Network Working Group                                        A. Melnikov
Internet-Draft                                                 Isode Ltd
Intended status: Informational                              July 8, 2019
Expires: January 9, 2020


          Extensions to JMAP for S/MIME signature verification
                        draft-ietf-jmap-smime-00

Abstract

   This document specifies extension to JMAP for returning S/MIME
   signature verification status.

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   This Internet-Draft will expire on January 9, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   2
   3.  Addition to the capabilities object . . . . . . . . . . . . .   2
   4.  Extension to Email/get for S/MIME signature verification  . .   2
   5.  Open Issues . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  JMAP capability registration for "smime"  . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   [I-D.ietf-jmap-mail] is a JSON based application protocol for
   synchronising email data between a client and a server.

   This document describes an extension to JMAP for returning S/MIME
   [RFC8551] signature verification status, without requiring a JMAP
   client to download the signature and all signed body parts or to
   download and decode CMS.

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].

3.  Addition to the capabilities object

   The capabilities object is returned as part of the standard JMAP
   Session object; see the JMAP spec.  Servers supporting _this_
   specification MUST add a property called "urn:ietf:params:jmap:smime"
   to the capabilities object.

   The value of this property is an empty object in both the JMAP
   session _capabilities_ property and an account's
   _accountCapabilities_ property.

4.  Extension to Email/get for S/MIME signature verification

   [I-D.ietf-jmap-mail] defines Email/get method for retrieving message
   specific information.  This document defines the following pseudo
   values in the _properties_ argument:
   o *smimeStatus*: If "smimeStatus" is included in the list of
   requested properties, it MUST be interpreted by the server as a
   request to return "smimeStatus" property.



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   The "smimeStatus" response property is defined as follows:

   *smimeStatus*: "String|null". null signifies that the message doesn't
   contain any signature.  Possible string values of the property are
   listed below.  Servers MAY return other values not defined below.
   Client MUST treat unrecognized values as "unknown":

   unknown  S/MIME message, but it is neither signed, nor encrypted.
      This can also be returned for a multipart/signed message which
      contains unrecognized signing protocol (for example OpenPGP).

   signed  S/MIME signed message, but the signature was not yet
      verified.  Some servers might not attempt to verify signature
      until a particular message is requested by the client.

   signed/verified  S/MIME signed message and the sender's signature was
      successfully verified, sender matches the From header field and
      the sender's certificate (and the certificate chain) is trusted
      for signing.

   signed/failed  S/MIME signed message, but the signature failed to
      verify.  This might be a policy related decision (message signer
      doesn't match the From header field), message was modified, the
      signer's certificate has expired or was revoked, etc.



























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      ["Email/get", {
      "ids": [ "f123u987" ],
      "properties": [ "mailboxIds", "from", "subject", "date", "smimeStatus" ]
      }, "#1"]

This will result in the following response:

      [["Email/get", {
         "accountId": "abc",
         "state": "41234123231",
         "list": [
           {
             id: "f123u457",
             mailboxIds: { "f123": true },
             from: [{name: "Joe Bloggs", email: "joe@bloggs.com"}],
             subject: "Dinner on Thursday?",
             date: "2013-10-13T14:12:00Z",
             smimeStatus: "signed/verified"
           }
         ]
      }, "#1"]]

                                  Example

5.  Open Issues

   [[This section should be empty before publication]]

6.  IANA Considerations

6.1.  JMAP capability registration for "smime"

   IANA is requested to register the "smime" JMAP Capability as follows:

   Capability Name: "urn:ietf:params:jmap:smime"

   Specification document: this document

   Intended use: common

   Change Controller: IETF

   Security and privacy considerations: this document, Section 7








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7.  Security Considerations

   Server side S/MIME signature verification requires the client to
   trust server verification code and configuration to perform S/MIME
   signature verification.  For example, if the server is not configured
   with some Trust Anchors, some messages will have "signed/failed"
   status instead of "signed/verified".

   TBD.

8.  Normative References

   [I-D.ietf-jmap-core]
              Jenkins, N. and C. Newman, "JSON Meta Application
              Protocol", draft-ietf-jmap-core-17 (work in progress),
              March 2019.

   [I-D.ietf-jmap-mail]
              Jenkins, N. and C. Newman, "JMAP (JSON Meta Application
              Protocol) for Mail", draft-ietf-jmap-mail-16 (work in
              progress), March 2019.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8551]  Schaad, J., Ramsdell, B., and S. Turner, "Secure/
              Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
              Message Specification", RFC 8551, DOI 10.17487/RFC8551,
              April 2019, <https://www.rfc-editor.org/info/rfc8551>.

Author's Address

   Alexey Melnikov
   Isode Ltd
   14 Castle Mews
   Hampton, Middlesex  TW12 2NP
   UK

   EMail: Alexey.Melnikov@isode.com










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