draft-ietf-extra-imap-list-myrights-07.txt   rfc8440.txt 
EXTRA K. Murchison Internet Engineering Task Force (IETF) K. Murchison
Internet-Draft B. Gondwana Request for Comments: 8440 B. Gondwana
Intended status: Standards Track FastMail Category: Standards Track FastMail
Expires: December 9, 2018 June 7, 2018 ISSN: 2070-1721 August 2018
IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST
draft-ietf-extra-imap-list-myrights-07
Abstract Abstract
This document defines an extension to the Internet Message Access This document defines an extension to the Internet Message Access
Protocol (IMAP) LIST command that allows the client to request the Protocol (IMAP) LIST command that allows the client to request the
set of rights that the logged-in user has been granted on mailboxes, set of rights that the logged-in user has been granted on mailboxes,
along with other information typically returned by the LIST command. along with other information typically returned by the LIST command.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on December 9, 2018. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8440.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. MYRIGHTS Return Option to LIST Command . . . . . . . . . . . 3 3. MYRIGHTS Return Option to LIST Command . . . . . . . . . . . 2
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 4 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 4
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
8.1. Registration of IMAP capability LIST-MYRIGHTS . . . . . . 4 8.1. Registration of IMAP Capability LIST-MYRIGHTS . . . . . . 4
8.2. Registration of LIST-EXTENDED option MYRIGHTS . . . . . . 5 8.2. Registration of LIST-EXTENDED Option MYRIGHTS . . . . . . 4
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 9.1. Normative References . . . . . . . . . . . . . . . . . . 5
10.1. Normative References . . . . . . . . . . . . . . . . . . 5 9.2. Informative References . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Change History (To be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
IMAP [RFC3501] clients typically fetch the set of rights granted on IMAP [RFC3501] clients typically fetch the set of rights granted on
mailboxes so they can expose the allowed functionality to the logged- mailboxes so they can expose the allowed functionality to the logged-
in user. In order to do that, the client is forced to issue a LIST in user. In order to do that, the client is forced to issue a LIST
or LSUB command to list all available mailboxes, followed by a or LSUB command to list all available mailboxes, followed by a
MYRIGHTS command for each mailbox found. This document defines an MYRIGHTS command for each mailbox found. This document defines an
extension to the to IMAP LIST command that is identified by the extension to the to IMAP LIST command that is identified by the
capability string "LIST-MYRIGHTS". The LIST-MYRIGHTS extension capability string "LIST-MYRIGHTS". The LIST-MYRIGHTS extension
skipping to change at page 2, line 46 skipping to change at page 2, line 43
user has been granted on mailboxes, along with other information user has been granted on mailboxes, along with other information
typically returned by the LIST command. typically returned by the LIST command.
2. Conventions Used in This Document 2. Conventions Used in This Document
In examples, "C:" indicates lines sent by a client that is connected In examples, "C:" indicates lines sent by a client that is connected
to a server. "S:" indicates lines sent by the server to the client. to a server. "S:" indicates lines sent by the server to the client.
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
14 [1] [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. MYRIGHTS Return Option to LIST Command 3. MYRIGHTS Return Option to LIST Command
[RFC4314] defines the MYRIGHTS command which is used by an IMAP [RFC4314] defines the MYRIGHTS command, which is used by an IMAP
client to determine the set of rights that the logged-in user has client to determine the set of rights that the logged-in user has
been granted on a given mailbox. Frequently, a client will have to been granted on a given mailbox. Frequently, a client will have to
look up the rights for some or all of the mailboxes returned by the look up the rights for some or all of the mailboxes returned by the
LIST command. Doing so in multiple MYRIGHTS commands wastes LIST command. Doing so in multiple MYRIGHTS commands wastes
bandwidth and can degrade performance if the client does not pipeline bandwidth and can degrade performance if the client does not pipeline
the requests. the requests.
This document extends the LIST command with a new "MYRIGHTS" return This document extends the LIST command with a new "MYRIGHTS" return
option [RFC5258], which allows the client to request all of the option [RFC5258] that allows the client to request all of the desired
desired information in a single command. For each listable mailbox information in a single command. For each listable mailbox matching
matching the list pattern and selection options, the server MUST the list pattern and selection options, the server MUST return an
return an untagged LIST response and SHOULD also return an untagged untagged LIST response and SHOULD also return an untagged MYRIGHTS
MYRIGHTS response containing the set of rights granted to the logged- response containing the set of rights granted to the logged-in user.
in user. The ordering of the responses is significant only in that The ordering of the responses is significant only in that the server
the server MUST NOT send a MYRIGHTS response for a given mailbox MUST NOT send a MYRIGHTS response for a given mailbox before it sends
before it sends the LIST response for that mailbox. the LIST response for that mailbox.
If the server is unable to look up the set of rights for a given If the server is unable to look up the set of rights for a given
mailbox, it does not send the MYRIGHTS reply for that mailbox. mailbox, it does not send the MYRIGHTS reply for that mailbox.
