rfc9219.original   rfc9219.txt 
Network Working Group A. Melnikov Internet Engineering Task Force (IETF) A. Melnikov
Internet-Draft Isode Ltd Request for Comments: 9219 Isode Ltd
Intended status: Standards Track 6 January 2022 Category: Standards Track March 2022
Expires: 10 July 2022 ISSN: 2070-1721
S/MIME signature verification extension to JMAP S/MIME Signature Verification Extension to the JSON Meta Application
draft-ietf-jmap-smime-12 Protocol (JMAP)
Abstract Abstract
This document specifies an extension to JMAP for Mail (RFC 8621) for This document specifies an extension to "The JSON Meta Application
returning S/MIME signature verification status. Protocol (JMAP) for Mail" (RFC 8621) for returning the S/MIME
signature verification status.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
2. Conventions Used in This Document . . . . . . . . . . . . . . 2 2. Conventions Used in This Document
3. Addition to the capabilities object . . . . . . . . . . . . . 3 3. Addition to the Capabilities Object
4. Extension for S/MIME signature verification . . . . . . . . . 3 4. Extension for S/MIME Signature Verification
4.1. Extension to Email/get . . . . . . . . . . . . . . . . . 3 4.1. Extension to Email/get
4.1.1. "smimeStatus" response property extensibility . . . . 7 4.1.1. "smimeStatus" Response Property Extensibility
4.2. Extension to Email/query . . . . . . . . . . . . . . . . 8 4.2. Extension to Email/query
4.3. Interaction with Email/changes . . . . . . . . . . . . . 8 4.3. Interaction with Email/changes
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations
5.1. JMAP capability registration for "smimeverify" . . . . . 9 5.1. JMAP Capability Registration for "smimeverify"
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. References
7.1. Normative References . . . . . . . . . . . . . . . . . . 10 7.1. Normative References
7.2. Informative References . . . . . . . . . . . . . . . . . 10 7.2. Informative References
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 10 Acknowledgements
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10 Author's Address
1. Introduction 1. Introduction
JMAP for Mail [RFC8621] is a JSON-based application protocol for JMAP for Mail [RFC8621] is a JSON-based application protocol for
synchronising email data between a client and a server. synchronizing email data between a client and a server.
This document describes an extension to JMAP for returning S/MIME This document describes an extension to JMAP for returning the S/MIME
[RFC8551] signature verification status, without requiring a JMAP signature verification status [RFC8551], without requiring a JMAP
client to download the signature body part and all signed body parts client to download the signature body part and all signed body parts
(when the multipart/signed media type [RFC1847] is used) or to (when the multipart/signed media type [RFC1847] is used) or to
download and decode CMS (when the application/pkcs7-mime media type download and decode the Cryptographic Message Syntax (CMS) (when the
(Section 3.2 of [RFC8551]) is used). The use of the extension application/pkcs7-mime media type (Section 3.2 of [RFC8551]) is
implies the client trusts the JMAP server's S/MIME signature used). The use of the extension implies the client trusts the JMAP
verification code and configuration. This extension is suitable for server's S/MIME signature verification code and configuration. This
cases where reduction in network bandwidth and client-side code extension is suitable for cases where reduction in network bandwidth
complexity outweigh security concerns about trusting the JMAP server and client-side code complexity outweigh security concerns about
to perform S/MIME signature verifications. One possible use case is trusting the JMAP server to perform S/MIME signature verifications.
when the same organization controls both the JMAP server and the JMAP One possible use case is when the same organization controls both the
client. JMAP server and the JMAP client.
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Type signatures, examples, and property descriptions in this document Type signatures, examples, and property descriptions in this document
follow the conventions established in Section 1.1 of [RFC8620]. Data follow the conventions established in Section 1.1 of [RFC8620]. Data
types defined in the core specification are also used in this types defined in the core specification are also used in this
document. document.
3. Addition to the capabilities object 3. Addition to the Capabilities Object
The capabilities object is returned as part of the standard JMAP The *capabilities* object is returned as part of the standard JMAP
Session object; see Section 2 of [RFC8620]. Servers supporting Session object; see Section 2 of [RFC8620]. Servers supporting this
_this_ specification MUST add a property called specification MUST add a property called
"urn:ietf:params:jmap:smimeverify" to the capabilities object. "urn:ietf:params:jmap:smimeverify" to the capabilities object.
