that the peer learns A side effect of the default ICE behavior is that the peer learns
one's IP address, which leaks large amounts of location one's IP address, which leaks large amounts of location
information. This has negative privacy consequences in some information. This has negative privacy consequences in some
circumstances. The API requirements in this section are intended to circumstances. The API requirements in this section are intended to
mitigate this issue. Note that these requirements are not intended to mitigate this issue. Note that these requirements are not intended to
protect the user's IP address from a malicious site. In general, the protect the user's IP address from a malicious site. In general, the
site will learn at least a user's server reflexive address from any site will learn at least a user's server-reflexive address from any
HTTP transaction. Rather, these requirements are intended to allow a HTTP transaction.
<!-- [rfced] Section 6.4: Per author feedback for RFC 8839 and per
other documents in this cluster, we hyphenated the term "server
reflexive". Please let us know any objections.
Original:
In general, the site will learn at
least a user's server reflexive address from any HTTP transaction.
Currently:
In general, the site will learn at
least a user's server-reflexive address from any HTTP transaction. -->
Rather, these requirements are intended to allow a
site to cooperate with the user to hide the user's IP address from the site to cooperate with the user to hide the user's IP address from the
other side of the call. Hiding the user's IP address from the server other side of the call. Hiding the user's IP address from the server
requires some sort of explicit privacy preserving mechanism on the requires some sort of explicit privacy-preserving mechanism on the
client (e.g., Tor Browser [https://www.torproject.org/projects/torbrow client (e.g., Tor Browser <eref brackets="angle" target="https://www.t
ser.html.en]) and orproject.org/projects/torbrowser.html.en"/>) and
is out of scope for this specification. is out of scope for this specification.
</t> </t>
<dl newline="false" spacing="normal">
<t> <dt>API Requirement:</dt>
<list style="hanging"> <dd>
<t hangText="API Requirement:"> The API <bcp14>MUST</bcp14> provide a mechanism to allow the JS to
The API MUST provide a mechanism to allow the JS to suppress ICE suppress ICE
negotiation (though perhaps to allow candidate gathering) until negotiation (though perhaps to allow candidate gathering) until
the user has decided to answer the call [note: determining when the user has decided to answer the call. (Note: Determining when
the call has been answered is a question for the JS.] This the call has been answered is a question for the JS.) This
enables a user to prevent a peer from learning their IP address if enables a user to prevent a peer from learning their IP address if
they elect not to answer a call and also from learning whether the they elect not to answer a call and also from learning whether the
user is online. user is online.
</t> </dd>
</list> </dl>
</t> <dl newline="false" spacing="normal">
<dt>API Requirement:</dt>
<t> <dd>
<list style="hanging"> The API <bcp14>MUST</bcp14> provide a mechanism for the calling ap
<t hangText="API Requirement:"> plication JS to
The API MUST provide a mechanism for the calling application JS to
indicate that only TURN candidates are to be used. This prevents indicate that only TURN candidates are to be used. This prevents
the peer from learning one's IP address at all. This mechanism the peer from learning one's IP address at all. This mechanism
MUST also permit suppression of the related address field, since <bcp14>MUST</bcp14> also permit suppression of the related address field, since
that leaks local addresses. that leaks local addresses.
</t> </dd>
</list> </dl>
</t> <dl newline="false" spacing="normal">
<dt>API Requirement:</dt>
<t> <dd>
<list style="hanging"> The API <bcp14>MUST</bcp14> provide a mechanism for the calling ap
<t hangText="API Requirement:"> plication to
The API MUST provide a mechanism for the calling application to
reconfigure an existing call to add non-TURN candidates. Taken reconfigure an existing call to add non-TURN candidates. Taken
together, this and the previous requirement allow ICE negotiation together, this and the previous requirement allow ICE negotiation
to start immediately on incoming call notification, thus reducing to start immediately on incoming call notification, thus reducing
post-dial delay, but also to avoid disclosing the user's IP post-dial delay, but also to avoid disclosing the user's IP
address until they have decided to answer. They also allow users address until they have decided to answer. They also allow users
to completely hide their IP address for the duration of the to completely hide their IP address for the duration of the
call. Finally, they allow a mechanism for the user to optimize call. Finally, they allow a mechanism for the user to optimize
performance by reconfiguring to allow non-TURN candidates during performance by reconfiguring to allow non-TURN candidates during
an active call if the user decides they no longer need to hide an active call if the user decides they no longer need to hide
their IP address their IP address.
</t> </dd>
</list> </dl>
</t>
<t> <t>
Note that some enterprises may operate proxies and/or NATs designed to Note that some enterprises may operate proxies and/or NATs designed to
hide internal IP addresses from the outside world. WebRTC provides no hide internal IP addresses from the outside world. WebRTC provides no
explicit mechanism to allow this function. Either such enterprises explicit mechanism to allow this function. Either such enterprises
need to proxy the HTTP/HTTPS and modify the SDP and/or the JS, or need to proxy the HTTP/HTTPS and modify the SDP and/or the JS, or
there needs to be browser support to set the "TURN-only" policy there needs to be browser support to set the "TURN-only" policy
regardless of the site's preferences. regardless of the site's preferences.
</t> </t>
</section> </section>
<section anchor="sec.proposal.comsec" numbered="true" toc="default">
<section title="Communications Security" anchor="sec.proposal.comsec"> <name>Communications Security</name>
<t> <t>
Implementations MUST support SRTP <xref target="RFC3711"/>. Implementations <bcp14>MUST</bcp14> support SRTP <xref target="RFC3711
Implementations MUST support DTLS <xref target="RFC6347"/> and " format="default"/>.
DTLS-SRTP <xref target="RFC5763"/><xref target="RFC5764"/> for SRTP Implementations <bcp14>MUST</bcp14> support DTLS <xref target="RFC6347
keying. Implementations MUST support SCTP over DTLS <xref " format="default"/> and
target="RFC8261"/>. DTLS-SRTP <xref target="RFC5763" format="default"/> <xref target="RFC5
764" format="default"/> for SRTP
keying. Implementations <bcp14>MUST</bcp14> support SCTP over DTLS <xr
ef target="RFC8261" format="default"/>.
</t> </t>
<t> <t>
All media channels MUST be secured via SRTP and SRTCP. Media traffic All media channels <bcp14>MUST</bcp14> be secured via SRTP and the
MUST NOT Secure Real-time Transport Control Protocol (SRTCP). Media traffic <bc
be sent over plain (unencrypted) RTP or RTCP; that is, implementations p14>MUST NOT</bcp14>
MUST be sent over plain (unencrypted) RTP or RTCP; that is, implementations
NOT negotiate cipher suites with NULL encryption modes. DTLS-SRTP <bcp14>MUST
MUST be offered for every media channel. WebRTC implementations MUST NOT</bcp14> negotiate cipher suites with NULL encryption modes. DTLS-
NOT SRTP
offer SDP Security Descriptions <xref target="RFC4568"/> or select it <bcp14>MUST</bcp14> be offered for every media channel. WebRTC implem
if offered. entations <bcp14>MUST NOT</bcp14>
A SRTP MKI MUST NOT be used. offer SDP security descriptions <xref target="RFC4568" format="default
"/> or select it if offered.
An SRTP Master Key Identifier (MKI) <bcp14>MUST NOT</bcp14> be used.
</t> </t>
<t> <t>
All data channels MUST be secured via DTLS. All data channels <bcp14>MUST</bcp14> be secured via DTLS.
</t> </t>
<t> <t>
All Implementations MUST support DTLS 1.2 with the All implementations <bcp14>MUST</bcp14> support DTLS 1.2 with the
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 cipher suite and the TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 cipher suite and the
<xref target="FIPS186">P-256 curve</xref>. <xref target="FIPS186" format="default">P-256 curve</xref>.
Earlier drafts of this specification required Earlier drafts of this specification required
DTLS 1.0 with the cipher suite DTLS 1.0 with the cipher suite
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, and at the time of this TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, and at the time of this
writing some implementations do not support DTLS 1.2; writing some implementations do not support DTLS 1.2;
endpoints which support only DTLS 1.2 might encounter endpoints that support only DTLS 1.2 might encounter
interoperability issues. interoperability issues.
The DTLS-SRTP protection profile The DTLS-SRTP protection profile
SRTP_AES128_CM_HMAC_SHA1_80 MUST be supported for SRTP_AES128_CM_HMAC_SHA1_80 <bcp14>MUST</bcp14> be supported for
SRTP. SRTP.
Implementations Implementations
MUST favor cipher suites which support (Perfect Forward Secrecy) PFS <bcp14>MUST</bcp14> favor cipher suites which support Perfect Forward
over non-PFS cipher suites and SHOULD favor AEAD over non-AEAD cipher Secrecy (PFS)
suites. over non-PFS cipher suites and <bcp14>SHOULD</bcp14> favor
Authenticated Encryption with Associated Data (AEAD) over non-AEAD ciph
er suites.
</t> </t>
<t> <t>
Implementations MUST NOT implement DTLS renegotiation and MUST reject Implementations <bcp14>MUST NOT</bcp14> implement DTLS renegotiation a nd <bcp14>MUST</bcp14> reject
it with a "no_renegotiation" alert if offered.</t> it with a "no_renegotiation" alert if offered.</t>
<t> <t>
Endpoints MUST NOT implement TLS False Start <xref target="RFC7918"/>. Endpoints <bcp14>MUST NOT</bcp14> implement TLS False Start <xref targ
</t> et="RFC7918" format="default"/>.</t>
<dl newline="false" spacing="normal">
<t> <dt>API Requirement:</dt>
<list style="hanging"> <dd>
<t hangText="API Requirement:"> The API <bcp14>MUST</bcp14> generate a new authentication key pair
The API MUST generate a new authentication key pair for every new for every new
call by default. This is intended to allow for unlinkability. call by default. This is intended to allow for unlinkability.
</t> </dd>
<t hangText="API Requirement:"> <dt>API Requirement:</dt>
The API MUST provide a means to reuse a key pair for calls. This <dd>
The API <bcp14>MUST</bcp14> provide a means to reuse a key pair fo
r calls. This
can be used to enable key continuity-based authentication, and can be used to enable key continuity-based authentication, and
could be used to amortize key generation costs. could be used to amortize key generation costs.
</t> </dd>
<t hangText="API Requirement:"> <dt>API Requirement:</dt>
<dd>
Unless Unless
the user specifically configures an external key pair, different the user specifically configures an external key pair, different
key pairs MUST be used for each origin. (This avoids creating a key pairs <bcp14>MUST</bcp14> be used for each origin. (This avoid s creating a
super-cookie.) super-cookie.)
</t> </dd>
<t hangText="API Requirement:"> <dt>API Requirement:</dt>
When DTLS-SRTP is used, the API MUST NOT permit the JS to obtain <dd>
When DTLS-SRTP is used, the API <bcp14>MUST NOT</bcp14> permit the
JS to obtain
the negotiated keying material. This requirement preserves the the negotiated keying material. This requirement preserves the
end-to-end security of the media. end-to-end security of the media.
</t> </dd>
</list> </dl>
</t> <dl newline="false" spacing="normal">
<dt>UI Requirements:</dt>
<t> <dd>
<list style="hanging"> A user-oriented client <bcp14>MUST</bcp14> provide an "inspector"
<t hangText="UI Requirements: "> interface which
A user-oriented client MUST provide an "inspector" interface which
allows the user to determine the security characteristics of the allows the user to determine the security characteristics of the
media. media.
</t> </dd>
<t> <dt/>
The following properties SHOULD be displayed "up-front" in the <dd>
The following properties <bcp14>SHOULD</bcp14> be displayed "up-fr
ont" in the
browser chrome, i.e., without requiring the user to ask for them: browser chrome, i.e., without requiring the user to ask for them:
</t> </dd>
<t> <dt/>
<list style="symbols"> <dd>
<t> <ul spacing="normal">
A client MUST provide a user interface through which a user <li>
A client <bcp14>MUST</bcp14> provide a user interface through
which a user
may determine the security characteristics for may determine the security characteristics for
currently-displayed audio and video stream(s) currently displayed audio and video stream(s).
</t> </li>
<li>
<t> A client <bcp14>MUST</bcp14> provide a user interface through
A client MUST provide a user interface through which a user which a user
may determine the security characteristics for transmissions may determine the security characteristics for transmissions
of their microphone audio and camera video. of their microphone audio and camera video.
