idnits 2.17.1 draft-ietf-jmap-smime-07.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 : ---------------------------------------------------------------------------- ** There is 1 instance of too long lines in the document, the longest one being 9 characters in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (July 26, 2021) is 997 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 issues found here. Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Melnikov 3 Internet-Draft Isode Ltd 4 Intended status: Standards Track July 26, 2021 5 Expires: January 27, 2022 7 S/MIME signature verification extension to JMAP 8 draft-ietf-jmap-smime-07 10 Abstract 12 This document specifies an extension to JMAP for returning S/MIME 13 signature verification status. 15 Status of This Memo 17 This Internet-Draft is submitted in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at https://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on January 27, 2022. 32 Copyright Notice 34 Copyright (c) 2021 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (https://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Table of Contents 49 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 50 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 51 3. Addition to the capabilities object . . . . . . . . . . . . . 2 52 4. Extension to Email/get for S/MIME signature verification . . 3 53 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 54 5.1. JMAP capability registration for "smimeverify" . . . . . 7 55 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 56 7. Normative References . . . . . . . . . . . . . . . . . . . . 7 57 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 59 1. Introduction 61 [RFC8621] is a JSON based application protocol for synchronising 62 email data between a client and a server. 64 This document describes an extension to JMAP for returning S/MIME 65 [RFC8551] signature verification status, without requiring a JMAP 66 client to download the signature body part and all signed body parts 67 (when multipart/signed media type is used) or to download and decode 68 CMS (when application/pkcs7-mime media type is used). 70 2. Conventions Used in This Document 72 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 73 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 74 document are to be interpreted as described in [RFC2119]. 76 Type signatures, examples, and property descriptions in this document 77 follow the conventions established in Section 1.1 of [RFC8620]. Data 78 types defined in the core specification are also used in this 79 document. 81 3. Addition to the capabilities object 83 The capabilities object is returned as part of the standard JMAP 84 Session object; see the JMAP spec. Servers supporting _this_ 85 specification MUST add a property called 86 "urn:ietf:params:jmap:smimeverify" to the capabilities object. 88 The value of this property is an empty object in both the JMAP 89 session _capabilities_ property and an account's 90 _accountCapabilities_ property. 92 4. Extension to Email/get for S/MIME signature verification 94 [RFC8621] defines Email/get method for retrieving message specific 95 information. This document defines the following pseudo values in 96 the _properties_ argument: 98 *smimeStatus*: If "smimeStatus" is included in the list of 99 requested properties, it MUST be interpreted by the server as a 100 request to return "smimeStatus" response property. 102 *smimeErrors*: If "smimeErrors" is included in the list of 103 requested properties, it MUST be interpreted by the server as a 104 request to return "smimeErrors" response property. 106 *smimeVerifiedAt*: If "smimeVerifiedAt" is included in the list of 107 requested properties, it MUST be interpreted by the server as a 108 request to return "smimeVerifiedAt" response property. 110 *smimeStatusAtDelivery*: If "smimeStatusAtDelivery" is included in 111 the list of requested properties, it MUST be interpreted by the 112 server as a request to return "smimeStatusAtDelivery" response 113 property. (It effectively the same as "smimeStatus" value 114 calculated at the date/time of deliver, as specified by 115 "receivedAt".) 117 The "smimeStatus" response property is defined as follows: 119 smimeStatus: "String|null". null signifies that the message doesn't 120 contain any signature. This property contains the S/MIME signature 121 and certificate verification status calculated according to [RFC8551] 122 and [RFC8550]. Possible string values of the property are listed 123 below. Servers MAY return other values not defined below. Client 124 MUST treat unrecognized values as "unknown" or "signed/failed". Note 125 that the value of this property might change over time. 127 unknown S/MIME message, but it is neither signed, nor encrypted. 128 This can also be returned for a multipart/signed message which 129 contains unrecognized signing protocol (for example OpenPGP). 131 signed S/MIME signed message, but the signature was not yet 132 verified. Some servers might not attempt to verify signature 133 until a particular message is requested by the client. JMAP 134 servers compliant with this document SHOULD return "signed/ 135 verified" or "signed/failed" instead of this signature status. 137 signed/verified S/MIME signed message and the sender's signature was 138 successfully verified, sender matches the From header field and 139 the sender's certificate (and the certificate chain) is trusted 140 for signing. 142 signed/failed S/MIME signed message, but the signature failed to 143 verify. This might be a policy related decision (message signer 144 doesn't match the From header field), message was modified, the 145 signer's certificate has expired or was revoked, etc. 147 The "smimeStatusAtDelivery" response property has the same syntax as 148 "smimeStatus", but calculated at the "receivedAt" date/time. Unlike 149 "smimeStatus", the "smimeStatusAtDelivery" response property value is 150 immutable. "smimeStatusAtDelivery" allows clients to compare S/MIME 151 signature verification status at delivery with the current status as 152 returned by "smimeStatus", for example it helps to answer questions 153 like "was the signature valid at the time of delivery?". 