The value of this property is an empty object in both the JMAP The value of this property is an empty object in both the JMAP
session _capabilities_ property and an account's Session _capabilities_ property and an account's
_accountCapabilities_ property. _accountCapabilities_ property.
4. Extension for S/MIME signature verification 4. Extension for S/MIME Signature Verification
4.1. Extension to Email/get 4.1. Extension to Email/get
[RFC8621] defines the Email/get method for retrieving message [RFC8621] defines the Email/get method for retrieving message-
specific information. This document defines the following pseudo specific information. This document defines the following pseudo
values in the _properties_ argument: values in the _properties_ argument:
* *smimeStatus*: If "smimeStatus" is included in the list of *smimeStatus*:
requested properties, it MUST be interpreted by the server as a If "smimeStatus" is included in the list of requested properties,
request to return the "smimeStatus" response property. it MUST be interpreted by the server as a request to return the
"smimeStatus" response property.
* *smimeStatusAtDelivery*: If "smimeStatusAtDelivery" is included in *smimeStatusAtDelivery*:
the list of requested properties, it MUST be interpreted by the If "smimeStatusAtDelivery" is included in the list of requested
server as a request to return the "smimeStatusAtDelivery" response properties, it MUST be interpreted by the server as a request to
property. (It is effectively the same as the "smimeStatus" value return the "smimeStatusAtDelivery" response property. (It is
calculated at the date/time of delivery, as specified by effectively the same as the "smimeStatus" value calculated at the
"receivedAt".) date/time of delivery, as specified by "receivedAt".)
* *smimeErrors*: If "smimeErrors" is included in the list of *smimeErrors*:
requested properties, it MUST be interpreted by the server as a If "smimeErrors" is included in the list of requested properties,
request to return the "smimeErrors" response property. it MUST be interpreted by the server as a request to return the
"smimeErrors" response property.
* *smimeVerifiedAt*: If "smimeVerifiedAt" is included in the list of *smimeVerifiedAt*:
requested properties, it MUST be interpreted by the server as a If "smimeVerifiedAt" is included in the list of requested
request to return the "smimeVerifiedAt" response property. properties, it MUST be interpreted by the server as a request to
return the "smimeVerifiedAt" response property.
The "smimeStatus" response property is defined as follows: The "smimeStatus" response property is defined as follows:
smimeStatus: "String|null" (server-set). null signifies that the *smimeStatus*:
message doesn't contain any signature. Otherwise, this property "String|null" (server-set). null signifies that the message
contains the S/MIME signature and certificate verification status doesn't contain any signature. Otherwise, this property contains
calculated according to [RFC8551] and [RFC8550]. Possible string the S/MIME signature and certificate verification status
values of the property are listed below. Servers MAY return other calculated according to [RFC8551], [RFC8550], and [RFC5280].
values not defined below, as defined in extensions to this document. Possible string values of the property are listed below. Servers
Clients MUST treat unrecognized values as "unknown" or "signed/ MAY return other values not defined below, as defined in
failed". Note that the value of this property might change over extensions to this document. Clients MUST treat unrecognized
time. values as "unknown" or "signed/failed". Note that the value of
this property might change over time.
unknown: S/MIME message, but it was neither signed nor encrypted. unknown:
This can also be returned for a multipart/signed message which An S/MIME message, but it was neither signed nor encrypted.
contains an unrecognized signing protocol (for example OpenPGP). This can also be returned for a multipart/signed message that
contains an unrecognized signing protocol (for example,
OpenPGP).
signed: S/MIME signed message, but the signature was not yet signed:
verified. Some servers might not attempt to verify a signature An S/MIME signed message, but the signature was not yet
until a particular message is requested by the client. (This is a verified. Some servers might not attempt to verify a signature
useful optimization for a JMAP server to avoid doing work until until a particular message is requested by the client. (This
exact information is needed. A JMAP client that only needs to is a useful optimization for a JMAP server to avoid doing work
display an icon that signifies presence of an S/MIME signature can until exact information is needed. A JMAP client that only
still use this value.) JMAP servers compliant with this document needs to display an icon that signifies presence of an S/MIME
SHOULD attempt signature verification and return "signed/verified" signature can still use this value.) JMAP servers compliant
or "signed/failed" instead of this signature status. with this document SHOULD attempt signature verification and
return "signed/verified" or "signed/failed" instead of this
signature status.
