idnits 2.17.1 draft-ietf-kitten-tls-channel-bindings-for-tls13-04.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 : ---------------------------------------------------------------------------- ** The document seems to lack an Introduction section. ** The document seems to lack a Security Considerations section. ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** The abstract seems to contain references ([RFC5929], [RFC8446], [RFC5802]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. ** The document seems to lack a both a reference to RFC 2119 and the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. RFC 2119 keyword, line 91: '... Implementations MUST NOT use the chan...' -- The draft header indicates that this document updates RFC8446, but the abstract doesn't seem to directly say this. It does mention RFC8446 though, so this could be OK. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year (Using the creation date from RFC5929, updated by this document, for RFC5378 checks: 2006-08-16) -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (May 25, 2021) is 1060 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) -- Missing reference section? 'RFC5802' on line 17 looks like a reference -- Missing reference section? 'RFC5929' on line 53 looks like a reference -- Missing reference section? 'RFC8446' on line 95 looks like a reference -- Missing reference section? 'TRIPLE-HANDSHAKE' on line 55 looks like a reference -- Missing reference section? 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Whited 3 Internet-Draft May 25, 2021 4 Updates: 5802,5929,8446 (if approved) 5 Intended status: Standards Track 6 Expires: November 26, 2021 8 Channel Bindings for TLS 1.3 9 draft-ietf-kitten-tls-channel-bindings-for-tls13-04 11 Abstract 13 This document defines a channel binding type, tls-exporter, that is 14 compatible with TLS 1.3 in accordance with RFC 5056, On Channel 15 Binding. Furthermore it updates the "default" channel binding to the 16 new binding for versions of TLS greater than 1.2. This document 17 updates [RFC5802], [RFC5929], and [RFC8446]. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at https://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on November 26, 2021. 36 Copyright Notice 38 Copyright (c) 2021 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (https://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 1. 53 The "unique" channel binding types defined in [RFC5929] were found to 54 be vulnerable to the "triple handshake vulnerability" 55 [TRIPLE-HANDSHAKE] without the extended master secret extension 56 defined in [RFC7627]. Because of this they were not defined for TLS 57 1.3 (see [RFC8446] section C.5). To facilitate channel binding with 58 TLS 1.3, a new channel binding type is needed. 60 1.1. 62 Throughout this document the acronym "EKM" is used to refer to 63 Exported Keying Material as defined in [RFC5705]. 65 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 66 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 67 "OPTIONAL" in this document are to be interpreted as described in BCP 68 14 [RFC2119] [RFC8174] when, and only when, they appear in all 69 capitals, as shown here. 71 2. 73 Channel binding mechanisms are not useful until TLS implementations 74 expose the required data. To facilitate this, "tls-exporter" uses 75 exported keying material (EKM) which is already widely exposed by TLS 76 implementations. The EKM is obtained using the keying material 77 exporters for TLS as defined in [RFC5705] and [RFC8446] section 7.5 78 by supplying the following inputs: 80 In previous versions of TLS the "tls-unique" channel binding type was 81 defined as the default channel binding if no mechanism was defined 82 for negotiating a different channel binding. Because "tls-unique" is 83 not defined for TLS 1.3, the default channel binding mechanism for 84 TLS versions 1.3 and greater 86 be "tls-exporter". 88 3. 90 Channel bindings do not leak secret information about the channel and 91 are considered public. Implementations MUST NOT use the channel 92 binding to protect secret information. 94 The Security Considerations sections of [RFC5056], [RFC5705], and 95 [RFC8446] apply to this document. 97 3.1. 99 While it is possible to use this channel binding mechanism with TLS 100 versions below 1.3, extra precaution must be taken to ensure that the 101 chosen cipher suites always result in unique master secrets. For 102 more information see the Security Considerations section of 103 [RFC5705]. 105 When TLS renegotiation is enabled the "tls-exporter" channel binding 106 type is not defined and implementations 108 support it. 110 In general, users wishing to take advantage of channel binding should 111 upgrade to TLS 1.3 or later. 113 The derived data 115 be used for any purpose other than channel bindings as described in 116 [RFC5056]. 118 4. 120 4.1. 122 This document adds the following registration in the "Channel-Binding 123 Types" registry: 125 4.2. 127 This document adds the following registration in the "TLS Exporter 128 Labels" registry: 130 5. References 132 Author's Address 134 Sam Whited 135 Atlanta GA 136 USA 138 Email: sam@samwhited.com 139 URI: https://blog.samwhited.com/