draft-ietf-rtcweb-security-arch-15.txt   draft-ietf-rtcweb-security-arch-16.txt 
RTCWEB E. Rescorla RTCWEB E. Rescorla
Internet-Draft RTFM, Inc. Internet-Draft RTFM, Inc.
Intended status: Standards Track July 17, 2018 Intended status: Standards Track October 22, 2018
Expires: January 18, 2019 Expires: April 25, 2019
WebRTC Security Architecture WebRTC Security Architecture
draft-ietf-rtcweb-security-arch-15 draft-ietf-rtcweb-security-arch-16
Abstract Abstract
This document defines the security architecture for WebRTC, a This document defines the security architecture for WebRTC, a
protocol suite intended for use with real-time applications that can protocol suite intended for use with real-time applications that can
be deployed in browsers - "real time communication on the Web". be deployed in browsers - "real time communication on the Web".
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 18, 2019. This Internet-Draft will expire on April 25, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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This document may contain material from IETF Documents or IETF This document may contain material from IETF Documents or IETF
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skipping to change at page 2, line 29 skipping to change at page 2, line 29
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Trust Model . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Trust Model . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Authenticated Entities . . . . . . . . . . . . . . . . . 5 3.1. Authenticated Entities . . . . . . . . . . . . . . . . . 5
3.2. Unauthenticated Entities . . . . . . . . . . . . . . . . 6 3.2. Unauthenticated Entities . . . . . . . . . . . . . . . . 6
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Initial Signaling . . . . . . . . . . . . . . . . . . . . 8 4.1. Initial Signaling . . . . . . . . . . . . . . . . . . . . 8
4.2. Media Consent Verification . . . . . . . . . . . . . . . 10 4.2. Media Consent Verification . . . . . . . . . . . . . . . 10
4.3. DTLS Handshake . . . . . . . . . . . . . . . . . . . . . 11 4.3. DTLS Handshake . . . . . . . . . . . . . . . . . . . . . 11
4.4. Communications and Consent Freshness . . . . . . . . . . 11 4.4. Communications and Consent Freshness . . . . . . . . . . 11
5. Detailed Technical Description . . . . . . . . . . . . . . . 12 5. SDP Identity Attribute . . . . . . . . . . . . . . . . . . . 12
5.1. Origin and Web Security Issues . . . . . . . . . . . . . 12 5.1. Offer/Answer Considerations . . . . . . . . . . . . . . . 13
5.2. Device Permissions Model . . . . . . . . . . . . . . . . 12 5.1.1. Generating the Initial SDP Offer . . . . . . . . . . 13
5.3. Communications Consent . . . . . . . . . . . . . . . . . 14 5.1.2. Answerer Processing of SDP Offer . . . . . . . . . . 14
5.4. IP Location Privacy . . . . . . . . . . . . . . . . . . . 14 5.1.3. Generating of SDP Answer . . . . . . . . . . . . . . 14
5.5. Communications Security . . . . . . . . . . . . . . . . . 15 5.1.4. Offerer Processing of SDP Answer . . . . . . . . . . 14
5.6. Web-Based Peer Authentication . . . . . . . . . . . . . . 17 5.1.5. Modifying the Session . . . . . . . . . . . . . . . . 14
5.6.1. Trust Relationships: IdPs, APs, and RPs . . . . . . . 18 6. Detailed Technical Description . . . . . . . . . . . . . . . 14
5.6.2. Overview of Operation . . . . . . . . . . . . . . . . 20 6.1. Origin and Web Security Issues . . . . . . . . . . . . . 14
5.6.3. Items for Standardization . . . . . . . . . . . . . . 21 6.2. Device Permissions Model . . . . . . . . . . . . . . . . 15
5.6.4. Binding Identity Assertions to JSEP Offer/Answer 6.3. Communications Consent . . . . . . . . . . . . . . . . . 17
Transactions . . . . . . . . . . . . . . . . . . . . 21 6.4. IP Location Privacy . . . . . . . . . . . . . . . . . . . 17
5.6.4.1. Carrying Identity Assertions . . . . . . . . . . 22 6.5. Communications Security . . . . . . . . . . . . . . . . . 18
5.6.4.2. a=identity Attribute . . . . . . . . . . . . . . 23 7. Web-Based Peer Authentication . . . . . . . . . . . . . . . . 20
5.6.5. Determining the IdP URI . . . . . . . . . . . . . . . 24 7.1. Trust Relationships: IdPs, APs, and RPs . . . . . . . . . 21
5.6.5.1. Authenticating Party . . . . . . . . . . . . . . 25 7.2. Overview of Operation . . . . . . . . . . . . . . . . . . 22
5.6.5.2. Relying Party . . . . . . . . . . . . . . . . . . 25 7.3. Items for Standardization . . . . . . . . . . . . . . . . 24
5.6.6. Requesting Assertions . . . . . . . . . . . . . . . . 25 7.4. Binding Identity Assertions to JSEP Offer/Answer
5.6.7. Managing User Login . . . . . . . . . . . . . . . . . 26 Transactions . . . . . . . . . . . . . . . . . . . . . . 24
5.7. Verifying Assertions . . . . . . . . . . . . . . . . . . 27 7.4.1. Carrying Identity Assertions . . . . . . . . . . . . 25
5.7.1. Identity Formats . . . . . . . . . . . . . . . . . . 27 7.5. Determining the IdP URI . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 28 7.5.1. Authenticating Party . . . . . . . . . . . . . . . . 27
6.1. Communications Security . . . . . . . . . . . . . . . . . 28 7.5.2. Relying Party . . . . . . . . . . . . . . . . . . . . 27
6.2. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 29 7.6. Requesting Assertions . . . . . . . . . . . . . . . . . . 27
6.3. Denial of Service . . . . . . . . . . . . . . . . . . . . 30 7.7. Managing User Login . . . . . . . . . . . . . . . . . . . 28
6.4. IdP Authentication Mechanism . . . . . . . . . . . . . . 31 8. Verifying Assertions . . . . . . . . . . . . . . . . . . . . 29
6.4.1. PeerConnection Origin Check . . . . . . . . . . . . . 31 8.1. Identity Formats . . . . . . . . . . . . . . . . . . . . 29
6.4.2. IdP Well-known URI . . . . . . . . . . . . . . . . . 31 9. Security Considerations . . . . . . . . . . . . . . . . . . . 30
6.4.3. Privacy of IdP-generated identities and the hosting 9.1. Communications Security . . . . . . . . . . . . . . . . . 30
site . . . . . . . . . . . . . . . . . . . . . . . . 32 9.2. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.4.4. Security of Third-Party IdPs . . . . . . . . . . . . 32 9.3. Denial of Service . . . . . . . . . . . . . . . . . . . . 32
6.4.4.1. Confusable Characters . . . . . . . . . . . . . . 32 9.4. IdP Authentication Mechanism . . . . . . . . . . . . . . 33
6.4.5. Web Security Feature Interactions . . . . . . . . . . 32 9.4.1. PeerConnection Origin Check . . . . . . . . . . . . . 33
6.4.5.1. Popup Blocking . . . . . . . . . . . . . . . . . 33 9.4.2. IdP Well-known URI . . . . . . . . . . . . . . . . . 34
6.4.5.2. Third Party Cookies . . . . . . . . . . . . . . . 33 9.4.3. Privacy of IdP-generated identities and the hosting
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 site . . . . . . . . . . . . . . . . . . . . . . . . 34
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 34 9.4.4. Security of Third-Party IdPs . . . . . . . . . . . . 34
9. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 9.4.4.1. Confusable Characters . . . . . . . . . . . . . . 34
9.1. Changes since -11 . . . . . . . . . . . . . . . . . . . . 34 9.4.5. Web Security Feature Interactions . . . . . . . . . . 35
9.2. Changes since -10 . . . . . . . . . . . . . . . . . . . . 34 9.4.5.1. Popup Blocking . . . . . . . . . . . . . . . . . 35
9.3. Changes since -06 . . . . . . . . . . . . . . . . . . . . 34 9.4.5.2. Third Party Cookies . . . . . . . . . . . . . . . 35
9.4. Changes since -05 . . . . . . . . . . . . . . . . . . . . 35 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
9.5. Changes since -03 . . . . . . . . . . . . . . . . . . . . 35 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36
9.6. Changes since -03 . . . . . . . . . . . . . . . . . . . . 35 12. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
9.7. Changes since -02 . . . . . . . . . . . . . . . . . . . . 35 12.1. Changes since -15 . . . . . . . . . . . . . . . . . . . 36
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 12.2. Changes since -11 . . . . . . . . . . . . . . . . . . . 36
10.1. Normative References . . . . . . . . . . . . . . . . . . 36 12.3. Changes since -10 . . . . . . . . . . . . . . . . . . . 36
10.2. Informative References . . . . . . . . . . . . . . . . . 39 12.4. Changes since -06 . . . . . . . . . . . . . . . . . . . 37
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 39 12.5. Changes since -05 . . . . . . . . . . . . . . . . . . . 37
12.6. Changes since -03 . . . . . . . . . . . . . . . . . . . 37
12.7. Changes since -03 . . . . . . . . . . . . . . . . . . . 37
12.8. Changes since -02 . . . . . . . . . . . . . . . . . . . 37
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 38
13.1. Normative References . . . . . . . . . . . . . . . . . . 38
13.2. Informative References . . . . . . . . . . . . . . . . . 41
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 42
1. Introduction 1. Introduction
The Real-Time Communications on the Web (WebRTC) working group is The Real-Time Communications on the Web (WebRTC) working group is
tasked with standardizing protocols for real-time communications tasked with standardizing protocols for real-time communications
between Web browsers. The major use cases for WebRTC technology are between Web browsers. The major use cases for WebRTC technology are
real-time audio and/or video calls, Web conferencing, and direct data real-time audio and/or video calls, Web conferencing, and direct data
transfer. Unlike most conventional real-time systems, (e.g., SIP- transfer. Unlike most conventional real-time systems, (e.g., SIP-
based [RFC3261] soft phones) WebRTC communications are directly based [RFC3261] 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
skipping to change at page 6, line 43 skipping to change at page 6, line 43
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 figures below. This topology is derived from the topology shown in
Figure 1, but separates Alice and Bob's identities from the process Figure 1, but separates Alice and Bob's identities from the process
of signaling. Specifically, Alice and Bob have relationships with of signaling. Specifically, Alice and Bob have relationships with
some Identity Provider (IdP) that supports a protocol (such as OpenID some Identity Provider (IdP) that supports a protocol (such as OpenID
Connect) that can be used to demonstrate their identity to other Connect) that can be used to demonstrate their identity to other
parties. For instance, Alice might have an account with a social 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 without explicitly having an account with those sites; this is a
fairly conventional pattern on the Web. Section 5.6.1 provides an fairly conventional pattern on the Web. Section 7.1 provides an
overview of Identity Providers and the relevant terminology. Alice overview of Identity Providers and the relevant terminology. Alice
and Bob might have relationships with different IdPs as well. and Bob might have relationships with different IdPs as well.
