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Re: [xacml] Comment on hierarchical Resource

  • 1.  Re: [xacml] Comment on hierarchical Resource

    Posted 06-02-2004 15:33
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    Subject: Re: [xacml] Comment on hierarchical Resource


    Michiharu,
    
    Thank you very much for your review.
    
    On 2 June, Michiharu Kudoh writes: Re: [xacml] Comment on hierarchical Resource
     > >I agree with this.
     > >The most recent working draft attached to
     > >http://lists.oasis-open.org/archives/xacml/200405/msg00104.html
     > >does not attempt to re-define xpath-node-match.  It merely refers
     > >to the existing definition.
     > 
     > OK. I am not clear on the sentence that "This function MAY be used with the
     > higher-order bag functions described in Appendix A.3.12". In my
     > understanding, this function only returns Boolean and nothing to do with
     > bag. Or I miss something?
    
    Since an <AttributeSelector> or <ResourceAttributeDesignator>
    returns a "bag" of Attributes, it is most natural to use the
    xpath-node-match function with a higher-order bag function as
    follows:
    
       <Apply FunctionId="any-of">
           <AttributeValue DataType="string">
               policy-needed value goes here
           </AttributeValue>
           <AttributeSelector RequestContextPath="path to
                                   corresponding node here"
                              DataType="string" />
       </Apply>
    
    The "string-is-in" function could also be used.
    
    Otherwise, you have to surround the <AttributeSelector> with an
    Apply element using the "string-one-and-only" function.
    
     > >It seems straightforward to implement, would need to be
     > >calculated only if the policy actually uses one of these
     > >Attributes, and would allow XACML implementations that do not
     > >support XPath expressions to express some useful policies with
     > >respect to XML documents.
     > 
     > This slipped out of my head. So you want to specify policy for XML
     > documents without XPath support. Correct?
     > If so, resource-ancestor etc. would be useful.
     > 
     > >Would it be OK if I define a new Resource AttributeId for this
     > >called "document-id" with type anyURI?  This new Attribute would
     > >be specified as containing the URI of the entire document of
     > >which the requested resource is a part.  This seems more clear to me.
     > 
     > Since "http://medico.com/medicalrec/Bert"; is meta info of the embedded XML
     > doc, then it might be appropriate to create a new attribute for this like
     > "document-id" as you wrote. I reconsider this.
     > 
     > >You did not describe "anyURI-path-match" above.  Why can't this
     > >function be part of "anyURI-match" with Tim's proposed "*"
     > >wildcard character?
     > 
     > I did not read Tim's proposal. I will comment after I read it.
    
    The current proposal, I think, is a combination of several
    e-mails.  Here is a summary.
    --------------------------
    Original proposal by Tim
    (http://lists.oasis-open.org/archives/xacml/200405/msg00075.html):
    
    Colleagues - Here is a draft of the proposed URL-match function (with help
    from JSR 115).  All the best.  Tim.
    
    urn:oasis:names:tc:xacml:2.0:function:url-match
    
    This function takes two arguments of type
    http://www.w3.org/2001/XMLSchema#anyURI and SHALL return an
    http://www.w3.org/2001/XMLSchema#boolean.   It SHALL return "True" if all of
    the following conditions hold.  Otherwise, it SHALL return "False".
    
    1.	The scheme part of both arguments SHALL be the same and SHALL be
        either "http", "https" or "file".  The scheme parts MAY be compared using
        urn:oasis:names:tc:xacml:1.0:function:string-equal, once both parts have
        been normalized to upper-case.
    
    2.	The authority part of the first argument SHALL match the authority
        part of the second argument by either
        urn:oasis:names:tc:xacml:2.0:function:ipAddress-match or
        urn:oasis:names:tc:xacml:2.0:function:dnsName-match.
    
    3.	The path part of the first argument SHALL match the path part of the
        second argument in at least one of the following ways.
    
     3a	The path part of the first argument matches the path part of the
        second argument by urn:oasis:names:tc:xacml:1.0:function:string-equal.
    
     3b	The path part of the first argument is the string "/*".
    
     3c	The path part of the first argument starts with "/" and ends with
        "/*" and the path part of the second argument starts with the same string as
        the path part of the first argument, minus its last 2 characters, and the
        next character of the path part of the second argument, if present, is "/".
    
     3d	The path part of the first argument starts with "*." and the path
        part of the second argument ends with the same string as the path part of
        the first argument, minus its first 2 characters.
    
     3e	The path part of the first argument is the special string, "/",
        which matches all other paths.
    --------------------------
    In a subsequent e-mail:
    
      Guys - "*" is an unreserved character, which IS allowed in a URI.  We should
      probably specify that "*" be escaped, unless it is the wild-card.  All the
      best.  Tim.
    --------------------------
    Then, in Minutes of 20 May 2004 XACML Focus Group
    (http://lists.oasis-open.org/archives/xacml/200405/msg00090.html):
    
       There was general agreement that Tim's URL match function
       should be extended to cover all URIs, and not just URLs.
       Since RFC2396 specifies that "/" is reserved as a separator
       between hierarchical components of the identifier, this means
       that matches can always be by component, regardless of the
       actual component syntax for various URI schemes.
    --------------------------
    
    Thanks again,
    Anne
    -- 
    Anne H. Anderson             Email: Anne.Anderson@Sun.COM
    Sun Microsystems Laboratories
    1 Network Drive,UBUR02-311     Tel: 781/442-0928
    Burlington, MA 01803-0902 USA  Fax: 781/442-1692
    
    


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