Sieve Extension: File Carbon Copy (FCC)
RFC 8580

Received changes through RFC Editor sync (created alias RFC 8580, changed title to 'Sieve Extension: File Carbon Copy (FCC)', changed abstract to 'The Sieve email filtering language provides a number of action commands, some of which can generate additional messages on behalf of the user. This document defines an extension to such commands to allow a copy of any generated message to be filed into a target mailbox.

This document updates RFCs 5230 and 5435 by adding a new tagged argument to the Vacation and Notify actions, respectively.', changed pages to 12, changed standardization level to Proposed Standard, changed state to RFC, added RFC published event at 2019-05-10, changed IESG state to RFC Published, created updates relation between draft-ietf-extra-sieve-fcc and RFC 5230, created updates relation between draft-ietf-extra-sieve-fcc and RFC 5435)

[Ballot comment]
I am clearing my DISCUSS, since conversation seems to be going in the right direction. I've included the DISCUSS text below for documentation purposes.


The security considerations say that this extension adds no new considerations not already present in [RFC5228], [RFC5230], [RFC5435], and [RFC6131]. I'm not sure that that is true.

It seems like the ability to insert a copy of message into a mailbox might have security and/or privacy considerations. This seems analogous to the "fileinto" action. I looked for security considerations for that in RFC 5228. All I found was a statement that "fileinfo" can be dangerous, but no elaboration on the nature of the danger or how it might be mitigated. So while I agree that fcc would have similar considerations as "fileinfo", I'm not sure those considerations have been adequately documented.  (I expect people will point me to something I missed, or where some other analogous feature is documented, in which case I will clear.)




§1, last paragraph (nit): Should "each action" be "each new action"?

§3.2, construction for FCC-OPTS: There is no extension point among the options, which would seem to require any new options update this RFC. Would it be reasonable to add one?

[Ballot comment]
I support Ben's Discuss.  I also have some other comments.

Section 1

  Each action that generates additional messages will need to specify
  how it interfacts with :fcc.  [...]

Do we need to Update: 5228 so that authors of such future actions are aware
of this requirement?

                        The syntax and semantics of the mailbox
  argument MUST match those of the mailbox argument to the "fileinto"
  action specified in Section 4.1 of [RFC5228].  If the specified
  mailbox doesn't exist, the implementation MUST file the message into
  the user's main mailbox (e.g.  IMAP "INBOX").

It's unclear that the "syntax and semantics MUST match" needs the 2119
MUST; it could just be "are defined to match".  (Except they don't, since
we add on the extra condition that a nonexistant mailbox name be delivered
to the no-longer-implementation-defined INBOX folder instead of the other
MAY options for fileinto.)

Section 3.1

                  Tagged arguments in future extensions to the
  "fileinto" action should describe their interaction with ":fcc", if
  any.

This is not a very strong statement.  What would an implementor be expected
to do upon encountering such future extensions that do not describe
interaction with :fcc?  (This requirement may also be a candidate for an
Updates: relationship with 5228.)

Section 3.1.2

Perhaps note that implementations are permitted but not required to create
the mailbox (if needed) without this extension.

Section 3.1.3

It's a bit odd to update the behavior of another document that's still an
I-D (vs. specifying the behavior in question in that document).

Section 5

  Usage:  vacation [FCC]
                    [":days" number | ":seconds" number]
                    [":subject" string]
                    [":from" string]
                    [":addresses" string-list]
                    [":mime"]
                    [":handle" string]
                   

This is presumably just my having skimmed RFC 5228 too quickly, but why is
this [FCC] instead of [":fcc" string]" or similar?
(Same for the notify action in Section 6.)

Section 7

Do we want to have a list of currently defined actions that are not
compatible with the "fcc" extension, to avoid any confusion by future
readers as to what was defined at the time of this writing?

[Ballot comment]
Thanks for the work everyone did on this document. The mechanism seems quite
useful. I have some minor suggestions that you may want to consider
incorporating.

I support Ben's discuss.

---------------------------------------------------------------------------

§1:

>  This extension defines a new optional tagged argument ":fcc" to
>  action commands which generate additional messages to allow a copy of

Nit: "...commands that generate..."

---------------------------------------------------------------------------

§3:

>  alters the behavior of action commands which generate additional

Nit: "...commands that generate..."

