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Privileged Components This specification provides a way for XMPP components to have a privileged access to entities data This XMPP Extension Protocol is copyright (c) 1999 - 2014 by the XMPP Standards Foundation (XSF). Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation. ## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. In no event shall the XMPP Standards Foundation or the authors of this Specification be liable for any claim, damages, or other liability, whether in an action of contract, tort, or otherwise, arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification. ## In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising out of the use or inability to use the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages. This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which may be found at <http://xmpp.org/extensions/ipr-policy.shtml> or obtained by writing to XSF, P.O. Box 1641, Denver, CO 80201 USA). xxxx ProtoXEP Standards Track Standards Council XMPP Core XEP-0114 XEP-0004 NOT_YET_ASSIGNED Jérôme Poisson goffi@goffi.org goffi@jabber.fr 0.0.1 2014-05-09 jp

First draft.

XMPP components are used for long through &xep0114;, but are quite limited: they have a restricted access to other entities data, similar to what a client can do. This is sufficient for components like gateways, but very limiting for more complex components like a PubSub service. The goal of this XEP is to allow a component to have a "privileged" status, and access an entity data with the same privileges than the entity itself, that means send and receive IQ stanzas on its behalf.

Privileged component have numerous advantages, including:

A privileged component can be used in two modes:

In admin mode, the component SHOULD be able to emit IQ stanzas in the same way as any entity, including managing roster or accessing persistent storage

In client mode, a component MUST have an explicit autorization for any IQ namespace he wants to use. Client MUST be able to check and revoke granted permssions.

Once the component is authentified and stream is started as explained in XEP-0114, the component can request its privileged status. It do it by sending an IQ stanza with 'urn:xmpp:tmp:privilege:0' namespace

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If the server accept the privileged status (e.g.: admin status specified in configuration), it MUST return empty IQ result stanza:

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If the server reject the privileged status, it MUST return a &forbidden; error:

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Sending an IQ stanzas is done by remplacing the &IQ; with a <privilege/> element of namespace 'urn:xmpp:tmp:privilege:0', and including it in a global IQ stanza. The <privilege/> element is then similar to the IQ stanza the client would have sent. In the following example, the PubSub service want to know juliet's roster because she own a node with roster access model:

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The server then answer normaly, as it would have done with the client entity:

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In the following example, the sync.capulet.net privileged component want to access client's bookmarks to synchronize them with an online service. It can request the bookmarks in the following way:

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and server answer:

JC ]]>

In client mode, the component is not certified by the server administrator, so the permissions MUST be explicitly allowed by the client. This is initiated by the component (it can be after an interaction with a client, like a subscription). It's done in a the same way as for admin mode with the following exceptions:

  1. the privilege type is client instead of admin
  2. the privilege is done per entity, so the entity MUST be specified in a 'to' attribute
  3. permission are explicitly asked for every needed namespace

Namespace permission are asked with a <perm/> element, which MUST contain a 'xmlns' attribute and a 'type' attribute which can be:

  • get — the component wants to send &IQ; stanza of type 'get'
  • set — the component wants to send &IQ; stanza of type 'set'
  • both — the component wants to send &IQ; stanza of type 'get' and 'set'

If a component want a read/write access to a client's roster (juliet) and a read only access to her pubsub, it can ask the permission like this:

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Once received the permission request, the server ask to the client if it grant access to the requested permission using &xep0004;. The form SHOULD allow to fine tune the granted permissions. The server use a challenge which it MUST have generated himself.

priv.montaigu.net wants some privileges. Do you you allow him to use the following features ? Be careful ! According permissions to component is a serious thing, think twice that you can trust the component before doing this. Privileges request priv.montaigu.net wants to use the following features: Do you allow it? 5439123 urn:xmpp:tmp:privilege:0 0 0 ]]>

The server SHOULD include a warning message, SHOULD translate the namespace to human friendly names (and MAY keep the original namespace in addition) and MUST set the default value to 'none' (permission refused).

The client can then answer to the form:

5439123 both none ]]>

Here juliet accept that priv.montaigu.net use 'set' and 'get' to manage her roster, but doesn't want it to do any 'get' on her pubsub nodes.

Finaly, the server notify the component of the permission granted. For this it use a &QUERY; element with the 'allowed' type, and put the client jid in a 'from' attribute:

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The privileged component can now act according to permission granted to him.

sending IQ stanza is done in the exact same way as for admin mode. If a component want to sent a non authorized IQ, it get a &forbidden; error:

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If a server or a component supports the component privilege protocol, it MUST report that fact by including a service discovery feature of "urn:xmpp:tmp:privilege:0" in response to a &xep0030; information request:

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  1. Server MAY keep permission granted to an component by a client from one session to an other, but if it do so, it MUST provide a way to client to check already granted permission, and revoke them (possibly using &xep0050;).
  2. If a client can't check or revoke permission (e.g. it doesn't support XEP-0050), the server MUST NOT keep granted permission from one session to an other, and permission will be asked on each new session.

As admin mode is far more easy to implement than client mode, a server MAY choose to only implement the former
  1. Privileged component nearly have the same possibility as the server itself, admin permission should be granted carefuly, only if you absolutely trust the component.
  2. A server MAY choose to filter allowed namespaces, to avoid giving dangerous permissions. In this case, it MUST always set the allowed type of filtered namespaces to none
  3. In case of filtering, a whitelist system is more secure and SHOULD be prefered to a blacklist (idealy, configuration would allow no filtering, whitelist filtering and blacklist filtering)

REQUIRED. TODO

REQUIRED. TODO

REQUIRED for protocol specifications. TODO