Network Working Group A. Melnikov Internet-Draft Isode Ltd Intended status: Standards Track March 13, 2013 Expires: September 14, 2013 Authentication-Results Registration for S/MIME signature verification draft-melnikov-authentication-results-smime-00 Abstract RFC 5451 specifies the Authentication-Results header field for conveying results of message authentication checks. This document defines a new authentication method to be used in the Authentication- Results header field for S/MIME related signature checks. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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Melnikov Expires September 14, 2013 [Page 1] Internet-DrafAuthentication-Results Registration for S/MIME March 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 3. "smime" Authentication Method . . . . . . . . . . . . . . . . 2 3.1. S/MIME Results . . . . . . . . . . . . . . . . . . . . . 2 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Normative References . . . . . . . . . . . . . . . . . . . . 5 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction [RFC5451] specifies the Authentication-Results header field for conveying results of message authentication checks. This document defines a new authentication method to be used in the Authentication- Results header field for S/MIME related signature checks. [[Explain in more details use cases, such as a border MTA performing check and MUA showing results.]] 2. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The formal syntax uses the Augmented Backus-Naur Form (ABNF) [RFC5234] notation including the core rules defined in Appendix B of RFC 5234 [RFC5234]. 3. "smime" Authentication Method 3.1. S/MIME Results The result values used by [RFC5751] are as follows: +-------------+-----------------------------------------------------+ | Result code | Meaning | +-------------+-----------------------------------------------------+ | none | The message was not signed. | | | | | pass | The message was signed, the signature or signatures | | | were acceptable to the verifier, and the | | | signature(s) passed verification tests. | | | | | fail | The message was signed and the signature or | Melnikov Expires September 14, 2013 [Page 2] Internet-DrafAuthentication-Results Registration for S/MIME March 2013 | | signatures were acceptable to the verifier, but | | | they failed the verification test(s). | | | | | policy | The message was signed but the signature or | | | signatures were not acceptable to the verifier. | | | | | neutral | The message was signed but the signature or | | | signatures contained syntax errors or were not | | | otherwise able to be processed. This result SHOULD | | | also be used for other failures not covered | | | elsewhere in this list. | | | | | temperror | The message could not be verified due to some error | | | that is likely transient in nature, such as a | | | temporary inability to retrieve a public key. A | | | later attempt may produce a final result. | | | | | permerror | The message could not be verified due to some error | | | that is unrecoverable, such as a required header | | | field being absent. A later attempt is unlikely to | | | produce a final result. | +-------------+-----------------------------------------------------+ A signature is "acceptable to the verifier" if it passes local policy checks (or there are no specific local policy checks). For example, a verifier might require that the signature(s) on the message be added using the DNS domain present in the From: header field of the message, thus making third-party signatures unacceptable. [RFC5751] advises that if a message fails verification, it should be treated as an unsigned message. A report of "fail" here permits the receiver of the report to decide how to handle the failure. A report of "neutral" or "none" preempts that choice, ensuring the message will be treated as if it had not been signed. 4. IANA Considerations IANA is requested to add the the following entries to the "Email Authentication Methods" subregistry of the "Email Authentication Parameters" registry: +--------+-----------+--------+------------------+------------------+ | Method | Defined | ptype | property | value | +--------+-----------+--------+------------------+------------------+ | smime | [RFC5751] | body | smime-part | The MIME body | | | | | | part reference | | | | | | which contains | | | | | | the signature. | Melnikov Expires September 14, 2013 [Page 3] Internet-DrafAuthentication-Results Registration for S/MIME March 2013 | | | | | See definition | | | | | | of
in | | | | | | Section 6.4.5 of | | | | | | [RFC3501] | | | | | | | | smime | [RFC5751] | body | smime-identifier | The email | | | | | | address | | | | | | [RFC5322] | | | | | | associated with | | | | | | the S/MIME | | | | | | signature. | +--------+-----------+--------+------------------+------------------+ IANA is requested to add the the following entries to the "Email Authentication Result Names" subregistry of the "Email Authentication Parameters" registry: +-------------+--------------+------------+---------------+---------+ | Code | Defined | Auth | Meaning | Status | | | | Method | | | +-------------+--------------+------------+---------------+---------+ | none | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | pass | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | fail | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | policy | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | neutral | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | temperror | this | smime | [this memo] | active | | | document | | Section 3.1 | | | | | | | | | permerror | this | smime | [this memo] | active | | | document | | Section 3.1 | | +-------------+--------------+------------+---------------+---------+ 5. Security Considerations TBD Melnikov Expires September 14, 2013 [Page 4] Internet-DrafAuthentication-Results Registration for S/MIME March 2013 6. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, March 2003. [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, October 2008. [RFC5451] Kucherawy, M., "Message Header Field for Indicating Message Authentication Status", RFC 5451, April 2009. [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Message Specification", RFC 5751, January 2010. Appendix A. Acknowledgements Thank you to Murray S. Kucherawy for comments and corrections on this document. Author's Address Alexey Melnikov Isode Ltd 5 Castle Business Village 36 Station Road Hampton, Middlesex TW12 2BX UK EMail: Alexey.Melnikov@isode.com Melnikov Expires September 14, 2013 [Page 5]