This separation of identity provision and signaling isn't This separation of identity provision and signaling isn't
particularly important in "closed world" cases where Alice and Bob particularly important in "closed world" cases where Alice and Bob
are users on the same social network and have identities based on are users on the same social network and have identities based on
that domain (Figure 3). However, there are important settings where that domain (Figure 3). However, there are important settings 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; Figure 4) and calling on untrusted sites, such as where two another; Figure 4) and calling on untrusted sites, such as where two
users who have a relationship via a given social network want to call users who have a relationship via a given social network want to call
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o Interactive Connectivity Establishment (ICE) [RFC5245] candidates o Interactive Connectivity Establishment (ICE) [RFC5245] candidates
o A fingerprint attribute binding the communication to a key pair o A fingerprint attribute binding the communication to a key pair
[RFC5763]. Note that this key may simply be ephemerally generated [RFC5763]. Note that this key may simply be ephemerally generated
for this call or specific to this domain, and Alice may have a for this call or specific to this domain, and Alice may have a
large number of such keys. large number of such keys.
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 contacts the identity service and obtains an assertion binding
Alice's identity to her fingerprint. The exact details depend on the Alice's identity to her fingerprint. The exact details depend on the
identity service (though as discussed in Section 5.6 PeerConnection identity service (though as discussed in Section 7 PeerConnection can
can be agnostic to them), but for now it's easiest to think of as an be agnostic to them), but for now it's easiest to think of as an
OAuth token. The assertion may bind other information to the OAuth token. The assertion may bind other information to the
identity besides the fingerprint, but at minimum it needs to bind the identity besides the fingerprint, but at minimum it needs to bind the
fingerprint. fingerprint.
This message is sent to the signaling server, e.g., by XMLHttpRequest This message is sent to the signaling server, e.g., by XMLHttpRequest
[XmlHttpRequest] or by WebSockets [RFC6455], preferably over TLS [XmlHttpRequest] or by WebSockets [RFC6455], preferably over TLS
[RFC5246]. The signaling server processes the message from Alice's [RFC5246]. The signaling server processes the message from Alice's
browser, determines that this is a call to Bob and sends a signaling browser, determines that this is a call to Bob and sends a signaling
message to Bob's browser (again, the format is currently undefined). message to Bob's browser (again, the format is currently undefined).
The JS on Bob's browser processes it, and alerts Bob to the incoming The JS on Bob's browser processes it, and alerts Bob to the incoming
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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 STUN keepalives 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 MUST be based on the consent freshness
mechanism specified in [RFC7675]. If a keepalive fails and no new mechanism specified in [RFC7675]. If a keepalive fails and no new
ICE channels can be established, then the session is terminated. ICE channels can be established, then the session is terminated.
5. Detailed Technical Description 5. SDP Identity Attribute
5.1. Origin and Web Security Issues The SDP 'identity' attribute is a session-level attribute that is
used by an endpoint to convey its identity assertion to its peer.
The identity assertion value is encoded as Base-64, as described in
Section 4 of [RFC4648].
The procedures in this section are based on the assumption that the
identity assertion of an endpoint is bound to the fingerprints of the
endpoint. This does not preclude the definition of alternative means
of binding an assertion to the endpoint, but such means are outside
the scope of this specification.
The semantics of multiple 'identity' attributes within an offer or
answer are undefined. Implementations SHOULD only include a single
'identity' attribute in an offer or answer and relying parties MAY
elect to ignore all but the first 'identity' attribute.
Name: identity
Value: identity-assertion
Usage Level: session
Charset Dependent: no
Default Value: N/A
Name: identity
Syntax:
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]>
Example:
a=identity:\
eyJpZHAiOnsiZG9tYWluIjoiZXhhbXBsZS5vcmciLCJwcm90b2NvbCI6ImJvZ3Vz\
In0sImFzc2VydGlvbiI6IntcImlkZW50aXR5XCI6XCJib2JAZXhhbXBsZS5vcmdc\
IixcImNvbnRlbnRzXCI6XCJhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3l6XCIsXCJz\
aWduYXR1cmVcIjpcIjAxMDIwMzA0MDUwNlwifSJ9
Note that long lines in the example are folded to meet the column
width constraints of this document; the backslash ("\") at the end of
a line and the carriage return that follows shall be ignored.
This specification does not define any extensions for the attribute.
The identity-assertion value is a JSON [RFC8259] encoded string. The
JSON object contains two keys: "assertion" and "idp". The
"assertion" key value contains an opaque string that is consumed by
the IdP. The "idp" key value contains a dictionary with one or two
further values that identify the IdP. See Section 7.6 for more
details.
5.1. Offer/Answer Considerations
This section defines the SDP Offer/Answer [RFC6454] considerations
for the SDP 'identity' attribute.
Within this section, 'initial offer' refers to the first offer in the
SDP session that contains an SDP "identity" attribute.
5.1.1. Generating the Initial SDP Offer
When an offerer sends an offer, in order to provide its identity
assertion to the peer, it includes an 'identity' attribute in the
offer. In addition, the offerer includes one or more SDP
'fingerprint' attributes. The 'identity' attribute MUST be bound to
all the 'fingerprint' attributes in the session description.
5.1.2. Answerer Processing of SDP Offer
When an answerer receives an offer that contains an 'identity'
attribute, the answerer can use the the attribute information to
contact the IdP, and verify the identity of the peer. If the
identity verification fails, the answerer MUST reject the offer.
5.1.3. Generating of SDP Answer
If the answerer elects to include an 'identity' attribute, it follows
the same steps as those in Section 5.1.1. The answerer can choose to
include or omit an 'identity' attribute independently, regardless of
whether the offerer did so.
5.1.4. Offerer Processing of SDP Answer
Offer processing of an 'identity' attribute is the same as that
described in Section 5.1.2.
5.1.5. Modifying the Session
When modifying a session, if the set of fingerprints is unchanged,
then the sender MAY send the same 'identity' attribute. In this
case, the established identity SHOULD be applied to existing DTLS
connections as well as new connections established using one of those
fingerprints. Note that [I-D.ietf-rtcweb-jsep], Section 5.2.1
requires that each media section use the same set of fingerprints for
every media section.
If the set of fingerprints changes, then the sender MUST either send
a new 'identity' attribute or none at all. Because a change in
fingerprints also causes a new DTLS connection to be established, the
receiver MUST discard all previously established identities.
6. Detailed Technical Description
6.1. Origin and Web Security Issues
The basic unit of permissions for WebRTC is the origin [RFC6454]. The basic unit of permissions for WebRTC is the origin [RFC6454].
Because the security of the origin depends on being able to Because the security of the origin depends on being able to
authenticate content from that origin, the origin can only be authenticate content from that origin, the origin can only be
securely established if data is transferred over HTTPS [RFC2818]. securely established if data is transferred over HTTPS [RFC2818].
