Independent Submission K. Murchison Internet-Draft CMU Intended status: Standards Track B. Gondwana Expires: November 22, 2017 FastMail May 21, 2017 IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST draft-murchison-imap-list-myrights-01 Abstract This document defines an extension to the to IMAP LIST command that allows the client to request the set of rights that the logged-in user has been granted on mailboxes, along with other information typically returned by the LIST command. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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Murchison & Gondwana Expires November 22, 2017 [Page 1] Internet-Draft IMAP LIST-MYRIGHTS May 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 3. MYRIGHTS Return Option to LIST Command . . . . . . . . . . . 2 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 3 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 8.1. Registration of IMAP capability LIST-MYRIGHTS . . . . . . 4 8.2. Registration of LIST-EXTENDED option MYRIGHTS . . . . . . 4 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 10.1. Normative References . . . . . . . . . . . . . . . . . . 5 10.2. Informative References . . . . . . . . . . . . . . . . . 5 Appendix A. Change History (To be removed by RFC Editor before publication) . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction IMAP clients typically fetch the set of rights granted on 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 or LSUB command to list all available mailboxes, followed by a MYRIGHTS command for each mailbox found. This document defines an extension to the to IMAP LIST command that is identified by the capability string "LIST-MYRIGHTS". The LIST-MYRIGHTS extension allows the client to request the set of rights that the logged-in user has been granted on mailboxes, along with other information typically returned by the LIST command. 2. Conventions Used in This Document 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. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. MYRIGHTS Return Option to LIST Command [RFC4314] defines the MYRIGHTS command which is used by an IMAP 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 Murchison & Gondwana Expires November 22, 2017 [Page 2] Internet-Draft IMAP LIST-MYRIGHTS May 2017 look up the rights for some or all of the mailboxes returned by the LIST command. Doing so in multiple MYRIGHTS commands wastes bandwidth and can degrade performance if the client does not pipeline the requests. This document extends the LIST command with a new return option, "MYRIGHTS", which allows the client to request all of the desired information in a single command. For each listable mailbox matching the list pattern and selection options, the server MUST return an untagged LIST response followed by an untagged MYRIGHTS response containing the set of rights granted to the logged-in user. If the server is unable to look up the set of rights for a given mailbox, it MAY drop the corresponding MYRIGHTS reply. In such a situation, the LIST command would still return a tagged OK reply. 4. Examples In this example the "bar" mailbox doesn't exist, so it has no MYRIGHTS reply. C: A01 LIST "" % RETURN (MYRIGHTS) S: * LIST () "." "INBOX" S: * MYRIGHTS "INBOX" lrswipkxtecdan S: * LIST () "." "foo" S: * MYRIGHTS "foo" lrs S: * LIST (\NonExistent) "." "bar" S: A01 OK List completed. In this example the LIST reply for the "foo" mailbox is returned because it has matching children, but no MYRIGHTS reply is returned because "foo" itself doesn't match the selection criteria. C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (MYRIGHTS) S: * LIST (\Subscribed) "." "INBOX" S: * MYRIGHTS "INBOX" lrswipkxtecdan S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED")) S: A02 OK List completed. 5. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) as described in [RFC5234]. Terms not defined here are taken from [RFC5258]. return-option =/ "MYRIGHTS" Murchison & Gondwana Expires November 22, 2017 [Page 3] Internet-Draft IMAP LIST-MYRIGHTS May 2017 6. Security Considerations This specification does not introduce any additional security concerns beyond those described in [RFC5258]. 7. Privacy Considerations This specification does not introduce any additional privacy concerns beyond those described in [RFC4314]. 8. IANA Considerations 8.1. Registration of IMAP capability LIST-MYRIGHTS This document defines the "LIST-MYRIGHTS" IMAP capability to be added to the registry defined in Section 12 of [RFC3501]. 8.2. Registration of LIST-EXTENDED option MYRIGHTS This section registers the "MYRIGHTS" option to be added to the registry defined in Section 9 of [RFC5258]. LIST-EXTENDED option name: MYRIGHTS LIST-EXTENDED option type: RETURN LIST-EXTENDED option description: Causes the LIST command to return MYRIGHTS responses in addition to LIST responses. Published specification: RFC XXXX, Section 3 Security considerations: RFC XXXX, Section 6 Intended usage: COMMON Person and email address to contact for further information: Kenneth Murchison Owner/Change controller: IESG 9. Acknowledgments This document is based largely on [RFC5819]. The author would like to thank the authors of that document for providing both inspiration and some borrowed text for this document. Murchison & Gondwana Expires November 22, 2017 [Page 4] Internet-Draft IMAP LIST-MYRIGHTS May 2017 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003, . [RFC4314] Melnikov, A., "IMAP4 Access Control List (ACL) Extension", RFC 4314, DOI 10.17487/RFC4314, December 2005, . [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008, . [RFC5258] Leiba, B. and A. Melnikov, "Internet Message Access Protocol version 4 - LIST Command Extensions", RFC 5258, DOI 10.17487/RFC5258, June 2008, . 10.2. Informative References [RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for Returning STATUS Information in Extended LIST", RFC 5819, DOI 10.17487/RFC5819, March 2010, . Appendix A. Change History (To be removed by RFC Editor before publication) Changes in draft-murchison-imap-list-myrights-01: o Augmented Introduction with mention of "LIST-MYRIGHTS" capability string. o Minor editorial changes. Murchison & Gondwana Expires November 22, 2017 [Page 5] Internet-Draft IMAP LIST-MYRIGHTS May 2017 Authors' Addresses Kenneth Murchison Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213 USA Email: murch@andrew.cmu.edu Bron Gondwana FastMail Pty Ltd Level 1, 91 William Street Melbourne, VIC 3000 Australia Email: brong@fastmail.fm Murchison & Gondwana Expires November 22, 2017 [Page 6]