</t> </li>
<li>
<t>
If the far endpoint was directly verified, either via a If the far endpoint was directly verified, either via a
third-party verifiable X.509 certificate or via a Web IdP third-party verifiable X.509 certificate or via a Web IdP
mechanism (see <xref target="sec.generic.idp"/>) the "security mechanism (see <xref target="sec.generic.idp" format="default"
characteristics" MUST include the verified information. X.509 />), the "security
characteristics" <bcp14>MUST</bcp14> include the verified info
rmation. X.509
identities and Web IdP identities have similar semantics and identities and Web IdP identities have similar semantics and
should be displayed in a similar way. should be displayed in a similar way.
</t> </li>
</list> </ul>
</t> </dd>
<t> <dt/>
</t> <dd>
<t>
The following properties are more likely to require some The following properties are more likely to require some
"drill-down" from the user: "drill-down" from the user:
</t> </dd>
<t> <dt/>
<list style="symbols"> <dd>
<t> <ul spacing="normal">
The "security characteristics" MUST indicate the cryptographic <li>
algorithms in use (For example: "AES-CBC".) The "security characteristics" <bcp14>MUST</bcp14> indicate th
</t> e cryptographic
algorithms in use (for example, "AES-CBC").
<t> </li>
The "security characteristics" MUST indicate whether PFS is <li>
The "security characteristics" <bcp14>MUST</bcp14> indicate wh
ether PFS is
provided. provided.
</t> </li>
<li>
<t> The "security characteristics" <bcp14>MUST</bcp14> include som
The "security characteristics" MUST include some mechanism to e mechanism to
allow an out-of-band verification of the peer, such as a allow an out-of-band verification of the peer, such as a
certificate fingerprint or a Short Authentication String (SAS) . certificate fingerprint or a Short Authentication String (SAS) .
These are compared by the peers to authenticate one another. These are compared by the peers to authenticate one another.
</t> </li>
</list> </ul>
</t> </dd>
</list> </dl>
</t>
</section> </section>
</section> </section>
<section anchor="sec.generic.idp" numbered="true" toc="default">
<section title="Web-Based Peer Authentication" anchor="sec.generic.idp"> <name>Web-Based Peer Authentication</name>
<t> <t>
In a number of cases, it is desirable for the endpoint (i.e., the In a number of cases, it is desirable for the endpoint (i.e., the
browser) to be able to directly identify the endpoint on the other browser) to be able to directly identify the endpoint on the other
side without trusting the signaling service to which they are side without trusting the signaling service to which they are
connected. For instance, users may be making a call via a federated connected. For instance, users may be making a call via a federated
system where they wish to get direct authentication of the other system where they wish to get direct authentication of the other
side. Alternately, they may be making a call on a site which they side. Alternately, they may be making a call on a site which they
minimally trust (such as a poker site) but to someone who has an minimally trust (such as a poker site) but to someone who has an
identity on a site they do trust (such as a social network.) identity on a site they do trust (such as a social network).
</t> </t>
<t> <t>
Recently, a number of Web-based identity technologies (OAuth, Recently, a number of Web-based identity technologies (OAuth,
Facebook Connect etc.) have been developed. While the Facebook Connect, etc.) have been developed. While the
details vary, what these technologies share is that they have a details vary, what these technologies share is that they have a
Web-based (i.e., HTTP/HTTPS) identity provider which attests to Alice' s Web-based (i.e., HTTP/HTTPS) identity provider that attests to Alice's
identity. For instance, if Alice has an account at example.org, Alice could identity. For instance, if Alice has an account at example.org, Alice could
use the example.org identity provider to prove to others that Alice is use the example.org identity provider to prove to others that Alice is
alice@example.org. The development of these technologies allows us to alice@example.org. The development of these technologies allows us to
separate calling from identity provision: Alice could call you on a separate calling from identity provision: Alice could call you on a
poker site but identify herself as alice@example.org. poker site but identify herself as alice@example.org.
</t> </t>
<t> <t>
Whatever the underlying technology, the general principle is that the Whatever the underlying technology, the general principle is that the
party which is being authenticated is NOT the signaling site but party which is being authenticated is NOT the signaling site but
rather the user (and their browser). Similarly, the relying party is rather the user (and their browser). Similarly, the relying party is
the browser and not the signaling site. Thus, the browser MUST the browser and not the signaling site. Thus, the browser <bcp14>MUST </bcp14>
generate the input to the IdP assertion process and generate the input to the IdP assertion process and
display the results of the verification process to the user display the results of the verification process to the user
in a way which cannot be imitated by the calling site. in a way which cannot be imitated by the calling site.
</t> </t>
<t> <t>
The mechanisms defined in this document do not require the browser to The mechanisms defined in this document do not require the browser to
implement any particular identity protocol or to support any implement any particular identity protocol or to support any
particular IdP. Instead, this document provides a generic interface particular IdP. Instead, this document provides a generic interface
which any IdP can implement. Thus, new IdPs and protocols can be which any IdP can implement. Thus, new IdPs and protocols can be
introduced without change to either the browser or the calling introduced without change to either the browser or the calling
service. This avoids the need to make a commitment to any particular service. This avoids the need to make a commitment to any particular
identity protocol, although browsers may opt to directly implement identity protocol, although browsers may opt to directly implement
some identity protocols in order to provide superior performance or UI some identity protocols in order to provide superior performance or UI
properties. properties.
</t> </t>
<section anchor="sec.trust-relationships" numbered="true" toc="default">
<section title="Trust Relationships: IdPs, APs, and RPs" anchor="sec.tru <name>Trust Relationships: IdPs, APs, and RPs</name>
st-relationships"> <t>
<t>
Any federated identity protocol has three major participants: Any federated identity protocol has three major participants:
</t> </t>
<t> <dl newline="false" spacing="normal">
<list style="hanging"> <dt>Authenticating Party (AP):</dt>
<t hangText="Authenticating Party (AP):"> <dd>
The entity which is trying to establish its identity. The entity which is trying to establish its identity.
</t> </dd>
<t> <dt>Identity Provider (IdP):</dt>
</t> <dd>
<t hangText="Identity Provider (IdP):">
The entity which is vouching for the AP's identity. The entity which is vouching for the AP's identity.
</t> </dd>
<dt>Relying Party (RP):</dt>
<t> <dd>
</t>
<t hangText="Relying Party (RP):">
The entity which is trying to verify the AP's identity. The entity which is trying to verify the AP's identity.
</t> </dd>
</list> </dl>
</t> <t>
<t>
The AP and the IdP have an account relationship of some kind: the AP The AP and the IdP have an account relationship of some kind: the AP
registers with the IdP and is able to subsequently authenticate registers with the IdP and is able to subsequently authenticate
directly to the IdP (e.g., with a password). This means that the directly to the IdP (e.g., with a password). This means that the
browser must somehow know which IdP(s) the user has an account browser must somehow know which IdP(s) the user has an account
relationship with. This can either be something that the user relationship with. This can either be something that the user
configures into the browser or that is configured at the calling configures into the browser or that is configured at the calling
site and then provided to the PeerConnection by the Web application site and then provided to the PeerConnection by the Web application
at the calling site. The use case for having this information at the calling site. The use case for having this information
configured into the browser is that the user may "log into" the configured into the browser is that the user may "log into" the
browser to bind it to some identity. This is becoming common in new browser to bind it to some identity. This is becoming common in new
browsers. However, it should also be possible for the IdP browsers. However, it should also be possible for the IdP
information to simply be provided by the calling application. information to simply be provided by the calling application.
</t> </t>
<t> <t>
At a high level there are two kinds of IdPs: At a high level, there are two kinds of IdPs:
</t> </t>
<t> <dl newline="false" spacing="normal">
<list style="hanging"> <dt>Authoritative:</dt>
<t hangText="Authoritative: "> <dd>
IdPs which have verifiable control of some section of the IdPs which have verifiable control of some section of the
identity space. For instance, in the realm of e-mail, the identity space. For instance, in the realm of email, the
operator of "example.com" has complete control of the namespace operator of "example.com" has complete control of the namespace
ending in "@example.com". Thus, "alice@example.com" is whoever ending in "@example.com". Thus, "alice@example.com" is whoever
the operator says it is. Examples of systems with authoritative the operator says it is. Examples of systems with authoritative
identity providers include DNSSEC, RFC 4474, and Facebook identity providers include DNSSEC, RFC 4474, and Facebook
Connect (Facebook identities only make sense within the context Connect (Facebook identities only make sense within the context
of the Facebook system). of the Facebook system).
</t>
<t> <!-- [rfced] Section 7.1: May we cite RFC 8224 (which obsoletes
</t> RFC 4474) here instead (with brackets, so that a hyperlink will be
<t hangText="Third-Party: "> available for the reader) and list it under Informative References?
Original:
Examples of systems with authoritative
identity providers include DNSSEC, RFC 4474, and Facebook Connect
(Facebook identities only make sense within the context of the
Facebook system).
Possibly:
Examples of systems with authoritative
identity providers include DNSSEC, an identity system for SIP
(see [RFC8224]), and Facebook Connect (Facebook identities only make
sense within the context of the Facebook system).
...
[RFC8224] Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
"Authenticated Identity Management in the Session
Initiation Protocol (SIP)", RFC 8224, DOI 10.17487/RFC8224,
February 2018, <https://www.rfc-editor.org/info/rfc8224>. -->
</dd>
<dt>Third-Party:</dt>
<dd>
IdPs which don't have control of their section of the identity IdPs which don't have control of their section of the identity
space but instead verify user's identities via some unspecified space but instead verify a user's identity via some unspecified
mechanism and then attest to it. Because the IdP doesn't mechanism and then attest to it. Because the IdP doesn't
actually control the namespace, RPs need to trust that the IdP actually control the namespace, RPs need to trust that the IdP
is correctly verifying AP identities, and there can potentially is correctly verifying AP identities, and there can potentially
be multiple IdPs attesting to the same section of the identity be multiple IdPs attesting to the same section of the identity
space. Probably the best-known example of a third-party identity space. Probably the best-known example of a third-party identity
provider is SSL/TLS certificates, where there are a large number of provider is SSL/TLS certificates, where there are a large number of
CAs all of whom can attest to any domain name. certification authorities (CAs) all of whom can attest to any do
</t> main name.
</list> </dd>
</t> </dl>
<t>
<t>
If an AP is authenticating via an authoritative IdP, then the RP If an AP is authenticating via an authoritative IdP, then the RP
does not need to explicitly configure trust in the IdP at all. The does not need to explicitly configure trust in the IdP at all. The
identity mechanism can directly verify that the IdP indeed made the identity mechanism can directly verify that the IdP indeed made the
relevant identity assertion (a function provided by the mechanisms relevant identity assertion (a function provided by the mechanisms
in this document), and any assertion it makes about an identity for in this document), and any assertion it makes about an identity for
which it is authoritative is directly verifiable. Note that this which it is authoritative is directly verifiable. Note that this
does not mean that the IdP might not lie, but that is a does not mean that the IdP might not lie, but that is a
trustworthiness judgement that the user can make at the time he trustworthiness judgement that the user can make at the time he
looks at the identity. looks at the identity.
</t> </t>
<t> <t>
By contrast, if an AP is authenticating via a third-party IdP, the By contrast, if an AP is authenticating via a third-party IdP, the
RP needs to explicitly trust that IdP (hence the need for an RP needs to explicitly trust that IdP (hence the need for an
explicit trust anchor list in PKI-based SSL/TLS clients). The list explicit trust anchor list in PKI-based SSL/TLS clients). The list
of trustable IdPs needs to be configured directly into the browser, of trustable IdPs needs to be configured directly into the browser,
either by the user or potentially by the browser manufacturer. This either by the user or potentially by the browser manufacturer. This
is a significant advantage of authoritative IdPs and implies that if is a significant advantage of authoritative IdPs and implies that if
third-party IdPs are to be supported, the potential number needs to third-party IdPs are to be supported, the potential number needs to
be fairly small. be fairly small.