Thus, clients MUST treat HTTP and HTTPS origins as different Thus, clients MUST treat HTTP and HTTPS origins as different
permissions domains. [Note: this follows directly from the origin permissions domains. [Note: this follows directly from the origin
security model and is stated here merely for clarity.] security model and is stated here merely for clarity.]
Many web browsers currently forbid by default any active mixed Many web browsers currently forbid by default any active mixed
content on HTTPS pages. That is, when JavaScript is loaded from an content on HTTPS pages. That is, when JavaScript is loaded from an
HTTP origin onto an HTTPS page, an error is displayed and the HTTP HTTP origin onto an HTTPS page, an error is displayed and the HTTP
content is not executed unless the user overrides the error. Any content is not executed unless the user overrides the error. Any
browser which enforces such a policy will also not permit access to browser which enforces such a policy will also not permit access to
WebRTC functionality from mixed content pages (because they never WebRTC functionality from mixed content pages (because they never
display mixed content). Browsers which allow active mixed content display mixed content). Browsers which allow active mixed content
MUST nevertheless disable WebRTC functionality in mixed content MUST nevertheless disable WebRTC functionality in mixed content
settings. settings.
skipping to change at page 12, line 33 skipping to change at page 15, line 20
display mixed content). Browsers which allow active mixed content display mixed content). Browsers which allow active mixed content
MUST nevertheless disable WebRTC functionality in mixed content MUST nevertheless disable WebRTC functionality in mixed content
settings. settings.
Note that it is possible for a page which was not mixed content to Note that it is possible for a page which 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 MUST 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.
5.2. Device Permissions Model Also note that the security architecture depends on the keying
material 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.
6.2. Device Permissions Model
Implementations MUST obtain explicit user consent prior to providing Implementations MUST obtain explicit user consent prior to providing
access to the camera and/or microphone. Implementations MUST at access to the camera and/or microphone. Implementations MUST at
minimum support the following two permissions models for HTTPS minimum support the following two permissions models for HTTPS
origins. origins.
o Requests for one-time camera/microphone access. o Requests for one-time camera/microphone access.
o Requests for permanent access. o Requests for permanent access.
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at the same time as camera and microphone. at the same time as camera and microphone.
o The browser MUST indicate any windows which are currently being o The browser MUST indicate any windows which are currently being
shared in some unambiguous way. Windows which are not visible shared in some unambiguous way. Windows which are not visible
MUST NOT be shared even if the application is being shared. If MUST NOT be shared even if the application is being shared. If
the screen is being shared, then that MUST be indicated. the screen is being shared, then that MUST be indicated.
Clients MAY permit the formation of data channels without any direct Clients MAY permit the formation of data channels without 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. (though see Section 5.3 for a related issue). additional security. (though see Section 6.3 for a related issue).
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 SHOULD also provide a policy by which a user can authorize calls only
to specific communicating peers. Specifically, the implementation to specific communicating peers. Specifically, the implementation
SHOULD provide the following interfaces/controls: SHOULD provide the following interfaces/controls:
o Allow future calls to this verified user. o Allow future calls to this verified user.
o Allow future calls to any verified user who is in my system o 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).
Implementations SHOULD also provide a different user interface Implementations SHOULD also provide a different user interface
indication when calls are in progress to users whose identities are indication when calls are in progress to users whose identities are
directly verifiable. Section 5.5 provides more on this. directly verifiable. Section 6.5 provides more on this.
5.3. Communications Consent 6.3. Communications Consent
Browser client implementations of WebRTC MUST implement ICE. Server Browser client implementations of WebRTC MUST implement ICE. Server
gateway implementations which operate only at public IP addresses gateway implementations which operate only at public IP addresses
MUST implement either full ICE or ICE-Lite [RFC5245]. MUST implement either full ICE or ICE-Lite [RFC5245].
Browser implementations MUST verify reachability via ICE prior to Browser implementations MUST verify reachability via ICE 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 MUST NOT provide the ICE transaction ID to JavaScript during 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 MUST
skipping to change at page 14, line 47 skipping to change at page 17, line 39
of course knows it. of course knows it.
While continuing consent is required, the ICE [RFC5245]; Section 10 While continuing consent is required, the ICE [RFC5245]; Section 10
keepalives use STUN Binding Indications which are one-way and keepalives use STUN Binding Indications which are one-way and
therefore not sufficient. The current WG consensus is to use ICE therefore not sufficient. The current WG consensus is to use ICE
Binding Requests for continuing consent freshness. ICE already 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 approach is maximally compatible. A separate document will profile
the ICE timers to be used; see [RFC7675]. the ICE timers to be used; see [RFC7675].
5.4. IP Location Privacy 6.4. IP Location Privacy
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 information. one's IP address, which leaks large amounts of location information.
This has negative privacy consequences in some circumstances. The This has negative privacy consequences in some circumstances. The
API requirements in this section are intended to mitigate this issue. API requirements in this section are intended to mitigate this issue.
Note that these requirements are NOT intended to protect the user's Note that these requirements are NOT intended to protect the user's
IP address from a malicious site. In general, the site will learn at IP address from a malicious site. In general, the site will learn at
least a user's server reflexive address from any HTTP transaction. least a user's server reflexive address from any HTTP transaction.
Rather, these requirements are intended to allow a site to cooperate Rather, these requirements are intended to allow a site to cooperate
with the user to hide the user's IP address from the other side of 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 requires some the call. Hiding the user's IP address from the server requires some
sort of explicit privacy preserving mechanism on the client (e.g., sort of explicit privacy preserving mechanism on the client (e.g.,
Tor Browser [https://www.torproject.org/projects/torbrowser.html.en]) Tor Browser [https://www.torproject.org/projects/torbrowser.html.en])
and is out of scope for this specification. and is out of scope for this specification.
skipping to change at page 15, line 48 skipping to change at page 18, line 40
turn candidates during an active call if the user decides they no turn candidates during an active call if the user decides they no
longer need to hide their IP address longer need to hide their IP address
Note that some enterprises may operate proxies and/or NATs designed Note that some enterprises may operate proxies and/or NATs designed
to hide internal IP addresses from the outside world. WebRTC to hide internal IP addresses from the outside world. WebRTC
provides no explicit mechanism to allow this function. Either such provides no explicit mechanism to allow this function. Either such
enterprises need to proxy the HTTP/HTTPS and modify the SDP and/or enterprises 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" the JS, or there needs to be browser support to set the "TURN-only"
policy regardless of the site's preferences. policy regardless of the site's preferences.
5.5. Communications Security 6.5. Communications Security
Implementations MUST implement SRTP [RFC3711]. Implementations MUST Implementations MUST implement SRTP [RFC3711]. Implementations MUST
implement DTLS [RFC6347] and DTLS-SRTP [RFC5763][RFC5764] for SRTP implement DTLS [RFC6347] and DTLS-SRTP [RFC5763][RFC5764] for SRTP
keying. Implementations MUST implement [RFC8261]. keying. Implementations MUST implement [RFC8261].
All media channels MUST be secured via SRTP and SRTCP. Media traffic All media channels MUST be secured via SRTP and SRTCP. Media traffic
MUST NOT be sent over plain (unencrypted) RTP or RTCP; that is, MUST NOT be sent over plain (unencrypted) RTP or RTCP; that is,
implementations MUST NOT negotiate cipher suites with NULL encryption implementations MUST NOT negotiate cipher suites with NULL encryption
modes. DTLS-SRTP MUST be offered for every media channel. WebRTC modes. DTLS-SRTP MUST be offered for every media channel. WebRTC
implementations MUST NOT offer SDP Security Descriptions [RFC4568] or implementations MUST NOT offer SDP Security Descriptions [RFC4568] or
skipping to change at page 17, line 15 skipping to change at page 20, line 7
* A client MUST provide a user interface through which a user may * A client MUST provide a user interface through which a user may
determine the security characteristics for currently-displayed determine the security characteristics for currently-displayed
audio and video stream(s) audio and video stream(s)
* A client MUST provide a user interface through which a user may * A client MUST provide a user interface through which a user may
determine the security characteristics for transmissions of determine the security characteristics for transmissions of
their microphone audio and camera video. their microphone audio and camera video.
* If the far endpoint was directly verified, either via a third- * If the far endpoint was directly verified, either via a third-
party verifiable X.509 certificate or via a Web IdP mechanism party verifiable X.509 certificate or via a Web IdP mechanism
(see Section 5.6) the "security characteristics" MUST include (see Section 7) the "security characteristics" MUST include the
the verified information. X.509 identities and Web IdP verified information. X.509 identities and Web IdP identities
identities have similar semantics and should be displayed in a have similar semantics and should be displayed in a similar
similar way. way.
The following properties are more likely to require some "drill- The following properties are more likely to require some "drill-
down" from the user: down" from the user:
* The "security characteristics" MUST indicate the cryptographic * The "security characteristics" MUST indicate the cryptographic
algorithms in use (For example: "AES-CBC".) However, if Null algorithms in use (For example: "AES-CBC".) However, if Null
ciphers are used, that MUST be presented to the user at the ciphers are used, that MUST be presented to the user at the
top-level UI. top-level UI.
