idnits 2.17.1 draft-melnikov-authentication-results-smime-06.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 are 16 instances of too long lines in the document, the longest one being 2 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 (November 12, 2013) is 3818 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'RFC5083' is defined on line 333, but no explicit reference was found in the text ** Obsolete normative reference: RFC 3501 (Obsoleted by RFC 9051) ** Obsolete normative reference: RFC 7001 (Obsoleted by RFC 7601) ** Obsolete normative reference: RFC 5751 (Obsoleted by RFC 8551) Summary: 4 errors (**), 0 flaws (~~), 2 warnings (==), 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: Informational November 12, 2013 5 Expires: May 16, 2014 7 Authentication-Results Registration for S/MIME signature verification 8 draft-melnikov-authentication-results-smime-06 10 Abstract 12 RFC 7001 specifies the Authentication-Results header field for 13 conveying results of message authentication checks. This document 14 defines a new authentication method to be used in the Authentication- 15 Results header field for S/MIME related signature checks. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on May 16, 2014. 34 Copyright Notice 36 Copyright (c) 2013 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 53 3. "smime" Authentication Method . . . . . . . . . . . . . . . . 2 54 3.1. S/MIME Results . . . . . . . . . . . . . . . . . . . . . 2 55 3.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 3 56 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 57 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 58 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 59 6.1. Normative References . . . . . . . . . . . . . . . . . . 7 60 6.2. Informative References . . . . . . . . . . . . . . . . . 8 61 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 8 63 1. Introduction 65 [RFC7001] specifies the Authentication-Results header field for 66 conveying results of message authentication checks. As S/MIME 67 signature verification (and alteration) is sometimes implemented in 68 border message transfer agents, guards and gateways (for example see 69 [RFC3183]), there is a need to convey signature verification status 70 to Mail User Agents (MUA) and downstream filters. This document 71 defines a new authentication method to be used in the Authentication- 72 Results header field for S/MIME related signature checks. 74 2. Conventions Used in This Document 76 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 77 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 78 document are to be interpreted as described in [RFC2119]. 80 The formal syntax uses the Augmented Backus-Naur Form (ABNF) 81 [RFC5234] notation including the core rules defined in Appendix B of 82 RFC 5234 [RFC5234]. 84 3. "smime" Authentication Method 86 S/MIME signature and countersignature verification is represented by 87 the "smime" method and is defined in [RFC5751]. 89 3.1. S/MIME Results 91 The result values used by S/MIME [RFC5751] are as follows: 93 +-------------+-----------------------------------------------------+ 94 | Result code | Meaning | 95 +-------------+-----------------------------------------------------+ 96 | none | The message was not signed. | 97 | | | 98 | pass | The message was signed, the signature or signatures | 99 | | were acceptable to the verifier, and the | 100 | | signature(s) passed verification tests. | 101 | | | 102 | fail | The message was signed and the signature or | 103 | | signatures were acceptable to the verifier, but | 104 | | they failed the verification test(s). | 105 | | | 106 | policy | The message was signed, signature(s) passed | 107 | | verification tests, but the signature or signatures | 108 | | were not acceptable to the verifier. | 109 | | | 110 | neutral | The message was signed but the signature or | 111 | | signatures contained syntax errors or were not | 112 | | otherwise able to be processed. This result SHOULD | 113 | | also be used for other failures not covered | 114 | | elsewhere in this list. | 115 | | | 116 | temperror | The message could not be verified due to some error | 117 | | that is likely transient in nature, such as a | 118 | | temporary inability to retrieve a certificate or | 119 | | CRL. A later attempt may produce a final result. | 120 | | | 121 | permerror | The message could not be verified due to some error | 122 | | that is unrecoverable, such as a required header | 123 | | field being absent or the signer's certificate not | 124 | | being