</t> </t>
</section> </section>
<section anchor="sec.overview" numbered="true" toc="default">
<section title="Overview of Operation" anchor="sec.overview"> <name>Overview of Operation</name>
<t> <t>
In order to provide security without trusting the calling site, the In order to provide security without trusting the calling site, the
PeerConnection component of the browser must interact directly with PeerConnection component of the browser must interact directly with
the IdP. The details of the mechanism are described in the W3C API the IdP. The details of the mechanism are described in the W3C API
specification, but the general idea is that the PeerConnection specification, but the general idea is that the PeerConnection
component downloads JS from a specific location on the IdP dictated component downloads JS from a specific location on the IdP dictated
by the IdP domain name. That JS (the "IdP proxy") runs in an by the IdP domain name. That JS (the "IdP proxy") runs in an
isolated security context within the browser and the PeerConnection isolated security context within the browser, and the PeerConnection
talks to it via a secure message passing channel. talks to it via a secure message passing channel.
</t> </t>
<t> <t>
Note that there are two logically separate functions here: Note that there are two logically separate functions here:
<list style="symbols"> </t>
<t> <ul spacing="normal">
<li>
Identity assertion generation. Identity assertion generation.
</t> </li>
<t> <li>
Identity assertion verification. Identity assertion verification.
</t> </li>
</list> </ul>
</t> <t>
<t> The same IdP JS "endpoint" is used for both functions, but of course
The same IdP JS "endpoint" is used for both functions but of course
a given IdP might behave differently and load new JS to perform one a given IdP might behave differently and load new JS to perform one
function or the other. function or the other.
</t> </t>
<figure> <artwork name="" type="" align="left" alt=""><![CDATA[
<artwork><![CDATA[
+--------------------------------------+ +--------------------------------------+
| Browser | | Browser |
| | | |
| +----------------------------------+ | | +----------------------------------+ |
| | https://calling-site.example.com | | | | https://calling-site.example.com | |
| | | | | | | |
| | Calling JS Code | | | | Calling JS Code | |
| | ^ | | | | ^ | |
| +---------------|------------------+ | | +---------------|------------------+ |
| | API Calls | | | API Calls |
skipping to change at line 1286 skipping to change at line 1401
| PeerConnection | | PeerConnection |
| ^ | | ^ |
| | API Calls | | | API Calls |
| +-----------|-------------+ | +---------------+ | +-----------|-------------+ | +---------------+
| | v | | | | | | v | | | |
| | IdP Proxy |<-------->| Identity | | | IdP Proxy |<-------->| Identity |
| | | | | Provider | | | | | | Provider |
| | https://idp.example.org | | | | | | https://idp.example.org | | | |
| +-------------------------+ | +---------------+ | +-------------------------+ | +---------------+
| | | |
+--------------------------------------+ +--------------------------------------+ ]]></artwork>
]]></artwork> <t>
</figure>
<t>
When the PeerConnection object wants to interact with the IdP, the When the PeerConnection object wants to interact with the IdP, the
sequence of events is as follows: sequence of events is as follows:
<list style="numbers"> </t>
<t> <ol spacing="normal" type="1">
<li>
The browser (the PeerConnection component) instantiates an IdP The browser (the PeerConnection component) instantiates an IdP
proxy. This allows the IdP to load whatever JS is necessary into proxy. This allows the IdP to load whatever JS is necessary into
the proxy. The resulting code runs in the IdP's security the proxy. The resulting code runs in the IdP's security
context. context.
</t> </li>
<t> <li>
The IdP registers an object with the browser that conforms to The IdP registers an object with the browser that conforms to
the API defined in <xref target="webrtc-api"/>. the API defined in <xref target="webrtc-api" format="default"/>.
</t> </li>
<t> <li>
The browser invokes methods on the object registered by the IdP The browser invokes methods on the object registered by the IdP
proxy to create or verify identity assertions. proxy to create or verify identity assertions.
</t> </li>
</list> </ol>
</t> <t>
<t>
This approach allows us to decouple the browser from any particular This approach allows us to decouple the browser from any particular
identity provider; the browser need only know how to load the IdP's identity provider; the browser need only know how to load the IdP's
JavaScript--the location of which is determined based on the IdP's JavaScript -- the location of which is determined based on the IdP's
identity--and to call the generic API for requesting and verifying identity -- and to call the generic API for requesting and verifying
identity assertions. The IdP provides whatever logic is necessary to identity assertions. The IdP provides whatever logic is necessary to
bridge the generic protocol to the IdP's specific bridge the generic protocol to the IdP's specific
requirements. Thus, a single browser can support any number of requirements. Thus, a single browser can support any number of
identity protocols, including being forward compatible with IdPs identity protocols, including being forward compatible with IdPs
which did not exist at the time the browser was written. which did not exist at the time the browser was written.
</t> </t>
</section> </section>
<section anchor="sec.standardized" numbered="true" toc="default">
<section title="Items for Standardization" anchor="sec.standardized"> <name>Items for Standardization</name>
<t> <t>
There are two parts to this work: There are two parts to this work:
</t> </t>
<t> <ul spacing="normal">
<list style="symbols"> <li>
<t>
The precise information from the signaling message that must be The precise information from the signaling message that must be
cryptographically bound to the user's identity and a mechanism cryptographically bound to the user's identity and a mechanism
for carrying assertions in JSEP messages. This is specified in for carrying assertions in JavaScript Session Establishment
<xref target="sec.jsep-binding"/>. Protocol (JSEP) messages. This is specified in
</t> <xref target="sec.jsep-binding" format="default"/>.
</li>
<t> <li>
The interface to the IdP, which is defined in the companion W3C The interface to the IdP, which is defined in the companion W3C
WebRTC API specification <xref target="webrtc-api"/>. WebRTC API specification <xref target="webrtc-api" format="defau
</t> lt"/>.
</list> </li>
</t> </ul>
<t> <t>
The WebRTC API specification also defines JavaScript interfaces that The WebRTC API specification also defines JavaScript interfaces that
the calling application can use to specify which IdP to use. That the calling application can use to specify which IdP to use. That
API also provides access to the assertion-generation capability and API also provides access to the assertion-generation capability and
the status of the validation process. the status of the validation process.
</t> </t>
</section> </section>
<section anchor="sec.jsep-binding" numbered="true" toc="default">
<section title="Binding Identity Assertions to JSEP Offer/Answer Transac <name>Binding Identity Assertions to JSEP Offer/Answer Transactions</nam
tions" anchor="sec.jsep-binding"> e>
<t>
<t>
An identity assertion binds the user's identity (as asserted by the An identity assertion binds the user's identity (as asserted by the
IdP) to the SDP offer/answer exchange and specifically to the IdP) to the SDP offer/answer exchange and specifically to the
media. In order to achieve this, the PeerConnection must provide the media. In order to achieve this, the PeerConnection must provide the
DTLS-SRTP fingerprint to be bound to the identity. This is provided DTLS-SRTP fingerprint to be bound to the identity. This is provided
as a JavaScript object (also known as a dictionary or hash) with a as a JavaScript object (also known as a dictionary or hash) with a
single <spanx style="verb">fingerprint</spanx> key, as shown below: single "fingerprint" key, as shown below:
</t> </t>
<figure> <!-- [rfced] Please review the type attribute set for each <sourcecode> and let
<artwork><![CDATA[ us know if any updates are needed.
{ -->
"fingerprint": <sourcecode name="json-1" type="json"><![CDATA[
[ {
{ "algorithm": "sha-256", "fingerprint":
"digest": "4A:AD:B9:B1:3F:...:E5:7C:AB" }, [
{ "algorithm": "sha-1", { "algorithm": "sha-256",
"digest": "74:E9:76:C8:19:...:F4:45:6B" } "digest": "4A:AD:B9:B1:3F:...:E5:7C:AB" },
] { "algorithm": "sha-1",
} "digest": "74:E9:76:C8:19:...:F4:45:6B" }
]]></artwork> ]
</figure> } ]]></sourcecode>
<t> <t>
The <spanx style="verb">fingerprint</spanx> value is an array of The "fingerprint" value is an array of
objects. Each object in the array contains <spanx objects. Each object in the array contains "algorithm" and "digest"
style="verb">algorithm</spanx> and <spanx values, which correspond directly to
style="verb">digest</spanx> values, which correspond directly to the algorithm and digest values in the "fingerprint" attribute of th
the algorithm and digest values in the <spanx e SDP <xref target="RFC8122" format="default"/>.
style="verb">fingerprint</spanx> attribute of the SDP <xref </t>
target="RFC8122"/>. <t>
</t> This object is encoded in a <xref target="RFC8259" format="default">
<t> JSON</xref>
This object is encoded in a <xref target="RFC8259">JSON</xref>
string for passing to the IdP. The identity assertion returned by string for passing to the IdP. The identity assertion returned by
the IdP, which is encoded in the <spanx the IdP, which is encoded in the "identity" attribute, is a JSON obj
style="verb">identity</spanx> attribute, is a JSON object that is ect that is
encoded as described in <xref target="sec.carry-assertion"/>. encoded as described in <xref target="sec.carry-assertion" format="d
</t> efault"/>.
<t> </t>
<t>
This structure does not need to be interpreted by the IdP or the This structure does not need to be interpreted by the IdP or the
IdP proxy. It is consumed solely by the RP's browser. The IdP IdP proxy. It is consumed solely by the RP's browser. The IdP
merely treats it as an opaque value to be attested to. Thus, new merely treats it as an opaque value to be attested to. Thus, new
parameters can be added to the assertion without modifying the parameters can be added to the assertion without modifying the
IdP. IdP.
</t> </t>
<section anchor="sec.carry-assertion" numbered="true" toc="default">
<section title="Carrying Identity Assertions" anchor="sec.carry-assert <name>Carrying Identity Assertions</name>
ion"> <t>
<t> Once an IdP has generated an assertion (see <xref target="sec.requ
Once an IdP has generated an assertion (see <xref est-assert" format="default"/>), it is attached to the SDP
target="sec.request-assert"/>), it is attached to the SDP offer/answer message. This is done by adding a new "identity"
offer/answer message. This is done by adding a new 'identity'
attribute to the SDP. The sole contents of this value is the attribute to the SDP. The sole contents of this value is the
identity assertion. The identity assertion produced by the IdP is identity assertion. The identity assertion produced by the IdP is
encoded into a UTF-8 JSON text, then <xref encoded into a UTF-8 JSON text, then <xref target="RFC4648" format
target="RFC4648">Base64-encoded</xref> to produce this string. ="default">base64-encoded</xref> to produce this string.
For example: For example:
</t> </t>
<figure>
<artwork><![CDATA[ <sourcecode name="sdp-1" type="sdp" ><![CDATA[
v=0 v=0
o=- 1181923068 1181923196 IN IP4 ua1.example.com o=- 1181923068 1181923196 IN IP4 ua1.example.com
s=example1 s=example1
c=IN IP4 ua1.example.com c=IN IP4 ua1.example.com
a=fingerprint:sha-1 \ a=fingerprint:sha-1 \
4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB 4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
a=identity:\ a=identity:\
eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\ eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\
In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\ In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\
IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\ IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\
aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9 aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9
a=... a=...
t=0 0 t=0 0
m=audio 6056 RTP/SAVP 0 m=audio 6056 RTP/SAVP 0
a=sendrecv a=sendrecv
... ... ]]></sourcecode>
Note that long lines in the example are folded to meet the column <aside><t>Note that long lines in the example are folded to meet the column
width constraints of this document; the backslash ("\") at the end of width constraints of this document; the backslash ("\") at the end of
a line, the carriage return that follows, and whitespace shall be ignored. a line, the carriage return that follows, and whitespace shall be ignored.</t> </aside>
]]></artwork> <t>
</figure> The "identity" attribute attests to all "fingerprint" attributes i
<t> n the session
The 'identity' attribute attests to all <spanx
style="verb">fingerprint</spanx> attributes in the session
description. It is therefore a session-level attribute. description. It is therefore a session-level attribute.
</t> </t>
<t> <t>
Multiple <spanx style="verb">fingerprint</spanx> values can be Multiple "fingerprint" values can be
used to offer alternative certificates for a peer. The <spanx used to offer alternative certificates for a peer. The "identity"
style="verb">identity</spanx> attribute MUST include all attribute <bcp14>MUST</bcp14> include all
fingerprint values that are included in <spanx "fingerprint" values that are included in "fingerprint" attributes
style="verb">fingerprint</spanx> attributes of the session of the session
description. description.
</t> </t>
<t> <t>
The RP browser MUST verify that the in-use certificate for a DTLS The RP browser <bcp14>MUST</bcp14> verify that the in-use certific
ate for a DTLS
connection is in the set of fingerprints returned from the IdP connection is in the set of fingerprints returned from the IdP
when verifying an assertion. when verifying an assertion.