* The "security characteristics" MUST indicate whether PFS is * The "security characteristics" MUST indicate whether PFS is
provided. provided.
* The "security characteristics" MUST include some mechanism to * The "security characteristics" MUST include some 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).
5.6. Web-Based Peer Authentication 7. Web-Based Peer Authentication
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.)
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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 some identity protocols in order to provide superior performance or
UI properties. UI properties.
5.6.1. Trust Relationships: IdPs, APs, and RPs 7.1. Trust Relationships: IdPs, APs, and RPs
Any federated identity protocol has three major participants: Any federated identity protocol has three major participants:
Authenticating Party (AP): The entity which is trying to establish Authenticating Party (AP): The entity which is trying to establish
its identity. its identity.
Identity Provider (IdP): The entity which is vouching for the AP's Identity Provider (IdP): The entity which is vouching for the AP's
identity. identity.
Relying Party (RP): The entity which is trying to verify the AP's Relying Party (RP): The entity which is trying to verify the AP's
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By contrast, if an AP is authenticating via a third-party IdP, the RP 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 explicit needs to explicitly trust that IdP (hence the need for an explicit
trust anchor list in PKI-based SSL/TLS clients). The list of trust anchor list in PKI-based SSL/TLS clients). The list of
trustable IdPs needs to be configured directly into the browser, 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.
5.6.2. Overview of Operation 7.2. Overview of Operation
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.
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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 requirements. bridge the generic protocol to the IdP's specific requirements.
Thus, a single browser can support any number of identity protocols, Thus, a single browser can support any number of identity protocols,
including being forward compatible with IdPs which did not exist at including being forward compatible with IdPs which did not exist at
the time the browser was written. the time the browser was written.
5.6.3. Items for Standardization 7.3. Items for Standardization
There are two parts to this work: There are two parts to this work:
o The precise information from the signaling message that must be o The precise information from the signaling message that must be
cryptographically bound to the user's identity and a mechanism for cryptographically bound to the user's identity and a mechanism for
carrying assertions in JSEP messages. This is specified in carrying assertions in JSEP messages. This is specified in
Section 5.6.4. Section 7.4.
o The interface to the IdP, which is defined in the companion W3C o The interface to the IdP, which is defined in the companion W3C
WebRTC API specification [webrtc-api]. WebRTC API specification [webrtc-api].
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.
5.6.4. Binding Identity Assertions to JSEP Offer/Answer Transactions 7.4. Binding Identity Assertions to JSEP Offer/Answer Transactions
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 media. IdP) to the SDP offer/answer exchange and specifically to the media.
In order to achieve this, the PeerConnection must provide the DTLS- In order to achieve this, the PeerConnection must provide the DTLS-
SRTP fingerprint to be bound to the identity. This is provided as a SRTP fingerprint to be bound to the identity. This is provided as a
JavaScript object (also known as a dictionary or hash) with a single JavaScript object (also known as a dictionary or hash) with a single
"fingerprint" key, as shown below: "fingerprint" key, as shown below:
{ {
"fingerprint": [ { "fingerprint": [ {
"algorithm": "sha-256", "algorithm": "sha-256",
"digest": "4A:AD:B9:B1:3F:...:E5:7C:AB" "digest": "4A:AD:B9:B1:3F:...:E5:7C:AB"
}, { }, {
"algorithm": "sha-1", "algorithm": "sha-1",
"digest": "74:E9:76:C8:19:...:F4:45:6B" "digest": "74:E9:76:C8:19:...:F4:45:6B"
} ] } ]
} }
The "fingerprint" value is an array of objects. Each object in the The "fingerprint" value is an array of objects. Each object in the
array contains "algorithm" and "digest" values, which correspond array contains "algorithm" and "digest" values, which correspond
directly to the algorithm and digest values in the "a=fingerprint" directly to the algorithm and digest values in the "fingerprint"
line of the SDP [RFC8122]. attribute of the SDP [RFC8122].
This object is encoded in a JSON [RFC8259] string for passing to the This object is encoded in a JSON [RFC8259] string for passing to the
IdP. IdP.
This structure does not need to be interpreted by the IdP or the IdP 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 merely 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 parameters treats it as an opaque value to be attested to. Thus, new parameters
can be added to the assertion without modifying the IdP. can be added to the assertion without modifying the IdP.
5.6.4.1. Carrying Identity Assertions 7.4.1. Carrying Identity Assertions
Once an IdP has generated an assertion, it is attached to the SDP Once an IdP has generated an assertion, 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 are a attribute to the SDP. The sole contents of this value are a
Base64-encoded [RFC4648] identity assertion. For example: Base64-encoded [RFC4648] identity assertion. For example:
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
... ...
The identity attribute attests to all "a=fingerprint" attributes in Note that long lines in the example are folded to meet the column
width constraints of this document; the backslash ("\") at the end of
a line and the carriage return that follows shall be ignored.
The 'identity' attribute attests to all "fingerprint" attributes in
the session description. It is therefore a session-level attribute. the session description. It is therefore a session-level attribute.
Multiple "a=fingerprint" values can be used to offer alternative Multiple "fingerprint" values can be used to offer alternative
certificates for a peer. The "a=identity" attribute MUST include all certificates for a peer. The "identity" attribute MUST include all
fingerprint values that are included in "a=fingerprint" lines of the fingerprint values that are included in "fingerprint" attributes of
session description. the session description.
The RP browser MUST verify that the in-use certificate for a DTLS The RP browser MUST verify that the in-use certificate for a DTLS
connection is in the set of fingerprints returned from the IdP when connection is in the set of fingerprints returned from the IdP when
verifying an assertion. verifying an assertion.
5.6.4.2. a=identity Attribute 7.5. Determining the IdP URI
The identity attribute is a session-level attribute only. It
contains an identity assertion, encoded as a Base-64 string
[RFC4648].
The syntax of this SDP attribute is defined using Augmented BNF
[RFC5234]:
identity-attribute = "identity:" identity-assertion
[ SP identity-extension
*(";" [ SP ] identity-extension) ]
identity-assertion = base64
base64 = 1*(ALPHA / DIGIT / "+" / "/" / "=" )
identity-extension = extension-att-name [ "=" extension-att-value ]
extension-att-name = token
extension-att-value = 1*(%x01-09 / %x0b-0c / %x0e-3a / %x3c-ff)
; byte-string from [RFC4566] omitting ";"
No extensions are defined for this attribute.
The identity assertion is a JSON [RFC8259] encoded dictionary that
contains two values. The "assertion" attribute contains an opaque
string that is consumed by the IdP. The "idp" attribute is a
dictionary with one or two further values that identify the IdP, as
described in Section 5.6.5.
An identity assertion as defined in this document relies on the value
of "a=fingerprint" attributes, but this does not preclude the
definition of alternative means of binding an assertion to the
identity of a peer.
The semantics of multiple identity attributes are undefined.
Implementations SHOULD only include a single identity attribute in an
offer and relying parties MAY elect to ignore all but the first
identity attribute.
5.6.5. Determining the IdP URI
In order to ensure that the IdP is under control of the domain owner In order to ensure that the IdP is under control of the domain owner
rather than someone who merely has an account on the domain owner's rather than someone who merely has an account on the domain owner's
server (e.g., in shared hosting scenarios), the IdP JavaScript is server (e.g., in shared hosting scenarios), the IdP JavaScript is
hosted at a deterministic location based on the IdP's domain name. hosted at a deterministic location based on the IdP's domain name.
Each IdP proxy instance is associated with two values: Each IdP proxy instance is associated with two values:
Authority: The authority [RFC3986] at which the IdP's service is Authority: The authority [RFC3986] at which the IdP's service is
hosted. Note that this may include a non-default port or a hosted. Note that this may include a non-default port or a
userinfo component, but neither will be available in a certificate userinfo component, but neither will be available in a certificate
skipping to change at page 25, line 5 skipping to change at page 27, line 13
"example", the URL would be: "example", the URL would be:
https://identity.example.com/.well-known/idp-proxy/example https://identity.example.com/.well-known/idp-proxy/example
The IdP MAY redirect requests to this URL, but they MUST retain the The IdP MAY redirect requests to this URL, but they MUST retain the
"https" scheme. This changes the effective origin of the IdP, but "https" scheme. This changes the effective origin of the IdP, but
not the domain of the identities that the IdP is permitted to assert not the domain of the identities that the IdP is permitted to assert
and validate. I.e., the IdP is still regarded as authoritative for and validate. I.e., the IdP is still regarded as authoritative for
the original domain. the original domain.
