TLS Metadata for Load Balancers
draft-schwartz-tls-lb-02

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tls                                                          B. Schwartz
Internet-Draft                                                Google LLC
Intended status: Standards Track                        October 31, 2019
Expires: May 3, 2020

                    TLS Metadata for Load Balancers
                        draft-schwartz-tls-lb-02

Abstract

   A load balancer that does not terminate TLS may wish to provide some
   information to the backend server, in addition to forwarding TLS
   data.  This draft proposes a protocol between load balancers and
   backends that enables secure, efficient delivery of TLS with
   additional information.  The need for such a protocol has recently
   become apparent in the context of split mode ESNI.

Status of This Memo

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

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   This Internet-Draft will expire on May 3, 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
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Conventions and Definitions . . . . . . . . . . . . . . . . .   2
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Encoding  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Defined ProxyExtensions . . . . . . . . . . . . . . . . . . .   6
     6.1.  padding . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.2.  client_address  . . . . . . . . . . . . . . . . . . . . .   6
     6.3.  destination_address . . . . . . . . . . . . . . . . . . .   6
     6.4.  esni_inner  . . . . . . . . . . . . . . . . . . . . . . .   6
     6.5.  certificate_padding . . . . . . . . . . . . . . . . . . .   7
     6.6.  overload  . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.7.  ratchet . . . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  Protocol wire format  . . . . . . . . . . . . . . . . . . . .   9
   8.  Security considerations . . . . . . . . . . . . . . . . . . .  10
     8.1.  Integrity . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.2.  Confidentiality . . . . . . . . . . . . . . . . . . . . .  10
     8.3.  Fingerprinting  . . . . . . . . . . . . . . . . . . . . .  11
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  12
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   Data encodings are expressed in the TLS 1.3 presentation language, as
   defined in Section 3 of [TLS13].

2.  Background

   A load balancer is a server or bank of servers that acts as an
   intermediary between the client and a range of backend servers.  As
   the name suggests, a load balancer's primary function is to ensure
   that client traffic is spread evenly across the available backend
   servers.  However load balancers also serve many other functions,

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