< draft-degener-sieve-copy-02.txt   draft-degener-sieve-copy-03.txt >
Network Working Group Jutta Degener Network Working Group Jutta Degener
Internet Draft Sendmail, Inc. Internet Draft Sendmail, Inc.
Expires: July 2004 January 2004 Expires: December 2004 June 2004
Sieve -- "copy" extension Sieve Extension: Copying Without Side Effects
<draft-degener-sieve-copy-02.txt> <draft-degener-sieve-copy-03.txt>
Status of this memo Status of this memo
This document is an Internet-Draft and is subject to all This document is an Internet-Draft and is subject to all
provisions of Section 10 of RFC2026. provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
skipping to change at line 32 skipping to change at line 32
"work in progress." "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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Abstract Abstract
This document defines a new keyword parameter, ":copy", to The sieve scripting language allows users to control
be used with the sieve "fileinto" and "redirect" actions. handling and disposal of their incoming e-mail. By default,
The new parameter prevents cancellation of the implicit keep. an e-mail message that is processed by a sieve script is saved
in the owner's "inbox". Actions such as "fileinto" and
"redirect" cancel this default behavior.
This document defines a new keyword parameter, ":copy", to be
used with the sieve "fileinto" and "redirect" actions. Adding
":copy" to an action suppresses cancellation of the default
"inbox" save. It allows users to add commands to an existing
script without changing the meaning of the rest of the script.
1. Introduction 1. Introduction
Some users have the notion of forwarding a copy of a message The sieve scripting language [SIEVE] allows users to control
for safekeeping to another e-mail address, or of saving a copy handling and disposal of their incoming e-mail. Two frequently
in a folder -- in addition to the regular message delivery, used sieve commands are "fileinto" (saving into a local message
which shouldn't be affected by the copy. store, such as an IMAP server) and "redirect" (forwarding
to another e-mail address). Both of these cancel the sieve
default behavior of saving into the user's "inbox".
But some users have the notion of forwarding an extra copy of a
message for safekeeping to another e-mail address, or of saving
a copy in a folder -- in addition to the regular message
delivery, which shouldn't be affected by the copy.
If saving an extra copy is all the user wanted to do, If saving an extra copy is all the user wanted to do,
fileinto "unfiltered"; fileinto "unfiltered";
keep; keep;
would do the job. But the explicit "keep" is a poor substitute would do the job. The "keep" command does explicitly what the
for the implicit keep when more processing follows: canceled default behavior did. But the explicit "keep" is a
poor substitute for the implicit keep when more processing follows:
fileinto "unfiltered"; fileinto "unfiltered";
keep; keep;
if header "Subject" "MAKE MONEY FAST!!!" if header "Subject" "MAKE MONEY FAST!!!"
{ {
discard; discard;
} }
In this example, the "discard" is ineffective against the In this example, the "discard" is ineffective against the
skipping to change at line 97 skipping to change at line 113
If the optional :copy keyword is specified with "fileinto" If the optional :copy keyword is specified with "fileinto"
or "redirect", the tagged command does not cancel the or "redirect", the tagged command does not cancel the
implicit keep. Instead, it merely files or redirects a implicit keep. Instead, it merely files or redirects a
copy in addition to whatever else is happening to the copy in addition to whatever else is happening to the
message. message.
Example: Example:
require ["copy", "fileinto"]; require ["copy", "fileinto"];
fileinto :copy "unfiltered"; fileinto :copy "incoming";
# ... more processing follows ...
4. Security Considerations 4. Security Considerations
The "copy" extension makes it easier to eavesdrop on a user's The "copy" extension makes it easier to eavesdrop on a user's
message stream without the user noticing. message stream without the user noticing. This was technically
possible before if an attacker gained read/write access to a
user's sieve scripts, but now an attacker no longer needs to
parse a script in order to modify it. Write access to sieve scripts
must be protected as strongly as read/write access to e-mail,
for example by using secure directory protocols such as correctly
parametrized LDAP over TLS [LDAP].
Organizations that wish to monitor their users' e-mail traffic
must familiarize themselves with local data protection laws
before creating stores of old e-mail traffic without control or
perhaps even knowledge of the sender or intended recipients.
Organizations that legally use redirect :copy to eavesdrop
on correspondence (for example, by keeping a log to later answer
questions about insider trading) can avoid later problems by
setting privacy expectations of their users correctly.
5. IANA Considerations 5. IANA Considerations
The following template specifies the IANA registration of the The following template specifies the IANA registration of the
"copy" Sieve extension specified in this document. "copy" Sieve extension specified in this document.
To: iana@iana.org To: iana@iana.org
Subject: Registration of new Sieve extension Subject: Registration of new Sieve extension
Capability name: copy Capability name: copy
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7. Author's Address 7. Author's Address
Jutta Degener Jutta Degener
Sendmail, Inc. Sendmail, Inc.
6425 Christie Ave, 4th Floor 6425 Christie Ave, 4th Floor
Emeryville, CA 94608 Emeryville, CA 94608
Email: jutta@sendmail.com Email: jutta@sendmail.com
8. Discussion
This section will be removed when this document leaves the
Internet-Draft stage.
This draft is intended as an extension to the Sieve mail filtering
language. Sieve extensions are discussed on the MTA Filters mailing
list at <ietf-mta-filters@imc.org>. Subscription requests can
be sent to <ietf-mta-filters-request@imc.org> (send an email
message with the word "subscribe" in the body).
More information on the mailing list along with a WWW archive of
back messages is available at <http://www.imc.org/ietf-mta-filters/>.
9.1 Changes from the previous version
Added IANA considerations.
Inserted Appendix B.
Changed Appendix A "References" to "Normative References".
Added brief example.
Appendices Appendices
Appendix A. Normative References Appendix A. Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997. Requirement Levels", RFC 2119, March 1997.
[LDAP] M. Wahl, H. Alvestrand, J. Hodges, R. Morgan,
"Authentication Methods for LDAP", RFC 2829, May 2000.
[SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", RFC 3028, [SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", RFC 3028,
January 2001. January 2001.
Appendix B. Intellectual Property Rights Statement Appendix B. Intellectual Property Rights Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances claims of rights made available for publication and any assurances
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