signed/verified: S/MIME signed message and the sender's signature signed/verified:
was successfully verified according to [RFC8551] and [RFC8550]. An S/MIME signed message, and the sender's signature was
Additionally the signer email address extracted from the S/MIME successfully verified according to [RFC8551] and [RFC8550].
certificate matches the From header field value, and the signer Additionally, the signer email address extracted from the S/
certificate SHOULD be checked for revocation. MIME certificate matches the From header field value, and the
signer certificate SHOULD be checked for revocation.
signed/failed: S/MIME signed message, but the signature failed to signed/failed:
verify according to [RFC8551] and [RFC8550]. This might be a S/MIME signed message, but the signature failed to verify
policy related decision (e.g. the message signer email address according to [RFC8551] and [RFC8550]. This might be because of
doesn't match the From header field value), message was modified, a policy-related decision (e.g., the message signer email
the signer's certificate has expired or was revoked, etc. address doesn't match the From header field value), the message
was modified, the signer's certificate has expired or was
revoked, etc.
encrypted+signed/verified: This value is reserved for future use. encrypted+signed/verified:
It is typically handled in the same way as "signed/verified". This value is reserved for future use. It is typically handled
in the same way as "signed/verified".
encrypted+signed/failed: This value is reserved for future use. It encrypted+signed/failed:
is typically handled in the same way as "signed/failed". This value is reserved for future use. It is typically handled
in the same way as "signed/failed".
The "smimeStatusAtDelivery" response property has the same syntax as The "smimeStatusAtDelivery" response property has the same syntax as
"smimeStatus" but is calculated in relationship to the "receivedAt" "smimeStatus" but is calculated in relationship to the "receivedAt"
date/time. Unlike "smimeStatus", the "smimeStatusAtDelivery" date/time. Unlike "smimeStatus", the "smimeStatusAtDelivery"
response property value doesn't change, unless Trust Anchors are response property value doesn't change unless trust anchors are
added. (For example, addition of a Trust Anchor can change the value added. (For example, addition of a trust anchor can change the value
of a message "smimeStatusAtDelivery" property from "signed/failed" to of a message "smimeStatusAtDelivery" property from "signed/failed" to
"signed/verified". Note that Trust Anchor removal doesn't affect "signed/verified". Note that trust anchor removal doesn't affect
this response property.) The "smimeStatusAtDelivery" allows clients this response property.) The "smimeStatusAtDelivery" response
to compare the S/MIME signature verification status at delivery with property value allows clients to compare the S/MIME signature
the current status as returned by "smimeStatus", for example to help verification status at delivery with the current status as returned
to answer questions like "was the signature valid at the time of by "smimeStatus", for example, to help to answer questions like "was
delivery?". the signature valid at the time of delivery?".
Note that the "smimeStatusAtDelivery" response property value doesn't Note that the "smimeStatusAtDelivery" response property value doesn't
have to be calculated at delivery time. A JMAP server can defer its have to be calculated at delivery time. A JMAP server can defer its
calculation until it is explicitly requested, but once calculated its calculation until it is explicitly requested; however, once it is
value is remembered for later use. calculated, its value is remembered for later use.
The "smimeErrors" response property is defined as follows: The "smimeErrors" response property is defined as follows:
smimeErrors: "String[]|null" (server-set). null signifies that the *smimeErrors*:
message doesn't contain any signature or that there were no errors "String[]|null" (server-set). null signifies that the message
when verifying the S/MIME signature. (I.e., this property is non doesn't contain any signature or that there were no errors when
null only when the corresponding "smimeStatus" response property verifying the S/MIME signature. (That is, this property is non-
value is "signed/failed" or "encrypted+signed/failed". Note that null only when the corresponding "smimeStatus" response property
future extensions to this document can specify other smimeStatus value is "signed/failed" or "encrypted+signed/failed". Note that
values that can be used with smimeErrors.) Each string in the array future extensions to this document can specify other "smimeStatus"
is a human readable description (in the language specified in the values that can be used with "smimeErrors".) Each string in the
Content-Language header field, if any) of a problem with the array is a human-readable description (in the language specified
signature, the signing certificate or the signing certificate chain. in the Content-Language header field, if any) of a problem with
(See Section 3.8 of [RFC8620] in regards to how this is affected by the signature, the signing certificate, or the signing certificate
the language selection.) In one example, the signing certificate chain. (See Section 3.8 of [RFC8620] in regards to how this is
might be expired and the message From email address might not affected by the language selection.) In one example, the signing
correspond to any of the email addresses in the signing certificate. certificate might be expired and the message From email address
In another example the certificate might be expired and the JMAP might not correspond to any of the email addresses in the signing
server might be unable to retrieve a CRL for the certificate. In certificate. In another example, the certificate might be expired
both of these cases there would be 2 elements in the array. and the JMAP server might be unable to retrieve a Certificate
Revocation List (CRL) for the certificate. In both of these
cases, there would be 2 elements in the array.