5.6.5.1. Authenticating Party 7.5.1. Authenticating Party
How an AP determines the appropriate IdP domain is out of scope of How an AP determines the appropriate IdP domain is out of scope of
this specification. In general, however, the AP has some actual this specification. In general, however, the AP has some actual
account relationship with the IdP, as this identity is what the IdP account relationship with the IdP, as this identity is what the IdP
is attesting to. Thus, the AP somehow supplies the IdP information is attesting to. Thus, the AP somehow supplies the IdP information
to the browser. Some potential mechanisms include: to the browser. Some potential mechanisms include:
o Provided by the user directly. o Provided by the user directly.
o Selected from some set of IdPs known to the calling site. E.g., a o Selected from some set of IdPs known to the calling site. E.g., a
button that shows "Authenticate via Facebook Connect" button that shows "Authenticate via Facebook Connect"
5.6.5.2. Relying Party 7.5.2. Relying Party
Unlike the AP, the RP need not have any particular relationship with Unlike the AP, the RP need not have any particular relationship with
the IdP. Rather, it needs to be able to process whatever assertion the IdP. Rather, it needs to be able to process whatever assertion
is provided by the AP. As the assertion contains the IdP's identity, is provided by the AP. As the assertion contains the IdP's identity,
the URI can be constructed directly from the assertion, and thus the the URI can be constructed directly from the assertion, and thus the
RP can directly verify the technical validity of the assertion with RP can 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 against verifiable. Third-party assertions also MUST be verified against
local policy, as described in Section 5.7.1. local policy, as described in Section 8.1.
5.6.6. Requesting Assertions 7.6. Requesting Assertions
The input to identity assertion is the JSON-encoded object described The input to identity assertion is the JSON-encoded object described
in Section 5.6.4 that contains the set of certificate fingerprints in Section 7.4 that contains the set of certificate fingerprints the
the browser intends to use. This string is treated as opaque from browser intends to use. This string is treated as opaque from the
the perspective of the IdP. perspective of the IdP.
The browser also identifies the origin that the PeerConnection is run The browser also identifies the origin that the PeerConnection is run
in, which allows the IdP to make decisions based on who is requesting in, which allows the IdP to make decisions based on who is requesting
the assertion. the assertion.
An application can optionally provide a user identifier hint when An application can optionally provide a user identifier hint when
specifying an IdP. This value is a hint that the IdP can use to specifying an IdP. This value is a hint that the IdP can use to
select amongst multiple identities, or to avoid providing assertions select amongst multiple identities, or to avoid providing assertions
for unwanted identities. The "username" is a string that has no for unwanted identities. The "username" is a string that has no
meaning to any entity other than the IdP, it can contain any data the meaning to any entity other than the IdP, it can contain any data the
skipping to change at page 26, line 28 skipping to change at page 28, line 37
"protocol": "bogus" "protocol": "bogus"
}, },
"assertion": "{\"identity\":\"bob@example.org\", "assertion": "{\"identity\":\"bob@example.org\",
\"contents\":\"abcdefghijklmnopqrstuvwyz\", \"contents\":\"abcdefghijklmnopqrstuvwyz\",
\"signature\":\"010203040506\"}" \"signature\":\"010203040506\"}"
} }
Figure 5: Example assertion Figure 5: Example assertion
For use in signaling, the assertion is serialized into JSON, For use in signaling, the assertion is serialized into JSON,
Base64-encoded [RFC4648], and used as the value of the "a=identity" Base64-encoded [RFC4648], and used as the value of the "identity"
attribute. attribute.
5.6.7. Managing User Login 7.7. Managing User Login
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 users the user's identity. It is common practice to authenticate users
(using passwords or multi-factor authentication), then use Cookies (using passwords or multi-factor authentication), then use Cookies
[RFC6265] or HTTP authentication [RFC7617] for subsequent exchanges. [RFC6265] or HTTP authentication [RFC7617] for subsequent exchanges.
The IdP proxy is able to access cookies, HTTP authentication or other The IdP proxy is able to access cookies, HTTP authentication or other
persistent session data because it operates in the security context persistent session data because it operates in the security context
of the IdP origin. Therefore, if a user is logged in, the IdP could of the IdP origin. Therefore, if a user is logged in, the IdP could
have all the information needed to generate an assertion. have all the information needed to generate an assertion.
skipping to change at page 27, line 5 skipping to change at page 29, line 16
logged in, or the IdP wants to interact with the user to acquire more logged in, or the IdP wants to interact with the user to acquire more
information before generating the assertion. If the IdP wants to information before generating the assertion. If the IdP wants to
interact with the user before generating an assertion, the IdP proxy interact with the user before generating an assertion, the IdP proxy
can fail to generate an assertion and instead indicate a URL where can fail to generate an assertion and instead indicate a URL where
login should proceed. login should proceed.
The application can then load the provided URL to enable the user to The application can then load the provided URL to enable the user to
enter credentials. The communication between the application and the enter credentials. The communication between the application and the
IdP is described in [webrtc-api]. IdP is described in [webrtc-api].
5.7. Verifying Assertions 8. Verifying Assertions
The input to identity validation is the assertion string taken from a The input to identity validation is the assertion string taken from a
decoded a=identity attribute. decoded 'identity' attribute.
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 servers. protocol, the proxy might contact the IdP server or other servers.
For instance, an OAuth-based protocol will likely require using the For instance, an OAuth-based protocol will likely require using the
IdP as an oracle, whereas with a signature-based scheme might be able IdP as an oracle, whereas with a signature-based scheme might be able
to verify the assertion without contacting the IdP, provided that it to verify the assertion without contacting the IdP, provided that it
has cached the relevant public key. has cached the relevant public key.
Regardless of the mechanism, if verification succeeds, a successful Regardless of the mechanism, if verification succeeds, a successful
response from the IdP proxy consists of the following information: response from the IdP proxy consists of the following information:
identity: The identity of the AP from the IdP's perspective. identity: The identity of the AP from the IdP's perspective.
Details of this are provided in Section 5.7.1. Details of this are provided in Section 8.1.
contents: The original unmodified string provided by the AP as input contents: The original unmodified string provided by the AP as input
to the assertion generation process. to the assertion generation process.
Figure 6 shows an example response formatted as JSON for illustrative Figure 6 shows an example response formatted as JSON for illustrative
purposes. purposes.
{ {
"identity": "bob@example.org", "identity": "bob@example.org",
"contents": "{\"fingerprint\":[ ... ]}" "contents": "{\"fingerprint\":[ ... ]}"
} }
Figure 6: Example verification result Figure 6: Example verification result
5.7.1. Identity Formats 8.1. Identity Formats
The identity provided from the IdP to the RP browser MUST consist of The identity provided from the IdP to the RP browser MUST consist of
a string representing the user's identity. This string is in the a string representing the user's identity. This string is in the
form "<user>@<domain>", where "user" consists of any character except form "<user>@<domain>", where "user" consists of any character except
'@', and domain is an internationalized domain name [RFC5890]. '@', and domain is an internationalized domain name [RFC5890].
The PeerConnection API MUST check this string as follows: The PeerConnection API MUST check this string as follows:
1. If the domain portion of the string is equal to the domain name 1. If the domain portion of the string is equal to the domain name
of the IdP proxy, then the assertion is valid, as the IdP is of the IdP proxy, then the assertion is valid, as the IdP is
skipping to change at page 28, line 22 skipping to change at page 30, line 32
2. local policy is configured to trust this IdP domain for the 2. local policy is configured to trust this IdP domain for the
domain portion of the identity string. domain portion of the identity string.
Sites that have identities that do not fit into the RFC822 style (for Sites that have identities that do not fit into the RFC822 style (for
instance, identifiers that are simple numeric values, or values that instance, identifiers that are simple numeric values, or values that
contain '@' characters) SHOULD convert them to this form by escaping contain '@' characters) SHOULD convert them to this form by escaping
illegal characters and appending their IdP domain (e.g., illegal characters and appending their IdP domain (e.g.,
user%40133@identity.example.com), thus ensuring that they are user%40133@identity.example.com), thus ensuring that they are
authoritative for the identity. authoritative for the identity.
6. Security Considerations 9. Security Considerations
Much of the security analysis of this problem is contained in Much of the security analysis of this problem is contained in
[I-D.ietf-rtcweb-security] or in the discussion of the particular [I-D.ietf-rtcweb-security] or in the discussion of the particular
issues above. In order to avoid repetition, this section focuses on issues above. In order to avoid repetition, this section focuses on
(a) residual threats that are not addressed by this document and (b) (a) residual threats that are not addressed by this document and (b)
threats produced by failure/misbehavior of one of the components in threats produced by failure/misbehavior of one of the components in
the system. the system.
6.1. Communications Security 9.1. Communications Security
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 Section 5.6 is not used, server, and the identity mechanism used in Section 7 is not used,
then any on-path attacker can replace the DTLS-SRTP fingerprints in then any on-path attacker can replace the DTLS-SRTP fingerprints in
the handshake and thus substitute its own identity for that of either the handshake and thus substitute its own identity for that of either
endpoint. endpoint.