available. A later attempt is unlikely to | 125 | | produce a final result. | 126 +-------------+-----------------------------------------------------+ 128 A signature is "acceptable to the verifier" if it passes local policy 129 checks (or there are no specific local policy checks). For example, 130 a verifier might require that the domain in the rfc822Name 131 subjectAltName in the signing certificate matches the domain in the 132 address of the sender of the message, thus making third-party 133 signatures unacceptable. [RFC5751] advises that if a message fails 134 verification, it should be treated as an unsigned message. A report 135 of "fail" here permits the receiver of the report to decide how to 136 handle the failure. A report of "neutral" or "none" preempts that 137 choice, ensuring the message will be treated as if it had not been 138 signed. 140 3.2. Examples 142 Return-Path: 143 Authentication-Results: example.net; 144 smime=fail (certificate is revoked by CRL) 145 body.smime-identifier=aliceDss@example.com 146 body.smime-part=2 147 Received: from ietfa.example.com (localhost [IPv6:::1]) 148 by ietfa.example.com (Postfix) with ESMTP id 2875111E81A0; 149 Fri, 06 Sep 2002 00:35:14 -0700 (PDT) 150 MIME-Version: 1.0 151 To: User2@example.com 152 From: aliceDss@example.com 153 Subject: Example 4.8 154 Message-Id: <020906002550300.249@example.com> 155 Date: Fri, 06 Sep 2002 00:25:21 -0700 156 Content-Type: multipart/signed; 157 micalg=SHA1; 158 boundary="----=_NextBoundry____Fri,_06_Sep_2002_00:25:21"; 159 protocol="application/pkcs7-signature" 161 This is a multi-part message in MIME format. 163 ------=_NextBoundry____Fri,_06_Sep_2002_00:25:21 165 This is some sample content. 166 ------=_NextBoundry____Fri,_06_Sep_2002_00:25:21 167 Content-Type: application/pkcs7-signature; name=smime.p7s 168 Content-Transfer-Encoding: base64 169 Content-Disposition: attachment; filename=smime.p7s 171 MIIDdwYJKoZIhvcNAQcCoIIDaDCCA2QCAQExCTAHBgUrDgMCGjALBgkqhkiG9w0BBwGgggL 172 gMIIC3DCCApugAwIBAgICAMgwCQYHKoZIzjgEAzASMRAwDgYDVQQDEwdDYXJsRFNTMB4XDT 173 k5MDgxNzAxMTA0OVoXDTM5MTIzMTIzNTk1OVowEzERMA8GA1UEAxMIQWxpY2VEU1MwggG2M 174 IIBKwYHKoZIzjgEATCCAR4CgYEAgY3N7YPqCp45PsJIKKPkR5PdDteoDuxTxauECE//lOFz 175 SH4M1vNESNH+n6+koYkv4dkwyDbeP5u/t0zcX2mK5HXQNwyRCJWb3qde+fz0ny/dQ6iLVPE 176 /sAcIR01diMPDtbPjVQh11Tl2EMR4vf+dsISXN/LkURu15AmWXPN+W9sCFQDiR6YaRWa4E8 177 baj7g3IStii/eTzQKBgCY40BSJMqo5+z5t2UtZakx2IzkEAjVc8ssaMMMeUF3dm1nizaoFP 178 VjAe6I2uG4Hr32KQiWn9HXPSgheSz6Q+G3qnMkhijt2FOnOLl2jB80jhbgvMAF8bUmJEYk2 179 RL34yJVKU1a14vlz7BphNh8Rf8K97dFQ/5h0wtGBSmA5ujY5A4GEAAKBgFzjuVp1FJYLqXr 180 d4z+p7Kxe3L23ExE0phaJKBEj2TSGZ3V1ExI9Q1tv5VG/+onyohs+JH09B41bY8i7RaWgSu 181 OF1s4GgD/oI34a8iSrUxq4Jw0e7wi/ZhSAXGKsZfoVi/G7NNTSljf2YUeyxDKE8H5BQP1Gp 182 2NOM/Kl4vTyg+W4o4GBMH8wDAYDVR0TAQH/BAIwADAOBgNVHQ8BAf8EBAMCBsAwHwYDVR0j 183 BBgwFoAUcEQ+gi5vh95K03XjPSC8QyuT8R8wHQYDVR0OBBYEFL5sobPjwfftQ3CkzhMB4v3 184 jl/7NMB8GA1UdEQQYMBaBFEFsaWNlRFNTQGV4YW1wbGUuY29tMAkGByqGSM44BAMDMAAwLQ 185 IUVQykGR9CK4lxIjONg2q1PWdrv0UCFQCfYVNSVAtcst3a53Yd4hBSW0NevTFjMGECAQEwG 186 DASMRAwDgYDVQQDEwdDYXJsRFNTAgIAyDAHBgUrDgMCGjAJBgcqhkjOOAQDBC4wLAIUM/mG 187 f6gkgp9Z0XtRdGimJeB/BxUCFGFFJqwYRt1WYcIOQoGiaowqGzVI 189 ------=_NextBoundry____Fri,_06_Sep_2002_00:25:21-- 191 4. IANA Considerations 193 IANA is requested to add the the following entries to the "Email 194 Authentication Methods" subregistry of the "Email Authentication 195 Parameters" registry: 197 +--------+---------+-------+---------------+------------------------+ 198 | Method | Defined | ptype | property | value | 199 +--------+---------+-------+---------------+------------------------+ 200 | smime | [RFC575 | body | smime-part | The MIME body part | 201 | | 1] | | | reference which | 202 | | | | | contains the | 203 | | | | | signature. Syntax of | 204 | | | | | this property is | 205 | | | | | described by the | 206 | | | | | smime-part ABNF | 207 | | | | | production below. app | 208 | | | | | lication/pkcs7-signatu | 209 | | | | | re or | 210 | | | | | application/pkcs7-mime | 211 | | | | | (containing | 212 | | | | | SignedData) media type | 213 | | | | | body parts are | 214 | | | | | references using the | 215 | | | | |