The "smimeVerifiedAt" response property is defined as follows: The "smimeVerifiedAt" response property is defined as follows:
smimeVerifiedAt: "UTCDate|null" (server-set). null signifies that the *smimeVerifiedAt*:
message doesn't contain any S/MIME signature or that there is a "UTCDate|null" (server-set). null signifies that the message
signature, but there was no attempt to verify it. (Retrieval of the doesn't contain any S/MIME signature or that there is a signature,
smimeStatus value can be used to distinguish these 2 cases). In all but there was no attempt to verify it. (Retrieval of the
other cases it is set to the date and time of when the S/MIME "smimeStatus" value can be used to distinguish these 2 cases). In
signature was most recently verified. Note that a request to fetch all other cases, it is set to the date and time of when the S/MIME
"smimeStatus", "smimeStatusAtDelivery" and/or "smimeErrors" would signature was most recently verified. Note that a request to
force this response property to be set to a non null value, if an S/ fetch "smimeStatus", "smimeStatusAtDelivery", and/or "smimeErrors"
MIME signature exists. would force this response property to be set to a non-null value
if an S/MIME signature exists.
"smimeStatus" and "smimeErrors" values are calculated at the time the The "smimeStatus" and "smimeErrors" values are calculated at the time
corresponding JMAP request was processed (but see below about the the corresponding JMAP request is processed (but see below about the
effect of result caching), not at the time when the message was effect of result caching), not at the time when the message is
generated (according to its Date header field value). In all cases generated (according to its Date header field value). In all cases,
"smimeVerifiedAt" is set to the time when "smimeStatus" and "smimeVerifiedAt" is set to the time when "smimeStatus" and
"smimeErrors" were last updated. As recalculating these values is "smimeErrors" were last updated. As recalculating these values is
expensive for the server, they MAY be cached for up to 24 hours from expensive for the server, they MAY be cached for up to 24 hours from
the moment when they were calculated. the moment when they were calculated.
Example 1: Retrieval of minimal information about a message, Example 1: Retrieval of minimal information about a message,
including its From, Subject and Date header fields, as well as S/MIME including its From, Subject, and Date header fields, as well as the
signature verification status at delivery and date/time when the S/MIME signature verification status at delivery and date/time when
message was received. the message was received.
["Email/get", { ["Email/get", {
"ids": [ "fe123u457" ], "ids": [ "fe123u457" ],
"properties": [ "mailboxIds", "from", "subject", "date", "properties": [ "mailboxIds", "from", "subject", "date",
"smimeStatusAtDelivery", "receivedAt" ] "smimeStatusAtDelivery", "receivedAt" ]
}, "#1"] }, "#1"]
This might result in the following response: This might result in the following response:
[["Email/get", { [["Email/get", {
"accountId": "abc", "accountId": "abc",
"state": "51234123231", "state": "51234123231",
"list": [ "list": [
{ {
"id": "fe123u457", "id": "fe123u457",
"mailboxIds": { "f123": true }, "mailboxIds": { "f123": true },
"from": [{"name": "Joe Bloggs", "email": "joe@bloggs.example.net"}], "from": [{"name": "Joe Bloggs",
"subject": "Dinner tonight?", "email": "joe@bloggs.example.net"}],
"date": "2020-07-07T14:12:00Z", "subject": "Dinner tonight?",
"smimeStatusAtDelivery": "signed/verified", "date": "2020-07-07T14:12:00Z",
"receivedAt": "2020-07-07T14:15:18Z" "smimeStatusAtDelivery": "signed/verified",
} "receivedAt": "2020-07-07T14:15:18Z"
] }
}, "#1"]] ]
}, "#1"]]
Example 2: Retrieval of minimal information about a message, Example 2: Retrieval of minimal information about a message,
including its From, Subject and Date header fields, as well as the including its From, Subject, and Date header fields, as well as the
latest S/MIME signature verification status, S/MIME verification latest S/MIME signature verification status, S/MIME verification
errors (if any) and when was the S/MIME signature status last errors (if any), and when the S/MIME signature status was last
verified. The response contains 2 S/MIME errors related to S/MIME verified. The response contains 2 S/MIME errors related to S/MIME
signature verification. signature verification.
