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888 lines
44 KiB
XML
888 lines
44 KiB
XML
<?xml version='1.0' encoding='UTF-8'?>
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<!DOCTYPE xep SYSTEM 'xep.dtd' [
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<!ENTITY % ents SYSTEM 'xep.ent'>
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<!ENTITY LABEL "<tt><label/></tt>">
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<!ENTITY CATALOG "<tt><catalog/></tt>">
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<!ENTITY ITEM "<tt><item/></tt>">
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<!ENTITY SECURITYLABEL "<tt><securitylabel/></tt>">
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<!ENTITY DISPLAYMARKING "<tt><displaymarking/></tt>">
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<!ENTITY EQUIVALENTLABEL "<tt><equivalentlabel/></tt>">
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<!ENTITY HEADLINE "<tt><headline/></tt>">
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<!ENTITY IDENTITY "<tt><identity/></tt>">
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%ents;
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]>
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<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
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<xep>
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<header>
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<title>Security Labels in XMPP</title>
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<abstract>This document describes the use of security labels in XMPP. The document specifies
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how security label meta-data is carried in XMPP, when this meta-data should or should
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not be provided, and how the meta-data is to be processed.</abstract> &LEGALNOTICE;
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<number>0258</number>
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<status>Draft</status>
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<interim/>
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<type>Standards Track</type>
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<sig>Standards</sig>
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<approver>Council</approver>
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<dependencies>
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<spec>XMPP Core</spec>
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<spec>XEP-0001</spec>
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</dependencies>
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<supersedes/>
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<supersededby/>
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<shortname>sec-label</shortname>
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<schemaloc>
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<ns>extension</ns>
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<url>http://xmpp.org/schemas/sec-label.xsd</url>
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</schemaloc>
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<schemaloc>
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<ns>catalog</ns>
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<url>http://xmpp.org/schemas/sec-label-catalog.xsd</url>
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</schemaloc>
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<schemaloc>
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<ns>esssecuritylabel</ns>
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<url>http://xmpp.org/schemas/sec-label-ess.xsd</url>
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</schemaloc>
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<author>
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<firstname>Kurt</firstname>
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<surname>Zeilenga</surname>
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<email>Kurt.Zeilenga@Isode.COM</email>
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<jid>Kurt.Zeilenga@Isode.COM</jid>
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</author>
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<revision>
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<version>1.1rc1</version>
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<date>2012-10-30</date>
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<initials>kdz</initials>
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<remark>
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<p>Clarify catalogs are temporal objects. Offer client handling suggestions.</p>
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</remark>
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</revision>
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<revision>
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<version>1.0</version>
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<date>2011-11-10</date>
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<initials>psa</initials>
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<remark><p>Per a vote of the XMPP Council, advanced specification to Draft; corrected version of catalog namespace in schema.</p></remark>
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</revision>
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<revision>
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<version>0.10</version>
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<date>2011-11-03</date>
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<initials>kdz</initials>
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<remark>
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<p>Address last call comments.</p>
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</remark>
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</revision>
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<revision>
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<version>0.9</version>
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<date>2011-09-21</date>
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<initials>kdz</initials>
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<remark>
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<p>Add optional <tt>from=</tt> attribute to catalog element for S2S requests. Make
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editorial changes.</p>
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</remark>
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</revision>
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<revision>
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<version>0.8</version>
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<date>2011-08-11</date>
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<initials>kdz</initials>
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<remark>
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<p>Correct catalog schema.</p>
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</remark>
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</revision>
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<revision>
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<version>0.7</version>
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<date>2011-03-08</date>
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<initials>kdz</initials>
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<remark>
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<p>Illustrate XEP Multi-User Chat room security label configuration. Make
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clarifications and minor editorial changes.</p>
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</remark>
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</revision>
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<revision>
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<version>0.6</version>
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<date>2010-07-30</date>
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<initials>kdz</initials>
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<remark>
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<p>Extend catalog handling. Minor editorial changes.</p>
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</remark>
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</revision>
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<revision>
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<version>0.5</version>
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<date>2009-07-27</date>
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<initials>kdz</initials>
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<remark>
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<p>Remove &LABEL;/&EQUIVALENTLABEL; <tt>type=</tt> attribute. Clarify label catalog
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discovery. Clarify syntax of <tt>selector=</tt> attribute.</p>
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</remark>
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</revision>
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<revision>
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<version>0.4</version>
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<date>2009-07-23</date>
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<initials>kdz</initials>
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<remark>
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<p>Update label catalogs to include user input selector.</p>
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</remark>
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</revision>
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<revision>
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<version>0.3</version>
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<date>2009-03-20</date>
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<initials>kdz</initials>
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<remark>
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<p>Add text regarding default bg/fg colors. Correct examples.</p>
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</remark>
