# HG changeset patch # User Goffi # Date 1423133807 -3600 # Node ID 57dfd2ab28815fc44cf6a26e4efe417bd80282c9 # Parent 2abfd0f6fd341200a194862c7866a0cab531c182 association: updated location (article 3) in statuts diff -r 2abfd0f6fd34 -r 57dfd2ab2881 association/statuts.odt Binary file association/statuts.odt has changed diff -r 2abfd0f6fd34 -r 57dfd2ab2881 association/statuts.pdf Binary file association/statuts.pdf has changed diff -r 2abfd0f6fd34 -r 57dfd2ab2881 xmpp/xep-proto-abac.xml --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/xmpp/xep-proto-abac.xml Thu Feb 05 11:56:47 2015 +0100 @@ -0,0 +1,350 @@ + + +%ents; +]> + + +
+ Attribute Based Access Control + This specification adapt Attribute Based Access Control (ABAC) model to XMPP + + 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.

 + +
+ + +

Different access control models are used in XMPP, most of time Role Based Access Model (RBAC) like in MUC, or Identity Based Access Model (IBAC) like [...]

+

Privileged entities have numerous advantages, including:

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  • a step forward in decentralization: it is possible for an entity to do tasks which were before reserved to server itself. For example, a privileged pubsub component can offer access model based on publisher's roster
    • +
  • better integration of components: a gateway can add items to an entity roster itself
    • +
  • possibility to overpass a server limitation (typically: incomplete PEP implementation)
    • +
  • quick development cycle: developers can implement the components they need without waiting for a new server release
    • +
  • server agnostic
    • +
+

Privileged entity has been created with the main goal to create an external, server agnostic, PEP service. It is restricted to only a couple of features, see Acknowledgements section for more details

+ + + +

A privileged entity must be able to do what a PEP service can do and to access roster, so it must be able to (according to configuration):

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  • get and modify the roster of any entity managed by the server
    • +
  • send a &MESSAGE; stanza on behalf of the server
    • +
  • access &PRESENCE; informations for entities in a managed entity's roster (and for managed entity itself)
    • +
+

The privilege mechanism MUST be totally transparent for the managed entities.

+ + + +
    +
  • Privileged entity — the entity which has a privileged status.
    • +
  • Managed entity — the entity that is managed by a privileged entity.
    • +
+ + + + + +

Roster access is granted in the server configuration. Roster access can have 4 types:

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  • none — the entity is not allowed to access managed entity roster at all. This MUST be the default value.
    • +
  • get — the entity is allowed to send &IQ; stanzas of type 'get' for the namespace 'jabber:iq:roster'.
    • +
  • set — the entity is allowed to send &IQ; stanzas of type 'set' for namespace 'jabber:iq:roster'.
    • +
  • both — the entity is allowed to send &IQ; stanzas of type 'get' and 'set' for namespace 'jabber:iq:roster'.
    • +
+ + + +

Once an entity is authenticated and stream is started, the server send it a &MESSAGE; stanza with a <privilege> elements which MUST have the namespace 'urn:xmpp:privilege:0'. This element contains <perm> elements which MUST contain a 'namespace' attribute of the value "jabber:iq:roster" and a 'type' attribute which must correspond to the type configured as specified in "Server Allows Roster Access" section

+ + + + + + ]]> +

Here pubsub.capulet.lit is allowed to do get and set operations on all entities managed by capulet.lit

+ + + +

Doing a get or set operation on the roster of a managed entity is done in the usual way (as described in &rfc6121; section 2), except that the 'to' attribute is set to the attribute of the managed entity. The server MUST check that the privileged entity has right to get or set the roster of managed entity, and MUST return a &forbidden; error if it is not the case:

+ + + + ]]> + +

The server then answers normally, as it would have done to the managed entity:

+ + + + + + + ]]> + + + + + + +

In some cases, it can be desirable to send notifications (e.g. PEP service), so the privileged entity must be able to send &MESSAGE; stanzas. This is allowed in server configuration in the same way as for roster permission. The permission type can have the following values:

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  • none — the entity is not allowed to send &MESSAGE; stanza in the name of the server. This MUST be the default value.
    • +
  • outgoing — the entity is allowed to send &MESSAGE; stanzas in the name of the server, according to following restrictions.
    • +
+

A privileged entity can then send message on the behalf either of the server or of a bare JID of the server, using &xep0297;, with the following restrictions:

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  1. forwarded &MESSAGE; 'type' attribute has the value of "headline"
    2. +
  2. forwarded &MESSAGE; 'from' attribute MUST be a bare JID from the server, no resource is allowed
    3. +
+

If any of this rules is violated, the server MUST return a <not-authorized/> stream error and close the connection, as explained in &rfc6120; section 4.9.3.12.

