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.
Status of This Memo
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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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