Internet-Draft QUICv2 November 2021
Duke Expires 27 May 2022 [Page]
Workgroup:
QUIC
Internet-Draft:
draft-ietf-quic-v2-latest
Published:
Intended Status:
Standards Track
Expires:
Author:
M. Duke
F5, Inc.

QUIC Version 2

Abstract

This document specifies QUIC version 2, which is identical to QUIC version 1 except for some trivial details. Its purpose is to combat various ossification vectors and exercise the version negotiation framework. It also serves as a template for the minimum changes in any future version of QUIC.

Note that "version 2" is an informal name for this proposal that indicates it is the second standards-track QUIC version. The protocol specified here will receive a version number other than 2 from IANA.

Discussion of this work is encouraged to happen on the QUIC IETF mailing list quic@ietf.org or on the GitHub repository which contains the draft: https://github.com/quicwg/quic-v2.

Discussion Venues

This note is to be removed before publishing as an RFC.

Source for this draft and an issue tracker can be found at https://github.com/quicwg/quic-v2.

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 27 May 2022.

Table of Contents

1. Introduction

QUIC [RFC9000] has numerous extension points, including the version number that occupies the second through fifth octets of every long header (see [RFC8999]). If experimental versions are rare, and QUIC version 1 constitutes the vast majority of QUIC traffic, there is the potential for middleboxes to ossify on the version octets always being 0x00000001.

Furthermore, version 1 Initial packets are encrypted with keys derived from a universally known salt, which allow observers to inspect the contents of these packets, which include the TLS Client Hello and Server Hello messages. Again, middleboxes may ossify on the version 1 key derivation and packet formats.

Finally [QUIC-VN] provides two mechanisms for endpoints to negotiate the QUIC version to use. The "incompatible" version negotiation method can support switching from any initial QUIC version to any other version with full generality, at the cost of an additional round-trip at the start of the connection. "Compatible" version negotiation eliminates the round-trip penalty but levies some restrictions on how much the two versions can differ semantically.

QUIC version 2 is meant to mitigate ossification concerns and exercise the version negotiation mechanisms. The only change is a tweak to the inputs of some crypto derivation functions to enforce full key separation. Any endpoint that supports two versions needs to implement version negotiation to protect against downgrade attacks.

[I-D.duke-quic-version-aliasing] is a more robust, but much more complicated, proposal to address these ossification problems. By design, it requires incompatible version negotiation. QUICv2 enables exercise of compatible version negotiation mechanism.

2. Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

3. Changes from QUIC Version 1

QUIC version 2 endpoints MUST implement the QUIC version 1 specification as described in [RFC9000], [RFC9001], and [RFC9002], with the following changes:

initial_salt = 0xa707c203a59b47184a1d62ca570406ea7ae3e5d3
secret = 0x3425c20cf88779df2ff71e8abfa78249891e763bbed2f13c048343d348c060e2
key = 0xba858dc7b43de5dbf87617ff4ab253db
nonce = 0x141b99c239b03e785d6a2e9f

4. Version Negotiation Considerations

QUIC version 2 endpoints SHOULD also support QUIC version 1. Any QUIC endpoint that supports multiple versions MUST fully implement [QUIC-VN] to prevent version downgrade attacks.

Note that version 2 meets that document's definition of a compatible version with version 1. Therefore, v2-capable servers MUST use compatible version negotiation unless they do not support version 1.

As version 1 support is more likely than version 2 support, a client SHOULD use QUIC version 1 for its original version unless it has out-of-band knowledge that the server supports version 2.

5. Ossification Considerations

QUIC version 2 provides protection against some forms of ossification. Devices that assume that all long headers will contain encode version 1, or that the version 1 Initial key derivation formula will remain version-invariant, will not correctly process version 2 packets.

However, many middleboxes such as firewalls focus on the first packet in a connection, which will often remain in the version 1 format due to the considerations above.

Clients interested in combating firewall ossification can initiate a connection using version 2 if they are either reasonably certain the server supports it, or are willing to suffer a round-trip penalty if they are incorrect.

6. Applicability

This version of QUIC provides no change from QUIC version 1 relating to the capabilities available to applications. Therefore, all Application Layer Protocol Negotiation (ALPN) ([RFC7301]) codepoints specified to operate over QUICv1 can also operate over this version of QUIC.

All QUIC extensions defined to work with version 1 also work with version 2.

7. Security Considerations

QUIC version 2 introduces no changes to the security or privacy properties of QUIC version 1.

The mandatory version negotiation mechanism guards against downgrade attacks, but downgrades have no security implications, as the version properties are identical.

8. IANA Considerations

This document requests that IANA add the following entry to the QUIC version registry:

Value: TBD

Status: permanent

Specification: This Document

Change Controller: IETF

Contact: QUIC WG

9. References

9.1. Normative References

[QUIC-VN]
Schinazi, D. and E. Rescorla, "Compatible Version Negotiation for QUIC", Work in Progress, Internet-Draft, draft-ietf-quic-version-negotiation-05, , <https://datatracker.ietf.org/doc/html/draft-ietf-quic-version-negotiation-05>.
[RFC9000]
Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, , <https://www.rfc-editor.org/rfc/rfc9000>.
[RFC9001]
Thomson, M., Ed. and S. Turner, Ed., "Using TLS to Secure QUIC", RFC 9001, DOI 10.17487/RFC9001, , <https://www.rfc-editor.org/rfc/rfc9001>.
[RFC9002]
Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection and Congestion Control", RFC 9002, DOI 10.17487/RFC9002, , <https://www.rfc-editor.org/rfc/rfc9002>.

9.2. Informative References

[I-D.duke-quic-version-aliasing]
Duke, M., "QUIC Version Aliasing", Work in Progress, Internet-Draft, draft-duke-quic-version-aliasing-07, , <https://datatracker.ietf.org/doc/html/draft-duke-quic-version-aliasing-07>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC7301]
Friedl, S., Popov, A., Langley, A., and E. Stephan, "Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, , <https://www.rfc-editor.org/rfc/rfc7301>.
[RFC8999]
Thomson, M., "Version-Independent Properties of QUIC", RFC 8999, DOI 10.17487/RFC8999, , <https://www.rfc-editor.org/rfc/rfc8999>.

Appendix A. Changelog

A.1. since draft-duke-quic-v2-02

  • Converted to adopted draft
  • Deleted references to QUIC improvements
  • Clarified status of QUIC extensions

A.2. since draft-duke-quic-v2-01

  • Made the final version number TBD.
  • Added ALPN considerations

A.3. since draft-duke-quic-v2-00

  • Added provisional versions for interop
  • Change the v1 Retry Tag secret
  • Change labels to create full key separation

Author's Address

Martin Duke
F5, Inc.