</t> </t>
</section>
</section> </section>
</section>
<section title="Determining the IdP URI" anchor="sec.idp-uri"> <section anchor="sec.idp-uri" numbered="true" toc="default">
<t> <name>Determining the IdP URI</name>
<t>
In order to ensure that the IdP is under control of the domain In order to ensure that the IdP is under control of the domain
owner rather than someone who merely has an account on the owner rather than someone who merely has an account on the
domain owner's server (e.g., in shared hosting scenarios), the domain owner's server (e.g., in shared hosting scenarios), the
IdP JavaScript is hosted at a deterministic location based on IdP JavaScript is hosted at a deterministic location based on
the IdP's domain name. Each IdP proxy instance is associated the IdP's domain name. Each IdP proxy instance is associated
with two values: with two values:
</t> </t>
<t> <dl newline="false" spacing="normal">
<list style="hanging"> <dt>authority:</dt>
<t hangText="Authority:"> <dd>
The <xref target="RFC3986"> authority</xref> at which the The <xref target="RFC3986" format="default"> authority</x
ref> at which the
IdP's service is hosted. IdP's service is hosted.
</t> </dd>
<t hangText="protocol:"> <dt>protocol:</dt>
<dd>
The specific IdP protocol which the IdP is using. This is a The specific IdP protocol which the IdP is using. This is a
completely opaque IdP-specific string, but allows an IdP to completely opaque IdP-specific string, but allows an IdP to
implement two protocols in parallel. This value may be the implement two protocols in parallel. This value may be the
empty string. If no value for protocol is provided, a value empty string. If no value for protocol is provided, a value
of "default" is used. of "default" is used.
</t> </dd>
</list> </dl>
</t> <t>
<t> Each IdP <bcp14>MUST</bcp14> serve its initial entry page (i.e.,
Each IdP MUST serve its initial entry page (i.e., the one loaded the one loaded
by the IdP proxy) from a <xref target="RFC5785">well-known by the IdP proxy) from a <xref target="RFC5785" format="default"
URI</xref>. The well-known URI for an IdP proxy is formed from >well-known
URI</xref>.
<!-- [rfced] Section 7.5: RFC 5785 has been obsoleted by RFC 8615.
May we change both citations as well as the reference listing for
RFC 5785?
(It looks like <https://www.iana.org/assignments/well-known-uris/>
and <https://www.iana.org/assignments/uri-schemes/> might be related
to this text, and we see that both have been updated to refer to
RFC 8615.)
Original:
Each IdP MUST serve its initial entry page (i.e., the one loaded by
the IdP proxy) from a well-known URI [RFC5785].
...
This section reqisters the "idp-proxy" well-known URI from [RFC5785].
...
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010,
<https://www.rfc-editor.org/info/rfc5785>.
Suggested ("reqisters" has been fixed):
Each IdP MUST serve its initial entry page (i.e., the one loaded by
the IdP proxy) from a well-known URI [RFC8615].
...
This section registers the "idp-proxy" well-known URI from [RFC8615].
...
[RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers
(URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
<https://www.rfc-editor.org/info/rfc8615>. -->
The well-known URI for an IdP proxy is formed from
the following URI components: the following URI components:
<list style="numbers"> </t>
<t> <ol spacing="normal" type="1">
The scheme, "https:". An IdP MUST be loaded using <xref <li>
target="RFC2818">HTTPS</xref>. The scheme, "https:". An IdP <bcp14>MUST</bcp14> be loaded
</t> using <xref target="RFC2818" format="default">HTTPS</xref>.
<t> </li>
The <xref target="RFC3986">authority</xref>. As noted above <li>
, The <xref target="RFC3986" format="default">authority</xref>
the authority MAY contain a non-default port number or . As noted above,
the authority <bcp14>MAY</bcp14> contain a non-default port
number or
userinfo sub-component. Both are removed when determining userinfo sub-component. Both are removed when determining
if an asserted identity matches the name of the IdP. if an asserted identity matches the name of the IdP.
</t> </li>
<t> <li>
The path, starting with "/.well-known/idp-proxy/" and The path, starting with "/.well-known/idp-proxy/" and
appended with the IdP protocol. Note that the separator appended with the IdP protocol. Note that the separator
characters '/' (%2F) and '\' (%5C) MUST NOT be permitted in characters '/' (%2F) and '\' (%5C) <bcp14>MUST NOT</bcp14> b e permitted in
the protocol field, lest an attacker be able to direct the protocol field, lest an attacker be able to direct
requests outside of the controlled "/.well-known/" prefix. requests outside of the controlled "/.well-known/" prefix.
Query and fragment values MAY be used by including '?' or Query and fragment values <bcp14>MAY</bcp14> be used by incl uding '?' or
'#' characters. '#' characters.
</t> </li>
</list> </ol>
<t>
For example, for the IdP "identity.example.com" and the protocol For example, for the IdP "identity.example.com" and the protocol
"example", the URL would be: "example", the URL would be:
</t> </t>
<figure>
<artwork><![CDATA[ <ul empty="true"><li>&lt;https://identity.example.com/.well-known/idp-proxy/ex
https://identity.example.com/.well-known/idp-proxy/example ample&gt;</li></ul>
]]></artwork>
</figure> <t>
<t> The IdP <bcp14>MAY</bcp14> redirect requests to this URL, but th
The IdP MAY redirect requests to this URL, but they MUST retain ey <bcp14>MUST</bcp14> retain
the "https" scheme. This changes the effective origin of the the "https" scheme. This changes the effective origin of the
IdP, but not the domain of the identities that the IdP is IdP, but not the domain of the identities that the IdP is
permitted to assert and validate. I.e., the IdP is still permitted to assert and validate. That is, the IdP is still
regarded as authoritative for the original domain. regarded as authoritative for the original domain.
</t> </t>
<section numbered="true" toc="default">
<section title="Authenticating Party"> <name>Authenticating Party</name>
<t> <t>
How an AP determines the appropriate IdP domain is out of How an AP determines the appropriate IdP domain is out of
scope of this specification. In general, however, the AP has scope of this specification. In general, however, the AP has
some actual account relationship with the IdP, as this some actual account relationship with the IdP, as this
identity is what the IdP is attesting to. Thus, the AP somehow identity is what the IdP is attesting to. Thus, the AP somehow
supplies the IdP information to the browser. Some potential supplies the IdP information to the browser. Some potential
mechanisms include: mechanisms include:
<list style="symbols"> </t>
<t> <ul spacing="normal">
<li>
Provided by the user directly. Provided by the user directly.
</t> </li>
<t> <li>
Selected from some set of IdPs known to the calling site. Selected from some set of IdPs known to the calling site
E.g., a button that shows "Authenticate via Facebook (e.g., a button that shows "Authenticate via Facebook
Connect" Connect").
</t> </li>
</list> </ul>
</t> </section>
</section> <section numbered="true" toc="default">
<name>Relying Party</name>
<section title="Relying Party"> <t>
<t>
Unlike the AP, the RP need not have any particular Unlike the AP, the RP need not have any particular
relationship with the IdP. Rather, it needs to be able to relationship with the IdP. Rather, it needs to be able to
process whatever assertion is provided by the AP. As the process whatever assertion is provided by the AP. As the
assertion contains the IdP's identity in the <spanx assertion contains the IdP's identity in the "idp" field of th
style="verb">idp</spanx> field of the JSON-encoded object (see e JSON-encoded object (see
<xref target="sec.request-assert"/>), the URI can be <xref target="sec.request-assert" format="default"/>), the URI
can be
constructed directly from the assertion, and thus the RP can constructed directly from the assertion, and thus the RP can
directly verify the technical validity of the assertion with directly verify the technical validity of the assertion with
no user interaction. Authoritative assertions need only be no user interaction. Authoritative assertions need only be
verifiable. Third-party assertions also MUST be verified verifiable. Third-party assertions also <bcp14>MUST</bcp14> be
against local policy, as described in <xref verified
target="sec.id-format"/>. against local policy, as described in <xref target="sec.id-for
</t> mat" format="default"/>.
</section> </t>
</section> </section>
</section>
<section title="Requesting Assertions" anchor="sec.request-assert"> <section anchor="sec.request-assert" numbered="true" toc="default">
<t> <name>Requesting Assertions</name>
<t>
The input to identity assertion is the JSON-encoded object The input to identity assertion is the JSON-encoded object
described in <xref target="sec.jsep-binding"/> that contains the described in <xref target="sec.jsep-binding" format="default"/> that contains the
set of certificate fingerprints the browser intends to use. set of certificate fingerprints the browser intends to use.
<!-- [rfced] Section 7.6: Should "input to identity assertion" be
"input to the IdP assertion process" (per Section 7) or possibly
"input to the assertion generation process" (per Section 8)?
Original:
The input to identity assertion is the JSON-encoded object described
in Section 7.4 that contains the set of certificate fingerprints the
browser intends to use. -->
This string is treated as opaque from the perspective of the This string is treated as opaque from the perspective of the
IdP. IdP.
</t> </t>
<t> <t>
The browser also identifies the origin that the PeerConnection The browser also identifies the origin that the PeerConnection
is run in, which allows the IdP to make decisions based on who is run in, which allows the IdP to make decisions based on who
is requesting the assertion. is requesting the assertion.
</t> </t>
<t> <t>
An application can optionally provide a user identifier hint An application can optionally provide a user identifier hint
when specifying an IdP. This value is a hint that the IdP can when specifying an IdP. This value is a hint that the IdP can
use to select amongst multiple identities, or to avoid providing use to select amongst multiple identities, or to avoid providing
assertions for unwanted identities. The <spanx assertions for unwanted identities. The "username" is a string
style="verb">username</spanx> is a string that has no meaning to that has no meaning to
any entity other than the IdP, it can contain any data the IdP any entity other than the IdP; it can contain any data the IdP
needs in order to correctly generate an assertion. needs in order to correctly generate an assertion.
</t> </t>
<t> <t>
An identity assertion that is successfully provided by the IdP An identity assertion that is successfully provided by the IdP
consists of the following information: consists of the following information:
</t> </t>
<t> <dl newline="false" spacing="normal">
<list style="hanging"> <dt>idp:</dt>
<t hangText="idp:"> <dd>
The domain name of an IdP and the protocol string. This MAY The domain name of an IdP and the protocol string. This <bc
p14>MAY</bcp14>
identify a different IdP or protocol from the one that identify a different IdP or protocol from the one that
generated the assertion. generated the assertion.
</t> </dd>
<t hangText="assertion:"> <dt>assertion:</dt>
<dd>
An opaque value containing the assertion itself. This is An opaque value containing the assertion itself. This is
only interpretable by the identified IdP or the IdP code only interpretable by the identified IdP or the IdP code
running in the client. running in the client.
</t> </dd>
</list> </dl>
</t> <t>
<t> <xref target="fig.assert-ex" format="default"/> shows an example
<xref target="fig.assert-ex"/> shows an example assertion assertion
formatted as JSON. In this case, the message has presumably formatted as JSON. In this case, the message has presumably
been digitally signed/MACed in some way that the IdP can later been digitally signed/MACed in some way that the IdP can later
verify it, but this is an implementation detail and out of scope verify it, but this is an implementation detail and out of scope
of this document. </t> of this document. </t>
<figure anchor="fig.assert-ex">
<figure title="Example assertion" anchor="fig.assert-ex"> <name>Example Assertion</name>
<artwork><![CDATA[ <sourcecode name="json-2" type="json"><![CDATA[
{ {
"idp":{ "idp":{
"domain": "example.org", "domain": "example.org",
"protocol": "bogus" "protocol": "bogus"
}, },
"assertion": "{\"identity\":\"bob@example.org\", "assertion": "{\"identity\":\"bob@example.org\",
\"contents\":\"abcdefghijklmnopqrstuvwyz\", \"contents\":\"abcdefghijklmnopqrstuvwyz\",
\"signature\":\"010203040506\"}" \"signature\":\"010203040506\"}"
} } ]]></sourcecode>
]]></artwork> </figure>
</figure> <t>
<t>
For use in signaling, the assertion is serialized into JSON, For use in signaling, the assertion is serialized into JSON,
<xref target="RFC4648">Base64-encoded</xref>, and used as the <xref target="RFC4648" format="default">base64-encoded</xref>, a
value of the <spanx style="verb">identity</spanx> attribute. nd used as the
IdPs SHOULD ensure that any assertions they value of the "identity" attribute.
generate cannot be interpreted in a different context. E.g., IdPs <bcp14>SHOULD</bcp14> ensure that any assertions they
generate cannot be interpreted in a different context. For examp
le,
they should use a distinct format or have separate cryptographic they should use a distinct format or have separate cryptographic
keys for assertion generation and other purposes. keys for assertion generation and other purposes.
Line breaks are inserted solely for Line breaks are inserted solely for
readability. readability.
</t> </t>
</section> </section>
<section anchor="sec.user-login" numbered="true" toc="default">
<section title="Managing User Login" anchor="sec.user-login"> <name>Managing User Login</name>
<t> <t>
In order to generate an identity assertion, the IdP needs proof of In order to generate an identity assertion, the IdP needs proof of
the user's identity. It is common practice to authenticate user s the user's identity. It is common practice to authenticate user s
(using passwords or multi-factor authentication), then use <xref (using passwords or multi-factor authentication), then use <xref
target="RFC6265">Cookies</xref> or <xref target="RFC7617">HTTP target="RFC6265" format="default">cookies</xref> or <xref target="RFC7617" form
at="default">HTTP
authentication</xref> for subsequent exchanges. authentication</xref> for subsequent exchanges.
</t> </t>
<t> <t>
The IdP proxy is able to access cookies, HTTP authentication or The IdP proxy is able to access cookies, HTTP authentication dat
a, or
other persistent session data because it operates in the securit y other persistent session data because it operates in the securit y
context of the IdP origin. Therefore, if a user is logged in, t he context of the IdP origin. Therefore, if a user is logged in, t he
IdP could have all the information needed to generate an IdP could have all the information needed to generate an
assertion. assertion.
</t> </t>
<t> <t>
An IdP proxy is unable to generate an assertion if the user is An IdP proxy is unable to generate an assertion if the user is
not logged in, or the IdP wants to interact with the user to not logged in, or the IdP wants to interact with the user to
acquire more information before generating the assertion. If acquire more information before generating the assertion. If
the IdP wants to interact with the user before generating an the IdP wants to interact with the user before generating an
assertion, the IdP proxy can fail to generate an assertion and assertion, the IdP proxy can fail to generate an assertion and
instead indicate a URL where login should proceed. instead indicate a URL where login should proceed.
</t> </t>
<t> <t>
The application can then load the provided URL to enable the The application can then load the provided URL to enable the
user to enter credentials. The communication between the user to enter credentials. The communication between the
application and the IdP is described in <xref application and the IdP is described in <xref target="webrtc-api
target="webrtc-api"/>. " format="default"/>.
</t> </t>
</section> </section>
</section> </section>
<section anchor="sec.verify-assert" numbered="true" toc="default">
<section title="Verifying Assertions" anchor="sec.verify-assert"> <name>Verifying Assertions</name>
<t> <t>
The input to identity validation is the assertion string taken The input to identity validation is the assertion string taken
from a decoded 'identity' attribute. from a decoded "identity" attribute.
</t> </t>
<t> <t>
The IdP proxy verifies the assertion. Depending on the identity The IdP proxy verifies the assertion. Depending on the identity
protocol, the proxy might contact the IdP server or other protocol, the proxy might contact the IdP server or other
servers. For instance, an OAuth-based protocol will likely servers. For instance, an OAuth-based protocol will likely
require using the IdP as an oracle, whereas with a require using the IdP as an oracle, whereas with a
signature-based scheme might be able to verify the assertion signature-based scheme it might be able to verify the assertion
without contacting the IdP, provided that it has cached the without contacting the IdP, provided that it has cached the
relevant public key. relevant public key.
</t> </t>
<t> <t>
Regardless of the mechanism, if verification succeeds, a Regardless of the mechanism, if verification succeeds, a
successful response from the IdP proxy consists of the following successful response from the IdP proxy consists of the following
information: information:
<list style="hanging"> </t>
<t hangText="identity:"> <dl newline="false" spacing="normal">
<dt>identity:</dt>
<dd>
The identity of the AP from the IdP's perspective. Details The identity of the AP from the IdP's perspective. Details
of this are provided in <xref target="sec.id-format"/>. of this are provided in <xref target="sec.id-format" format=
</t> "default"/>.
<t hangText="contents:"> </dd>
<dt>contents:</dt>
<dd>
The original unmodified string provided by the AP as input The original unmodified string provided by the AP as input
to the assertion generation process. to the assertion generation process.
</t> </dd>
</list> </dl>
</t> <t>
<t> <xref target="fig.verify-ex" format="default"/> shows an example
<xref target="fig.verify-ex"/> shows an example response, response,
which is JSON-formatted. which is JSON-formatted.
</t> </t>
<figure anchor="fig.verify-ex">
<figure title="Example verification result" anchor="fig.verify-ex" <name>Example Verification Result</name>
> <sourcecode name="json-3" type="json"><![CDATA[
<artwork>
<![CDATA[
{ {
"identity": "bob@example.org", "identity": "bob@example.org",
"contents": "{\"fingerprint\":[ ... ]}" "contents": "{\"fingerprint\":[ ... ]}"
} } ]]></sourcecode>
]]></artwork> </figure>
</figure> <section anchor="sec.id-format" numbered="true" toc="default">
<name>Identity Formats</name>
<section title="Identity Formats" anchor="sec.id-format"> <t>
<t> The identity provided from the IdP to the RP browser <bcp14>MU
The identity provided from the IdP to the RP browser MUST ST</bcp14>
consist of a string representing the user's identity. This consist of a string representing the user's identity. This
string is in the form "&lt;user>@&lt;domain>", where <spanx string is in the form "&lt;user&gt;@&lt;domain&gt;", where "us
style="verb">user</spanx> consists of any character, er" consists of any character,
and domain is aninternationalized and domain is an internationalized
domain name <xref target="RFC5890"></xref> encoded as a sequen domain name <xref target="RFC5890" format="default"/> encoded
ce of U-labels. as a sequence of U-labels.
</t> </t>
<t> <t>
The PeerConnection API MUST check this string as follows: The PeerConnection API <bcp14>MUST</bcp14> check this string a
<list style="numbers"> s follows:
<t> </t>
<ol spacing="normal" type="1">
<li>
If the "domain" portion of the string is equal to the doma in If the "domain" portion of the string is equal to the doma in
name of the IdP proxy, then the assertion is valid, as the name of the IdP proxy, then the assertion is valid, as the
IdP is authoritative for this domain. Comparison of IdP is authoritative for this domain. Comparison of
domain names is done using the label equivalence rule domain names is done using the label equivalence rule
defined in Section 2.3.2.4 of <xref target="RFC5890"/>. defined in <xref target="RFC5890" sectionFormat="of" secti
</t> on="2.3.2.4"/>.
<t> </li>
<li>
<t>
If the "domain" portion of the string is not equal to the If the "domain" portion of the string is not equal to the
domain name of the IdP proxy, then the PeerConnection domain name of the IdP proxy, then the PeerConnection
object MUST reject the assertion unless both: object <bcp14>MUST</bcp14> reject the assertion unless bot
<list style="numbers"> h:
<t> </t>
<ol spacing="normal" type="1">
<li>
the IdP domain is trusted as an acceptable third-party the IdP domain is trusted as an acceptable third-party
IdP; and IdP; and
</t> </li>
<t> <li>
local policy is configured to trust this IdP domain local policy is configured to trust this IdP domain
for the domain portion of the identity string. for the domain portion of the identity string.
</t> </li>
</list> </ol>
</t> </li>
</list> </ol>
</t> <t>
<t> Any '@' or '%' characters in the "user" portion of the
Any "@" or "%" characters in the "user" portion of the identity <bcp14>MUST</bcp14> be escaped according to the "perc
identity MUST be escaped according to the "Percent-Encoding" ent-encoding"
rules defined in Section 2.1 of <xref rules defined in <xref target="RFC3986" sectionFormat="of" sec
target="RFC3986"/>. Characters other than "@" and "%" MUST NOT tion="2.1"/>. Characters other than '@' and '%' <bcp14>MUST NOT</bcp14>
be percent-encoded. For example, with a "user" of "user@133" a nd be percent-encoded. For example, with a "user" of "user@133" a nd
a "domain" of "identity.example.com", the resulting string wil l a "domain" of "identity.example.com", the resulting string wil l
be encoded as "user%40133@identity.example.com". be encoded as "user%40133@identity.example.com".
</t> </t>
<t> <t>
Implementations are cautioned to take care when displaying Implementations are cautioned to take care when displaying
user identities containing escaped "@" characters. If such user identities containing escaped '@' characters. If such
characters are unescaped prior to display, implementations characters are unescaped prior to display, implementations
MUST distinguish between the domain of the IdP proxy and any <bcp14>MUST</bcp14> distinguish between the domain of the IdP proxy and any
domain that might be implied by the portion of the domain that might be implied by the portion of the
"&lt;user&gt;" portion that appears after the escaped "@" "&lt;user&gt;" portion that appears after the escaped "@"
sign. sign.
</t> </t>
</section> </section>
</section>
<section anchor="sec.sec-cons" numbered="true" toc="default">
<name>Security Considerations</name>
<t>
Much of the security analysis of this problem is contained in <xref ta
rget="RFC8826" format="default"/> or in the discussion of the
particular issues above.
</section> <!-- [rfced] Section 9: What does "this problem" refer to here?
<section title="Security Considerations" anchor="sec.sec-cons"> Original:
<t> Much of the security analysis of this problem is contained in
Much of the security analysis of this problem is contained in <xref [I-D.ietf-rtcweb-security] or in the discussion of the particular
target="I-D.ietf-rtcweb-security"/> or in the discussion of the issues above. -->
particular issues above. In order to avoid repetition, this section
In order to avoid repetition, this section
focuses on (a) residual threats that are not addressed by this focuses on (a) residual threats that are not addressed by this
document and (b) threats produced by failure/misbehavior of one of the document and (b) threats produced by failure/misbehavior of one of the
components in the system. components in the system.
</t> </t>
<section numbered="true" toc="default">
<section title="Communications Security"> <name>Communications Security</name>
<t> <t>
IF HTTPS is not used to secure communications to the signaling If HTTPS is not used to secure communications to the signaling
server, and the identity mechanism used in server, and the identity mechanism used in
<xref target="sec.generic.idp"/> is not used, <xref target="sec.generic.idp" format="default"/> is not used,
then any on-path attacker can replace the DTLS-SRTP fingerprints then any on-path attacker can replace the DTLS-SRTP fingerprints
in the handshake and thus substitute its own identity for that in the handshake and thus substitute its own identity for that
of either endpoint. of either endpoint.
</t>
<t> <!-- [rfced] Section 9.1: Should "the identity mechanism used in
Section 7" be "the identity mechanism used in Section 7.1" or
"the identity mechanisms used in Section 7"? We ask because we see
"identity service mechanisms in Section 7" in the next paragraph.
Also, we changed "IF" to "If"; please let us know if the
capitalization was intentional.
Original:
IF HTTPS is not used to secure communications to the signaling
server, and the identity mechanism used in Section 7 is not used,
then any on-path attacker can replace the DTLS-SRTP fingerprints in
the handshake and thus substitute its own identity for that of either
endpoint. -->
</t>
<t>
Even if HTTPS is used, the signaling server can Even if HTTPS is used, the signaling server can
potentially mount a man-in-the-middle attack unless implementations potentially mount a man-in-the-middle attack unless implementations
have some mechanism for independently verifying keys. The UI have some mechanism for independently verifying keys. The UI
requirements in <xref target="sec.proposal.comsec"/> are designed to requirements in <xref target="sec.proposal.comsec" format="default"/ > are designed to
provide such a mechanism for motivated/security conscious users, but provide such a mechanism for motivated/security conscious users, but
are not suitable for general use. The identity service mechanisms are not suitable for general use. The identity service mechanisms
in <xref target="sec.generic.idp"/> are more suitable for general in <xref target="sec.generic.idp" format="default"/> are more suitab le for general
use. Note, however, that a malicious signaling service can strip off use. Note, however, that a malicious signaling service can strip off
any such identity assertions, though it cannot forge new ones. Note any such identity assertions, though it cannot forge new ones. Note
that all of the third-party security mechanisms available (whether that all of the third-party security mechanisms available (whether
X.509 certificates or a third-party IdP) rely on the security of the X.509 certificates or a third-party IdP) rely on the security of the
third party--this is of course also true of the user's connection to the third party -- this is of course also true of the user's connection to the
Web site itself. Users who wish to assure themselves of security Web site itself. Users who wish to assure themselves of security
against a malicious identity provider can only do so by verifying against a malicious identity provider can only do so by verifying
peer credentials directly, e.g., by checking the peer's fingerprint peer credentials directly, e.g., by checking the peer's fingerprint
against a value delivered out of band. against a value delivered out of band.