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</revision>
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<revision>
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<version>0.2</version>
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<date>2009-03-10</date>
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<initials>kdz</initials>
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<remark>
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<p>Reworked discovery and various updates.</p>
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</remark>
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</revision>
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<revision>
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<version>0.1</version>
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<date>2009-01-05</date>
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<initials>psa</initials>
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<remark>
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<p>Initial published version.</p>
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</remark>
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</revision>
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<revision>
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<version>0.0.081203</version>
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<date>2008-12-03</date>
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<initials>kdz</initials>
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<remark>
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<p>Initial draft.</p>
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</remark>
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</revision>
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</header>
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<section1 topic="Introduction" anchor="intro">
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<p>A security label, sometimes referred to as a confidentiality label, is a structured
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representation of the sensitivity of a piece of information. A security label is used in
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conjunction with a clearance, a structured representation of what information
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sensitivities a person (or other entity) is authorized to access, and a security policy
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to control access to each piece of information. For instance, a message could be labeled
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as "SECRET", and hence requiring the sender and the receiver to each have a clearance
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granting access to "SECRET" information. &X.841; provides a discussion of security
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labels, clearances, and security policy.</p>
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<p>Sensitivity-based authorization is used in networks which operate under a set of
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information classification rules, such as in government agency networks. The
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standardized formats for security labels, clearances, and security policy are
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generalized and do have application in non-government networks.</p>
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<p>This document describes the use of security labels in &xmpp;. The document specifies how
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security label meta-data is carried in XMPP. It standardizes a mechanism for carrying
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ESS Security Labels in XMPP, as well as provides for use of other label formats. ESS
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Security Labels are specified in &rfc2634;. ESS Security Labels are commonly used in
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conjunction with &X.500; clearances and either X.841 or &SDN.801c; security
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policies.</p>
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<example caption="Message with ESS Security Label"><![CDATA[
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<message to='romeo@example.net' from='juliet@example.com/balcony'>
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<body>This content is classified.</body>
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='red'>SECRET</displaymarking>
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<label><esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'>
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MQYCAQQGASk=
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</esssecuritylabel></label>
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</securitylabel>
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</message>
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]]></example>
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<example caption="Message with IC-ISM Label"><![CDATA[
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<message to='romeo@example.net' from='juliet@example.com/balcony'>
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<body>This content is classified.</body>
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='red'>SECRET</displaymarking>
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<label><icismlabel xmlns='http://example.gov/IC-ISM/0' classification='S'
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ownerProducer='USA'/></label>
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</securitylabel>
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</message>
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]]></example>
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<p>Note: The &IC-ISM; label example is for <em>illustrative purposes only</em>.</p>
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<p>The document details when security label meta-data should or should not be provided, and
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how this meta-data is to be processed.</p>
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<p>This document does not provide: <ul>
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<li>any mechanism for a client to discover the security policy in force at its home
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server, or any other server;</li>
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<li>any mechanism for a client to discover the user's clearance, or the clearance of
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associated with any resource; nor</li>
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<li>any administrative mechanism for a client to configure configure policy,
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clearance, and labels of any resource.</li>
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</ul> Such mechanisms may be introduced in subsequent documents.</p>
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<p>This document does not discuss how one might securely bind a security label to a stanza.
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It is expected a subsequent document will tackle this topic.</p>
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</section1>
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<section1 topic="Discovering Feature Support" anchor="disco">
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<p>An entity (client or server) which supports the XMPP Security Label protocol MUST report
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that fact by including a service discovery feature of "<tt>urn:xmpp:sec-label:0</tt>" in
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response to a &xep0030; information request.</p>
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<p>Clients wishing to include a XMPP Security Label element in any stanza they generate
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SHOULD determine if their server supports the XMPP Security Label protocol. If their
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server does not support XMPP Security Label, the client SHOULD NOT generate XMPP
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Security Labels as the server not supporting this protocol will generally ignore XMPP
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Security Labels as they would any other unrecognized element.</p>
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<p>As each service domain may have different support for security labels, servers should
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advertise and clients should perform appropriate discovery lookups on a per service
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basis.</p>
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<example caption="Service Discovery information request"><![CDATA[
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<iq type='get'
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from='user@example.com/Work'
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to='example.com'
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id='disco1'>
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<query xmlns='http://jabber.org/protocol/disco#info'/>
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</iq>
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]]></example>
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<example caption="Service Discovery information response"><![CDATA[
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<iq type='result'
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from='example.com'
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to='user@example.com/Work'
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id='disco1'>
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<query xmlns='http://jabber.org/protocol/disco#info'>
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...
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<feature var='urn:xmpp:sec-label:0'/>
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...
