以下是针对中国墙的XACML策略，该策略使用stringAtLeastOneMemberOf比较两个属性，两个属性看看它们是否包含值列表中的相同值。
即如果请求访问对象的主题的标签为[1, 4, 5]，而对象的标签为[2, 3, 5]，则访问将被拒绝，因为两者都包含5。
attribute subjectConflicts {
id = "urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts"
type = string
category = subjectCat
}
attribute resourceConflicts {
id = "urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts"
type = string
category = resourceCat
}
namespace models {
import Attributes.*
/*
*
* This policy implements the Chinese Wall model.
*
*/
policy ChineseWall {
target clause resourceType=="calcert"
apply firstApplicable
/*
* Check subject is not in conflict with object OEMs and calibrators
*
* This rule will deny access is user.label contains at least 1 value that is also present
* in object.label
*/
rule noconflict {
target clause actionId=="read" or actionId=="write"
condition stringAtLeastOneMemberOf(subjectConflicts, resourceConflicts)
deny
}
}
}
<?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/models.ChineseWall" RuleCombiningAlgId="urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:first-applicable" Version="1.0">
<xacml3:Description>This policy implements the Chinese Wall model.</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">calcert</xacml3:AttributeValue>
<xacml3:AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-type" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="false" />
</xacml3:Match>
</xacml3:AllOf>
</xacml3:AnyOf>
</xacml3:Target>
<xacml3:Rule Effect="Deny" RuleId="models.ChineseWall.noconflict">
<xacml3:Description>Check subject is not in conflict with object OEMs and calibrators
This rule will deny access is user.label contains at least 1 value that is also present
in object.label</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">read</xacml3:AttributeValue>
<xacml3: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="false" />
</xacml3:Match>
</xacml3:AllOf>
<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">write</xacml3:AttributeValue>
<xacml3: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="false" />
</xacml3:Match>
</xacml3:AllOf>
</xacml3:AnyOf>
</xacml3:Target>
<xacml3:Condition>
<xacml3:Apply FunctionId="urn:oasis:names:tc:xacml:1.0:function:string-at-least-one-member-of">
<xacml3:AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts" Category="urn:oasis:names:tc:xacml:1.0:subject-category:access-subject" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="false" />
<xacml3:AttributeDesignator AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts" Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource" DataType="http://www.w3.org/2001/XMLSchema#string" MustBePresent="false" />
</xacml3:Apply>
</xacml3:Condition>
</xacml3:Rule>
</xacml3:Policy>
我正在使用Authzforce Core PDP for Java模拟PDP，并且按以下方式评估请求：
private DecisionRequest parseJSONAndBuildXACML(JSONObject obj) {
DecisionRequestBuilder builder = server.pdpEngine.getEngine().newRequestBuilder(-1, -1);
/** Add Principle **/
// Principle ID
AttributeFqn principleID = AttributeFqns.newInstance(XACML_1_0_ACCESS_SUBJECT.value(), Optional.empty(), XacmlAttributeId.XACML_1_0_SUBJECT_ID.value());
AttributeBag<?> principleIDValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue("Principle" + obj.getJSONObject("principle").getString("id")));
builder.putNamedAttributeIfAbsent(principleID, principleIDValue);
// Principle Label
AttributeFqn principleLabel = AttributeFqns.newInstance(XACML_1_0_ACCESS_SUBJECT.value(), Optional.<String>empty(), XACML_1_0_SUBJECT_LABEL);
AttributeBag<?> principleLabelValue = Bags.singletonAttributeBag(StandardDatatypes.INTEGER, new IntegerValue(new MediumInteger(obj.getJSONObject("principle").getInt("label"))));
builder.putNamedAttributeIfAbsent(principleLabel, principleLabelValue);
// Principle Conflict Set
AttributeFqn principleConflicts = AttributeFqns.newInstance(XACML_1_0_ACCESS_SUBJECT.value(), Optional.empty(), XACML_1_0_SUBJECT_CONFLICTS);
Collection<StringValue> pconflicts = getStringListFromJsonArray(obj.getJSONObject("principle").getJSONArray("conflicts"));
AttributeBag<?> principleConflictsValue = Bags.newAttributeBag(StandardDatatypes.STRING, pconflicts);
//AttributeBag<?> principleConflictsValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getJSONObject("principle").getString("conflicts")));
builder.putNamedAttributeIfAbsent(principleConflicts, principleConflictsValue);
// Object ID
AttributeFqn objectID = AttributeFqns.newInstance(XACML_3_0_RESOURCE.value(), Optional.empty(), XACML_1_0_RESOURCE_ID.value());
AttributeBag<?> objectIDValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getJSONObject("object").getString("id")));
builder.putNamedAttributeIfAbsent(objectID, objectIDValue);
// Object Type
AttributeFqn objectType = AttributeFqns.newInstance(XACML_3_0_RESOURCE.value(), Optional.empty(), XACML_1_0_RESOURCE_TYPE);
AttributeBag<?> objectTypeValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getJSONObject("object").getString("type")));
builder.putNamedAttributeIfAbsent(objectType, objectTypeValue);
// Object Label
AttributeFqn objectLabel = AttributeFqns.newInstance(XACML_3_0_RESOURCE.value(), Optional.<String>empty(), XACML_1_0_RESOURCE_LABEL);
AttributeBag<?> objectLabelValue = Bags.singletonAttributeBag(StandardDatatypes.INTEGER, new IntegerValue(new MediumInteger(obj.getJSONObject("object").getInt("label"))));
builder.putNamedAttributeIfAbsent(objectLabel, objectLabelValue);
// Object Conflict Set
AttributeFqn objectConflicts = AttributeFqns.newInstance(XACML_3_0_RESOURCE.value(), Optional.empty(), XACML_1_0_RESOURCE_CONFLICTS);
Collection<StringValue> oconflicts = getStringListFromJsonArray(obj.getJSONObject("object").getJSONArray("conflicts"));
AttributeBag<?> objectConflictsValue = Bags.newAttributeBag(StandardDatatypes.STRING, oconflicts);
//AttributeBag<?> objectConflictsValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getJSONObject("object").getString("conflicts")));
builder.putNamedAttributeIfAbsent(objectConflicts, objectConflictsValue);
// Action
AttributeFqn action = AttributeFqns.newInstance(XACML_3_0_ACTION.value(), Optional.empty(), XacmlAttributeId.XACML_1_0_ACTION_ID.value());
AttributeBag<?> actionValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getString("action")));
builder.putNamedAttributeIfAbsent(action, actionValue);
return builder.build(false);
}
在这种情况下，JSONObject就是我将请求从客户端发送到PDP引擎的方式。其他政策可行，这里的问题是我正在向书包中发送一个字符串，即"[2, 4, 5]"，但它总是导致NotApplicable。有没有我应该在此处使用的列表类型，以符合政策？
这是我要发送的JSON：
{
"principle": {
"conflicts": [
"1",
"2",
"10"
],
"id": "Principle 1",
"label": 3
},
"action": "read",
"object": {
"conflicts": [
"4",
"5",
"9"
],
"id": "Object 1",
"label": 2,
"type": "calcert"
}
}
更准确地说，用于冲突集的Java代码中对Authzforce的Java代码中的JSON输出将是一个字符串，即"[2,3,5]"，而我认为这需要是另一种格式（因为它总是导致NotApplicable），但是这是我的问题。
答案 0 :(得分：2)
您需要修复代码中的至少两个问题：
由于要从字符串列表中提取一个包，可能不止一个，因此必须使用更通用的Bags.newAttributeBag(...)-第二个参数必须是您的实际字符串列表-而不是 Bags.singletonAttributeBag()。只有这样，PDP才会将其视为String类型的多个AttributeValue。
您两次使用相同的主题属性XACML_1_0_SUBJECT_CONFLICTS，而第二次是 objectConflicts 属性，因此我猜这是错误的，需要修复，因为必须而是使用资源属性urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts。
答案 1 :(得分：0)
首先，您必须了解XACML中的所有属性默认情况下都是值的袋子。因此，urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts是一个可以包含0（零），1或更多值的包。但这仍然是一个袋子。对于ALFA / XACML中的任何属性都是如此。这意味着您编写时：
target clause resourceType=="calcert"
您实际上是在说如果resourceType的至少一个值等于calcert ...
