Question

我对使用WSO2 Balana库的XACML策略有疑问。

制定政策：

<Policy xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17" PolicyId="Policy1" RuleCombiningAlgId="urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:first-applicable" Version="1.0">
    <Target>
        <AnyOf>
            <AllOf>
                <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                    <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">MyApp</AttributeValue>
                    <AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-id" 
                                    Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
                </Match>            
            </AllOf>
        </AnyOf>
    </Target>
    <Rule Effect="Permit" RuleId="RuleFor_user1_myapp">
        <Target>
            <AnyOf>
                <AllOf>
                    <Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                        <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">user1</AttributeValue>
                        <AttributeDesignator AttributeId="http://example.site.com/id/user" 
                                       Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject" 
                                       DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="true"/>
                    </Match>
                </AllOf>           
            </AnyOf>
        </Target>
        <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>                                
            </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>
    </Rule>   
</Policy>

应该定义user1在MyApp上只具有READ权限。

我有一个评估请求，询问user1是否具有READ权限，并且我在响应中获得“Permit”，这是正常的。

但是当我有一个请求来评估哪个用户1是否具有WRITE权限时，我也会得到“Permit”，而不是“不适用”。

有人可以告诉我，制定我刚才描述的结果的政策是否正确？

提前谢谢！

祝你好运， Jurica Krizanic

Answer 1

首先，策略不是XACML3架构的有效策略。您需要在规则中包含Apply元素所包含的元素。规则基本上包含Target和Condition元素。 Balana没有对您的政策进行架构验证。它使用policy元素构建对象模块。由于它无法在规则中找到元素，因此忽略了您的元素。因此，您的规则实际上只有仅评估主题属性的目标元素。请使用如下。此外，当您将策略上载到WSO2标识服务器时，它会进行模式验证。您可以轻松上传或创建策略。

Answer 2

您可以使用http://validator.xacml.eu/来验证您的XACML策略是XACML 2.0还是符合XACML 3.0。

另外，我建议您使用ALFA编写策略 - 它更容易并且与Eclipse集成。

ALFA代码如下所示：

namespace sample{
    // Import standard XACML attributes
    import Attributes.*

    /**
     * Define custom attributes here
     */
    attribute user{
        category = subjectCat
        id = "http://example.site.com/id/user"
        type = string
    }

    /**
     * MyApp Policy
     */
    policy Policy1{
        target clause resourceId=="MyApp"
        apply firstApplicable
        /**
         * This rule grants READ access for user 1
         */
        rule RuleFor_user1_myapp{
            target clause user=="user1" and actionId=="READ"
            permit
        }
    }
}

生成的XACML 3.0如下所示：

<?xml version="1.0" encoding="UTF-8"?>
 <!--This file was generated by the ALFA Plugin for Eclipse from Axiomatics AB (http://www.axiomatics.com). 
 Any modification to this file will be lost upon recompilation of the source ALFA file-->
<xacml3:Policy xmlns:xacml3="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17"
    PolicyId="http://axiomatics.com/alfa/identifier/sample.Policy1"
    RuleCombiningAlgId="urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:first-applicable"
    Version="1.0">
    <xacml3:Description>MyApp Policy</xacml3:Description>
    <xacml3:PolicyDefaults>
        <xacml3:XPathVersion>http://www.w3.org/TR/1999/REC-xpath-19991116</xacml3:XPathVersion>
    </xacml3:PolicyDefaults>
    <xacml3:Target>
        <xacml3:AnyOf>
            <xacml3:AllOf>
                <xacml3:Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                    <xacml3:AttributeValue
                        DataType="http://www.w3.org/2001/XMLSchema#string">MyApp</xacml3:AttributeValue>
                    <xacml3:AttributeDesignator 
                        AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-id"
                        DataType="http://www.w3.org/2001/XMLSchema#string"
                        Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"
                        MustBePresent="false"
                    />
                </xacml3:Match>
            </xacml3:AllOf>
        </xacml3:AnyOf>
    </xacml3:Target>
    <xacml3:Rule 
            Effect="Permit"
            RuleId="http://axiomatics.com/alfa/identifier/sample.Policy1.RuleFor_user1_myapp">
        <xacml3:Description>This rule grants READ access for user 1</xacml3:Description>
        <xacml3:Target>
            <xacml3:AnyOf>
                <xacml3:AllOf>
                    <xacml3:Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                        <xacml3:AttributeValue
                            DataType="http://www.w3.org/2001/XMLSchema#string">user1</xacml3:AttributeValue>
                        <xacml3:AttributeDesignator 
                            AttributeId="http://example.site.com/id/user"
                            DataType="http://www.w3.org/2001/XMLSchema#string"
                            Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject"
                            MustBePresent="false"
                        />
                    </xacml3:Match>
                    <xacml3:Match MatchId="urn:oasis:names:tc:xacml:1.0:function:string-equal">
                        <xacml3:AttributeValue
                            DataType="http://www.w3.org/2001/XMLSchema#string">READ</xacml3:AttributeValue>
                        <xacml3:AttributeDesignator 
                            AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id"
                            DataType="http://www.w3.org/2001/XMLSchema#string"
                            Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action"
                            MustBePresent="false"
                        />
                    </xacml3:Match>
                </xacml3:AllOf>
            </xacml3:AnyOf>
        </xacml3:Target>
    </xacml3:Rule>
</xacml3:Policy>

XACML政策 - 这是正确的吗？

2 个答案: