idnits 2.17.1 draft-vvv-httpbis-alps-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (21 January 2021) is 1190 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- No information found for draft-vvv-tls-alps-latest - is the name correct? -- Possible downref: Normative reference to a draft: ref. 'ALPS' -- No information found for draft-ietf-quic-http-latest - is the name correct? -- Possible downref: Normative reference to a draft: ref. 'HTTP3' ** Obsolete normative reference: RFC 7540 (Obsoleted by RFC 9113) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 HTTP Working Group V. Vasiliev 3 Internet-Draft Google 4 Intended status: Standards Track 21 January 2021 5 Expires: 25 July 2021 7 Using TLS Application-Layer Protocol Settings (ALPS) in HTTP 8 draft-vvv-httpbis-alps-01 10 Abstract 12 This document describes the use of TLS Application-Level Protocol 13 Settings (ALPS) in HTTP/2 and HTTP/3. Additionally, it defines a set 14 of additional HTTP SETTINGS parameters that would normally be 15 impractical without ALPS. 17 Discussion Venues 19 This note is to be removed before publishing as an RFC. 21 Discussion of this document takes place on the HTTPBIS Working Group 22 mailing list (httpbis@ietf.org), which is archived at 23 https://mailarchive.ietf.org/arch/browse/httpbis/ 24 (https://mailarchive.ietf.org/arch/browse/httpbis/). 26 Source for this draft and an issue tracker can be found at 27 https://github.com/vasilvv/httpbis-alps (https://github.com/vasilvv/ 28 httpbis-alps). 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on 25 July 2021. 47 Copyright Notice 49 Copyright (c) 2021 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 54 license-info) in effect on the date of publication of this document. 55 Please review these documents carefully, as they describe your rights 56 and restrictions with respect to this document. Code Components 57 extracted from this document must include Simplified BSD License text 58 as described in Section 4.e of the Trust Legal Provisions and are 59 provided without warranty as described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 64 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 65 3. Use of ALPS in HTTP . . . . . . . . . . . . . . . . . . . . . 3 66 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 68 6. Normative References . . . . . . . . . . . . . . . . . . . . 4 69 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4 70 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 72 1. Introduction 74 HTTP/2 defines a mechanism for exchanging the protocol settings using 75 a SETTINGS frame ([RFC7540], Section 6.5). HTTP/3 uses a similar 76 mechanism ([HTTP3], Section 7.2.4). One of the properties of the 77 mechanism as defined by both of those protocols is that the parties 78 start out without having access to the entirety of the peer's 79 settings. This means that they have to initially operate using the 80 default settings, and after receiving the SETTINGS frame, they have 81 to find a way to transition from the default to the exchanged 82 settings. 84 HTTP is commonly used in conjunction with TLS. TLS performs its own 85 handshake that precedes any data being exchanged by the HTTP layer 86 itself. The TLS Application-Level Protocol Settings extension [ALPS] 87 allows settings negotiation to be performed within the TLS handshake, 88 thus making the result immediately available to the HTTP layer as 89 soon as the handshake completes. This removes the need for 90 synchronizing settings, and makes them available earlier than they 91 would be otherwise. 93 This document defines how ALPS is used with HTTP/2 and HTTP/3, and 94 introduces certain new settings that would not be practical without 95 ALPS. 97 2. Conventions and Definitions 99 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 100 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 101 "OPTIONAL" in this document are to be interpreted as described in BCP 102 14 [RFC2119] [RFC8174] when, and only when, they appear in all 103 capitals, as shown here. 105 3. Use of ALPS in HTTP 107 If ALPS is successfully negotiated during the TLS handshake for an 108 HTTP/2 connection, the ALPS payload for both peers SHALL be a 109 sequence of HTTP/2 frames. Frames SHALL NOT be present in ALPS 110 unless they are explicitly allowed to be there; this document only 111 allows the SETTINGS frame ([RFC7540], Section 6.5.1). Sending a 112 SETTINGS frame in ALPS supersedes the requirement to send a SETTINGS 113 frame at the beginning of the connection. All settings exchanged via 114 ALPS SHALL be automatically treated as acknowledged. 116 If ALPS is successfully negotiated during TLS handshake for an HTTP/3 117 connection, the ALPS payload for both peers SHALL be a sequence of 118 HTTP/3 frames. Frames SHALL NOT be present in ALPS unless they are 119 explicitly allowed to be there; this document only allows the 120 SETTINGS frame ([HTTP3], Section 7.2.4). Sending a SETTINGS frame in 121 ALPS supersedes the requirement to send a SETTINGS frame at the 122 beginning of the control stream. 124 Since settings exchanged through ALPS are always available at the 125 beginning of the connection, some HTTP extensions may opt to require 126 those to be sent through ALPS. Such extensions are exempt from the 127 initialization requirements of the Section 7.2.4.2 of [HTTP3]. 129 4. Security Considerations 131 In ALPS, both client and server settings are sent encrypted. 132 Settings communicated through ALPS are presented to all clients 133 before they are authenticated; thus, if a server relies on TLS client 134 authentication and considers its settings private, it MUST NOT use 135 the mechanism defined in this document. 137 5. IANA Considerations 139 IANA will add an "Allowed in ALPS" column to the "HTTP/2 Frames" 140 section of the "Hypertext Transfer Protocol version 2 (HTTP/2) 141 Parameters" registry, with a value set to "Yes" for SETTINGS (0x4), 142 and to "No" for all other previously defined settings. 144 TODO: Add HTTP/3 once IANA has an HTTP/3 registry. 146 6. Normative References 148 [ALPS] Vasiliev, V., "TLS Application-Layer Protocol Settings 149 Extension", Work in Progress, Internet-Draft, draft-vvv- 150 tls-alps-latest, 151 . 153 [HTTP3] Bishop, M., Ed., "Hypertext Transfer Protocol Version 3 154 (HTTP/3)", Work in Progress, Internet-Draft, draft-ietf- 155 quic-http-latest, 156 . 158 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 159 Requirement Levels", BCP 14, RFC 2119, 160 DOI 10.17487/RFC2119, March 1997, 161 . 163 [RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext 164 Transfer Protocol Version 2 (HTTP/2)", RFC 7540, 165 DOI 10.17487/RFC7540, May 2015, 166 . 168 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 169 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 170 May 2017, . 172 Acknowledgments 174 This document has benefited from contributions and suggestions from 175 David Benjamin, Nick Harper, David Schinazi, and many others. 177 Author's Address 179 Victor Vasiliev 180 Google 182 Email: vasilvv@google.com