Client authors ought to note that generating the MYRIGHTS responses Client authors ought to note that generating the MYRIGHTS responses
for a large number of mailboxes may be an expensive operation for the for a large number of mailboxes may be an expensive operation for the
server. Clients SHOULD use a suitable match pattern and/or selection server. Clients SHOULD use a suitable match pattern and/or selection
option to limit the set of mailboxes returned to only those whose option to limit the set of mailboxes returned to only those in whose
rights in which they are interested. rights they are interested.
4. Examples 4. Examples
In this example the "bar" mailbox doesn't exist, so it has no In this example, the "bar" mailbox doesn't exist, so it has no
MYRIGHTS reply. MYRIGHTS reply.
C: A01 LIST "" % RETURN (MYRIGHTS) C: A01 LIST "" % RETURN (MYRIGHTS)
S: * LIST () "." "INBOX" S: * LIST () "." "INBOX"
S: * MYRIGHTS "INBOX" lrswipkxtecda S: * MYRIGHTS "INBOX" lrswipkxtecda
S: * LIST () "." "foo" S: * LIST () "." "foo"
S: * MYRIGHTS "foo" lrs S: * MYRIGHTS "foo" lrs
S: * LIST (\NonExistent) "." "bar" S: * LIST (\NonExistent) "." "bar"
S: A01 OK List completed. S: A01 OK List completed.
In this example the LIST reply for the "foo" mailbox is returned In this example, the LIST reply for the "foo" mailbox is returned
because it has matching children, but no MYRIGHTS reply is returned because it has matching children, but no MYRIGHTS reply is returned,
because "foo" itself doesn't match the selection criteria. because "foo" itself doesn't match the selection criteria.
C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (MYRIGHTS) C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (MYRIGHTS)
S: * LIST (\Subscribed) "." "INBOX" S: * LIST (\Subscribed) "." "INBOX"
S: * MYRIGHTS "INBOX" lrswipkxtecda S: * MYRIGHTS "INBOX" lrswipkxtecda
S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED")) S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED"))
S: A02 OK List completed. S: A02 OK List completed.
5. Formal Syntax 5. Formal Syntax
skipping to change at page 4, line 28 skipping to change at page 4, line 18
Form (BNF) as described in [RFC5234]. Terms not defined here are Form (BNF) as described in [RFC5234]. Terms not defined here are
taken from [RFC5258]. taken from [RFC5258].
return-option =/ "MYRIGHTS" return-option =/ "MYRIGHTS"
6. Security Considerations 6. Security Considerations
In addition to the security considerations described in [RFC4314], In addition to the security considerations described in [RFC4314],
this extension makes it a bit easier for clients to overload the this extension makes it a bit easier for clients to overload the
server by requesting MYRIGHTS information for a large number of server by requesting MYRIGHTS information for a large number of
mailboxes. However, as already noted in the introduction, existing mailboxes. However, as noted in the introduction, existing clients
clients already try to do that by generating a large number of already try to do that by generating a large number of MYRIGHTS
MYRIGHTS commands for each mailbox in which they are interested. commands for each mailbox in which they are interested. While
While performing MYRIGHTS information retrieval for big lists of performing MYRIGHTS information retrieval for big lists of mailboxes,
mailboxes, a server implementation needs to make sure that it can a server implementation needs to make sure that it can still serve
still serve other IMAP connections and yield execution to other other IMAP connections and yield execution to other connections, when
connections, when necessary. necessary.
7. Privacy Considerations 7. Privacy Considerations
This specification does not introduce any additional privacy concerns This specification does not introduce any additional privacy concerns
beyond those described in [RFC4314]. beyond those described in [RFC4314].
8. IANA Considerations 8. IANA Considerations
8.1. Registration of IMAP capability LIST-MYRIGHTS 8.1. Registration of IMAP Capability LIST-MYRIGHTS
This document defines the "LIST-MYRIGHTS" IMAP capability to be added This document defines the "LIST-MYRIGHTS" IMAP capability that has
to the "IMAP Capabilities" registry: been added to the "IMAP Capabilities" registry [CAPABILITIES].
<https://www.iana.org/assignments/imap-capabilities/imap-
capabilities.xhtml#imap-capabilities-1>.
8.2. Registration of LIST-EXTENDED option MYRIGHTS 8.2. Registration of LIST-EXTENDED Option MYRIGHTS
This section registers the "MYRIGHTS" option to be added to the This section registers the "MYRIGHTS" option that has been added to
"LIST-EXTENDED options" registry: <https://www.iana.org/assignments/ the "LIST-EXTENDED options" registry [EXTENDED].
imap-list-extended/imap-list-extended.xhtml#imap-list-extended-1>.
LIST-EXTENDED option name: MYRIGHTS LIST-EXTENDED option name: MYRIGHTS
LIST-EXTENDED option type: RETURN LIST-EXTENDED option type: RETURN
LIST-EXTENDED option description: Causes the LIST command to return LIST-EXTENDED option description: Causes the LIST command to return
MYRIGHTS responses in addition to LIST responses. MYRIGHTS responses in addition to LIST responses.
