如何实施Custom Spring Security ACL？

Question

I'm developing an Application using Spring. In Access Control Access section I want to use Spring Security Acl (I'm new at Acl). I want to implement ACL in my application base on 2 points:

1. Application should has five permissions, read , create , modify , delete and Administrator .
2. Permissions be hierarchy, When a user has create permission, it should be able to read , Or when it has modify permission, it should be able to read , create and modify and etc.

Is it possible? How?

update :
My application is base on Spring MVC RESTFUL. When a user wants to modify own information, he send some json data with Ajax. An example of json data is as follow:

{
  "id": 1,//user Id
  "name": "my name",
  "password": "my password",
  "email": "email@email.com",
   ...
}

Now, a malicious user can login to own account. This user can modify its data like all other users. Before he send data, change his id, and modify another account user information. I want to use ACL to prevent this Subversive work. And user can get some access to other that others can modify his info.

Answer 1

You can implement a simple solution with spring security. The idea is to create a class that implements org.springframework.security.access.PermissionEvaluator and override the method hasPermission . Look the next example:

@Component("permissionEvaluator")
public class PermissionEvaluator implements org.springframework.security.access.PermissionEvaluator {

    /**
     * @param authentication     represents the user in question. Should not be null.
     * @param targetDomainObject the domain object for which permissions should be
     *                           checked. May be null in which case implementations should return false, as the null
     *                           condition can be checked explicitly in the expression.
     * @param permission         a representation of the permission object as supplied by the
     *                           expression system. Not null.
     * @return true if the permission is granted, false otherwise
     */
    @Override
    public boolean hasPermission(Authentication authentication, Object targetDomainObject, Object permission) {
        if (authentication != null && permission instanceof String) {
            User loggedUser = (User) authentication.getPrincipal();
            String permissionToCheck = (String) permission;
            // in this part of the code you need to check if the loggedUser has the "permission" over the
            // targetDomainObject. In this implementation the "permission" is a string, for example "read", or "update"
            // The targetDomainObject is an actual object, for example a object of UserProfile class (a class that
            // has the profile information for a User)

            // You can implement the permission to check over the targetDomainObject in the way that suits you best
            // A naive approach:
            if (targetDomainObject.getClass().getSimpleName().compareTo("UserProfile") == 0) {
                if ((UserProfile) targetDomainObject.getId() == loggedUser.getId())
                    return true;
            }
            // A more robust approach: you can have a table in your database holding permissions to each user over
            // certain targetDomainObjects
            List<Permission> userPermissions = permissionRepository.findByUserAndObject(loggedUser,
                targetDomainObject.getClass().getSimpleName());
            // now check if in userPermissions list we have the "permission" permission.

            // ETC...
        }
        //access denied
        return false;
    }

}

Now, with this implementation you can use in for example your service layer the @PreAuthorize annotation like this:

@PreAuthorize("hasPermission(#profile, 'update')")
public void updateUserProfileInASecureWay(UserProfile profile) {
    //code to update user profile
}

The "hasPermission" inside the @PreAuthorize annotation receives the targetDomainObject #profile from the params of the updateUserProfileInASecureWay method and also we pass the required permission (in this case 'update').

This solution avoids all the complexity of the ACL by implementing a "small" ACL. Maybe it can work for you.

Answer 2

You can use the role hierarchy combination as used in the following examples.Spring acl has base permissions,If you want to implement Custom permissions you need to create a custom Permission class extending Base Permissions class in the api. we can define roles for each kind of permission and define role hierarchy as below.