["Email/get", { ["Email/get", {
"ids": [ "ag123u123" ], "ids": [ "ag123u123" ],
"properties": [ "mailboxIds", "from", "subject", "date", "properties": [ "mailboxIds", "from", "subject", "date",
"smimeStatus", "smimeErrors", "smimeVerifiedAt" ] "smimeStatus", "smimeErrors", "smimeVerifiedAt" ]
}, "#1"] }, "#1"]
This might result in the following response: This might result in the following response:
[["Email/get", { [["Email/get", {
"accountId": "abc", "accountId": "abc",
"state": "47234123231", "state": "47234123231",
"list": [ "list": [
{ {
"id": "ag123u123", "id": "ag123u123",
"mailboxIds": { "f123": true }, "mailboxIds": { "f123": true },
"from": [{"name": "Jane Doe", "from": [{"name": "Jane Doe",
"email": "jdoe@example.com"}], "email": "jdoe@example.com"}],
"subject": "Company takeover", "subject": "Company takeover",
"date": "2020-01-31T23:00:00Z", "date": "2020-01-31T23:00:00Z",
"smimeStatus": "signed/failed", "smimeStatus": "signed/failed",
"smimeErrors": [ "smimeErrors": [
"From email address doesn't match the certificate", "From email address doesn't match the certificate",
"Can't retrieve CRL from the CRL URL"], "Can't retrieve CRL from the CRL URL"],
"smimeVerifiedAt": "2020-03-01T12:11:19Z" "smimeVerifiedAt": "2020-03-01T12:11:19Z"
} }
] ]
}, "#1"]] }, "#1"]]
4.1.1. "smimeStatus" response property extensibility 4.1.1. "smimeStatus" Response Property Extensibility
Future extensions to this document can specify extra allowed values Future extensions to this document can specify extra allowed values
for the smimeStatus response property. All values (defined in this for the "smimeStatus" response property. All values (defined in this
document or in extensions to this document) MUST be in ASCII. (Note document or in extensions to this document) MUST be in ASCII. (Note
that this response property contains tokens, thus it is not subject that this response property contains tokens; thus, it is not subject
to Internationalization or Localization). to internationalization or localization).
New smimeStatus response property values defined in extensions may New "smimeStatus" response property values defined in extensions may
affect behaviour of properties such as smimeErrors response property affect the behavior of properties, such as the "smimeErrors" response
of Email/get (see Section 4.1) or hasVerifiedSmime property of Email/ property of Email/get (see Section 4.1) or the "hasVerifiedSmime"
query (see Section 4.2). In particular the new values can be treated property of Email/query (see Section 4.2). In particular, the new
similar to values defined in this document. values can be treated similarly to values defined in this document.
For example a putative JMAP extension for automatically decrypting S/ For example, a putative JMAP extension for automatically decrypting
MIME messages can specify two additional values, one specifying that S/MIME messages can specify two additional values, one specifying
a message is both encrypted and signed with a valid S/MIME signature that a message is both encrypted and signed with a valid S/MIME
and another one specifying that a message is both encrypted and signature (e.g. "encrypted+signed/verified") and another one
signed with an invalid S/MIME signature. The former value can be specifying that a message is both encrypted and signed with an
treated as "signed/verified" (and would thus affect hasVerifiedSmime) invalid S/MIME signature (e.g. "encrypted+signed/failed"). The
and the latter can be treated as "signed/failed" (and thus can be former value can be treated as "signed/verified" (and would thus
used with smimeErrors). affect "hasVerifiedSmime") and the latter can be treated as "signed/
failed" (and thus can be used with "smimeErrors").
