Secure Negotiation of Incompatible Protocols in TLS
draft-thomson-tls-snip-01
|
Document |
Type |
|
Active Internet-Draft (individual)
|
|
Author |
|
Martin Thomson
|
|
Last updated |
|
2021-01-03
|
|
Stream |
|
(None)
|
|
Intended RFC status |
|
(None)
|
|
Formats |
|
plain text
html
xml
pdf
htmlized (tools)
htmlized
bibtex
|
Stream |
Stream state |
|
(No stream defined) |
|
Consensus Boilerplate |
|
Unknown
|
|
RFC Editor Note |
|
(None)
|
IESG |
IESG state |
|
I-D Exists
|
|
Telechat date |
|
|
|
Responsible AD |
|
(None)
|
|
Send notices to |
|
(None)
|
Network Working Group M. Thomson
Internet-Draft Mozilla
Intended status: Informational 4 January 2021
Expires: 8 July 2021
Secure Negotiation of Incompatible Protocols in TLS
draft-thomson-tls-snip-01
Abstract
An extension is defined for TLS that allows a client and server to
detect an attempt to force the use of less-preferred application
protocol even where protocol options are incompatible. This
supplements application-layer protocol negotiation, which allows
choices between compatible protocols to be authenticated.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the TLS Working Group
mailing list (tls@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/tls/.
Source for this draft and an issue tracker can be found at
https://github.com/martinthomson/snip.
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 8 July 2021.
Thomson Expires 8 July 2021 [Page 1]
Internet-Draft Authenticating Incompatible Protocols January 2021
Copyright Notice
Copyright (c) 2021 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 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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Incompatible Protocols and SVCB . . . . . . . . . . . . . . . 4
4. Authenticating Incompatible Protocols . . . . . . . . . . . . 4
5. Incompatible Protocol Selection . . . . . . . . . . . . . . . 6
6. Protocol Authentication Scope . . . . . . . . . . . . . . . . 7
6.1. The Default Scope . . . . . . . . . . . . . . . . . . . . 8
6.2. SVCB Scope . . . . . . . . . . . . . . . . . . . . . . . 8
6.3. QUIC Version Negotiation Scope . . . . . . . . . . . . . 8
7. Other Discovery Methods . . . . . . . . . . . . . . . . . . . 9
7.1. Alternative Services . . . . . . . . . . . . . . . . . . 9
8. Operational Considerations . . . . . . . . . . . . . . . . . 10
9. Security Considerations . . . . . . . . . . . . . . . . . . . 11
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
11.1. Normative References . . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 13
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
With increased diversity in protocol choice, some applications are
able to use one of several semantically-equivalent protocols to
achieve their goals. This is particularly notable in HTTP where
there are currently three distinct protocols: HTTP/1.1 [HTTP11],
HTTP/2 [HTTP2], and HTTP/3 [HTTP3]. This is also true of protocols
that support variants based on both TLS [TLS] and DTLS [DTLS].
For protocols that are mutually compatible, Application-Layer
Protocol Negotiation (ALPN; [ALPN]) provides a secure way to
negotiate protocol selection.
Thomson Expires 8 July 2021 [Page 2]
Internet-Draft Authenticating Incompatible Protocols January 2021
In ALPN, the client offers a list of options in a TLS ClientHello and
the server chooses the option that it most prefers. A downgrade
attack occurs where both client and server support a protocol that
the server prefers more than than the selected protocol. ALPN
Show full document text