</t> </t>
<t>
<t>
In order to protect against malicious content JavaScript, that In order to protect against malicious content JavaScript, that
JavaScript MUST NOT be allowed to have direct access to---or perform JavaScript <bcp14>MUST NOT</bcp14> be allowed to have direct
computations with---DTLS keys. For instance, if content JS were able access to -- or perform
computations with -- DTLS keys. For instance, if content JS were abl
e
to compute digital signatures, then it would be possible for content to compute digital signatures, then it would be possible for content
JS to get an identity assertion for a browser's generated key and JS to get an identity assertion for a browser's generated key and
then use that assertion plus a signature by the key to authenticate then use that assertion plus a signature by the key to authenticate
a call protected under an ephemeral Diffie-Hellman (DH) key controll ed by the content a call protected under an ephemeral Diffie-Hellman (DH) key controll ed by the content
JS, thus violating the security guarantees otherwise provided by the JS, thus violating the security guarantees otherwise provided by the
IdP mechanism. Note that it is not sufficient merely to deny the IdP mechanism. Note that it is not sufficient merely to deny the
content JS direct access to the keys, as some have suggested doing content JS direct access to the keys, as some have suggested doing
with the WebCrypto API <xref target="webcrypto"/>. The JS must with the WebCrypto API <xref target="webcrypto" format="default"/>. The JS must
also not be allowed to perform operations that would be valid for a also not be allowed to perform operations that would be valid for a
DTLS endpoint. By far the safest approach is simply to deny the DTLS endpoint. By far the safest approach is simply to deny the
ability to perform any operations that depend on secret information ability to perform any operations that depend on secret information
associated with the key. Operations that depend on public associated with the key. Operations that depend on public
information, such as exporting the public key are of course safe. information, such as exporting the public key, are of course safe.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="Privacy"> <name>Privacy</name>
<t> <t>
The requirements in this document are intended to allow: The requirements in this document are intended to allow:
</t> </t>
<t> <ul spacing="normal">
<list style="symbols"> <li>
<t>
Users to participate in calls without revealing their location. Users to participate in calls without revealing their location.
</t> </li>
<t> <li>
Potential callees to avoid revealing their location and even Potential callees to avoid revealing their location and even
presence status prior to agreeing to answer a call. presence status prior to agreeing to answer a call.
</t> </li>
</list> </ul>
</t> <t>
<t>
However, these privacy protections come at a performance cost in However, these privacy protections come at a performance cost in
terms of using TURN relays and, in the latter case, delaying terms of using TURN relays and, in the latter case, delaying
ICE. Sites SHOULD make users aware of these tradeoffs. ICE. Sites <bcp14>SHOULD</bcp14> make users aware of these trade&nbh
</t> y;offs.
<t> </t>
<t>
Note that the protections provided here assume a non-malicious Note that the protections provided here assume a non-malicious
calling service. As the calling service always knows the users calling service. As the calling service always knows the user's
status and (absent the use of a technology like Tor) their IP status and (absent the use of a technology like Tor) their IP
address, they can violate the users privacy at will. Users who wish address, they can violate the user's privacy at will. Users who wis h
privacy against the calling sites they are using must use separate privacy against the calling sites they are using must use separate
privacy enhancing technologies such as Tor. Combined WebRTC/Tor privacy-enhancing technologies such as Tor. &nbsp;Combined WebRTC/To
implementations SHOULD arrange to route the media as well as the r
signaling through Tor. Currently this will produce very suboptimal implementations <bcp14>SHOULD</bcp14> arrange to route the media as
well as the
signaling through Tor. &nbsp;Currently this will produce very subopt
imal
performance. performance.
</t> </t>
<t> <t>
Additionally, any identifier which persists across multiple calls is Additionally, any identifier that persists across multiple calls is
potentially a problem for privacy, especially for anonymous calling potentially a problem for privacy, especially for anonymous calling
services. Such services SHOULD instruct the browser to use separate services. Such services <bcp14>SHOULD</bcp14> instruct the browser t o use separate
DTLS keys for each call and also to use TURN throughout the DTLS keys for each call and also to use TURN throughout the
call. Otherwise, the other side will learn linkable information that call. Otherwise, the other side will learn linkable information that
would allow them to correlate the browser across multiple calls. would allow them to correlate the browser across multiple calls.
Additionally, browsers SHOULD implement the privacy-preserving CNAME Additionally, browsers <bcp14>SHOULD</bcp14> implement the privacy-p
generation mode of <xref target="RFC7022"/>. reserving CNAME
</t> generation mode of <xref target="RFC7022" format="default"/>.
</section> </t>
</section>
<section title="Denial of Service"> <section numbered="true" toc="default">
<t> <name>Denial of Service</name>
<t>
The consent mechanisms described in this document are intended to The consent mechanisms described in this document are intended to
mitigate denial of service attacks in which an attacker uses clients mitigate DoS attacks in which an attacker uses clients
to send large amounts of traffic to a victim without the consent of to send large amounts of traffic to a victim without the consent of
the victim. While these mechanisms are sufficient to protect victims the victim. While these mechanisms are sufficient to protect victims
who have not implemented WebRTC at all, WebRTC implementations need who have not implemented WebRTC at all, WebRTC implementations need
to be more careful. to be more careful.
</t> </t>
<t> <t>
Consider the case of a call center which accepts calls via Consider the case of a call center which accepts calls via
WebRTC. An attacker proxies the call center's front-end and arranges WebRTC. An attacker proxies the call center's front-end and arranges
for multiple clients to initiate calls to the call center. Note that for multiple clients to initiate calls to the call center. Note that
this requires user consent in many cases but because the data this requires user consent in many cases, but because the data
channel does not need consent, he can use that directly. Since ICE channel does not need consent, he can use that directly. Since ICE
will complete, browsers can then be induced to send large amounts of will complete, browsers can then be induced to send large amounts of
data to the victim call center if it supports the data channel at data to the victim call center if it supports the data channel at
all. Preventing this attack requires that automated WebRTC all. Preventing this attack requires that automated WebRTC
implementations implement sensible flow control and have the ability implementations implement sensible flow control and have the ability
to triage out (i.e., stop responding to ICE probes on) calls which to triage out (i.e., stop responding to ICE probes on) calls which
are behaving badly, and especially to be prepared to remotely are behaving badly, and especially to be prepared to remotely
throttle the data channel in the absence of plausible audio and throttle the data channel in the absence of plausible audio and
video (which the attacker cannot control). video (which the attacker cannot control).
</t> </t>
<t> <t>
Another related attack is for the signaling service to swap the ICE Another related attack is for the signaling service to swap the ICE
candidates for the audio and video streams, thus forcing a browser candidates for the audio and video streams, thus forcing a browser
to send video to the sink that the other victim expects will contain to send video to the sink that the other victim expects will contain
audio (perhaps it is only expecting audio!) potentially causing audio (perhaps it is only expecting audio!), potentially causing
overload. Muxing multiple media flows over a single transport makes overload. Muxing multiple media flows over a single transport makes
it harder to individually suppress a single flow by denying ICE it harder to individually suppress a single flow by denying ICE
keepalives. Either media-level (RTCP) mechanisms must be used or the keepalives. Either media-level (RTCP) mechanisms must be used or the
implementation must deny responses entirely, thus terminating the implementation must deny responses entirely, thus terminating the
call. call.
</t> </t>
<t> <t>
Yet another attack, suggested by Magnus Westerlund, is for the Yet another attack, suggested by Magnus Westerlund, is for the
attacker to cross-connect offers and answers as follows. It induces attacker to cross-connect offers and answers as follows. It induces
the victim to make a call and then uses its control of other users the victim to make a call and then uses its control of other users'
browsers to get them to attempt a call to someone. It then browsers to get them to attempt a call to someone. It then
translates their offers into apparent answers to the victim, which translates their offers into apparent answers to the victim, which
looks like large-scale parallel forking. The victim still responds looks like large-scale parallel forking. The victim still responds
to ICE responses and now the browsers all try to send media to the to ICE responses, and now the browsers all try to send media to the
victim. Implementations can defend themselves from this attack by victim. Implementations can defend themselves from this attack by
only responding to ICE Binding Requests for a limited number of only responding to ICE Binding Requests for a limited number of
remote ufrags (this is the reason for the requirement that the JS remote ufrags (this is the reason for the requirement that the JS
not be able to control the ufrag and password). not be able to control the ufrag and password).
</t> </t>
<t> <t>
<xref target="I-D.ietf-rtcweb-rtp-usage"/> Section 13 documents a nu <xref target="RFC8834" sectionFormat="comma" section="13"/> document
mber s a number
of potential RTCP-based DoS attacks and countermeasures. of potential RTCP-based DoS attacks and countermeasures.
</t> </t>
<t> <t>
Note that attacks based on confusing one end or the other about Note that attacks based on confusing one end or the other about
consent are possible even in the face of the third-party identity consent are possible even in the face of the third-party identity
mechanism as long as major parts of the signaling messages are not mechanism as long as major parts of the signaling messages are not
signed. On the other hand, signing the entire message severely signed. On the other hand, signing the entire message severely
restricts the capabilities of the calling application, so there are restricts the capabilities of the calling application, so there are
difficult tradeoffs here. difficult trade&nbhy;offs here.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="IdP Authentication Mechanism"> <name>IdP Authentication Mechanism</name>
<t> <t>
This mechanism relies for its security on the IdP and on the This mechanism relies for its security on the IdP and on the
PeerConnection correctly enforcing the security invariants described PeerConnection correctly enforcing the security invariants described
above. At a high level, the IdP is attesting that the user above. At a high level, the IdP is attesting that the user
identified in the assertion wishes to be associated with the identified in the assertion wishes to be associated with the
assertion. Thus, it must not be possible for arbitrary third parties assertion. Thus, it must not be possible for arbitrary third parties
to get assertions tied to a user or to produce assertions that RPs to get assertions tied to a user or to produce assertions that RPs
will accept. will accept.
</t> </t>
<section anchor="sec.pc-origin" numbered="true" toc="default">
<section title="PeerConnection Origin Check" anchor="sec.pc-origin"> <name>PeerConnection Origin Check</name>
<t> <t>
Fundamentally, the IdP proxy is just a piece of HTML and JS loaded Fundamentally, the IdP proxy is just a piece of HTML and JS loaded
by the browser, so nothing stops a Web attacker from creating by the browser, so nothing stops a Web attacker from creating
their own IFRAME, loading the IdP proxy HTML/JS, and requesting a their own IFRAME, loading the IdP proxy HTML/JS, and requesting a
signature over his own keys rather than those generated in signature over his own keys rather than those generated in
the browser. However, that proxy would be in the the browser. However, that proxy would be in the
attacker's origin, not the IdP's origin. Only the attacker's origin, not the IdP's origin. Only the
browser itself can instantiate a context that (a) is in the IdP's browser itself can instantiate a context that (a)&nbsp;is in the I
origin and dP's origin and
(b) exposes the correct API surface. Thus, the IdP proxy on (b)&nbsp;exposes the correct API surface. Thus, the IdP proxy on
the sender's side MUST ensure that it is running in the IdP's orig the sender's side <bcp14>MUST</bcp14> ensure that it is running in
in the IdP's origin
prior to issuing assertions. prior to issuing assertions.
</t> </t>
<t> <t>
Note that this check only asserts that the browser (or some other Note that this check only asserts that the browser (or some other
entity with access to the user's authentication data) attests to entity with access to the user's authentication data) attests to
the request and hence to the fingerprint. It does not demonstrate the request and hence to the fingerprint. It does not demonstrate
that the browser has access to the associated private that the browser has access to the associated private
key, and therefore an attacker can attach their own identity key, and therefore an attacker can attach their own identity
to another party's keying material, thus making a call which to another party's keying material, thus making a call which
comes from Alice appear to come from the attacker. comes from Alice appear to come from the attacker.