Published specification: RFC XXXX, Section 3 Published specification: RFC 8440, Section 3
Security considerations: RFC XXXX, Section 6
Security considerations: RFC 8440, Section 6
Intended usage: COMMON Intended usage: COMMON
Person and email address to contact for further Person and email address to contact for further information:
information: Kenneth Murchison <murch@fastmailteam.com>
Kenneth Murchison <murch@fastmail.com>
Owner/Change controller: IESG <iesg@ietf.org> Owner/Change controller: IESG <iesg@ietf.org>
9. Acknowledgments 9. References
This document is based largely on [RFC5819]. The authors would like 9.1. Normative References
to thank the authors of that document for providing both inspiration
and some borrowed text for this document. The authors would also
like to thank the following individuals for contributing their ideas
and support for writing this specification: Barry Leiba.
10. References [CAPABILITIES]
IANA, "Internet Message Access Protocol (IMAP)
Capabilities Registry", <https://www.iana.org/assignments/
imap-capabilities/imap-capabilities>.
10.1. Normative References [EXTENDED]
IANA, "Internet Message Access Protocol (IMAP) LIST
EXTENDED Registry",
<https://www.iana.org/assignments/imap-list-extended>.
[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>.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003, 4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
<https://www.rfc-editor.org/info/rfc3501>. <https://www.rfc-editor.org/info/rfc3501>.
skipping to change at page 6, line 23 skipping to change at page 6, line 5
[RFC5258] Leiba, B. and A. Melnikov, "Internet Message Access [RFC5258] Leiba, B. and A. Melnikov, "Internet Message Access
Protocol version 4 - LIST Command Extensions", RFC 5258, Protocol version 4 - LIST Command Extensions", RFC 5258,
DOI 10.17487/RFC5258, June 2008, DOI 10.17487/RFC5258, June 2008,
<https://www.rfc-editor.org/info/rfc5258>. <https://www.rfc-editor.org/info/rfc5258>.
[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>.
10.2. Informative References 9.2. Informative References
[RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for [RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for
Returning STATUS Information in Extended LIST", RFC 5819, Returning STATUS Information in Extended LIST", RFC 5819,
DOI 10.17487/RFC5819, March 2010, DOI 10.17487/RFC5819, March 2010,
<https://www.rfc-editor.org/info/rfc5819>. <https://www.rfc-editor.org/info/rfc5819>.
10.3. URIs Acknowledgments
[1] https://tools.ietf.org/html/bcp14
Appendix A. Change History (To be removed by RFC Editor before
publication)
Changes from draft-ietf-extra-imap-list-myrights-06:
o Editorial fix.
Changes from draft-ietf-extra-imap-list-myrights-05:
o Updated Keywords boilerplate.
o Referenced security concerns in RFC 4314.
o Reworded first sentence in second paragraph of Section 3.
o Added informative reference to RFC5819.
Changes from draft-ietf-extra-imap-list-myrights-04:
o Added references for "IMAP" and "return option".
Changes from draft-ietf-extra-imap-list-myrights-03:
o Fixed a typo in the Abstract.
Changes from draft-ietf-extra-imap-list-myrights-02:
o WGLC editorial changes from Barry Leiba.
Changes from draft-ietf-extra-imap-list-myrights-01:
o Removed 'n' right from example.
o Added advice to client authors regarding expense of calculating
MYRIGHTS.
o Replicated Security Considerations section from RFC 5819.
Changes from draft-ietf-extra-imap-list-myrights-00:
o Corrected contact email address in IANA registration.
o Fixed typos (extra SP) in examples.
Changes from draft-murchison-imap-list-myrights-01:
o Renamed document to be a work product of the EXTRA WG.
o Updated authors' addresses.
Changes from draft-murchison-imap-list-myrights-00:
o Augmented Introduction with mention of "LIST-MYRIGHTS" capability
string.
o Minor editorial changes. This document is based largely on [RFC5819]. The authors would like
to thank the authors of that document for providing both inspiration
and some borrowed text for this document. The authors would also
like to thank Barry Leiba for contributing his ideas and support for
writing this specification.
Authors' Addresses Authors' Addresses
Kenneth Murchison Kenneth Murchison
FastMail Pty Ltd FastMail Pty Ltd.
Level 2, 114 William Street Level 2, 114 William Street
Melbourne, VIC 3000 Melbourne, VIC 3000
Australia Australia
Email: murch@fastmailteam.com Email: murch@fastmailteam.com
Bron Gondwana Bron Gondwana
FastMail Pty Ltd FastMail Pty Ltd.
Level 2, 114 William Street Level 2, 114 William Street
Melbourne, VIC 3000 Melbourne, VIC 3000
Australia Australia
Email: brong@fastmailteam.com Email: brong@fastmailteam.com
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