Incrementally Better Cookies
draft-west-cookie-incrementalism-00

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Last updated 2019-05-07
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Network Working Group                                            M. West
Internet-Draft                                                    Google
Intended status: Standards Track                             May 7, 2019
Expires: November 8, 2019

                      Incrementally Better Cookies
                  draft-west-cookie-incrementalism-00

Abstract

   This document proposes two changes to cookies inspired by the
   properties of the HTTP State Tokens mechanism proposed in
   [I-D.west-http-state-tokens].  First, cookies should be treated as
   "SameSite=Lax" by default.  Second, cookies that explicitly assert
   "SameSite=None" in order to enable cross-site delivery should also be
   marked as "Secure".

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
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   This Internet-Draft will expire on November 8, 2019.

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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   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   to this document.  Code Components extracted from this document must
   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.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
     2.1.  Conformance . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Syntax  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Monkey-Patches against RFC6265bis . . . . . . . . . . . . . .   3
     3.1.  "Lax" by Default  . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Requiring "Secure" for "SameSite=None"  . . . . . . . . .   4
   4.  Security and Privacy Considerations . . . . . . . . . . . . .   5
     4.1.  CSRF  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Secure Transport  . . . . . . . . . . . . . . . . . . . .   5
     4.3.  Tracking  . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Implementation Considerations . . . . . . . . . . . . . . . .   6
     5.1.  Sequencing  . . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  Deployment  . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The HTTP State Tokens proposal ([I-D.west-http-state-tokens]) aims to
   replace cookies with a state management mechanism that has better
   security and privacy properties.  That proposal is somewhat
   aspirational: it's going to take a long time to come to agreement on
   the exact contours of a cookie replacement, and an even longer time
   to actually do so.

   While we're debating the details of a new state management primitive,
   it seems quite reasonable to reevaluate some aspects of the existing
   primitive: cookies.  When we can find consensus on some aspect of
   HTTP State Tokens, we can apply those aspirations to cookies, driving
   incremental improvements to state management in the status quo.

   Based on conversations at [HTTP-Workshop-2019] and elsewhere, I'd
   suggest that we have something like agreement on at least two
   principles:

   1.  HTTP requests should not carry state along with cross-site
       requests by default (see Section 8.2 of [RFC6265bis]).

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   2.  HTTP requests should not carry state over non-secure channels
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