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</query>
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</iq>
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]]></example>
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</section1>
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<section1 topic="Protocol" anchor="protocol">
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<p>An element, &SECURITYLABEL;, is defined to carry security label meta-data. This meta-data
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includes a security label, zero or more equivalent security labels, and optionally
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display marking data.</p>
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<example caption="Labeled Message"><![CDATA[
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<message to='romeo@example.net' from='juliet@example.com/balcony'>
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<body>This content is classified.</body>
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='red'>SECRET</displaymarking>
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<label>
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<esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'
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>MQYCAQIGASk=</esssecuritylabel>
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</label>
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<equivalentlabel>
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<esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'
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>MRUCAgD9DA9BcXVhIChvYnNvbGV0ZSk=</esssecuritylabel>
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</equivalentlabel>
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</securitylabel>
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</message>
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]]></example>
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<p>The security label meta-data is carried in an &SECURITYLABEL; element. The
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&SECURITYLABEL; element which contains one and only one &LABEL; element, zero or more
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&EQUIVALENTLABEL; elements, and an optional &DISPLAYMARKING; element.</p>
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<p>The &LABEL; provides the primary security label. It is commonly issued by the sender
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under the security policy of that they and their home server operating under. The
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&LABEL; contains either a single element representing the primary security label or is
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empty to indicate use of a default.</p>
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<p>Each &EQUIVALENTLABEL; represents an equivalent security label under other policies. Each
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&EQUIVALENTLABEL; contains a single element representing the equivalent label. This
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element might be used when a recipient is known to hold a clearance under a different
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policy than the sender.</p>
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<p>The &DISPLAYMARKING; element contains a display string for use by implementations which
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are unable to utilize the applicable security policy to generate display markings. The
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element may optionally contain two attributes, <tt>fgcolor=</tt> and <tt>bgcolor=</tt>,
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whose values are HTML color strings (e.g., '<tt>red</tt>' or '<tt>#ff0000</tt>'), for
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use in colorizing the display marking. The <tt>fgcolor=</tt> default is <tt>black</tt>.
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The <tt>bgcolor=</tt> default is <tt>white</tt>. </p>
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</section1>
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<section1 topic="Label Catalog Discovery" anchor="label-catalog">
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<p>A client can request a catalog for a particular JID by sending a catalog discovery
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request to the client's server. Where the JID is hosted by some other server, the
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client's server is expected to produce a suitable catalog (or fail the request). The
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client's server may, as needed, query catalogs from other servers in order to fulfill
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the client's request.</p>
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<p>While this specification does not preclude a client from directing a catalog request
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elsewhere, it is noted that catalog returned by a party other than its server may not be
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directly usable by the client. For instance, the client's server might require a
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particular only-locally-known label be used in messages to a particular remote JID.</p>
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<p>It is RECOMMENDED the server publish catalogs of security label for use by clients.</p>
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<p>Two identical catalog requests may return different results, even for the same
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requester, as the results may depend on numerous factors. It is suggested that clients
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request a catalog for use in a short-lived context, such as short-lived 1-to-1 chat
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session, for all use in stanzas of that session. For use in long-lived context, such
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as a long-lived Multi-User Chat session, it is suggested the client request the
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current catalog when the user becomes present after a period of extended absence.
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Alternatively, a client could simply cache catalog results for a configurable amount of
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time. With either approach, it is also suggested clients provide a means for the user
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to request an immediate refresh of all catalogs in all contexts. This is useful where
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the user made changes to a personal label catalog which the XMPP server uses as input
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in processing catalog requests. Note: there is no requirement that XMPP servers
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support 'personal label catalogs' (such details are beyond the scope of this document).</p>
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<p>If catalog is restrictive, as indicated by the <tt>restrict=</tt> attribute with value of
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true, the client SHOULD restrict the user to choosing one of the items from the catalog
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and use the label of that item (or no label if the selected item is empty).</p>
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<p>One and only one of the items may have a <tt>default=</tt> attribute with value of true.
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The client should default the label selection to this item in cases where the user has
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not selected an item.</p>
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<p>An item may have no security label. Such an item explicitly offers a choice of sending a
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stanza without a label. A non-restrictive catalog implicitly offers this choice when it
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does not contain an empty item.</p>
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<p>Each catalog provided should only contain labels for which the client is allowed to use
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(based upon the user's authorization) in a particular context (such as in chat room). A
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catalog may not include the complete set of labels available for the use by the client
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in the context.</p>
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<blockquote>Note: the single catalog per context approach used here is likely inadequate in
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environments where there are a large number of labels in use. It is expected that a more
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sophisticated approach will be introduced in a subsequent revision of this
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specification.</blockquote>
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<p>As each service domain may have different support for security labels, servers should
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advertise and clients should perform appropriate discovery lookups on a per service
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basis.</p>
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<p>To indicate the support for label catalog discovery, a server advertises the
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<tt>urn:xmpp:sec-label:catalog:2</tt> feature. The following pair of examples
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illustrates this feature discovery.</p>
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<p>Items in the catalog may contain a <tt>selector=</tt> attribute. The value of this
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attribute represents the item's placement in a hierarchical organization of the items.
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If one item has a <tt>selector=</tt> attribute, all items should have a
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<tt>selector=</tt> attribute. The value of the <tt>selector=</tt> attribute conforms
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to the <tt>selector-value</tt> ABNF production: <blockquote><tt>
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<![CDATA[
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selector-value = (<item>"|")*<item>
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]]>
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</tt></blockquote>
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</p>
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<p>where &ITEM; is a sequence of characters not including "|".</p>
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<p>A value of "X|Y|Z" indicates that this item is "Z" in the the "Y" subset of the "X"
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subset of items. This information may be used, for instance, in generating label
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selection menus in graphical user interfaces.</p>
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<blockquote>Note: use of unnecessarily deep hierarchies should be avoided.</blockquote>
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<example caption="Label Catalog Feature Discovery request"><![CDATA[
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<iq type='get'
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to='example.com'
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from='user@example.com/Work'
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id='disco1'>
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<query xmlns='http://jabber.org/protocol/disco#info'/>
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</iq>
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]]></example>
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<example caption="Label Information Feature Discovery response"><![CDATA[
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<iq type='result'
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from='example.com'
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to='user@example.com/Work'
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id='disco1'>
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<query xmlns='http://jabber.org/protocol/disco#info'>
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...
