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WSO2 Identity / XACML Evaluation for Standard Editor / Any Debug Feature Available?

having difficulties to interpret the "Try It" result data from a policy definition made by a WSO2 XACML standard editor.

Questions about the handling of the XACML engine and definitions:

  • Is there a debug support available that shows the partial results from each rule and statement evaluation?
  • Does the boolean logic apply to "or", "and" combinations?
  • Is there a tool available to modify the default attribute values (string), like for example the use of "current-time" attribute as a valid environment setting?

Policy (typed by Standard Editor) 

<Policy xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17" PolicyId="TodaysPolicy1" RuleCombiningAlgId="urn:oasis:names:tc:xacml:3.0:rule-combining-algorithm:permit-overrides" Version="1.0">
   <Description>Standard Editor Doctor Rule                        </Description>
   <Target>
      <AnyOf>
         <AllOf>
            <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-regexp-match">
               <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">^(http:)</AttributeValue>
               <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:environment:environment-id" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
            </Match>
         </AllOf>
      </AnyOf>
   </Target>
   <Rule Effect="Permit" RuleId="DoctorAdmin">
      <Target>
         <AnyOf>
            <AllOf>
               <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-regexp-match">
                  <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">^(http:)</AttributeValue>
                  <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:environment:environment-id" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
               </Match>
            </AllOf>
         </AnyOf>
      </Target>
      <Condition>
         <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:or">
            <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:and">
               <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                  <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-one-and-only">
                     <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:subject:subject-id" Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
                  </Apply>
                  <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">admin</AttributeValue>
               </Apply>
               <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-at-least-one-member-of">
                  <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-bag">
                     <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">read</AttributeValue>
                     <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">write</AttributeValue>
                     <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">update</AttributeValue>
                     <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">delete</AttributeValue>
                  </Apply>
                  <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
               </Apply>
               <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:not">
                  <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:and">
                     <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-greater-than">
                        <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-one-and-only">
                           <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:environment:environment-id" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
                        </Apply>
                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">07:00:00 05:00</AttributeValue>
                     </Apply>
                     <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-less-than">
                        <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-one-and-only">
                           <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:environment:environment-id" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
                        </Apply>
                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">20:00:00 05:00</AttributeValue>
                     </Apply>
                  </Apply>
               </Apply>
            </Apply>
            <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
               <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-one-and-only">
                  <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:subject:subject-id" Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
               </Apply>
               <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">doctor</AttributeValue>
            </Apply>
         </Apply>
      </Condition>
   </Rule>
</Policy>

Request (generated by Try It) 

                     <Request xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17" CombinedDecision="false" ReturnPolicyIdList="false">
<Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action">
<Attribute AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id" IncludeInResult="false">
<AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">read</AttributeValue>
</Attribute>
</Attributes>
<Attributes Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject">
<Attribute AttributeId="urn:oasis:names:tc:xacml:1.0:subject:subject-id" IncludeInResult="false">
<AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">doctor</AttributeValue>
</Attribute>
</Attributes>
<Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:environment">
<Attribute AttributeId="urn:oasis:names:tc:xacml:1.0:environment:environment-id" IncludeInResult="false">
<AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">08:00:00 05:00</AttributeValue>
</Attribute>
</Attributes>
<Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource">
<Attribute AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-id" IncludeInResult="false">
<AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">http://localhost:9444/medicalrecords</AttributeValue>
</Attribute>
</Attributes>
</Request>

Results via [Test Evaluate] 

                     <Response xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17">
<Result>
<Decision>NotApplicable</Decision>
<Status>
<StatusCode Value="urn:oasis:names:tc:xacml:1.0:status:ok"/>
</Status>
</Result>
</Response>

Thanks in advance for your guidance.

Solution

  • The debug feature is missing indeed in WSO2. I write and test all my policies using the Axiomatics Policy Administration Point and its plugin.

    I tried your policy within the PAP. This is what it looks like when expanded inside the PAP.

    Exploring a policy with the Axiomatics Policy Administration Point

    Now I checked your XACML request too.

    a XACML 3.0 request inside the Axiomatics PAP

    There one major reason why your policy won't work.

    • the policy expects a resource id but your request sends in an environment id.

    That said, there are other issues with your policy:

    • first of all you use a string-regexp-match on resource-id but in fact you should use string-starts-with since what you want to do is check that the string starts with http://. You would also want to make that an anyURI type not a string.
    • secondly you do the check twice: once in the policy and once in the rule. Once is enough, not twice.
    • thirdly you compare subject-id to doctor. Doctor is a role not a subject id so create an attribute for that
    • you use environment-id to convey the current time when in fact there is an attribute in XACML for that called urn:oasis:names:tc:xacml:1.0:environment:current-time.
    • you use conditions for things you could easily express in a target.
    • lastly you put too much logic in the condition e.g. the 4 different actions which you could split across 4 rules.