syntax (see | 216 | | | | | Section 6.4.5 of | 217 | | | | | [RFC3501]). If the | 218 | | | | | signature being | 219 | | | | | verified is | 220 | | | | | encapsulated by | 221 | | | | | another CMS content | 222 | | | | | type (e.g. | 223 | | | | | application/pkcs7-mime | 224 | | | | | containing | 225 | | | | | EnvelopedData, which | 226 | | | | | contains SignedData), | 227 | | | | | such inner signature | 228 | | | | | body part can be | 229 | | | | | references using | 230 | | | | | "section[/section..." | 231 | | | | | syntax. | 232 | | | | | | 233 | smime | [RFC575 | body | smime- | The email address | 234 | | 1] | | identifier | [RFC5322] associated | 235 | | | | | with the S/MIME | 236 | | | | | signature. The email | 237 | | | | | address can be | 238 | | | | | specified explicitly | 239 | | | | | or derived from the | 240 | | | | | identity of the | 241 | | | | | signer. Note that | 242 | | | | | this email address can | 243 | | | | | correspond to a | 244 | | | | | counter signature. | 245 +--------+---------+-------+---------------+------------------------+ 247 smime-part = section ["/" smime-subpart] 248 smime-subpart = smime-part 249 section = 251 IANA is requested to add the the following entries to the "Email 252 Authentication Result Names" subregistry of the "Email Authentication 253 Parameters" registry: 255 +-------------+--------------+------------+---------------+---------+ 256 | Code | Defined | Auth | Meaning | Status | 257 | | | Method | | | 258 +-------------+--------------+------------+---------------+---------+ 259 | none | this | smime | [this memo] | active | 260 | | document | | Section 3.1 | | 261 | | | | | | 262 | pass | this | smime | [this memo] | active | 263 | | document | | Section 3.1 | | 264 | | | | | | 265 | fail | this | smime | [this memo] | active | 266 | | document | | Section 3.1 | | 267 | | | | | | 268 | policy | this | smime | [this memo] | active | 269 | | document | | Section 3.1 | | 270 | | | | | | 271 | neutral | this | smime | [this memo] | active | 272 | | document | | Section 3.1 | | 273 | | | | | | 274 | temperror | this | smime | [this memo] | active | 275 | | document | | Section 3.1 | | 276 | | | | | | 277 | permerror | this | smime | [this memo] | active | 278 | | document | | Section 3.1 | | 279 +-------------+--------------+------------+---------------+---------+ 281 5. Security Considerations 282 This document doesn't add new security considerations not already 283 covered by [RFC7001] and [RFC5751]. In particular security 284 considerations related to use of weak cryptography over plaintext, 285 weakening and breaking of cryptographic algorithms over time, as well 286 as changing the behavior of message processing based on presence of a 287 signature specified in [RFC5751] are relevant to this document. 288 Similarly, the following security considerations specified in 289 [RFC7001] are particularly relevant to this document: Forged Header 290 Fields, Misleading Results, Internal MTA Lists and Compromised 291 Internal Hosts. 293 Note that agents adding Authentication-Results header fields 294 containing S/MIME Authentication Method might be unable to verify 295 S/MIME signatures inside encrypted CMS content types such as 296 EnvelopedData [RFC5652] . So agents processing Authentication- 297 Results header fields shouldn't treat lack of an Authentication- 298 Results header field with S/MIME Authentication Method as an 299 indication that the corresponding S/MIME signature is missing or 300 invalid. 302 6. References 304 6.1. Normative References 306 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 307 Requirement Levels", BCP 14, RFC 2119, March 1997. 309 [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 310 4rev1", RFC 3501, March 2003. 312 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 313 Specifications: ABNF", STD 68, RFC 5234, January 2008. 315 [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, 316 October 2008. 318 [RFC7001] Kucherawy, M., "Message Header Field for Indicating 319 Message Authentication Status", RFC 7001, September 2013. 321 [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet 322 Mail Extensions (S/MIME) Version 3.2 Message 323 Specification", RFC 5751, January 2010. 325 6.2. Informative References 327 [RFC3183] Dean, T. and W. Ottaway, "Domain Security Services using S 328 /MIME", RFC 3183, October 2001. 330 [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, 331 RFC 5652, September 2009. 333 [RFC5083] Housley, R., "Cryptographic Message Syntax (CMS) 334 Authenticated-Enveloped-Data Content Type", RFC 5083, 335 November 2007. 337 Appendix A. Acknowledgements 339 Thank you to Murray S. Kucherawy, David Wilson, Jim Schaad, SM and 340 Steve Kille for comments and corrections on this document. 342 Author's Address 344 Alexey Melnikov 345 Isode Ltd 346 5 Castle Business Village 347 36 Station Road 348 Hampton, Middlesex TW12 2BX 349 UK 351 EMail: Alexey.Melnikov@isode.com