---------------------------------------------------------------------------

§3.2:

>  FCC        = ":fcc" string *FCC-OPTS
>                  ; per Section 2.6.2 of RFC5228,
>                  ; the tagged arguments in FCC may appear in any order


This threw me for a bit of a loop when I got to the example in section 5, and I
had to go carefully read RFC 5228 to figure out what was going on. I think this
would be much clearer and more accurate if the rule were described as:

>  FCC        = *FCC-OPTS ":fcc" string *FCC-OPTS

---------------------------------------------------------------------------

General:

I'm a little concerned about the fact that this extension is generating a
new message and attempting to store it into a potentially quota-controlled
user folder. This would seem to be a run-time error, about which RFC 5228
says:

>  When an error happens, implementations MUST notify the user that an
>  error occurred and which actions (if any) were taken, and do an
>  implicit keep.

This probably isn't the right behavior for FCC. I think a sentence or two of
guidance about what happens when an FCC action would put the destination
mailbox over quota are in order, particularly since they'll be different than
the guidance in the base SIEVE spec.

I might just be confused here -- corrections to any incorrect notions I've
expressed would be appreciated.

[Ballot discuss]
Thanks for the work on this. I plan to ballot "yes", but have one item I think needs to be discussed first:

The security considerations say that this extension adds no new considerations not already present in [RFC5228], [RFC5230], [RFC5435], and [RFC6131]. I'm not sure that that is true.

It seems like the ability to insert a copy of message into a mailbox might have security and/or privacy considerations. This seems analogous to the "fileinto" action. I looked for security considerations for that in RFC 5228. All I found was a statement that "fileinfo" can be dangerous, but no elaboration on the nature of the danger or how it might be mitigated. So while I agree that fcc would have similar considerations as "fileinfo", I'm not sure those considerations have been adequately documented.  (I expect people will point me to something I missed, or where some other analogous feature is documented, in which case I will clear.)

[Ballot comment]
§1, last paragraph (nit): Should "each action" be "each new action"?

§3.2, construction for FCC-OPTS: There is no extension point among the options, which would seem to require any new options update this RFC. Would it be reasonable to add one?

[Ballot comment]
I also have a minor comment on this sentence:

"If the specified
  mailbox doesn't exist, the implementation MUST file the message into
  the user's main mailbox (e.g.  IMAP "INBOX")."

Beside the conflict Ekr mentioned, I'm wondering why this is a MUST. I guess the other option would be to not copy it anywhere (and file an error message to the user). I'm not an expert on mail at all but as a user I would find it confusing to find such messages in my INBOX. However, if there is a good reason that it must be ensured that such a message is stored, I guess that's the only viable default option.

[Ballot comment]
Rich version of this review at:
https://mozphab-ietf.devsvcdev.mozaws.net/D3898



IMPORTANT
S 3.
>      copy of the generated message into the mailbox provided in the
>      subsequent argument.  The syntax and semantics of the mailbox
>      argument MUST match those of the mailbox argument to the "fileinto"
>      action specified in Section 4.1 of [RFC5228].  If the specified
>      mailbox doesn't exist, the implementation MUST file the message into
>      the user's main mailbox (e.g.  IMAP "INBOX").

This seems to sort of conflict with S 3.1.1. I assume that the logic
is: if (!exists && :create) { try_to_create() }; if (!exists) {
file_in_inbox()} else { file_in_fcc_mailbox()}, but this text isn't
celar.

COMMENTS
S 1.
> 
>      The capability string associated with this extension is "fcc".
> 
>      Each action that generates additional messages will need to specify
>      how it interfacts with :fcc.  This document specifies the interaction
>      of :fcc with the Vacation [RFC5230] and Notify [RFC5435] extensions.

Are these the only such actions?

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has completed its review of draft-ietf-extra-sieve-fcc-08. If any part of this review is inaccurate, please let us know.

The IANA Functions Operator understands that, upon approval of this document, there are two actions which we must complete.

First, in the Sieve Extensions registry located at:

https://www.iana.org/assignments/sieve-extensions/

a single, new registration will be made as follows:

Capability name: fcc
Description: Adds the ":fcc" parameter to Sieve action commands that generate additional messages.
RFC Number: [ RFC-to-be ]
Contact address: sieve@ietf.org
Registration date: [ TBD-at-Registration ]

Second, in the Notification-Capability Parameters registry located at:

https://www.iana.org/assignments/notification-capability-parameters/

a single, new parameter will be registered as follows:

Capability name: fcc
Description: Returns whether a copy of the notification message sent using the method identified by the notification-uri parameter to the notify_method_capability test can be filed into a target mailbox.
Syntax: Can contain one of two values: "yes" or "no". Values MUST be in lowercase.
Contact: ietf-mta-filters@imc.org
Reference: [ RFC-to-be ]

As this document requests registrations in a Specification Required (see RFC 8126) registry, we will initiate the required Expert Review via a separate request. Expert review will need to be completed before your document can be approved for publication as an RFC.