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<feature var='urn:xmpp:sec-label:catalog:2'/>
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...
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</query>
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</iq>
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]]></example>
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<p>The following example pair illustrates catalog discovery. The client directs the <tt>&IQ;</tt> to
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its server regardless of which catalog it requests via the <tt>to=</tt> attribute of in
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&CATALOG; element. The client SHOULD NOT provide a <tt>from=</tt> attribute in the
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&CATALOG; element.</p>
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<example caption="Label Catalog request"><![CDATA[
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<iq to='example.com' type='get' id='cat1'>
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<catalog xmlns='urn:xmpp:sec-label:catalog:2' to='example.com'/>
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</iq>
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]]></example>
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<example caption="Label Catalog Get response"><![CDATA[
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<iq type='result' to='user@example.com/Work' id='cat1'>
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<catalog xmlns='urn:xmpp:sec-label:catalog:2'
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to='example.com' name='Default'
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desc='an example set of labels'
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restrict='false'>
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<item selector="Classified|SECRET">
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='red'>SECRET</displaymarking>
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<label>
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<esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'
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>MQYCAQQGASk=</esssecuritylabel>
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</label>
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</securitylabel>
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</item>
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<item selector="Classified|CONFIDENTIAL">
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='navy'>CONFIDENTIAL</displaymarking>
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<label>
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<esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'
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>MQYCAQMGASk</esssecuritylabel>
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</label>
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</securitylabel>
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</item>
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<item selector="Classified|RESTRICTED">
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<securitylabel xmlns='urn:xmpp:sec-label:0'>
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<displaymarking fgcolor='black' bgcolor='aqua'>RESTRICTED</displaymarking>
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<label>
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<esssecuritylabel xmlns='urn:xmpp:sec-label:ess:0'
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>MQYCAQIGASk=</esssecuritylabel>
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</label>
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</securitylabel>
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</item>
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<item selector="UNCLASSIFIED" default="true"/>
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</catalog>
|
|
</iq>
|
|
]]></example>
|
|
|
|
<p> Where the server needs to obtain a catalog from another server in order to respond to
|
|
its client, it can send an &IQ; to that server requesting that catalog. The requesting
|
|
server provides the bare JID of the requesting user in the <tt>from=</tt> attribute in
|
|
the &CATALOG; element when it desires a catalog to be prepared specifically for the
|
|
user. Otherwise the <tt>from=</tt> attribute in the &CATALOG; element is absent. </p>
|
|
|
|
</section1>
|
|
|
|
<section1 topic="Use in XMPP" anchor="xmpp-use">
|
|
<p>The sensitivity-based access control decisions discussed herein are to be made
|
|
independently of other access control decisions or other facilities. That is, the
|
|
sensitivity-based access control decisions are not conditional on other factors.</p>
|
|
<p>It is intended that &SECURITYLABEL; elements are only used as prescribed by this
|
|
document, documents extending this document, or other formal specifications. Any other
|
|
use of &SECURITYLABEL; SHOULD be viewed as a protocol violation. The stanza SHOULD be
|
|
discarded with, if appropriate, an error response. Such error responses SHOULD NOT
|
|
include content from the violating stanza, excepting that necessary to well-formed error
|
|
responses. Error responses MUST NOT contain a &SECURITYLABEL; element. Any such error
|
|
response violates this protocol and MUST be discarded by servers implementing this
|
|
specification. Error responses MUST NOT be subjected to security label authorization
|
|
checks. However, this prohibition does not preclude a server from taking appropriate
|
|
action to prevent the disclosure of sensitive information, such as closing the
|
|
stream.</p>
|
|
<p>When use of a &SECURITYLABEL; element is prescribed, that use is RECOMMENDED. Absence of
|
|
a &SECURITYLABEL; element implies the stanza has the default label as specified in the
|
|
governing security policy. Given that the governing policy may not specify a default
|
|
label, hence denying access to the stanza, supporting clients SHOULD provide a
|
|
&SECURITYLABEL; element where prescribed.</p>
|
|
<p>Typically, a client would allow the user to choose populate the &SECURITYLABEL; from one
|
|
of from a small set of security labels selections known to it (through configuration
|
|
and/or discovery and/or other means), such as from a pull-down menu. That selection
|
|
would include appropriate values for the &LABEL;, &DISPLAYMARKING;, and
|
|
&EQUIVALENTLABEL; elements.</p>
|
|
<p>A policy-aware client may provide the user with an interface allowing the user to produce
|
|
custom labeling data for inclusion in this set. A policy-aware client SHOULD preclude
|
|
the user from producing &LABEL; values which the user's own clearance does not grant
|
|
access to, and SHOULD preclude sending any label which the user's own clearance does not
|
|
grant access to. Each &EQUIVALENTLABEL; value, if any, MUST be equivalent under an
|
|
equivalent policy to the &LABEL;. The &DISPLAYMARKING; element SHOULD be set the display
|
|
marking prescribed for the &LABEL; under the governing policy, or, if the governing
|
|
policy prescribes no display marking for the &LABEL;, absent.</p>
|
|
<p>A client which receives a stanza with &SECURITYLABEL; element is to prominently display
|
|
the &DISPLAYMARKING; value. A policy-aware client may alternatively prominently display
|
|
the marking for the &LABEL; prescribed by the governing policy.</p>
|
|
<p>Each server is expected to make a number of sensitivity-based authorization decisions.
|
|
Each decision is made by evaluating an Access Control Decision Function (ACDF) with a
|
|
governing policy, a clearance, and a security label. The ACDF yields either
|
|
<em>Grant</em> or <em>Deny</em>.</p>
|
|
<p>If the user holds a valid clearance (known to the server) under the governing policy, the
|
|
clearance input is the user's clearance. Otherwise, if the governing policy provides a
|
|
default clearance, the clearance input is the default clearance. Otherwise, the
|
|
clearance input is the nil clearance. The nil clearance is a clearance for which the
|
|
ACDF always returns Deny when given as the clearance input.</p>
|
|
<p>If the stanza contains a &SECURITYLABEL; element and the either the &LABEL; element or
|
|
one of the &EQUIVALENTLABEL; elements contain an appropriate label, that label input is
|
|
that label. Otherwise, the label input is the default label provided the governing
|
|
policy or, if no default label is provided, the nil label. The nil label is a label for
|
|
which the ACDF always returns Deny when given as the label input.</p>
|
|
<p>The term "effective clearance" and "effective label" refer, respectively, to the
|
|
clearance and label provided as input to the ACDF.</p>
|
|
<p>Not all sensitivity-based authorization decisions an XMPP server might make involve a
|
|
user clearance and/or stanza label. A server may only provide service to users which
|
|
hold an appropriate clearance as determined by calling the ACDF with the user's
|
|
clearance and a label associated with the service. A clearance might also be associated
|
|
with the service to restrict the set of labels may be used in labeling stanzas. Labels
|
|
and clearances can also be associated with network interfaces, remote servers, and chat
|
|
rooms.</p>
|
|
<section2 topic="Use in Instant Messaging" anchor="im-use">
|
|
<p>A client may provide a &SECURITYLABEL; element in any <tt>&MESSAGE;</tt> it sends.</p>
|
|
<!--
|
|
<p>The server will make, at a minimum, the following accessing control decisions:
|
|
<ul>
|
|
<li>TBD</li>
|
|
</ul>
|
|
</p>
|
|
-->
|
|
</section2>
|
|
<section2 topic="Use in Group Chat and Multi-User Chat" anchor="muc-use">
|
|
<p>A client may provide a &SECURITYLABEL; element in <tt>&MESSAGE;</tt> stanzas.</p>
|
|
|
|
<section3 topic="Discovery" anchor="muc-disco">
|
|
<p>A server SHOULD provide a label feature and information discovery for the
|
|
room.</p>
|
|
<p>Clients SHOULD discover label feature and information on a per room basis.</p>
|
|
</section3>
|
|
|
|
<section3 topic="Sending Messages" anchor="muc-send">
|
|
<p>Sending groupchat messages is similar to sending normal messages, however their
|
|
are a few differences.</p>
|
|
<p>Groupchat messages are addressed to the room. The room clearance must be suitable
|
|
for the message label, else it should be rejected.</p>
|
|
<p>The room's clearance may allow a variety of labels to be used. Not all
|
|
participants may be cleared for all labels allowed in the room. The server MUST
|
|
only deliver messages to participants for which they are cleared to receive.</p>
|
|
</section3>
|
|
<section3 topic="Room History" anchor="muc-history">
|
|
<p>The server MUST only deliver messages to participants for which they are cleared
|
|
to receive.</p>
|
|
</section3>
|
|
<section3 topic="Private Messages" anchor="muc-private">
|
|
<p>Private messages SHOULD be handled much like groupchat messages, including
|
|
rejection of messages for a label not suitable for the room. The server MUST NOT
|
|
deliver messages to participants for which they are cleared to receive.</p>
|
|
</section3>
|
|
<section3 topic="Invitations" anchor="muc-invite">
|
|
<p>Invitations may be labeled.</p>
|
|
</section3>
|
|
<section3 topic="Room Subject" anchor="muc-subject">
|
|
<p>A stanza intended to change the room subject SHOULD not carry a security label
|
|
and SHOULD NOT be subject to security-label authorization checks. Such a stanza
|
|
does not have any impact on the security-label parameters associated with the
|
|
room.</p>
|
|
</section3>
|
|
<section3 topic="Room Configuration" anchor="muc-config">
|
|
<p>The server may allow for configuration of security label parameters via room
|
|
configuration mechanisms. The approach is intended to be ad-hoc. Hence this
|
|
section is intended to be illustrative of one possible approach. Implementations
|
|
are free to utilize other approaches.</p>
|
|
<example caption="Room Configuration Form"><![CDATA[
|
|
<iq from='room@muc.example.com'
|
|
id='create1'
|
|
to='user@example.com/Work'
|
|
type='result'>
|
|
<query xmlns='http://jabber.org/protocol/muc#owner'>
|
|
<x xmlns='jabber:x:data' type='form'>
|
|
<title>"darkcave" room configuration</title>
|
|
...