See <xref target="I-D.ietf-mmusic-sdp-uks"/> for defenses against this See <xref target="RFC8844" format="default"/> for defenses against this
form of attack. form of attack.
</t> </t>
</section> </section>
<section anchor="sec.sec-idp-uri" numbered="true" toc="default">
<section title="IdP Well-known URI" anchor="sec.sec-idp-uri"> <name>IdP Well-Known URI</name>
<t> <t>
As described in <xref target="sec.idp-uri"/> the IdP proxy HTML/JS As described in <xref target="sec.idp-uri" format="default"/>, the
IdP proxy HTML/JS
landing page is located at a well-known URI based on the IdP's landing page is located at a well-known URI based on the IdP's
domain name. This requirement prevents an attacker who can write domain name. This requirement prevents an attacker who can write
some resources at the IdP (e.g., on one's Facebook wall) from some resources at the IdP (e.g., on one's Facebook wall) from
being able to impersonate the IdP. being able to impersonate the IdP.
</t> </t>
</section> </section>
<section numbered="true" toc="default">
<section title="Privacy of IdP-generated identities and the hosting si <name>Privacy of IdP-Generated Identities and the Hosting Site</name>
te"> <t>
<t>
Depending on the structure of the IdP's assertions, the calling Depending on the structure of the IdP's assertions, the calling
site may learn the user's identity from the perspective of the site may learn the user's identity from the perspective of the
IdP. In many cases this is not an issue because the user is IdP. In many cases, this is not an issue because the user is
authenticating to the site via the IdP in any case, for instance authenticating to the site via the IdP in any case -- for instance
,
when the user has logged in with Facebook Connect and is then when the user has logged in with Facebook Connect and is then
authenticating their call with a Facebook identity. However, in authenticating their call with a Facebook identity. However, in
other case, the user may not have already revealed their identity other cases, the user may not have already revealed their identity
to the site. In general, IdPs SHOULD either verify that the user to the site. In general, IdPs <bcp14>SHOULD</bcp14> either verify
that the user
is willing to have their identity revealed to the site (e.g., is willing to have their identity revealed to the site (e.g.,
through the usual IdP permissions dialog) or arrange that the through the usual IdP permissions dialog) or arrange that the
identity information is only available to known RPs (e.g., social identity information is only available to known RPs (e.g., social
graph adjacencies) but not to the calling site. The "domain" field graph adjacencies) but not to the calling site. The "domain" field
of the assertion request can be used to check that the user has of the assertion request can be used to check that the user has
agreed to disclose their identity to the calling site; because it agreed to disclose their identity to the calling site; because it
is supplied by the PeerConnection it can be trusted to be correct. is supplied by the PeerConnection it can be trusted to be correct.
</t> </t>
</section> </section>
<section anchor="sec.sec-third-party" numbered="true" toc="default">
<section title="Security of Third-Party IdPs" anchor="sec.sec-third-pa <name>Security of Third-Party IdPs</name>
rty"> <t>
<t>
As discussed above, each third-party IdP represents a new As discussed above, each third-party IdP represents a new
universal trust point and therefore the number of these IdPs needs universal trust point and therefore the number of these IdPs needs
to be quite limited. Most IdPs, even those which issue unqualified to be quite limited. Most IdPs, even those which issue unqualified
identities such as Facebook, can be recast as authoritative IdPs identities such as Facebook, can be recast as authoritative IdPs
(e.g., 123456@facebook.com). However, in such cases, the user (e.g., 123456@facebook.com). However, in such cases, the user
interface implications are not entirely desirable. One interface implications are not entirely desirable. One
intermediate approach is to have special (potentially user intermediate approach is to have a special (potentially user
configurable) UI for large authoritative IdPs, thus allowing the configurable) UI for large authoritative IdPs, thus allowing the
user to instantly grasp that the call is being authenticated by user to instantly grasp that the call is being authenticated by
Facebook, Google, etc. Facebook, Google, etc.
</t> </t>
<section numbered="true" toc="default">
<section title="Confusable Characters"> <name>Confusable Characters</name>
<t> <t>
Because a broad range of characters are permitted in identity Because a broad range of characters are permitted in identity
strings, it may be possible for attackers to craft identities strings, it may be possible for attackers to craft identities
which are confusable with other identities (see which are confusable with other identities (see
<xref target="RFC6943"/> for more on this topic). This is <xref target="RFC6943" format="default"/> for more on this topic ). This is
a problem with any identifier space of this type a problem with any identifier space of this type
(e.g., e-mail addresses). (e.g., email addresses).
Those minting identifers should avoid mixed scripts and similar Those minting identifiers should avoid mixed scripts and similar
confusable characters. Those presenting these identifiers to a confusable characters. Those presenting these identifiers to a
user should consider highlighting cases of mixed script usage user should consider highlighting cases of mixed script usage
(see <xref target="RFC5890"/>, section 4.4). Other best practice (see <xref target="RFC5890" sectionFormat="comma" section="4.4"/
s are still in development. >). Other best practices are still in development.
</t> </t>
</section>
</section> </section>
</section>
<section title="Web Security Feature Interactions"> <section numbered="true" toc="default">
<t> <name>Web Security Feature Interactions</name>
<t>
A number of optional Web security features have the potential to A number of optional Web security features have the potential to
cause issues for this mechanism, as discussed below. cause issues for this mechanism, as discussed below.
</t> </t>
<section anchor="sec.popup-blocking" numbered="true" toc="default">
<section title="Popup Blocking" anchor="sec.popup-blocking"> <name>Popup Blocking</name>
<t> <t>
When popup blocking is in use, the IdP proxy is unable to genera When popup blocking is in use, the IdP proxy is unable to genera
te popup windows, dialogs or te popup windows, dialogs, or
any other form of user interactions. This prevents the IdP any other form of user interactions. This prevents the IdP
proxy from being used to circumvent user interaction. The proxy from being used to circumvent user interaction. The
"LOGINNEEDED" message allows the IdP proxy to inform the calling "LOGINNEEDED" message allows the IdP proxy to inform the calling
site of a need for user login, providing the information site of a need for user login, providing the information
necessary to satisfy this requirement without resorting to necessary to satisfy this requirement without resorting to
direct user interaction from the IdP proxy itself. direct user interaction from the IdP proxy itself.
</t> </t>
</section> </section>
<section anchor="sec.3rd-party-cookies" numbered="true" toc="default">
<section title="Third Party Cookies" anchor="sec.3rd-party-cookies"> <name>Third Party Cookies</name>
<t> <t>
Some browsers allow users to block third party cookies (cookies Some browsers allow users to block third party cookies (cookies
associated with origins other than the top level page) for associated with origins other than the top-level page) for
privacy reasons. Any IdP which uses cookies to persist logins privacy reasons. Any IdP which uses cookies to persist logins
will be broken by third-party cookie blocking. One option is to will be broken by third-party cookie blocking. One option is to
accept this as a limitation; another is to have the accept this as a limitation; another is to have the
PeerConnection object disable third-party cookie blocking for PeerConnection object disable third-party cookie blocking for
the IdP proxy. the IdP proxy.
</t> </t>
</section>
</section> </section>
</section> </section>
</section> </section>
</section>
<section title="IANA Considerations" anchor="sec.iana-cons"> <section anchor="sec.iana-cons" numbered="true" toc="default">
<t> <name>IANA Considerations</name>
This specification defines the <spanx style="verb">identity</spanx> <t>
SDP attribute per the procedures of Section 8.2.4 of <xref This specification defines the "identity"
target="RFC4566"/>. The required information for the registration is SDP attribute per the procedures of <xref target="RFC4566" sectionForm
at="of" section="8.2.4"/>. The required information for the registration is
included here: included here:
<list style="hanging"> </t>
<t hangText="Contact Name:">IESG (iesg@ietf.org)</t> <dl newline="false" spacing="normal">
<t hangText="Attribute Name:">identity</t> <dt>Contact Name:</dt>
<t hangText="Long Form:">identity</t> <dd>IESG (iesg@ietf.org)</dd>
<t hangText="Type of Attribute:">session-level</t> <dt>Attribute Name:</dt>
<t hangText="Charset Considerations:">This attribute is not subject <dd>identity</dd>
to the charset attribute.</t> <dt>Long Form:</dt>
<t hangText="Purpose:">This attribute carries an identity assertion, <dd>identity</dd>
binding an identity to the transport-level security session.</t> <dt>Type of Attribute:</dt>
<t hangText="Appropriate Values:">See <xref <dd>session</dd>
target="sec.sdp-id-attr"/> of RFCXXXX [[Editor Note: This <dt>Charset Considerations:</dt>
document.]]</t> <dd>This attribute is not subject
<t hangText="Mux Category:">NORMAL.</t> to the charset attribute.</dd>
</list> <dt>Purpose:</dt>
</t> <dd>This attribute carries an identity assertion,
<t> binding an identity to the transport-level security session.</dd>
This section reqisters the <spanx style="verb">idp-proxy</spanx> well- <dt>Appropriate Values:</dt>
known <dd>See <xref target="sec.sdp-id-attr" format="default"/> of RFC 8827.</
URI from <xref target="RFC5785"/>. dd>
<list style="hanging"> <dt>Mux Category:</dt>
<t hangText="URI suffix:">idp-proxy</t> <dd>NORMAL</dd>
<t hangText="Change controller:">IETF</t> </dl>
</list>
</t>
</section>
<section title="Acknowledgements">
<t> <t>
Bernard Aboba, Harald Alvestrand, Richard Barnes, Dan Druta, Cullen This section registers the "idp-proxy" well-known
Jennings, Hadriel Kaplan, Matthew Kaufman, Jim McEachern, Martin URI from <xref target="RFC5785" format="default"/>.
Thomson, Magnus Westerland. Matthew Kaufman provided the UI material in
<xref target="sec.proposal.comsec"/>. Christer Holmberg provided
the initial version of <xref target="sec.sdp-id-attr-oa"/>.
</t> </t>
<dl newline="false" spacing="normal">
<dt>URI suffix:</dt>
<dd>idp-proxy</dd>
<dt>Change controller:</dt>
<dd>IETF</dd>
</dl>
</section> </section>
</middle>
<back>
<references>
<name>References</name>
<references>
<name>Normative References</name>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2818.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3264.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3711.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3986.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4566.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4568.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4648.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5246.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5763.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5764.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5785.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5890.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6347.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6454.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7022.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7675.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7918.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8122.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8259.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8261.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8445.
xml"/>
<section title="Changes"> <!-- draft-ietf-rtcweb-overview: RFC 8825 -->
<t> [RFC Editor: Please remove this section prior to publication.]</t> <reference anchor="RFC8825" target="https://www.rfc-editor.org/info/rfc8825">
<section title="Changes since -15"> <front>
<t>Rewrite the Identity section in more conventional offer/answer format <title>Overview: Real-Time Protocols for Browser-Based Applications</title>
.</t> <author initials="H." surname="Alvestrand" fullname="Harald T. Alvestrand">
<t>Clarify rules on changing identities.</t> <organization />
</section> </author>
<date month="June" year="2020" />
</front>
<seriesInfo name="RFC" value="8825" />
<seriesInfo name="DOI" value="10.17487/RFC8825"/>
</reference>
<section title="Changes since -11"> <!--draft-ietf-rtcweb-security: RFC 8826 -->
<t> <reference anchor="RFC8826" target="https://www.rfc-editor.org/info/rfc8826">
Update discussion of IdP security model <front>
</t> <title>Security Considerations for WebRTC</title>
<author initials='E.' surname='Rescorla' fullname='Eric Rescorla'>
<organization/>
</author>
<date month='June' year='2020'/>
</front>
<seriesInfo name="RFC" value="8826"/>
<seriesInfo name="DOI" value="10.17487/RFC8826"/>
</reference>
<t> <!-- draft-ietf-rtcweb-rtp-usage; RFC 8834 -->
Replace "domain name" with RFC 3986 Authority <reference anchor="RFC8834" target="https://www.rfc-editor.org/info/rfc8834">
</t> <front>
<title>Media Transport and Use of RTP in WebRTC</title>
<author initials="C." surname="Perkins" fullname="Colin Perkins">
<organization />
</author>
<author initials="M." surname="Westerlund" fullname="Magnus Westerlund">
<organization />
</author>
<author initials="J." surname="Ott" fullname="Jörg Ott">
<organization />
</author>
<date month="June" year="2020" />
</front>
<seriesInfo name="RFC" value="8834" />
<seriesInfo name="DOI" value="10.17487/RFC8834"/>
</reference>
<t> <!-- draft-ietf-mmusic-sdp-uks; RFC 8844 -->
Clean up discussion of how to generate IdP URI. <reference anchor='RFC8844' target="https://www.rfc-editor.org/info/rfc8844">
</t> <front>
<title>Unknown Key Share Attacks on uses of TLS with the Session Description Pro
tocol (SDP)</title>
<t> <author initials='M' surname='Thomson' fullname='Martin Thomson'>
Remove obsolete text about null cipher suites. <organization />
</t> </author>
<t> <author initials='E' surname='Rescorla' fullname='Eric Rescorla'>
Remove obsolete appendixes about older IdP systems <organization />
</t> </author>
<t> <date month="June" year="2020"/>
Require support for ECDSA, PFS, and AEAD
</t>
</section>
<section title="Changes since -10">
<t>
Update cipher suite profiles.
