如何创建用于spring安全表达式语言注释的自定义方法

Question

我想创建一个类,添加自定义方法,以便在spring安全表达式语言中通过注释进行基于方法的授权.

例如,我想创建一个像'customMethodReturningBoolean'这样的自定义方法,以某种方式使用:

  @PreAuthorize("customMethodReturningBoolean()")
  public void myMethodToSecure() { 
    // whatever
  }

我的问题是这个.如果可能,我应该创建自定义方法的子类,我将如何在spring xml配置文件中配置它,并且有人给我一个以这​​种方式使用的自定义方法的示例？

Answer 1

所提到的技术都不会再起作用了.好像Spring已经花了很大力气来阻止用户覆盖SecurityExpressionRoot.

编辑11/19/14设置Spring使用安全注释:

<beans ... xmlns:sec="http://www.springframework.org/schema/security" ... >
...
<sec:global-method-security pre-post-annotations="enabled" />

像这样创建一个bean:

@Component("mySecurityService")
public class MySecurityService {
    public boolean hasPermission(String key) {
        return true;
    }
}

然后在你的jsp中做这样的事情:

<sec:authorize access="@mySecurityService.hasPermission('special')">
    <input type="button" value="Special Button" />
</sec:authorize>

或者注释方法:

@PreAuthorize("@mySecurityService.hasPermission('special')")
public void doSpecialStuff() { ... }

此外,您可以在注释中使用Spring Expression Language@PreAuthorize来访问当前身份验证以及方法参数.

例如:

@Component("mySecurityService")
public class MySecurityService {
    public boolean hasPermission(Authentication authentication, String foo) { ... }
}

然后更新您@PreAuthorize的匹配新方法签名:

@PreAuthorize("@mySecurityService.hasPermission(authentication, #foo)")
public void doSpecialStuff(String foo) { ... }

Answer 2

您需要子类化两个类.

首先,设置一个新方法表达式处理程序

<global-method-security>
  <expression-handler ref="myMethodSecurityExpressionHandler"/>
</global-method-security>

myMethodSecurityExpressionHandler将是的一个子类DefaultMethodSecurityExpressionHandler,其覆盖createEvaluationContext(),设置的一个子类MethodSecurityExpressionRoot的MethodSecurityEvaluationContext.

例如:

@Override
public EvaluationContext createEvaluationContext(Authentication auth, MethodInvocation mi) {
    MethodSecurityEvaluationContext ctx = new MethodSecurityEvaluationContext(auth, mi, parameterNameDiscoverer);
    MethodSecurityExpressionRoot root = new MyMethodSecurityExpressionRoot(auth);
    root.setTrustResolver(trustResolver);
    root.setPermissionEvaluator(permissionEvaluator);
    root.setRoleHierarchy(roleHierarchy);
    ctx.setRootObject(root);

    return ctx;
}

Answer 3

谢谢ericacm,但由于以下几个原因它不起作用:

• DefaultMethodSecurityExpressionHandler的属性是私有的(反射可见性kludges不合需要)
• 至少在我的Eclipse中,我无法解析MethodSecurityEvaluationContext对象

不同之处在于我们调用现有的createEvaluationContext方法,然后添加自定义根对象.最后,我刚刚返回了一个StandardEvaluationContext对象类型,因为MethodSecurityEvaluationContext无法在编译器中解析(它们都来自同一个接口).这是我现在生产的代码.

Make MethodSecurityExpressionHandler使用我们的自定义root:

public class CustomMethodSecurityExpressionHandler extends DefaultMethodSecurityExpressionHandler  {

    // parent constructor
    public CustomMethodSecurityExpressionHandler() {
        super();
    }

    /**
     * Custom override to use {@link CustomSecurityExpressionRoot}
     * 
     * Uses a {@link MethodSecurityEvaluationContext} as the <tt>EvaluationContext</tt> implementation and
     * configures it with a {@link MethodSecurityExpressionRoot} instance as the expression root object.
     */
    @Override
    public EvaluationContext createEvaluationContext(Authentication auth, MethodInvocation mi) {
        // due to private methods, call original method, then override it's root with ours
        StandardEvaluationContext ctx = (StandardEvaluationContext) super.createEvaluationContext(auth, mi);
        ctx.setRootObject( new CustomSecurityExpressionRoot(auth) );
        return ctx;
    }
}

这将通过扩展SecurityExpressionRoot来替换默认根.在这里,我将hasRole重命名为hasEntitlement:

public class CustomSecurityExpressionRoot extends SecurityExpressionRoot  {

    // parent constructor
    public CustomSecurityExpressionRoot(Authentication a) {
        super(a);
    }

    /**
     * Pass through to hasRole preserving Entitlement method naming convention
     * @param expression
     * @return boolean
     */
    public boolean hasEntitlement(String expression) {
        return hasRole(expression);
    }

}

最后更新securityContext.xml(并确保它从applcationContext.xml引用):

<!-- setup method level security using annotations -->
<security:global-method-security
        jsr250-annotations="disabled"
        secured-annotations="disabled"
        pre-post-annotations="enabled">
    <security:expression-handler ref="expressionHandler"/>
</security:global-method-security>

<!--<bean id="expressionHandler" class="org.springframework.security.access.expression.method.DefaultMethodSecurityExpressionHandler">-->
<bean id="expressionHandler" class="com.yourSite.security.CustomMethodSecurityExpressionHandler" />

注意: @Secured注释不会接受此覆盖,因为它通过不同的验证处理程序运行.因此,在上面的xml中我禁用它们以防止以后出现混淆.