|
|
<field label='Room Label' type='list-single' var='sec-label#label'>
|
|
<value>Catalog:UNCLASSIFIED</value>
|
|
<option label='SECRET'><value>Catalog:SECRET</value></option>
|
|
<option label='CONFIDENTIAL'><value>Catalog:CONFIDENTIAL</value></option>
|
|
<option label='UNCLASSIFED'><value>Catalog:UNCLASSIFIED</value></option>
|
|
<option label='Custom'><value>Custom</value></option>
|
|
</field>
|
|
<field label='Custom Room Label' type='text-single'
|
|
var='sec-label#custom-label'/>
|
|
|
|
<field label='Room Allowed Markings' type='list-multi' var='sec-label#clearance'>
|
|
<value>Catalog:UNCLASSIFIED</value>
|
|
<option label='SECRET'><value>Catalog:SECRET</value></option>
|
|
<option label='CONFIDENTIAL'><value>Catalog:CONFIDENTIAL</value></option>
|
|
<option label='UNCLASSIFED'><value>Catalog:UNCLASSIFIED</value></option>
|
|
<option label='Custom'><value>Custom</value></option>
|
|
</field>
|
|
<field label='Custom Room Clearance' type='text-single'
|
|
var='sec-label#custom-clearance'/>
|
|
</x>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
<p>In the above example, the server allows the room label to be set to one of to a
|
|
subset of labels from the label catalog (see below), using the display name for
|
|
selection, as well as custom label support. For custom label choice support, the
|
|
server offers an single text box for entry of an appropriate text string
|
|
indicating the label to use. Likewise for the room clearance and default room
|
|
clearance.</p>
|
|
<p>Though offering choices from the label catalog is often desirable, a server could
|
|
only offer custom label and/or clearance support.</p>
|
|
<example caption="Room Configuration Form"><![CDATA[
|
|
<iq from='room@muc.example.com'
|
|
id='create1'
|
|
to='user@example.com/Work'
|
|
type='result'>
|
|
<query xmlns='http://jabber.org/protocol/muc#owner'>
|
|
<x xmlns='jabber:x:data' type='form'>
|
|
<title>"darkcave" room configuration</title>
|
|
...
|
|
<field label='Room Label' type='text-single'
|
|
var='sec-label#custom-label'/>
|
|
<field label='Room Clearance' type='text-single'
|
|
var='sec-label#custom-clearance'/>
|
|
</x>
|
|
</query>
|
|
</iq>
|
|
]]></example>
|
|
</section3>
|
|
</section2>
|
|
<section2 topic="Use in Presence" anchor="presence-use">
|
|
<p>&SECURITYLABEL; elements are not to appear in <tt>&PRESENCE;</tt> stanzas. Server SHALL treat
|
|
any <tt>&PRESENCE;</tt> stanza that contains a &SECURITYLABEL; as a protocol violation.</p>
|
|
<p>Presence information is subject to sensitivity-base authorization decisions, however
|
|
these decisions are made are made using a label associated with the presence
|
|
resource, such as a chat room's label.</p>
|
|
</section2>
|
|
</section1>
|
|
|
|
<section1 topic="Extension Considerations" anchor="exts">
|
|
<p> This extension is itself extensible. In particular, the &LABEL; and &EQUIVALENTLABEL;
|
|
elements are designed to hold a range of security labels formats. XML name spaces SHOULD
|
|
be used to avoid name clashes. </p>
|
|
<p> Future documents may specify how security-labels are used in other areas of XMPP, such
|
|
as PubSub.</p>
|
|
</section1>
|
|
|
|
<!--
|
|
<section1 topic='Implementation Notes' anchor='impl'>
|
|
<p>OPTIONAL.</p>
|
|
</section1>
|
|
-->
|
|
<section1 topic="Security Considerations" anchor="security">
|
|
<p>This document is all about authorization, a key aspect of security. Hence, security
|
|
considerations are discussed through this document.</p>
|
|
<p>Nothing in this document ensures appropriate labeling the sensitivity of a piece of
|
|
information. Addressing inappropriate labeling of information is beyond the scope of
|
|
this document.</p>
|
|
<p>Certain XMPP stanzas, such as <tt>&PRESENCE;</tt> stanzas, are not themselves subject to any
|
|
sensitivity-based authorization decisions, and may be forwarded throughout the XMPP
|
|
network. The content of these stanzas should not contain information requiring
|
|
sensitivity-based dissemination controls.</p>
|
|
<p>It is desirable to securely bind the security label to the object it labels. This may be
|
|
accomplished through use of digital signatures. Specification of such is left to a
|
