draft-ietf-httpbis-http2-tls13-03.txt   rfc8740.txt 
HTTP D. Benjamin Internet Engineering Task Force (IETF) D. Benjamin
Internet-Draft Google LLC Request for Comments: 8740 Google LLC
Updates: 7540 (if approved) October 17, 2019 Updates: 7540 February 2020
Intended status: Standards Track Category: Standards Track
Expires: April 19, 2020 ISSN: 2070-1721
Using TLS 1.3 with HTTP/2 Using TLS 1.3 with HTTP/2
draft-ietf-httpbis-http2-tls13-03
Abstract Abstract
This document updates RFC 7540 by forbidding TLS 1.3 post-handshake This document updates RFC 7540 by forbidding TLS 1.3 post-handshake
authentication, as an analog to the existing TLS 1.2 renegotiation authentication, as an analog to the existing TLS 1.2 renegotiation
restriction. restriction.
Note to Readers
_RFC EDITOR: please remove this section before publication_
Discussion of this draft takes place on the HTTP working group
mailing list (ietf-http-wg@w3.org), which is archived at
https://lists.w3.org/Archives/Public/ietf-http-wg/ [1].
Working Group information can be found at https://httpwg.org/ [2];
source code and issues list for this draft can be found at
https://github.com/httpwg/http-extensions/labels/http2-tls13 [3].
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on April 19, 2020. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8740.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language
3. Post-Handshake Authentication in HTTP/2 . . . . . . . . . . . 3 3. Post-Handshake Authentication in HTTP/2
4. Other Post-Handshake TLS Messages in HTTP/2 . . . . . . . . . 3 4. Other Post-Handshake TLS Messages in HTTP/2
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7. References
7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.1. Normative References
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References
7.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
TLS 1.2 [RFC5246] and earlier support renegotiation, a mechanism for TLS 1.2 [RFC5246] and earlier versions of TLS support renegotiation,
changing parameters and keys partway through a connection. This was a mechanism for changing parameters and keys partway through a
sometimes used to implement reactive client authentication in connection. This was sometimes used to implement reactive client
HTTP/1.1 [RFC7230], where the server decides whether to request a authentication in HTTP/1.1 [RFC7230], where the server decides
client certificate based on the HTTP request. whether or not to request a client certificate based on the HTTP
request.
HTTP/2 [RFC7540] multiplexes multiple HTTP requests over a single HTTP/2 [RFC7540] multiplexes multiple HTTP requests over a single
connection, which is incompatible with the mechanism above. Clients connection, which is incompatible with the mechanism above. Clients
cannot correlate the certificate request with the HTTP request which cannot correlate the certificate request with the HTTP request that
triggered it. Thus, Section 9.2.1 of [RFC7540] forbids triggered it. Thus, Section 9.2.1 of [RFC7540] forbids
renegotiation. renegotiation.
TLS 1.3 [RFC8446] updates TLS 1.2 to remove renegotiation in favor of TLS 1.3 [RFC8446] removes renegotiation and replaces it with separate
separate post-handshake authentication and key update mechanisms. post-handshake authentication and key update mechanisms. Post-
The former shares the same problems with multiplexed protocols, but handshake authentication has the same problems with multiplexed
the prohibition in [RFC7540] only applies to TLS 1.2 renegotiation. protocols as TLS 1.2 renegotiation, but the prohibition in [RFC7540]
only applies to renegotiation.
This document updates HTTP/2 to similarly forbid TLS 1.3 post- This document updates HTTP/2 [RFC7540] to similarly forbid TLS 1.3
handshake authentication. post-handshake authentication.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Post-Handshake Authentication in HTTP/2 3. Post-Handshake Authentication in HTTP/2
HTTP/2 servers MUST NOT send post-handshake TLS 1.3 HTTP/2 servers MUST NOT send post-handshake TLS 1.3
CertificateRequest messages. HTTP/2 clients MUST treat such messages CertificateRequest messages. HTTP/2 clients MUST treat such messages
as connection errors (see Section 5.4.1 of [RFC7540]) of type as connection errors (see Section 5.4.1 of [RFC7540]) of type
PROTOCOL_ERROR. PROTOCOL_ERROR.