Even if HTTPS is used, the signaling server can potentially mount a Even if HTTPS is used, the signaling server can potentially mount a
man-in-the-middle attack unless implementations have some mechanism man-in-the-middle attack unless implementations have some mechanism
for independently verifying keys. The UI requirements in Section 5.5 for independently verifying keys. The UI requirements in Section 6.5
are designed to provide such a mechanism for motivated/security are designed to provide such a mechanism for motivated/security
conscious users, but are not suitable for general use. The identity conscious users, but are not suitable for general use. The identity
service mechanisms in Section 5.6 are more suitable for general use. service mechanisms in Section 7 are more suitable for general use.
Note, however, that a malicious signaling service can strip off any Note, however, that a malicious signaling service can strip off any
such identity assertions, though it cannot forge new ones. Note that such identity assertions, though it cannot forge new ones. Note that
all of the third-party security mechanisms available (whether X.509 all of the third-party security mechanisms available (whether X.509
certificates or a third-party IdP) rely on the security of the third certificates or a third-party IdP) rely on the security of the third
party--this is of course also true of your connection to the Web site party--this is of course also true of your connection to the Web site
itself. Users who wish to assure themselves of security against a itself. Users who wish to assure themselves of security against a
malicious identity provider can only do so by verifying peer malicious identity provider can only do so by verifying peer
credentials directly, e.g., by checking the peer's fingerprint credentials directly, e.g., by checking the peer's fingerprint
against a value delivered out of band. against a value delivered out of band.
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by the content JS, thus violating the security guarantees otherwise by the content JS, thus violating the security guarantees otherwise
provided by the IdP mechanism. Note that it is not sufficient merely provided by the IdP mechanism. Note that it is not sufficient merely
to deny the content JS direct access to the keys, as some have to deny the content JS direct access to the keys, as some have
suggested doing with the WebCrypto API [webcrypto]. The JS must also suggested doing with the WebCrypto API [webcrypto]. The JS must also
not be allowed to perform operations that would be valid for a DTLS not be allowed to perform operations that would be valid for a DTLS
endpoint. By far the safest approach is simply to deny the ability endpoint. By far the safest approach is simply to deny the ability
to perform any operations that depend on secret information 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.
6.2. Privacy 9.2. Privacy
The requirements in this document are intended to allow: The requirements in this document are intended to allow:
o Users to participate in calls without revealing their location. o Users to participate in calls without revealing their location.
o Potential callees to avoid revealing their location and even o 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.
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 ICE. terms of using TURN relays and, in the latter case, delaying ICE.
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privacy enhancing technologies such as Tor. Combined WebRTC/Tor privacy enhancing technologies such as Tor. Combined WebRTC/Tor
implementations SHOULD arrange to route the media as well as the implementations SHOULD arrange to route the media as well as the
signaling through Tor. Currently this will produce very suboptimal signaling through Tor. Currently this will produce very suboptimal
performance. performance.
Additionally, any identifier which persists across multiple calls is Additionally, any identifier which 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 SHOULD instruct the browser to use separate
DTLS keys for each call and also to use TURN throughout the call. DTLS keys for each call and also to use TURN throughout the call.
Otherwise, the other side will learn linkable information. Otherwise, the other side will learn linkable information.
Additionally, browsers SHOULD implement the privacy-preserving CNAME Additionally, browsers SHOULD implement the privacy-preserving CNAME
generation mode of [RFC7022]. generation mode of [RFC7022].
6.3. Denial of Service 9.3. Denial of Service
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 denial of service 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.
Consider the case of a call center which accepts calls via WebRTC. Consider the case of a call center which accepts calls via WebRTC.
An attacker proxies the call center's front-end and arranges for An attacker proxies the call center's front-end and arranges for
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[I-D.ietf-rtcweb-rtp-usage] Section 13 documents a number of [I-D.ietf-rtcweb-rtp-usage] Section 13 documents a number of
potential RTCP-based DoS attacks and countermeasures. potential RTCP-based DoS attacks and countermeasures.
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 tradeoffs here.
6.4. IdP Authentication Mechanism 9.4. IdP Authentication Mechanism
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.
6.4.1. PeerConnection Origin Check 9.4.1. PeerConnection Origin Check
Fundamentally, the IdP proxy is just a piece of HTML and JS loaded by 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 the browser, so nothing stops a Web attacker from creating their own
IFRAME, loading the IdP proxy HTML/JS, and requesting a signature IFRAME, loading the IdP proxy HTML/JS, and requesting a signature
over his own keys rather than those generated in the browser. over his own keys rather than those generated in the browser.
However, that proxy would be in the attacker's origin, not the IdP's However, that proxy would be in the attacker's origin, not the IdP's
origin. Only the browser itself can instantiate a context that (a) origin. Only the browser itself can instantiate a context that (a)
is in the IdP's origin and (b) exposes the correct API surface. is in the IdP's origin and (b) exposes the correct API surface.
Thus, the IdP proxy on the sender's side MUST ensure that it is Thus, the IdP proxy on the sender's side MUST ensure that it is
running in the IdP's origin prior to issuing assertions. running in the IdP's origin prior to issuing assertions.
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 the entity with access to the user's authentication data) attests to the
request and hence to the fingerprint. It does not demonstrate that request and hence to the fingerprint. It does not demonstrate that
the browser has access to the associated private key, and therefore the browser has access to the associated private key, and therefore
an attacker can attach their own identity to another party's keying an attacker can attach their own identity to another party's keying
material, thus making a call which comes from Alice appear to come material, thus making a call which comes from Alice appear to come
from the attacker. See [I-D.ietf-mmusic-sdp-uks] for defenses from the attacker. See [I-D.ietf-mmusic-sdp-uks] for defenses
against this form of attack. against this form of attack.
6.4.2. IdP Well-known URI 9.4.2. IdP Well-known URI
As described in Section 5.6.5 the IdP proxy HTML/JS landing page is As described in Section 7.5 the IdP proxy HTML/JS landing page is
located at a well-known URI based on the IdP's domain name. This located at a well-known URI based on the IdP's domain name. This
requirement prevents an attacker who can write some resources at the requirement prevents an attacker who can write some resources at the
IdP (e.g., on one's Facebook wall) from being able to impersonate the IdP (e.g., on one's Facebook wall) from being able to impersonate the
IdP. IdP.
6.4.3. Privacy of IdP-generated identities and the hosting site 9.4.3. Privacy of IdP-generated identities and the hosting site
Depending on the structure of the IdP's assertions, the calling site Depending on the structure of the IdP's assertions, the calling site
may learn the user's identity from the perspective of the IdP. In may learn the user's identity from the perspective of the IdP. In
many cases this is not an issue because the user is authenticating to many cases this is not an issue because the user is authenticating to
the site via the IdP in any case, for instance when the user has the site via the IdP in any case, for instance when the user has
logged in with Facebook Connect and is then authenticating their call logged in with Facebook Connect and is then authenticating their call
with a Facebook identity. However, in other case, the user may not with a Facebook identity. However, in other case, the user may not
have already revealed their identity to the site. In general, IdPs have already revealed their identity to the site. In general, IdPs
SHOULD either verify that the user is willing to have their identity SHOULD either verify that the user is willing to have their identity
revealed to the site (e.g., through the usual IdP permissions dialog) revealed to the site (e.g., through the usual IdP permissions dialog)
or arrange that the identity information is only available to known or arrange that the identity information is only available to known
RPs (e.g., social graph adjacencies) but not to the calling site. RPs (e.g., social graph adjacencies) but not to the calling site.
The "origin" field of the signature request can be used to check that The "origin" field of the signature request can be used to check that
the user has agreed to disclose their identity to the calling site; the user has agreed to disclose their identity to the calling site;
because it is supplied by the PeerConnection it can be trusted to be because it is supplied by the PeerConnection it can be trusted to be
correct. correct.
6.4.4. Security of Third-Party IdPs 9.4.4. Security of Third-Party IdPs
As discussed above, each third-party IdP represents a new universal As discussed above, each third-party IdP represents a new universal
trust point and therefore the number of these IdPs needs to be quite trust point and therefore the number of these IdPs needs to be quite
limited. Most IdPs, even those which issue unqualified identities limited. Most IdPs, even those which issue unqualified identities
such as Facebook, can be recast as authoritative IdPs (e.g., such as Facebook, can be recast as authoritative IdPs (e.g.,
123456@facebook.com). However, in such cases, the user interface 123456@facebook.com). However, in such cases, the user interface
implications are not entirely desirable. One intermediate approach implications are not entirely desirable. One intermediate approach
is to have special (potentially user configurable) UI for large is to have special (potentially user configurable) UI for large
authoritative IdPs, thus allowing the user to instantly grasp that authoritative IdPs, thus allowing the user to instantly grasp that
the call is being authenticated by Facebook, Google, etc. the call is being authenticated by Facebook, Google, etc.