4.2. Extension to Email/query 4.2. Extension to Email/query
[RFC8621] defines the Email/query method for searching for messages [RFC8621] defines the Email/query method for searching for messages
with specific properties. This document defines the following with specific properties. This document defines the following
properties of the *FilterCondition* object: properties of the *FilterCondition* object:
* *hasSmime*: "Boolean". If "hasSmime" has the value true, only *hasSmime*:
messages with "smimeStatus" other than null match the condition. "Boolean". If "hasSmime" has the value true, only messages with
If "hasSmime" has the value false, only messages with "smimeStatus" other than null match the condition. If "hasSmime"
"smimeStatus" equal to null match the condition. has the value false, only messages with "smimeStatus" equal to
null match the condition.
* *hasVerifiedSmime*: "Boolean". If "hasVerifiedSmime" has the *hasVerifiedSmime*:
value true, only messages with "smimeStatus" equal to "signed/ "Boolean". If "hasVerifiedSmime" has the value true, only
verified" or "encrypted+signed/verified" (*), match the condition. messages with "smimeStatus" equal to "signed/verified" or
If "hasVerifiedSmime" has the value false, only messages with "encrypted+signed/verified" (*) match the condition. If
"hasVerifiedSmime" has the value false, only messages with
"smimeStatus" not equal to "signed/verified" and not equal to "smimeStatus" not equal to "signed/verified" and not equal to
"encrypted+signed/verified" (*) (including the value null) match "encrypted+signed/verified" (*) (including the value null) match
the condition. Note that use of this attribute is potentially the condition. Note that use of this attribute is potentially
expensive for a JMAP server, as it forces calculation of expensive for a JMAP server, as it forces calculation of the
smimeStatus property value for each message. However caching of "smimeStatus" property value for each message. However, caching
smimeStatus values should ameliorate this cost somewhat. of the "smimeStatus" values should ameliorate this cost somewhat.
(*) as well as "smimeStatus" values added by future extensions to (*) as well as the "smimeStatus" values added by future extensions
this document that are explicitly specified as having similar to this document that are explicitly specified as having similar
effect to "signed/verified" as far as "hasVerifiedSmime" effect to "signed/verified" as far as "hasVerifiedSmime"
calculation is concerned. calculation is concerned.
* *hasVerifiedSmimeAtDelivery*: "Boolean". The *hasVerifiedSmimeAtDelivery*:
"hasVerifiedSmimeAtDelivery" property is handled similar to "Boolean". The "hasVerifiedSmimeAtDelivery" property is handled
"hasVerifiedSmime" property, but the value of similarly to the "hasVerifiedSmime" property, but the value of
"smimeStatusAtDelivery" is used instead of "smimeStatus" to assess "smimeStatusAtDelivery" is used instead of "smimeStatus" to assess
whether a particular message matches the condition. whether a particular message matches the condition.
4.3. Interaction with Email/changes 4.3. Interaction with Email/changes
Changes to "smimeVerifiedAt" response property value MUST NOT cause Changes to the "smimeVerifiedAt" response property value MUST NOT
the message to be included in the "updated" argument of Email/changes cause the message to be included in the "updated" argument of the
response. However changes to "smimeStatus", "smimeStatusAtDelivery" Email/changes response. However, changes to the "smimeStatus",
and/or "smimeErrors" response properties MUST result in message "smimeStatusAtDelivery", and/or "smimeErrors" response properties
inclusion in the "updated" argument of Email/changes response. MUST result in message inclusion in the "updated" argument of the
Email/changes response.
5. IANA Considerations 5. IANA Considerations
5.1. JMAP capability registration for "smimeverify" 5.1. JMAP Capability Registration for "smimeverify"
IANA is requested to register the "smimeverify" JMAP Capability as
follows:
Capability Name: "urn:ietf:params:jmap:smimeverify"
Specification document: this document
Intended use: common
Change Controller: IETF IANA has registered the "smimeverify" JMAP capability as follows:
Security and privacy considerations: this document, Section 6 Capability Name: urn:ietf:params:jmap:smimeverify
Specification document: RFC 9219
Intended use: common
Change Controller: IETF
Security and privacy considerations: RFC 9219, Section 6
6. Security Considerations 6. Security Considerations
Use of the server-side S/MIME signature verification JMAP extension Use of the server-side S/MIME signature verification JMAP extension
requires the client to trust the server signature verification code, requires the client to trust the server signature verification code,
server configuration and its operational practices to perform S/MIME the server configuration, and the server's operational practices to
signature verification, as well as to trust that the channel between perform S/MIME signature verification, as well as to trust that the
the client and the server is integrity protected. (For example, if channel between the client and the server is integrity protected.