在您的情况下，您正在使用名为stringAtLeastOneMemberOf的函数。此函数接收两个类型为string的包，如果第一个包中的第二个包中至少包含一个值，则返回true。它与stringIsIn相似，除了后者接受一个原子字符串和一袋字符串。您必须编写stringIsIn(stringOneAndOnly(a), b)才能使其正常工作。属性a还必须是包含单个值的包。
在您的情况下，您有2个属性（subjectConflicts和resourceConflicts）可以是多值的。这意味着，如果您“打印”它们，将会看到类似[[a]，“ b”，“ c”，“ a”]的字样。这是一袋价值观。袋子可以包含重复项。而且顺序无关紧要（属性的顺序或属性值的顺序都没有。）
现在，您要做的是发送一个表示此内容的XACML JSON请求。生成的JSON应该如下所示：
在此示例中，两个属性都是多值的：
{
"Request":{
"Resource":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-type",
"Value":"calcert"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts",
"Value":[
"4",
"5",
"6"
]
}
]
}
],
"Action":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:action:action-id",
"Value":"read"
}
]
}
],
"AccessSubject":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts",
"Value":[
"1",
"2",
"3"
]
}
]
}
]
}
}
请求也可以写为
{
"Request":{
"Resource":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-type",
"Value":"calcert"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts",
"Value":"4"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts",
"Value":"5"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts",
"Value":"6"
}
]
}
],
"Action":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:action:action-id",
"Value":"read"
}
]
}
],
"AccessSubject":[
{
"Attribute":[
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts",
"Value":"1"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts",
"Value":"2"
},
{
"AttributeId":"urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts",
"Value":"3"
}
]
}
]
}
}
{
"Response":[
{
"Decision":"NotApplicable"
}
]
}
在代码中，您使用AuthZForce的PEP SDK。西里尔在他的另一个答案中指出了主要错误：
AttributeBag<?> objectConflictsValue = Bags.singletonAttributeBag(StandardDatatypes.STRING, new StringValue(obj.getJSONObject("object").getString("conflicts")));
问题是，您要在XACML包内的单个值中添加冲突[“ 1”，...]的整个字符串表示形式，而不是分别添加每个部分。
在我的示例中，我使用了自己的Java JSON PEP SDK。该代码如下所示：
将每个值一一添加：
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "4"));
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "5"));
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "6"));
或添加为值数组：
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", new String[]{"4","5","6"}));
package io.xacml.pep.json.so;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.xacml.json.model.Attribute;
import io.xacml.json.model.Category;
import io.xacml.json.model.Request;
import io.xacml.json.model.Response;
import io.xacml.json.model.Result;
import io.xacml.pep.json.client.AuthZClient;
import io.xacml.pep.json.client.ClientConfiguration;
import io.xacml.pep.json.client.DefaultClientConfiguration;
import io.xacml.pep.json.client.jaxrs.JaxRsAuthZClient;
import lombok.extern.slf4j.Slf4j;
/**
* This class contains sample code using JAX-RS to invoke a Policy Decision Point.
* It supports both the JSON Profile of XACML 1.0 (where the response could be either an Object or
* an Array) and the JSON Profile of XACML 1.1 (where the response is always an array - to simplify
* things)
*
* @author djob
*/
@Slf4j
public class Example {
public static void main(String[] args) {
ObjectMapper mapper = new ObjectMapper();
ClientConfiguration clientConfiguration = DefaultClientConfiguration.builder()
.pdpUrl("http://djob-hp:8080")
.username("ads-user")
.password("secret")
.build();
// Add user attributes
Category subject = new Category();
subject.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts", "1"));
subject.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts", "2"));
subject.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:subject:subject-conflicts", "3"));
// Add action attributes - if any
Category action = new Category();
action.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:action:action-id", "read"));
// Add user attributes
Category resource = new Category();
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-type", "calcert"));
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "4"));
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "5"));
resource.addAttribute(new Attribute("urn:oasis:names:tc:xacml:1.0:resource:resource-conflicts", "6"));
Request authZRequest = new Request();
authZRequest.addAccessSubjectCategory(subject);
authZRequest.addActionCategory(action);
authZRequest.addResourceCategory(resource);
AuthZClient authZClient = new JaxRsAuthZClient(clientConfiguration, mapper);
Response authZResponse = authZClient.makeAuthorizationRequest(authZRequest);
for (Result r : authZResponse.getResults()) {
log.debug(r.getDecision().name());
}
}
}