draft-ietf-httpbis-http2-tls13-00.txt   draft-ietf-httpbis-http2-tls13-01.txt 
HTTP D. Benjamin HTTP D. Benjamin
Internet-Draft Google LLC Internet-Draft Google LLC
Updates: 7540 (if approved) May 13, 2019 Updates: 7540 (if approved) September 13, 2019
Intended status: Standards Track Intended status: Standards Track
Expires: November 14, 2019 Expires: March 16, 2020
Using TLS 1.3 with HTTP/2 Using TLS 1.3 with HTTP/2
draft-ietf-httpbis-http2-tls13-00 draft-ietf-httpbis-http2-tls13-01
Abstract Abstract
This document clarifies the use of TLS 1.3 post-handshake This document updates HTTP/2 to prohibit TLS 1.3 post-handshake
authentication and key update with HTTP/2. authentication, as an analog to existing TLS 1.2 renegotiation
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 Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 14, 2019. This Internet-Draft will expire on March 16, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Post-Handshake Authentication in HTTP/2 . . . . . . . . . . . 2 3. Post-Handshake Authentication in HTTP/2 . . . . . . . . . . . 3
4. Key Updates in HTTP/2 . . . . . . . . . . . . . . . . . . . . 3 4. Other Post-Handshake TLS Messages in HTTP/2 . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 3 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
7.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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 support renegotiation, a mechanism for
changing parameters and keys partway through a connection. This was changing parameters and keys partway through a connection. This was
sometimes used to implement reactive client authentication in sometimes used to implement reactive client authentication in
HTTP/1.1 [RFC7230], where the server decides whether to request a HTTP/1.1 [RFC7230], where the server decides whether to request a
client certificate based on the HTTP request. 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 which
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] updates TLS 1.2 to remove renegotiation in favor of
separate post-handshake authentication and key update mechanisms. separate post-handshake authentication and key update mechanisms.
The former shares the same problems with multiplexed protocols, but The former shares the same problems with multiplexed protocols, but
has a different name. This makes it ambiguous whether post-handshake the prohibition in HTTP/2 only applies to TLS 1.2 renegotiation.
authentication is allowed in TLS 1.3.
This document clarifies that the prohibition applies to post- This document updates HTTP/2 to similarly forbid TLS 1.3 post-
handshake authentication but not to key updates. 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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 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
The prohibition on renegotiation in section 9.2.1 of [RFC7540]
additionally applies to TLS 1.3 post-handshake authentication.
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 TLS 1.3 post- CertificateRequest messages. HTTP/2 clients MUST treat TLS 1.3 post-
handshake authentication as a connection error (see section 5.4.1 of handshake authentication as a connection error (see section 5.4.1 of
[RFC7540]) of type PROTOCOL_ERROR. [RFC7540]) of type 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 ALPN protocol [RFC7301], so it is not
sufficient to resolve the conflict with HTTP/2. HTTP/2 clients that sufficient to resolve the conflict with HTTP/2. HTTP/2 clients that
also offer other ALPN protocols, notably HTTP/1.1, in a TLS also offer other ALPN protocols, notably HTTP/1.1, in a TLS
ClientHello MAY include the "post_handshake_auth" extension to ClientHello MAY include the "post_handshake_auth" extension to
support those other protocols. This does not indicate support in support those other protocols. This does not indicate support in
HTTP/2. HTTP/2.
4. Key Updates in HTTP/2 4. Other Post-Handshake TLS Messages in HTTP/2
Section 9.2.1 of [RFC7540] does not extend to TLS 1.3 KeyUpdate [RFC8446] defines two other messages that are exchanged after the
messages. HTTP/2 implementations MUST support key updates when TLS handshake is complete, KeyUpdate and NewSessionTicket.
1.3 is negotiated.
KeyUpdate messages only affect TLS itself and do not require any
interaction with the application protocol. HTTP/2 implementations
MUST support key updates when TLS 1.3 is negotiated.
NewSessionTicket messages are also permitted. Though these interact
with HTTP when early data is enabled, these interactions are defined
in [RFC8470] and allowed for in the design of HTTP/2.
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
after the handshake completes.
5. Security Considerations 5. Security Considerations
This document clarifies how to use HTTP/2 with TLS 1.3 and resolves a This document resolves a compatibility concern between HTTP/2 and TLS
compatibility concern when supporting post-handshake authentication 1.3 when supporting post-handshake authentication with HTTP/1.1.
with HTTP/1.1. This lowers the barrier for deploying TLS 1.3, a This lowers the barrier for deploying TLS 1.3, a major security
major security improvement over TLS 1.2. Permitting key updates improvement over TLS 1.2.
allows key material to be refreshed in long-lived HTTP/2 connections.
6. IANA Considerations 6. IANA Considerations
This document has no IANA actions. This document has no IANA actions.
7. Normative References 7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, (TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008, DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>. <https://www.rfc-editor.org/info/rfc5246>.
skipping to change at page 4, line 28 skipping to change at page 5, line 9
<https://www.rfc-editor.org/info/rfc7540>. <https://www.rfc-editor.org/info/rfc7540>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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
[RFC8470] Thomson, M., Nottingham, M., and W. Tarreau, "Using Early
Data in HTTP", RFC 8470, DOI 10.17487/RFC8470, September
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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