|
future document. </p>
|
|
</section1>
|
|
<section1 topic="IANA Considerations" anchor="iana">
|
|
<p>This document requires no interaction with &IANA;.</p>
|
|
</section1>
|
|
<section1 topic="XMPP Registrar Considerations" anchor="registrar">
|
|
<section2 topic='Protocol Namespaces' anchor='registrar-ns'>
|
|
<p>This specification defines the following XML namespaces:</p>
|
|
<ul>
|
|
<li>urn:xmpp:sec-label:0</li>
|
|
<li>urn:xmpp:sec-label:catalog:2</li>
|
|
<li>urn:xmpp:sec-label:ess:0</li>
|
|
</ul>
|
|
<p>The ®ISTRAR; includes the foregoing namespaces in the registry located at &NAMESPACES;, as described in Section 4 of &xep0053;.</p>
|
|
</section2>
|
|
<section2 topic='Protocol Versioning' anchor='registrar-versioning'>
|
|
&NSVER;
|
|
</section2>
|
|
</section1>
|
|
<section1 topic="XML Schemas" anchor="schema">
|
|
<section2 topic="Extension Schema" anchor="schema-sl">
|
|
<p>
|
|
<code><![CDATA[
|
|
<?xml version='1.0' encoding='UTF-8'?>
|
|
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:xmpp:sec-label:0"
|
|
xmlns="urn:xmpp:sec-label:0" elementFormDefault="qualified">
|
|
|
|
<xs:annotation>
|
|
<xs:documentation>
|
|
The protocol documented by this schema is defined in
|
|
XEP-0258: http://xmpp.org/extensions/xep-0258.html
|
|
</xs:documentation>
|
|
</xs:annotation>
|
|
|
|
<xs:simpleType name="colorCSS">
|
|
<xs:annotation>
|
|
<xs:documentation>CSS colors (W3C colors + "orange")</xs:documentation>
|
|
</xs:annotation>
|
|
<xs:restriction base="xs:string">
|
|
<xs:enumeration value="aqua"/>
|
|
<xs:enumeration value="black"/>
|
|
<xs:enumeration value="blue"/>
|
|
<xs:enumeration value="fuschia"/>
|
|
<xs:enumeration value="gray"/>
|
|
<xs:enumeration value="green"/>
|
|
<xs:enumeration value="lime"/>
|
|
<xs:enumeration value="maroon"/>
|
|
<xs:enumeration value="navy"/>
|
|
<xs:enumeration value="olive"/>
|
|
<xs:enumeration value="purple"/>
|
|
<xs:enumeration value="red"/>
|
|
<xs:enumeration value="silver"/>
|
|
<xs:enumeration value="teal"/>
|
|
<xs:enumeration value="white"/>
|
|
<xs:enumeration value="yellow"/>
|
|
<xs:enumeration value="orange"/>
|
|
</xs:restriction>
|
|
</xs:simpleType>
|
|
|
|
<xs:simpleType name="colorRGB">
|
|
<xs:annotation>
|
|
<xs:documentation>Hex encoded RGB</xs:documentation>
|
|
</xs:annotation>
|
|
<xs:restriction base="xs:string">
|
|
<xs:pattern value="#[0-9A-Fa-f]{6}"/>
|
|
</xs:restriction>
|
|
</xs:simpleType>
|
|
|
|
<xs:simpleType name="color">
|
|
<xs:annotation>
|
|
<xs:documentation>Color</xs:documentation>
|
|
</xs:annotation>
|
|
<xs:union memberTypes="colorCSS colorRGB"/>
|
|
</xs:simpleType>
|
|
|
|
<xs:complexType name="displaymarking">
|
|
<xs:annotation>
|
|
<xs:documentation>Display Marking</xs:documentation>
|
|
<xs:documentation>String to be prominently displayed along with labeled
|
|
object.</xs:documentation>
|
|
</xs:annotation>
|
|
<xs:simpleContent>
|
|
<xs:extension base="xs:string">
|
|
<xs:attribute name="bgcolor" type="color" use="optional" default="white"/>
|
|
<xs:attribute name="fgcolor" type="color" use="optional" default="black"/>
|
|
</xs:extension>
|
|
</xs:simpleContent>
|
|
</xs:complexType>
|
|
|
|
<xs:complexType name="label">
|
|
<xs:choice minOccurs="0">
|
|
<xs:any namespace="##other" processContents="lax"/>
|
|
</xs:choice>
|
|
</xs:complexType>
|
|
|
|
<xs:element name="securitylabel">
|
|
<xs:annotation>
|
|
<xs:documentation>A Security Label</xs:documentation>
|
|
</xs:annotation>
|
|
<xs:complexType>
|
|
<xs:sequence>
|
|
<xs:element name="displaymarking" type="displaymarking">
|
|
<xs:annotation>
|
|
<xs:documentation>A Display Marking</xs:documentation>
|
|
<xs:documentation>To be prominently displayed</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:element>
|
|
<xs:element name="label" type="label">
|
|
<xs:annotation>
|
|
<xs:documentation>The Primary Label</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:element>
|
|
<xs:element name="equivalentlabel" type="label" minOccurs="0" maxOccurs="unbounded">
|
|
<xs:annotation>
|
|
<xs:documentation>An Equivalent Label</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:element>
|
|
</xs:sequence>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