</t>
<t>
Rework IdP interaction based on implementation experience in
Firefox.
</t>
</section>
<section title="Changes since -06"> </front>
<t> <seriesInfo name="RFC" value="8859"/>
Replaced RTCWEB and RTC-Web with WebRTC, except when referring to the <seriesInfo name="DOI" value="10.17487/RFC8859"/>
IETF WG
</t>
<t>
Forbade use in mixed content as discussed in Orlando.
</t>
<t>
Added a requirement to surface NULL ciphers to the top-level.
</t>
<t>
Tried to clarify SRTP versus DTLS-SRTP.
</t>
<t>
Added a section on screen sharing permissions.
</t>
<t>
Assorted editorial work.
</t>
</section>
<section title="Changes since -05"> </reference>
<t>
The following changes have been made since the -05 draft.
</t>
<t>
<list style="symbols">
<t>
Response to comments from Richard Barnes
</t>
<t>
More explanation of the IdP security properties and the federation
use case.
</t>
<t>
Editorial cleanup.
</t>
</list>
</t>
</section>
<section title="Changes since -03"> <!-- draft-ietf-rtcweb-jsep; RFC 8829 -->
<t> <reference anchor="RFC8829" target="https://www.rfc-editor.org/info/rfc8829">
Version -04 was a version control mistake. Please ignore. <front>
</t> <title>JavaScript Session Establishment Protocol (JSEP)</title>
<t> <author initials='J.' surname='Uberti' fullname='Justin Uberti'>
The following changes have been made since the -04 draft. <organization/>
</t> </author>
<t> <author initials="C." surname="Jennings" fullname="Cullen Jennings">
<list style="symbols"> <organization/>
<t> </author>
Move origin check from IdP to RP per discussion in YVR. <author initials="E." surname="Rescorla" fullname="Eric Rescorla"
</t> role="editor">
<t> <organization/>
Clarified treatment of X.509-level identities. </author>
</t> <date month='June' year='2020'/>
<t> </front>
Editorial cleanup. <seriesInfo name="RFC" value="8829"/>
</t> <seriesInfo name="DOI" value="10.17487/RFC8829"/>
</list> </reference>
</t>
</section>
<section title="Changes since -03"> <reference anchor="webcrypto" target="https://www.w3.org/TR/2017/REC-Web
</section> CryptoAPI-20170126/">
<front>
<title>Web Cryptography API</title>
<author initials="M" surname="Watson" fullname="Mark Watson">
</author>
<date month="January" year="2017" day="26"/>
</front>
<refcontent>W3C Recommendation</refcontent>
</reference>
<section title="Changes since -02"> <!-- [rfced] Normative References: Because the citation for
<t> [webcrypto] is used generally in text, we updated this listing per
The following changes have been made since the -02 draft. <https://www.w3.org/TR/WebCryptoAPI/>. Please let us know any
</t> objections.
<t>
<list style="symbols">
<t>
Forbid persistent HTTP permissions.
</t>
<t>
Clarified the text in S 5.4 to clearly refer to requirements on
the API to provide functionality to the site.
</t>
<t>
Fold in the IETF portion of draft-rescorla-rtcweb-generic-idp
</t>
<t>
Retarget the continuing consent section to assume Binding Requests
</t>
<t>
Added some more privacy and linkage text in various places.
</t>
<t>
Editorial improvements
</t>
</list>
</t>
</section>
</section>
</middle>
<back> Original:
[webcrypto]
editors, W., "Web Cryptography API", June 2013.
<references title="Normative References"> Available at http://www.w3.org/TR/WebCryptoAPI/
&RFC2119;
&RFC2818;
&RFC3264;
&RFC3711;
&RFC3986;
&RFC4566;
&RFC4568;
&RFC4648;
&RFC5246;
&RFC5763;
&RFC5764;
&RFC5785;
&RFC5890;
&RFC6347;
&RFC6454;
&RFC7022;
&RFC7675;
&RFC7918;
&RFC8174;
&RFC8122;
&RFC8259;
&RFC8261;
&RFC8445;
&I-D.ietf-rtcweb-overview; Currently:
&I-D.ietf-rtcweb-security; [webcrypto]
&I-D.ietf-rtcweb-rtp-usage; Watson, M., "Web Cryptography API", W3C Recommendation,
&I-D.ietf-mmusic-sdp-uks; 26 January 2017,
&I-D.ietf-rtcweb-jsep; <https://www.w3.org/TR/2017/REC-WebCryptoAPI-20170126/>.
-->
<reference anchor="webcrypto"> <reference anchor="webrtc-api" target="https://www.w3.org/TR/2019/CR-web
<front> rtc-20191213/">
<title>Web Cryptography API</title> <front>
<title>WebRTC 1.0: Real-time Communication Between Browsers</title>
<author initials="C." surname="Jennings" fullname="Cullen Jennings">
<organization/>
</author>
<author initials="H." surname="Boström" fullname="Henrik Boström">
<organization/>
</author>
<author initials="J-I." surname="Bruaroey" fullname="Jan-Ivar Bruaro
ey">
<organization/>
</author>
<date year="2019" month="December" day="13"/>
</front>
<refcontent>W3C Candidate Recommendation</refcontent>
</reference>
<author fullname="W3C editors" <!-- [rfced] Normative References: The URL as provided for
surname="Dahl, Sleevi"> [webrtc-api] in the original document -
<organization>W3C</organization> <http://dev.w3.org/2011/webrtc/editor/webrtc.html> - steers to
</author> <http://w3c.github.io/webrtc-pc/>, dated October 2019. Please note
that this GitHub page says "Editor's draft" and also says
"Latest published version: https://www.w3.org/TR/webrtc/." We have updated
this to refer to the "Latest published version". Please let us know any
objections.
<date day="25" month="June" year="2013" /> Original:
</front> [webrtc-api]
editors, W., "WebRTC 1.0: Real-time Communication Between
Browsers", October 2011.
<annotation>Available at Available at http://dev.w3.org/2011/webrtc/editor/
http://www.w3.org/TR/WebCryptoAPI/</annotation> webrtc.html
</reference>
<reference anchor="webrtc-api"> Currently:
<front> [webrtc-api]
<title>WebRTC 1.0: Real-time Communication Between Browsers</title> Jennings, C., Boström, H., and J-I. Bruaroey, "WebRTC 1.0:
Real-time Communication Between Browsers", W3C Candidate
Recommendation, 13 December 2019,
<https://www.w3.org/TR/2019/CR-webrtc-20191213/>.
-->
<author fullname="W3C editors" <reference anchor="FIPS186">
surname="Bergkvist, Burnett, Jennings, Narayanan"> <front>
<organization>W3C</organization> <title>Digital Signature Standard (DSS)</title>
</author> <author>
<organization>National Institute of Standards and Technology (NIST
)</organization>
</author>
<date year="2013" month="July"/>
</front>
<seriesInfo name="NIST PUB" value="186-4"/>
<seriesInfo name="DOI" value="10.6028/NIST.FIPS.186-4"/>
</reference>
</references>
<references>
<name>Informative References</name>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7617.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3261.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5705.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6455.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6265.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6943.
xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6120.
xml"/>
<reference anchor="XmlHttpRequest" target="https://www.w3.org/TR/XMLHttp
Request/">
<front>
<title>XMLHttpRequest Level 2</title>
<author initials="A." surname="van Kesteren">
<organization/>
</author>
<date month="January" year="2012"/>
</front>
</reference>
<date day="4" month="October" year="2011" /> <!-- [rfced] Informative References: The URL as provided for
</front> [XmlHttpRequest] in the original document -
<http://www.w3.org/TR/XMLHttpRequest/> - steers to a page with the
title "XMLHttpRequest Level 1," dated October 2016. When we did a
Google search for "XMLHttpRequest Level 2," we found
<https://www.w3.org/TR/2012/WD-XMLHttpRequest-20120117/>, which is
partially obscured by a red box that says "This version is
outdated!" The link in the box in turn steers to the October 2016
"XMLHttpRequest Level 1" page.
<annotation>Available at Please advise.
http://dev.w3.org/2011/webrtc/editor/webrtc.html</annotation>
</reference>
<reference anchor="FIPS186"> Original:
<front> [XmlHttpRequest]
<title>Digital Signature Standard (DSS)</title> van Kesteren, A., "XMLHttpRequest Level 2", January 2012. -->
<author >
<organization>National Institute of Standards and Technology (NIST)<
/organization>
</author>
<date year="2013" month="July"/>
</front>
<seriesInfo name="NIST PUB 186-4" value=""/>
</reference>
</references>
</references> </references>
<references title="Informative References"> <section numbered="false" toc="default">
&RFC7617; <name>Acknowledgements</name>
&RFC3261; <t>
&RFC5705; <contact fullname="Bernard Aboba"/>, <contact fullname="Harald
&RFC6455; Alvestrand"/>, <contact fullname="Richard Barnes"/>, <contact
&RFC6265; fullname="Dan Druta"/>, <contact fullname="Cullen
&RFC6943; Jennings"/>, <contact fullname="Hadriel Kaplan"/>, <contact
&RFC6120; fullname="Matthew Kaufman"/>, <contact fullname="Jim McEachern"/>,
<contact fullname="Martin Thomson"/>, <contact fullname="Magnus
Westerlund"/>. <contact fullname="Matthew Kaufman"/> provided the UI mat
erial in
<xref target="sec.proposal.comsec" format="default"/>. <contact fullname
="Christer Holmberg"/> provided
the initial version of <xref target="sec.sdp-id-attr-oa" format="default
"/>.
</t>
</section>
</back>
<reference anchor="XmlHttpRequest"> <!-- [rfced] Please let us know if any changes are needed for the
<front> following:
<title>XMLHttpRequest Level 2</title>
<author initials="A." surname="van Kesteren"> a) The following term was used inconsistently in this document.
<organization></organization> We chose to use the latter form. Please let us know any objections.
</author>
<date day="17" month="January" year="2012"/> Cookies ("use Cookies") / cookies ("access cookies") (Section 7.7)
</front>
<format target="http://www.w3.org/TR/XMLHttpRequest/" type="TXT"/> b) In the v2 XML file, <spanx style="verb"> was used to create single quotes
</reference> for some keys, values, and attribute names. Per RFC 7991, the xml2rfc v3
vocab, <spanx> has been deprecated:
Deprecate <spanx>; replace it with <strong>, <em>, and <tt>.
C238 uses single or double quotes when referring to SDP attributes. Note that
we have replaced instances of <spanx> with double quotes. Please let us know
if any updates are needed.
c) Please let us know how/if the following should be made consistent:
interdomain ("interdomain calling") /
inter-domain ("inter-domain protocol")
(Usage post-RFC 6000 is mixed but leans heavily toward
"inter-domain.")
Identity Providers ("overview of Identity Providers and the relevant
terminology") / identity providers
The rest of this document, and the rest of the documents in
Cluster 238, use the lowercase form. Changing "overview of
Identity Providers" to "overview of IdPs" in this document would
resolve this issue.
Relying Party (Section 4) / relying party (Section 7)
security characteristics / "security characteristics"
"https:" (The scheme, "https:") / "https" scheme (the "https" scheme)
-->
</references>
</back>
</rfc> </rfc>
 End of changes. 371 change blocks. 
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