calext B. Gondwana, Ed. Internet-Draft FastMail Updates: 6638 (if approved) March 19, 2018 Intended status: Standards Track Expires: September 20, 2018 CalDAV Extension for scheduling controls draft-gondwana-caldav-scheduling-controls-00 Abstract This document adds headers to control and restrict the scheduling behaviour of CalDAV servers when updating calendaring resources. 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 https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 20, 2018. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Gondwana Expires September 20, 2018 [Page 1] Internet-Draft JMAP IMAPData March 2018 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions Used In This Document . . . . . . . . . . . . . . 2 3. Scheduling header . . . . . . . . . . . . . . . . . . . . . . 3 4. Schedule-User-Address header . . . . . . . . . . . . . . . . 3 5. Implementation considerations . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 7. Security Considerations . . . . . . . . . . . . . . . . . . . 3 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 9.1. Normative References . . . . . . . . . . . . . . . . . . 4 9.2. Informative References . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction [RFC6638] defines automatic scheduling operations for resources stored on [RFC4719] CalDAV servers. While [RFC6638] does define the "Schedule-Reply" header is Section 8.1 to handle the case where spam needs to be cleaned up from a server without creating backscatter or notifications to the sender, this is only one case where it might be necessary to update the data store on a server without causing scheduling messages to be sent. Other cases include restoring from backup after a data loss event on the server, or importing calendar events from another system. Calendar server operators deal with these other needs by either using a different method than CalDAV to update their server, or by adding a custom method to suppress scheduling. This document defines a standard method to suppress scheduling, allowing CalDAV to be directly used for restores and imports. Complex sites can have users who have multiple aliases, and in the most complex cases, a user may have multiple identities who are present on a scheduling event as organizer and/or attendee. When an event is updated over CalDAV, the server must calculate or guess which of those addresses the current user is acting as. This document defines a header which allows the client to inform the server precisely which address they are acting as when adding, modifying or removing a resource. 2. Conventions Used In This Document In examples, "C:" indicates data sent by a client that is connected to a server. "S:" indicates data sent by the server to the client. Gondwana Expires September 20, 2018 [Page 2] Internet-Draft JMAP IMAPData March 2018 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] when they appear in ALL CAPS. These words may also appear in this document in lower case as plain English words, absent their normative meanings. 3. Scheduling header This document adds a new header on PUT, PROPPATCH and DELETE: Scheduling: {all|none|internal|X-...} Default: all e.g. Scheduling: none 4. Schedule-User-Address header This document adds a new header on PUT, PROPPATCH and DELETE: Schedule-User-Address: URI Default: not present e.g. Schedule-User-Address: mailto:foo@example.com 5. Implementation considerations 6. IANA Considerations TBD 7. Security Considerations The "Scheduling" header only allows reduction of the cases in which the server will creating scheduling requests, so does not increase security exposure. The "Schedule-User-Address" header allows the client to override the server choice of address for the user to act as. Servers MUST sanity check this value to ensure that the authenticated user has permission to act as the specified address, and MAY apply further policy limitations. Gondwana Expires September 20, 2018 [Page 3] Internet-Draft JMAP IMAPData March 2018 8. Acknowledgments TBD. 9. References 9.1. 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, . [RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012, . 9.2. Informative References [RFC4719] Aggarwal, R., Ed., Townsley, M., Ed., and M. Dos Santos, Ed., "Transport of Ethernet Frames over Layer 2 Tunneling Protocol Version 3 (L2TPv3)", RFC 4719, DOI 10.17487/RFC4719, November 2006, . Author's Address Bron Gondwana (editor) FastMail Level 2, 114 William St Melbourne VIC 3000 Australia Email: brong@fastmailteam.com URI: https://www.fastmail.com Gondwana Expires September 20, 2018 [Page 4]