Re: [xacml-comment] Re: Broken Rule in Privacy Policy Profile

[Farrukh Najmi <farrukh@wellfleetsoftware.com>]

Unless the function definition has changed in some way its URI should 
not be changed between versions. Doing so would break existing 
implementations. The URI just needs to be unique for each specific 
version of a function.

It seems sensible to use a convention to use the release number of the 
release where the new version was introduced and not changing it between 
releases until another new version is introduced.

Sorry if I misunderstood your comment.

On 02/22/2012 09:53 PM, Steven Legg wrote:
> The URI for the string-regexp-match function is wrong also (in the 
> profile
> and in my suggested corrections). The version should be 1.0 rather 
> than 2.0.
>
> Regards,
> Steven
>
> On 22/02/2012 9:58 AM, Steven Legg wrote:
> > The rule in section 4.1 of Committee Specification 1 of the XACML v3.0
> > Privacy Policy Profile Version 1.0 is broken. The arguments to the
> > string-regexp-match function are both bags (<AttributeDesignator>) 
> > when they
> > should be primitive values.
> >
> > Noting that it is reasonable for the purpose attributes to be 
> > multi-valued,
> > a correct form for the condition would be:
> >
> > <Condition>
> > <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:any-of-any">
> > <Function
> > FunctionId="urn:oasis:names:tc:xacml:2.0:function:string-regexp-match"/>
> > <AttributeDesignator MustBePresent="false"
> > Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"
> > AttributeId="urn:oasis:names:tc:xacml:2.0:resource:purpose"
> > DataType="http://www.w3.org/2001/XMLSchema#string"/>
> > <AttributeDesignator MustBePresent="false"
> > Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action"
> > AttributeId="urn:oasis:names:tc:xacml:2.0:action:purpose"
> > DataType="http://www.w3.org/2001/XMLSchema#string"/>
> > </Apply>
> > </Condition>
> >
> > However, even when corrected, the rule is not as useful as it could be.
> > The rule is described as stipulating "that access SHALL be denied 
> > unless the
> > purpose for which access is requested matches ... the purpose for 
> > which the
> > data resource was collected" but the rule actually permits access if the
> > purposes match. The only way access is denied when the purposes don't 
> > match
> > is if the specified rule is the *only* permit rule, which is a 
> > significant
> > limitation.
> >
> > A better formulation would be to change the effect to Deny and negate 
> > the
> > condition so that when the purposes don't match, the overall effect 
> > is Deny
> > regardless of whether any other rules permit or deny access. That is, 
> > I think
> > the rule should be:
> >
> > <Rule xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17"
> > xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
> > xsi:schemaLocation="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17
> > xacml-core-v3-schema-wd-17.xsd"
> > RuleId="urn:oasis:names:tc:xacml:2.0:matching-purpose"
> > Effect="Deny">
> > <Condition>
> > <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:not">
> > <Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:any-of-any">
> > <Function
> > FunctionId="urn:oasis:names:tc:xacml:2.0:function:string-regexp-match"/>
> > <AttributeDesignator MustBePresent="false"
> > Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"
> > AttributeId="urn:oasis:names:tc:xacml:2.0:resource:purpose"
> > DataType="http://www.w3.org/2001/XMLSchema#string"/>
> > <AttributeDesignator MustBePresent="false"
> > Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action"
> > AttributeId="urn:oasis:names:tc:xacml:2.0:action:purpose"
> > DataType="http://www.w3.org/2001/XMLSchema#string"/>
> > </Apply>
> > </Apply>
> > </Condition>
> > </Rule>
> >
> >
> > Regards,
> > Steven


--
Regards,
Farrukh Najmi

Web: http://www.wellfleetsoftware.com