The IANA Functions Operator understands that these are the only actions required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2018-12-18):

From: The IESG
To: IETF-Announce
CC: draft-ietf-extra-sieve-fcc@ietf.org, Jiankang Yao , extra@ietf.org, yaojk@cnnic.cn, extra-chairs@ietf.org, alexey.melnikov@isode.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Sieve Extension: File Carbon Copy (Fcc)) to Proposed Standard


The IESG has received a request from the Email mailstore and eXtensions To
Revise or Amend WG (extra) to consider the following document: - 'Sieve
Extension: File Carbon Copy (Fcc)'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2018-12-18. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  The Sieve Email Filtering Language provides a number of action
  commands, some of which can generate additional messages on behalf of
  the user.  This document defines an extension to such commands to
  allow a copy of any generated message to be filed into a target
  mailbox.

  This document updates RFC5230 and RFC5435 by adding a new tagged
  argument to the "vacation" and "enotify" actions respectively.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-extra-sieve-fcc/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-extra-sieve-fcc/ballot/


No IPR declarations have been submitted directly on this I-D.


The document contains these normative downward references.
See RFC 3967 for additional information:
    draft-ietf-extra-sieve-special-use: Sieve Email Filtering: Delivering to Special-Use Mailboxes (None - IETF stream)

Document Shepherd Write-Up for draft-ietf-extra-sieve-fcc

1. This document is being requested as a Proposed Standard because it
updates existing Standards Track documents(RFC 5230, RFC 5435).
The request type is indicated in the title page header.

2.

Technical Summary

  The Sieve Email Filtering Language provides a number of action
  commands, some of which can generate additional messages on behalf of
  the user.  This document defines an extension to such commands to
  allow a copy of any generated message to be filed into a target
  mailbox.

Working Group Summary

  The EXTRA WG meeting in IETF 101 had detailed discussion about this draft. The authors had updated it
  accordingly.
  Before WGLC, several experts reviewed the draft in detail. All identified issues were reflected in the
  new version of the
  draft. The EXTRA WG meeting in IETF 102 decided to poll list for WGLC after the new vesion.
  During WGLC, some minor issues were identified and fixed in the new version.
  The WG has looked throught this document in detail.

Document Quality

  The document is in good shape and is ready to be published.
  One expert has indicated that he has implemented it.
  He noted that this was far more difficult to implement than he
  expected. Specially, section 4 of the document
  records the status of some known implementations.

Personnel

  Document Shepherd - Jiankang Yao (EXTRA co-chair)
  Responsible Area Director - Alexey Melnikov


3. The Document Shepherd has read the document through in detail and
think that it is ready to go.

4. There has no concerns.

5. There is no review required for the document by other areas, it's
very self-contained.

6. There are no concerns with this document that IESG should be aware of.

7. There have been no IPR disclosures for this spec.

8. There have been no IPR disclosures for this spec.

9. The WG consensus is very solid, while not everybody spoke, it was
clear that the entire group understood and agreed with the idea and
the method chosen.

10. There has been no discontent.

11. The ID nits tool shows the following:

No issues found here.

Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 5 comments (--).


12. This document doesn't define anything which needs formal review
outside the working group.

13. All references have been identified as either normative or
informative.

14. All normative references are published standards.

15. There are no downward normative references references.

16. This RFC updates RFC5230 and RFC5435.
RFC5230 and RFC5435 have been listed on the title page header, listed in the abstract.
In the introduction, there has only one sentence which mentions

" This document also specifies the interaction of :fcc with the Vacation [RFC5230] and Notify [RFC5435]
extensions.
"
but it does not clearly indicates which part of RFC5230 and RFC5435 is updated by this document.
I think that the author might need to clarify it in the introduction of the future new version.


17. The IANA considerations ask for the following two items to be added to the registry:

  IANA is requested to add the new entry spcified in section 6.1 to the "Sieve Extensions".
  IANA is requested to add the new entry spcified in section 6.2 to the "Notification-Capability
  Parameters"


18. None of the IANA registries mentioned require Expert Review.

19. Have run Bill's ABNF Parser for checking of ABNF, and no issue was found.

This document has been updated for several versions based comments received and do not receive any more comments since new version published in 12 Aug. This document is ready for WGLC.