Using Multicast DNS to protect privacy when exposing ICE candidates
draft-ietf-rtcweb-mdns-ice-candidates-04

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RTCWEB                                                         Y. Fablet
Internet-Draft                                                Apple Inc.
Intended status: Informational                               J. de Borst
Expires: April 18, 2020                                        J. Uberti
                                                                 Q. Wang
                                                                  Google
                                                        October 16, 2019

  Using Multicast DNS to protect privacy when exposing ICE candidates
              draft-ietf-rtcweb-mdns-ice-candidates-04

Abstract

   WebRTC applications collect ICE candidates as part of the process of
   creating peer-to-peer connections.  To maximize the probability of a
   direct peer-to-peer connection, client private IP addresses are
   included in this candidate collection.  However, disclosure of these
   addresses has privacy implications.  This document describes a way to
   share local IP addresses with other clients while preserving client
   privacy.  This is achieved by concealing IP addresses with
   dynamically generated Multicast DNS (mDNS) names.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 18, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of

Fablet, et al.           Expires April 18, 2020                 [Page 1]
Internet-Draft             mdns-ice-candidates              October 2019

   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Description . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  ICE Candidate Gathering . . . . . . . . . . . . . . . . .   3
       3.1.1.  Procedure . . . . . . . . . . . . . . . . . . . . . .   4
       3.1.2.  Implementation Guidance . . . . . . . . . . . . . . .   5
     3.2.  ICE Candidate Processing  . . . . . . . . . . . . . . . .   6
       3.2.1.  Procedure . . . . . . . . . . . . . . . . . . . . . .   6
       3.2.2.  Implementation Guidance . . . . . . . . . . . . . . .   7
     3.3.  Additional Privacy Considerations . . . . . . . . . . . .   7
       3.3.1.  Statistics  . . . . . . . . . . . . . . . . . . . . .   7
       3.3.2.  Interactions With TURN Servers  . . . . . . . . . . .   7
       3.3.3.  Generated Name Reuse  . . . . . . . . . . . . . . . .   8
       3.3.4.  Specific Browsing Contexts  . . . . . . . . . . . . .   8
       3.3.5.  Network Interface Enumeration . . . . . . . . . . . .   8
       3.3.6.  Monitoring of Sessions  . . . . . . . . . . . . . . .   9
   4.  Potential Limitations . . . . . . . . . . . . . . . . . . . .   9
     4.1.  Reduced Connectivity  . . . . . . . . . . . . . . . . . .   9
     4.2.  Connection Setup Latency  . . . . . . . . . . . . . . . .  10
     4.3.  Backward Compatibility  . . . . . . . . . . . . . . . . .  10
   5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Normal Handling . . . . . . . . . . . . . . . . . . . . .  11
     5.2.  Peer-reflexive Candidate From Slow Signaling  . . . . . .  12
     5.3.  Peer-reflexive Candidate From Slow Resolution . . . . . .  12
     5.4.  IPv4, IPv6, and STUN handling . . . . . . . . . . . . . .  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
     6.1.  mDNS Message Flooding . . . . . . . . . . . . . . . . . .  15
     6.2.  Malicious Responses to Deny Name Registration . . . . . .  16
     6.3.  Unsolicited ICE Communications  . . . . . . . . . . . . .  16
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  16