[RFC7540] permitted renegotiation before the HTTP/2 connection [RFC7540] permitted renegotiation before the HTTP/2 connection
preface to provide confidentiality of the client certificate. TLS preface to provide confidentiality of the client certificate. TLS
1.3 encrypts the client certificate in the initial handshake, so this 1.3 encrypts the client certificate in the initial handshake, so this
is no longer necessary. HTTP/2 servers MUST NOT send post-handshake is no longer necessary. HTTP/2 servers MUST NOT send post-handshake
TLS 1.3 CertificateRequest messages before the connection preface. TLS 1.3 CertificateRequest messages before the connection preface.
The above applies even if the client offered the The above applies even if the client offered the
"post_handshake_auth" TLS extension. This extension is advertised "post_handshake_auth" TLS extension. This extension is advertised
independently of the selected ALPN protocol [RFC7301], so it is not independently of the selected Application-Layer Protocol Negotiation
sufficient to resolve the conflict with HTTP/2. HTTP/2 clients that (ALPN) protocol [RFC7301], so it is not sufficient to resolve the
also offer other ALPN protocols, notably HTTP/1.1, in a TLS conflict with HTTP/2. HTTP/2 clients that also offer other ALPN
ClientHello MAY include the "post_handshake_auth" extension to protocols, notably HTTP/1.1, in a TLS ClientHello MAY include the
support those other protocols. This does not indicate support in "post_handshake_auth" extension to support those other protocols.
HTTP/2. This does not indicate support in HTTP/2.
4. Other Post-Handshake TLS Messages in HTTP/2 4. Other Post-Handshake TLS Messages in HTTP/2
[RFC8446] defines two other messages that are exchanged after the [RFC8446] defines two other messages that are exchanged after the
handshake is complete, KeyUpdate and NewSessionTicket. handshake is complete: KeyUpdate and NewSessionTicket.
KeyUpdate messages only affect TLS itself and do not require any KeyUpdate messages only affect TLS itself and do not require any
interaction with the application protocol. HTTP/2 implementations interaction with the application protocol. HTTP/2 implementations
MUST support key updates when TLS 1.3 is negotiated. MUST support key updates when TLS 1.3 is negotiated.
NewSessionTicket messages are also permitted. Though these interact NewSessionTicket messages are also permitted. Though these interact
with HTTP when early data is enabled, these interactions are defined with HTTP when early data is enabled, these interactions are defined
in [RFC8470] and allowed for in the design of HTTP/2. in [RFC8470] and are allowed for in the design of HTTP/2.
Unless the use of a new type of TLS message depends on an interaction Unless the use of a new type of TLS message depends on an interaction
with the application-layer protocol, that TLS message can be sent with the application-layer protocol, that TLS message can be sent
after the handshake completes. after the handshake completes.
5. Security Considerations 5. Security Considerations
This document resolves a compatibility concern between HTTP/2 and TLS This document resolves a compatibility concern between HTTP/2 and TLS
1.3 when supporting post-handshake authentication with HTTP/1.1. 1.3 when supporting post-handshake authentication with HTTP/1.1.
This lowers the barrier for deploying TLS 1.3, a major security This lowers the barrier for deploying TLS 1.3, a major security
skipping to change at page 5, line 15 skipping to change at line 183
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
7.2. Informative References 7.2. Informative References
[RFC8470] Thomson, M., Nottingham, M., and W. Tarreau, "Using Early [RFC8470] Thomson, M., Nottingham, M., and W. Tarreau, "Using Early
Data in HTTP", RFC 8470, DOI 10.17487/RFC8470, September Data in HTTP", RFC 8470, DOI 10.17487/RFC8470, September
2018, <https://www.rfc-editor.org/info/rfc8470>. 2018, <https://www.rfc-editor.org/info/rfc8470>.
7.3. URIs
[1] https://lists.w3.org/Archives/Public/ietf-http-wg/
[2] https://httpwg.org/
[3] https://github.com/httpwg/http-extensions/labels/http2-tls13
Author's Address Author's Address
David Benjamin David Benjamin
Google LLC Google LLC
Email: davidben@google.com Email: davidben@google.com
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