6.4.4.1. Confusable Characters 9.4.4.1. Confusable Characters
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 which strings, it may be possible for attackers to craft identities which
are confusable with other identities (see [RFC6943] for more on this are confusable with other identities (see [RFC6943] for more on this
topic). This is a problem with any identifier space of this type topic). This is a problem with any identifier space of this type
(e.g., e-mail addresses). Those minting identifers should avoid (e.g., e-mail addresses). Those minting identifers should avoid
mixed scripts and similar confusable characters. Those presenting mixed scripts and similar confusable characters. Those presenting
these identifiers to a user should consider highlighting cases of these identifiers to a user should consider highlighting cases of
mixed script usage (see [RFC5890], section 4.4). Other best mixed script usage (see [RFC5890], section 4.4). Other best
practices are still in development. practices are still in development.
6.4.5. Web Security Feature Interactions 9.4.5. Web Security Feature Interactions
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.
6.4.5.1. Popup Blocking 9.4.5.1. Popup Blocking
The IdP proxy is unable to generate popup windows, dialogs or any The IdP proxy is unable to generate popup windows, dialogs or any
other form of user interactions. This prevents the IdP proxy from other form of user interactions. This prevents the IdP proxy from
being used to circumvent user interaction. The "LOGINNEEDED" message being used to circumvent user interaction. The "LOGINNEEDED" message
allows the IdP proxy to inform the calling site of a need for user allows the IdP proxy to inform the calling site of a need for user
login, providing the information necessary to satisfy this login, providing the information necessary to satisfy this
requirement without resorting to direct user interaction from the IdP requirement without resorting to direct user interaction from the IdP
proxy itself. proxy itself.
6.4.5.2. Third Party Cookies 9.4.5.2. Third Party Cookies
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 privacy associated with origins other than the top level page) for privacy
reasons. Any IdP which uses cookies to persist logins will be broken reasons. Any IdP which uses cookies to persist logins will be broken
by third-party cookie blocking. One option is to accept this as a by third-party cookie blocking. One option is to accept this as a
limitation; another is to have the PeerConnection object disable limitation; another is to have the PeerConnection object disable
third-party cookie blocking for the IdP proxy. third-party cookie blocking for the IdP proxy.
7. IANA Considerations 10. IANA Considerations
This specification defines the "identity" SDP attribute per the This specification defines the "identity" SDP attribute per the
procedures of Section 8.2.4 of [RFC4566]. The required information procedures of Section 8.2.4 of [RFC4566]. The required information
for the registration is included here: for the registration is included here:
Contact Name: Eric Rescorla (ekr@rftm.com) Contact Name: Eric Rescorla (ekr@rftm.com)
Attribute Name: identity Attribute Name: identity
Long Form: identity Long Form: identity
Type of Attribute: session-level Type of Attribute: session-level
Charset Considerations: This attribute is not subject to the charset Charset Considerations: This attribute is not subject to the charset
attribute. attribute.
Purpose: This attribute carries an identity assertion, binding an Purpose: This attribute carries an identity assertion, binding an
identity to the transport-level security session. identity to the transport-level security session.
Appropriate Values: See Section 5.6.4.2 of RFCXXXX [[Editor Note: Appropriate Values: See Section 5 of RFCXXXX [[Editor Note: This
This document.]] document.]]
Mux Category: NORMAL. Mux Category: NORMAL.
8. Acknowledgements 11. Acknowledgements
Bernard Aboba, Harald Alvestrand, Richard Barnes, Dan Druta, Cullen Bernard Aboba, Harald Alvestrand, Richard Barnes, Dan Druta, Cullen
Jennings, Hadriel Kaplan, Matthew Kaufman, Jim McEachern, Martin Jennings, Hadriel Kaplan, Matthew Kaufman, Jim McEachern, Martin
Thomson, Magnus Westerland. Matthew Kaufman provided the UI material Thomson, Magnus Westerland. Matthew Kaufman provided the UI material
in Section 5.5. in Section 6.5. Christer Holmberg provided the initial version of
Section 5.1.
9. Changes 12. Changes
[RFC Editor: Please remove this section prior to publication.] [RFC Editor: Please remove this section prior to publication.]
9.1. Changes since -11 12.1. Changes since -15
Rewrite the Identity section in more conventional offer/answer
format.
Clarify rules on changing identities.
12.2. Changes since -11
Update discussion of IdP security model Update discussion of IdP security model
Replace "domain name" with RFC 3986 Authority Replace "domain name" with RFC 3986 Authority
Clean up discussion of how to generate IdP URI. Clean up discussion of how to generate IdP URI.
Remove obsolete text about null cipher suites. Remove obsolete text about null cipher suites.
Remove obsolete appendixes about older IdP systems Remove obsolete appendixes about older IdP systems
Require support for ECDSA, PFS, and AEAD Require support for ECDSA, PFS, and AEAD
9.2. Changes since -10 12.3. Changes since -10
Update cipher suite profiles. Update cipher suite profiles.
Rework IdP interaction based on implementation experience in Firefox. Rework IdP interaction based on implementation experience in Firefox.
9.3. Changes since -06 12.4. Changes since -06
Replaced RTCWEB and RTC-Web with WebRTC, except when referring to the Replaced RTCWEB and RTC-Web with WebRTC, except when referring to the
IETF WG IETF WG
Forbade use in mixed content as discussed in Orlando. Forbade use in mixed content as discussed in Orlando.
Added a requirement to surface NULL ciphers to the top-level. Added a requirement to surface NULL ciphers to the top-level.
Tried to clarify SRTP versus DTLS-SRTP. Tried to clarify SRTP versus DTLS-SRTP.
Added a section on screen sharing permissions. Added a section on screen sharing permissions.
Assorted editorial work. Assorted editorial work.
9.4. Changes since -05 12.5. Changes since -05
The following changes have been made since the -05 draft. The following changes have been made since the -05 draft.
o Response to comments from Richard Barnes o Response to comments from Richard Barnes
o More explanation of the IdP security properties and the federation o More explanation of the IdP security properties and the federation
use case. use case.
o Editorial cleanup. o Editorial cleanup.
9.5. Changes since -03 12.6. Changes since -03
Version -04 was a version control mistake. Please ignore. Version -04 was a version control mistake. Please ignore.
The following changes have been made since the -04 draft. The following changes have been made since the -04 draft.
o Move origin check from IdP to RP per discussion in YVR. o Move origin check from IdP to RP per discussion in YVR.
o Clarified treatment of X.509-level identities. o Clarified treatment of X.509-level identities.
o Editorial cleanup. o Editorial cleanup.
9.6. Changes since -03 12.7. Changes since -03
9.7. Changes since -02 12.8. Changes since -02
The following changes have been made since the -02 draft. The following changes have been made since the -02 draft.
o Forbid persistent HTTP permissions. o Forbid persistent HTTP permissions.
o Clarified the text in S 5.4 to clearly refer to requirements on o Clarified the text in S 5.4 to clearly refer to requirements on
the API to provide functionality to the site. the API to provide functionality to the site.
o Fold in the IETF portion of draft-rescorla-rtcweb-generic-idp o Fold in the IETF portion of draft-rescorla-rtcweb-generic-idp
o Retarget the continuing consent section to assume Binding Requests o Retarget the continuing consent section to assume Binding Requests
o Added some more privacy and linkage text in various places. o Added some more privacy and linkage text in various places.
o Editorial improvements o Editorial improvements
10. References 13. References
10.1. Normative References
13.1. Normative References
[FIPS186] National Institute of Standards and Technology (NIST), [FIPS186] National Institute of Standards and Technology (NIST),
"Digital Signature Standard (DSS)", NIST PUB 186-4 , July "Digital Signature Standard (DSS)", NIST PUB 186-4 , July
2013. 2013.
[I-D.ietf-mmusic-sdp-uks] [I-D.ietf-mmusic-sdp-uks]
Thomson, M. and E. Rescorla, "Unknown Key Share Attacks on Thomson, M. and E. Rescorla, "Unknown Key Share Attacks on
uses of Transport Layer Security with the Session uses of Transport Layer Security with the Session
Description Protocol (SDP)", draft-ietf-mmusic-sdp-uks-01 Description Protocol (SDP)", draft-ietf-mmusic-sdp-uks-02
(work in progress), January 2018. (work in progress), August 2018.
[I-D.ietf-rtcweb-rtp-usage] [I-D.ietf-rtcweb-rtp-usage]
Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time
Communication (WebRTC): Media Transport and Use of RTP", Communication (WebRTC): Media Transport and Use of RTP",
draft-ietf-rtcweb-rtp-usage-26 (work in progress), March draft-ietf-rtcweb-rtp-usage-26 (work in progress), March
2016. 2016.