the server is not configured with some Trust Anchors, some messages (For example, if the server is not configured with some trust
will have "signed/failed" status instead of "signed/verified".) A anchors, some messages will have the "signed/failed" status instead
malicious or compromised server could return false verification of "signed/verified".) A malicious or compromised server could
status to a client. A successful verification could be conveyed to a return a false verification status to a client. A successful
client for a forged or altered message. A properly signed message verification could be conveyed to a client for a forged or altered
could be signaled as having a failed signature verification or no message. A properly signed message could be signaled as having a
signature at all. In the case of the latter attack, no new attack failed signature verification or no signature at all. In the case of
surface is presented with this extension above what malicious or the latter attack, no new attack surface is presented with this
compromised server could already do by stripping or tampering with extension above what a malicious or compromised server could already
the S/MIME information in the message. In the case of the former do by stripping or tampering with the S/MIME information in the
attack, client software capable of performing S/MIME signature message. In the case of the former attack, client software capable
verification could detect this attack. Local configuration of the of performing S/MIME signature verification could detect this attack.
client should determine if this client-side verification should Local configuration of the client should determine if this client-
occur. For clients without local verification capabilities, such an side verification should occur. For clients without local
attack would be difficult to detect. verification capabilities, such an attack would be difficult to
detect.
Integrity protection of the channel between the client and the server Integrity protection of the channel between the client and the server
is provided by use of TLS, as required by JMAP specification (see is provided by use of TLS, as required by the JMAP specification (see
Section 8.1 of [RFC8620]). Section 8.1 of [RFC8620]).
Constant recalculation of S/MIME signature status can result in a Constant recalculation of the S/MIME signature status can result in a
Denial-of-Service condition. For that reason, it is RECOMMENDED that denial-of-service condition. For that reason, it is RECOMMENDED that
servers cache results of signature verification for up to 24 hours. servers cache results of signature verification for up to 24 hours.
7. References 7. References
7.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8550] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ [RFC8550] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
Certificate Handling", RFC 8550, DOI 10.17487/RFC8550, Certificate Handling", RFC 8550, DOI 10.17487/RFC8550,
April 2019, <https://www.rfc-editor.org/info/rfc8550>. April 2019, <https://www.rfc-editor.org/info/rfc8550>.
[RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ [RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
skipping to change at page 10, line 43 skipping to change at line 474
Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621, Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621,
August 2019, <https://www.rfc-editor.org/info/rfc8621>. August 2019, <https://www.rfc-editor.org/info/rfc8621>.
7.2. Informative References 7.2. Informative References
[RFC1847] Galvin, J., Murphy, S., Crocker, S., and N. Freed, [RFC1847] Galvin, J., Murphy, S., Crocker, S., and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and "Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, DOI 10.17487/RFC1847, Multipart/Encrypted", RFC 1847, DOI 10.17487/RFC1847,
October 1995, <https://www.rfc-editor.org/info/rfc1847>. October 1995, <https://www.rfc-editor.org/info/rfc1847>.
Appendix A. Acknowledgements Acknowledgements
This document is a product of the JMAP Working Group. Special thank This document is a product of the JMAP Working Group. Special thank
you to Bron Gondwana, Neil Jenkins, Murray Kucherawy, Kirsty Paine, you to Bron Gondwana, Neil Jenkins, Murray Kucherawy, Kirsty Paine,
Benjamin Kaduk, Roman Danyliw, Peter Yee, Robert Wilton, Erik Kline Benjamin Kaduk, Roman Danyliw, Peter Yee, Robert Wilton, Erik Kline,
and Menachem Dodge for suggestions, comments and corrections to this and Menachem Dodge for suggestions, comments, and corrections to this
document. document.
Author's Address Author's Address
Alexey Melnikov Alexey Melnikov
Isode Ltd Isode Ltd
14 Castle Mews 14 Castle Mews
Hampton Hampton, Middlesex
TW12 2NP TW12 2NP
United Kingdom United Kingdom
Email: Alexey.Melnikov@isode.com Email: Alexey.Melnikov@isode.com
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