</xs:schema>
|
|
]]></code> A copy of this schema is available at <link
|
|
url="http://xmpp.org/schemas/sec-label.xsd">
|
|
http://xmpp.org/schemas/sec-label.xsd</link>. </p>
|
|
</section2>
|
|
<section2 topic="<catalog/> schema" anchor="schema-catalog">
|
|
<p>
|
|
<code><![CDATA[
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:sl="urn:xmpp:sec-label:0"
|
|
xmlns="urn:xmpp:sec-label:catalog:2" targetNamespace="urn:xmpp:sec-label:catalog:2"
|
|
elementFormDefault="qualified">
|
|
|
|
<xs:annotation>
|
|
<xs:documentation>
|
|
The protocol documented by this schema is defined in
|
|
XEP-0258: http://xmpp.org/extensions/xep-0258.html
|
|
</xs:documentation>
|
|
</xs:annotation>
|
|
|
|
<xs:import schemaLocation="sec-label.xsd" namespace="urn:xmpp:sec-label:0"/>
|
|
|
|
<xs:attribute name="to" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>Target JabberId</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="from" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>Target JabberId</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="name" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>Name</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="desc" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>Description</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="id" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>Identifer for current revision, commonly a hash</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="size" type="xs:integer">
|
|
<xs:annotation>
|
|
<xs:documentation>Number of items</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="restrict" type="xs:boolean">
|
|
<xs:annotation>
|
|
<xs:documentation>Restrictive</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="selector" type="xs:string">
|
|
<xs:annotation>
|
|
<xs:documentation>User input selector</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:attribute name="default" type="xs:boolean">
|
|
<xs:annotation>
|
|
<xs:documentation>default selection</xs:documentation>
|
|
</xs:annotation>
|
|
</xs:attribute>
|
|
|
|
<xs:element name="catalog">
|
|
<xs:annotation>
|
|
<xs:documentation>A Catalog of Labels</xs:documentation>
|
|
</xs:annotation>
|
|
|
|
<xs:complexType>
|
|
<xs:sequence>
|
|
<xs:element name="item" minOccurs="0" maxOccurs="unbounded">
|
|
<xs:complexType>
|
|
<xs:sequence minOccurs="0">
|
|
<xs:element ref="sl:securitylabel"/>
|
|
</xs:sequence>
|
|
<xs:attribute ref="selector" use="optional"/>
|
|
<xs:attribute ref="default" use="optional"/>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
</xs:sequence>
|
|
<xs:attribute ref="to" use="optional"/>
|
|
<xs:attribute ref="from" use="optional"/>
|
|
<xs:attribute ref="name" use="optional"/>
|
|
<xs:attribute ref="desc" use="optional"/>
|
|
<xs:attribute ref="id" use="optional"/>
|
|
<xs:attribute ref="size" use="optional"/>
|
|
<xs:attribute ref="restrict" use="optional"/>
|
|
</xs:complexType>
|
|
</xs:element>
|
|
</xs:schema>
|
|
]]></code> A copy of this schema is available at <link
|
|
url="http://xmpp.org/schemas/sec-label-catalog.xsd">
|
|
http://xmpp.org/schemas/sec-label-catalog.xsd</link>. </p>
|
|
</section2>
|
|
<section2 topic="<esssecuritylabel/> schema" anchor="schema-ess">
|
|
<p>
|
|
<code><![CDATA[
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:xmpp:sec-label:ess:0"
|
|
xmlns="urn:xmpp:sec-label:ess:0" elementFormDefault="qualified">
|
|
|
|
<xs:annotation>
|
|
<xs:documentation>
|
|
The protocol documented by this schema is defined in
|
|
XEP-0258: http://xmpp.org/extensions/xep-0258.html
|
|
</xs:documentation>
|
|
</xs:annotation>
|
|
|
|
<xs:element name="esssecuritylabel" type="xs:base64Binary">
|
|
<xs:annotation>
|
|
<xs:documentation>An S/MIME ESS SecurityLabel [RFC2634]</xs:documentation>
|
|
<xs:documentation>Value is the base64 encoding of the BER/DER encoding of an ASN.1
|
|
ESSSecurityLabel type as defined in RFC 2634. </xs:documentation>
|
|
</xs:annotation>
|
|
</xs:element>
|
|
</xs:schema>
|
|
]]></code> A copy of this schema is available at <link
|
|
url="http://xmpp.org/schemas/sec-label-ess.xsd">
|
|
http://xmpp.org/schemas/sec-label-ess.xsd</link>. </p>
|
|
</section2>
|
|
</section1>
|
|
</xep>
|