<bean id="expressionHandler"
    class="org.springframework.security.access.expression.method.DefaultMethodSecurityExpressionHandler">
    <property name="permissionEvaluator" ref="permissionEvaluator" />
    <property name="roleHierarchy" ref="roleHierarchy" />
</bean>

<!-- A customized PermissionEvaluator that evaluates permissions via the ACL module -->
<bean class="org.springframework.security.acls.AclPermissionEvaluator" id="permissionEvaluator">
    <!-- Reference to the ACL service which performs JDBC calls to an ACL database -->
    <constructor-arg ref="aclService"/>
     <property name="permissionFactory" ref="customPermissionFactory" /> 
</bean>
<bean id="customPermissionFactory" class="org.krams.tutorial.security.CustomPermissionFactory"></bean>

<!-- A customized ACL service which provides default JDBC implementation -->
<bean class="org.springframework.security.acls.jdbc.JdbcMutableAclService" id="aclService">
    <constructor-arg ref="dataSource"/>
    <constructor-arg ref="lookupStrategy"/>
    <constructor-arg ref="aclCache"/>
</bean>

<!-- A lookup strategy for optimizing database queries -->
<bean id="lookupStrategy" class="org.springframework.security.acls.jdbc.BasicLookupStrategy">
    <constructor-arg ref="dataSource"/>
    <constructor-arg ref="aclCache"/>
    <constructor-arg ref="aclAuthorizationStrategy"/>
    <constructor-arg ref="auditLogger"/>
    <property name="permissionFactory" ref="customPermissionFactory"/>
</bean>

<!-- A MySQL datasource with pooling capabalities for the ACL module -->
<!-- <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
     destroy-method="close"
     p:driverClass="com.mysql.jdbc.Driver"
     p:jdbcUrl="jdbc:mysql://localhost/acl"
     p:user="root"
     p:password=""
     p:acquireIncrement="5"
     p:idleConnectionTestPeriod="60"
     p:maxPoolSize="100"
     p:maxStatements="50"
     p:minPoolSize="10" /> -->




<bean id="dataSource"
    class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="org.h2.Driver" />
    <property name="url" value="jdbc:h2:tcp://localhost/~/springsecurity" />

    <!--<property name="url" value="jdbc:h2:tcp://ggk-wrl-win1/~/dev" /> -->
    <property name="username" value="sa" />
    <property name="password" value="" />
</bean>

<!-- An ACL cache to minimize calls to the ACL database -->   
<bean id="aclCache" class="org.springframework.security.acls.domain.EhCacheBasedAclCache">
    <constructor-arg>
        <bean class="org.springframework.cache.ehcache.EhCacheFactoryBean">
            <property name="cacheManager">
                <bean class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"/>
            </property>
            <property name="cacheName" value="aclCache"/>
        </bean>
    </constructor-arg>
</bean>

<!-- An ACL authorization strategy to determine whether a principal is permitted to call administrative methods -->
<bean id="aclAuthorizationStrategy" class="org.springframework.security.acls.domain.AclAuthorizationStrategyImpl">
    <constructor-arg>
        <list>
            <bean class="org.springframework.security.core.authority.GrantedAuthorityImpl">
                <constructor-arg value="ROLE_USER"/>
            </bean>
            <bean class="org.springframework.security.core.authority.GrantedAuthorityImpl">
                <constructor-arg value="ROLE_USER"/>
            </bean>
            <bean class="org.springframework.security.core.authority.GrantedAuthorityImpl">
                <constructor-arg value="ROLE_USER"/>
            </bean>
        </list>
    </constructor-arg>
</bean>

<!-- An audit logger used to log audit events -->
<bean id="auditLogger" class="org.springframework.security.acls.domain.ConsoleAuditLogger"/>

<!-- Defines the role order -->
<!-- http://static.springsource.org/spring-security/site/docs/3.0.x/apidocs/org/springframework/security/access/hierarchicalroles/RoleHierarchyImpl.html -->
<bean id="roleHierarchy"  class="org.springframework.security.access.hierarchicalroles.RoleHierarchyImpl">
    <property name="hierarchy">
        <value>
            ROLE_ADMIN > ROLE_USER
            ROLE_USER > ROLE_VISITOR
        </value>
    </property>
</bean>