[I-D.ietf-rtcweb-security] [I-D.ietf-rtcweb-security]
Rescorla, E., "Security Considerations for WebRTC", draft- Rescorla, E., "Security Considerations for WebRTC", draft-
ietf-rtcweb-security-10 (work in progress), January 2018. ietf-rtcweb-security-10 (work in progress), January 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, <https://www.rfc- DOI 10.17487/RFC2119, March 1997,
editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000, <https://www.rfc- DOI 10.17487/RFC2818, May 2000,
editor.org/info/rfc2818>. <https://www.rfc-editor.org/info/rfc2818>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)", Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, DOI 10.17487/RFC3711, March 2004, RFC 3711, DOI 10.17487/RFC3711, March 2004,
<https://www.rfc-editor.org/info/rfc3711>. <https://www.rfc-editor.org/info/rfc3711>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
skipping to change at page 37, line 16 skipping to change at page 39, line 25
Description Protocol (SDP) Security Descriptions for Media Description Protocol (SDP) Security Descriptions for Media
Streams", RFC 4568, DOI 10.17487/RFC4568, July 2006, Streams", RFC 4568, DOI 10.17487/RFC4568, July 2006,
<https://www.rfc-editor.org/info/rfc4568>. <https://www.rfc-editor.org/info/rfc4568>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008, <https://www.rfc- DOI 10.17487/RFC5234, January 2008,
editor.org/info/rfc5234>. <https://www.rfc-editor.org/info/rfc5234>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment [RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) (ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, Traversal for Offer/Answer Protocols", RFC 5245,
DOI 10.17487/RFC5245, April 2010, <https://www.rfc- DOI 10.17487/RFC5245, April 2010,
editor.org/info/rfc5245>. <https://www.rfc-editor.org/info/rfc5245>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, (TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008, <https://www.rfc- DOI 10.17487/RFC5246, August 2008,
editor.org/info/rfc5246>. <https://www.rfc-editor.org/info/rfc5246>.
[RFC5763] Fischl, J., Tschofenig, H., and E. Rescorla, "Framework [RFC5763] Fischl, J., Tschofenig, H., and E. Rescorla, "Framework
for Establishing a Secure Real-time Transport Protocol for Establishing a Secure Real-time Transport Protocol
(SRTP) Security Context Using Datagram Transport Layer (SRTP) Security Context Using Datagram Transport Layer
Security (DTLS)", RFC 5763, DOI 10.17487/RFC5763, May Security (DTLS)", RFC 5763, DOI 10.17487/RFC5763, May
2010, <https://www.rfc-editor.org/info/rfc5763>. 2010, <https://www.rfc-editor.org/info/rfc5763>.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer [RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure Security (DTLS) Extension to Establish Keys for the Secure
Real-time Transport Protocol (SRTP)", RFC 5764, Real-time Transport Protocol (SRTP)", RFC 5764,
DOI 10.17487/RFC5764, May 2010, <https://www.rfc- DOI 10.17487/RFC5764, May 2010,
editor.org/info/rfc5764>. <https://www.rfc-editor.org/info/rfc5764>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010, <https://www.rfc- DOI 10.17487/RFC5785, April 2010,
editor.org/info/rfc5785>. <https://www.rfc-editor.org/info/rfc5785>.
[RFC5890] Klensin, J., "Internationalized Domain Names for [RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework", Applications (IDNA): Definitions and Document Framework",
RFC 5890, DOI 10.17487/RFC5890, August 2010, RFC 5890, DOI 10.17487/RFC5890, August 2010,
<https://www.rfc-editor.org/info/rfc5890>. <https://www.rfc-editor.org/info/rfc5890>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>. January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454, [RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
DOI 10.17487/RFC6454, December 2011, <https://www.rfc- DOI 10.17487/RFC6454, December 2011,
editor.org/info/rfc6454>. <https://www.rfc-editor.org/info/rfc6454>.
[RFC7022] Begen, A., Perkins, C., Wing, D., and E. Rescorla, [RFC7022] Begen, A., Perkins, C., Wing, D., and E. Rescorla,
"Guidelines for Choosing RTP Control Protocol (RTCP) "Guidelines for Choosing RTP Control Protocol (RTCP)
Canonical Names (CNAMEs)", RFC 7022, DOI 10.17487/RFC7022, Canonical Names (CNAMEs)", RFC 7022, DOI 10.17487/RFC7022,
September 2013, <https://www.rfc-editor.org/info/rfc7022>. September 2013, <https://www.rfc-editor.org/info/rfc7022>.
[RFC7675] Perumal, M., Wing, D., Ravindranath, R., Reddy, T., and M. [RFC7675] Perumal, M., Wing, D., Ravindranath, R., Reddy, T., and M.
Thomson, "Session Traversal Utilities for NAT (STUN) Usage Thomson, "Session Traversal Utilities for NAT (STUN) Usage
for Consent Freshness", RFC 7675, DOI 10.17487/RFC7675, for Consent Freshness", RFC 7675, DOI 10.17487/RFC7675,
October 2015, <https://www.rfc-editor.org/info/rfc7675>. October 2015, <https://www.rfc-editor.org/info/rfc7675>.
[RFC8122] Lennox, J. and C. Holmberg, "Connection-Oriented Media [RFC8122] Lennox, J. and C. Holmberg, "Connection-Oriented Media
Transport over the Transport Layer Security (TLS) Protocol Transport over the Transport Layer Security (TLS) Protocol
in the Session Description Protocol (SDP)", RFC 8122, in the Session Description Protocol (SDP)", RFC 8122,
DOI 10.17487/RFC8122, March 2017, <https://www.rfc- DOI 10.17487/RFC8122, March 2017,
editor.org/info/rfc8122>. <https://www.rfc-editor.org/info/rfc8122>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259, Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017, <https://www.rfc- DOI 10.17487/RFC8259, December 2017,
editor.org/info/rfc8259>. <https://www.rfc-editor.org/info/rfc8259>.
[RFC8261] Tuexen, M., Stewart, R., Jesup, R., and S. Loreto, [RFC8261] Tuexen, M., Stewart, R., Jesup, R., and S. Loreto,
"Datagram Transport Layer Security (DTLS) Encapsulation of "Datagram Transport Layer Security (DTLS) Encapsulation of
SCTP Packets", RFC 8261, DOI 10.17487/RFC8261, November SCTP Packets", RFC 8261, DOI 10.17487/RFC8261, November
2017, <https://www.rfc-editor.org/info/rfc8261>. 2017, <https://www.rfc-editor.org/info/rfc8261>.
[webcrypto] [webcrypto]
Dahl, Sleevi, "Web Cryptography API", June 2013. Dahl, Sleevi, "Web Cryptography API", June 2013.
Available at http://www.w3.org/TR/WebCryptoAPI/ Available at http://www.w3.org/TR/WebCryptoAPI/
[webrtc-api] [webrtc-api]
Bergkvist, Burnett, Jennings, Narayanan, "WebRTC 1.0: Bergkvist, Burnett, Jennings, Narayanan, "WebRTC 1.0:
Real-time Communication Between Browsers", October 2011. Real-time Communication Between Browsers", October 2011.
Available at http://dev.w3.org/2011/webrtc/editor/ Available at http://dev.w3.org/2011/webrtc/editor/
webrtc.html webrtc.html
10.2. Informative References 13.2. Informative References
[I-D.ietf-rtcweb-jsep] [I-D.ietf-rtcweb-jsep]
Uberti, J., Jennings, C., and E. Rescorla, "JavaScript Uberti, J., Jennings, C., and E. Rescorla, "JavaScript
Session Establishment Protocol", draft-ietf-rtcweb-jsep-24 Session Establishment Protocol", draft-ietf-rtcweb-jsep-24
(work in progress), October 2017. (work in progress), October 2017.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, <https://www.rfc- DOI 10.17487/RFC3261, June 2002,
editor.org/info/rfc3261>. <https://www.rfc-editor.org/info/rfc3261>.
[RFC5705] Rescorla, E., "Keying Material Exporters for Transport [RFC5705] Rescorla, E., "Keying Material Exporters for Transport
Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705, Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705,
March 2010, <https://www.rfc-editor.org/info/rfc5705>. March 2010, <https://www.rfc-editor.org/info/rfc5705>.
[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265,
DOI 10.17487/RFC6265, April 2011, <https://www.rfc- DOI 10.17487/RFC6265, April 2011,
editor.org/info/rfc6265>. <https://www.rfc-editor.org/info/rfc6265>.
[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol", [RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011, RFC 6455, DOI 10.17487/RFC6455, December 2011,
<https://www.rfc-editor.org/info/rfc6455>. <https://www.rfc-editor.org/info/rfc6455>.
[RFC6943] Thaler, D., Ed., "Issues in Identifier Comparison for [RFC6943] Thaler, D., Ed., "Issues in Identifier Comparison for
Security Purposes", RFC 6943, DOI 10.17487/RFC6943, May Security Purposes", RFC 6943, DOI 10.17487/RFC6943, May
2013, <https://www.rfc-editor.org/info/rfc6943>. 2013, <https://www.rfc-editor.org/info/rfc6943>.
[RFC7617] Reschke, J., "The 'Basic' HTTP Authentication Scheme", [RFC7617] Reschke, J., "The 'Basic' HTTP Authentication Scheme",
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