155 The "smimeErrors" response property is defined as follows: 157 smimeErrors: "String[]|null". null signifies that the message doesn't 158 contain any signature or that there were no errors when verifying 159 S/MIME signature. (I.e. this property is non null only when the 160 corresponding "smimeStatus" response property value is "signed/ 161 failed".) Each string in the array is a human readable description 162 (in the language specified in Content-Language header field, if any) 163 of a problem with the signature or the signing certificate. (See 164 Section 3.8 of [RFC8620] in regards to how this is affected by the 165 language selection.) For example, the signing certificate might be 166 expired and the message From email address might not correspond to 167 any of the email addresses in the signing certificate. Or the 168 certificate might be expired and the JMAP server might be unable to 169 retrieve CRL for the certificate. In both of these cases there would 170 be 2 elements in the array. 172 The "smimeVerifiedAt" response property is defined as follows: 174 smimeVerifiedAt: "UTCDate|null" (server-set). null signifies that the 175 message doesn't contain any S/MIME signature or that there is a 176 signature, but there was no attempt to verify it. In all other cases 177 it is set to the date and time of when S/MIME signature was most 178 recently verified. Note that a request to fetch "smimeStatus" and/or 179 "smimeErrors" would force this response property to be set to a non 180 null value, if S/MIME signature exists. 182 "smimeStatus" and "smimeErrors" values are calculated at the time the 183 corresponding JMAP request was processed (but see below about result 184 caching), not at the time when the message was generated (according 185 to it's Date header field value). In all cases "smimeVerifiedAt" is 186 set to time when "smimeStatus" and "smimeErrors" were last updated. 188 As recalculating these values is expensive for the server they MAY be 189 cached for up to 10 minutes from the moment when they were 190 calculated. 192 ["Email/get", { 193 "ids": [ "f123u987" ], 194 "properties": [ "mailboxIds", "from", "subject", "date", 195 "smimeStatusAtDelivery", "receivedAt" ] 196 }, "#1"] 198 This will result in the following response: 200 [["Email/get", { 201 "accountId": "abc", 202 "state": "41234123231", 203 "list": [ 204 { 205 "id": "f123u457", 206 "mailboxIds": { "f123": true }, 207 "from": [{"name": "Joe Bloggs", "email": "joe@bloggs.example.net"}], 208 "subject": "Dinner tonight?", 209 "date": "2020-07-07T14:12:00Z", 210 "smimeStatusAtDelivery": "signed/verified", 211 "receivedAt": "2020-07-07T14:15:18Z" 212 } 213 ] 214 }, "#1"]] 216 Example 1: 218 ["Email/get", { 219 "ids": [ "af123u123" ], 220 "properties": [ "mailboxIds", "from", "subject", "date", 221 "smimeStatus", "smimeErrors", "smimeVerifiedAt" ] 222 }, "#1"] 224 This will result in the following response: 226 [["Email/get", { 227 "accountId": "abc", 228 "state": "41234123231", 229 "list": [ 230 { 231 "id": "af123u123", 232 "mailboxIds": { "f123": true }, 233 "from": [{"name": "Jane Doe", 234 "email": "jdoe@example.com"}], 235 "subject": "Company takeover", 236 "date": "2020-01-31T23:00:00Z", 237 "smimeStatus": "signed/failed", 238 "smimeErrors": [ 239 "From email address doesn't match the certificate", 240 "Can't retrieve CRL from the CRL URL"], 241 "smimeVerifiedAt": "2020-03-01T12:11:19Z" 242 } 243 ] 244 }, "#1"]] 246 Example 2: 248 [RFC8621] defines Email/query method for searching for messages with 249 specific properties. This document defines the following properties 250 of the *FilterCondition* object: 252 *hasSmime*: "Boolean". If "hasSmime" has the value true, only 253 messages with "smimeStatus" other than null match the condition. 254 If "hasSmime" has the value false, only messages with 255 "smimeStatus" equal to null match the condition. 257 *hasVerifiedSmime*: "Boolean". If "hasVerifiedSmime" has the 258 value true, only messages with "smimeStatus" equal to "signed/ 259 verified" match the condition. If "hasVerifiedSmime" has the 260 value false, only messages with "smimeStatus" not equal to 261 "signed/verified" (including the value null) match the condition. 263 5. IANA Considerations 265 5.1. JMAP capability registration for "smimeverify" 267 IANA is requested to register the "smime" JMAP Capability as follows: 269 Capability Name: "urn:ietf:params:jmap:smimeverify" 271 Specification document: this document 273 Intended use: common 275 Change Controller: IETF 277 Security and privacy considerations: this document, Section 6 279 6. Security Considerations 281 Server side S/MIME signature verification requires the client to 282 trust server verification code and configuration to perform S/MIME 283 signature verification. For example, if the server is not configured 284 with some Trust Anchors, some messages will have "signed/failed" 285 status instead of "signed/verified". 287 Constant recalculation of S/MIME signature status can result in 288 Denial-of-Service condition. For that reason it is RECOMMENDED to 289 cache results of signature verification for 10 minutes. 291 7. Normative References 293 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 294 Requirement Levels", BCP 14, RFC 2119, 295 DOI 10.17487/RFC2119, March 1997, 296 . 298 [RFC8550] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ 299 Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 300 Certificate Handling", RFC 8550, DOI 10.17487/RFC8550, 301 April 2019, . 303 [RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ 304 Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 305 Message Specification", RFC 8551, DOI 10.17487/RFC8551, 306 April 2019, . 308 [RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application 309 Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July 310 2019, . 312 [RFC8621] Jenkins, N. and C. Newman, "The JSON Meta Application 313 Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621, 314 August 2019, . 316 Author's Address 318 Alexey Melnikov 319 Isode Ltd 320 14 Castle Mews 321 Hampton, Middlesex TW12 2NP 322 UK 324 EMail: Alexey.Melnikov@isode.com