+ + + +

Server advertise "message" permission in the same way as for "roster" permission, except that 'namespace' attribute has the value of "message", and the 'type' attribute as a value of 'outgoing':

+ + + + + + +]]> + + + +

Now that pubsub.capulet.lit is allowed, it can send messages using <forwarded/> elements.

+ + + + + + + + Gerald Finzi + 255 + Music for "Love's Labors Lost" (Suite for small orchestra) + Introduction (Allegro vigoroso) + 1 + + + + + + + + + ]]> +

The server sees that forwarded message type is 'headline', that juliet@capulet.lit is a bare JID of the server, and that outgoing message permission was granted in admin mode (so all bare JIDs from server are allowed); it can now send the notification:

+ + + + + + Gerald Finzi + 255 + Music for "Love's Labors Lost" (Suite for small orchestra) + Introduction (Allegro vigoroso) + 1 + + + + + + + ]]> + + + + + +

It can be often desirable for a privileged entity to have presence information of the managed entities (e.g. to know when to send them notificiations). As privileges must be transparent for the managed entity, this presence has to be sent by the server without modifying managed entity roster.

+

This is allowed in server configuration in the same way as for roster and message permissions. The "presence" type can have the following values:

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  • none — the entity is not allowed to access &PRESENCE; informations at all. This MUST be the default value.
    • +
  • managed_entity — the entity is allowed to receive managed entity presence (see below).
    • +
  • roster — the entity is allowed to receive presence informations of managed entity contacts, see Roster Presence section.
    • +
+

If the privilege is granted, the server MUST use a directed presence, as specified in &rfc6121; section 4.6 on the behalf of managed entity each time its presence information change.

+ + + +

Server advertise "presence" permission in the same way as for "roster" or "message" permissions, except that 'namespace' attribute has the value of "presence", and the 'type' attribute has a value of "managed_entity"

+ + + +

Once the "presence" permission is granted, the server send presence informations:

+ + chat + Staying on the balcony + +]]> + + + chat + Staying on the balcony + +]]> + + + + +

In addition to "managed entity presence", a privileged entity may need to know when a contact in managed entity roster is online (for example, it's necessary for a PEP service because of the presence default access model).

+

As for other permissions, the access in granted in server's configuration, but there is a additional restriction: the privileged entity MUST have read permission on roster namespace (i.e. 'type' attribute in allowed <perm> of namespace jabber:iq:roster MUST have a value of either get or both).

+

If the delegation is granted, the server MUST send to the privileged entity every presence information that the privileged entity is receiving. Having "roster" type for "presence" permission imply that you have also implicitly "managed_entity" type.

The server MUST reject the permission if the privileged entity doesn't have read permission on roster namespace.

+

Note: this permission should be given carefully, as it gives access to presence of potentially a lot of entities to the privileged entity (see security considerations).

+ + + +

Server advertise roster "presence" permission in the same way as for other permissions, except that the 'namespace' attribute has the value of "presence", and the 'type' attribute has a value of "roster"

+ + + + + + + +]]> +

Note the presence of jabber:iq:roster permission request.

+ + + + +]]> + + +]]> + + + + +
    +
  1. Privileged entitiy has access to sensitive data, and can act as the server itself, permissions should be granted carefuly, only if you absolutely trust the entity.
    2. +
  2. Roster presence is particulary sensitive, because presence informations of whole rosters are shared.
    3. +
+ + + +

This document requires no interaction with &IANA;.

+ + + + +

The ®ISTRAR; includes 'urn:xmpp:privilege:0' in its registry of protocol namespaces (see &NAMESPACES;).

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  • urn:xmpp:privilege:0
    • +
+ + + &NSVER; + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ]]> + + + +

Thanks to Sergey Dobrov, Dave Cridland, Steven Lloyd Watkin, Lance Stout and Johannes Hund for their feedbacks. Thanks to Adrien Cossa for his typos/style corrections.

+

Privileged entity was initialy written to be a generic identity based access control (IBAC) which allows an entity to access sensitive data. After a discussion on standard mailing list, it has been decided to restrict the current XEP to immediate needs to build an external PEP service, and to implement separately an Attribute Based Access Control (ABAC) which is more modern, generic and flexible. This XEP is still interesting for being easy to implement and doing the job.

+ + + +