the role and permission in spring security 3

Question

I am new in ss3,and I have read its reference,also I read the spring security book.

However I do not find anything about the role-permission.

For example,here is the config for form-based authentication.

  <http auto-config='true'>
    <intercept-url pattern="/user/add/**" access="hasRole('USER_ADMIN')"/>
    <intercept-url pattern="/user/delete/**" access="hasRole('USER_ADMIN')"/>
    <intercept-url pattern="/login.jsp*" access="IS_AUTHENTICATED_ANONYMOUSLY"/>
    <intercept-url pattern="/**" access="ROLE_USER" />
    <form-login login-page='/login.jsp'/>
  </http>

I want to control the user operation(add/delete):

<intercept-url pattern="/user/add/**" access="hasRole('USER_ADMIN')"/>
<intercept-url pattern="/user/delete/**" access="hasRole('USER_ADMIN')"/>

I define the role of 'USER_ADMIN',but this is not enough,since I want to differ the user who have 'add' permission from user who have 'delete' permission.

Maybe I can add more roles like 'user_admin_add' and 'user_admin_delete'.

But I do not think this is a good idea since the 'add' or 'delete' are permissions,not roles.

How to make it?

Also,it seems that all the roles should be configed to the xml file,I wonder if I can add new roles and permissions dynamically(in the administrator page)?

Answer 1

Think of roles as a privileges. And granulate them as much as you need. Another thing is that maybe you should make a more RESTFul implementation. But this is another thread.

For example, your "delete" could be a "DELETE" HTTP method. Then you could be:

<security:intercept-url pattern="/users/*" method="DELETE" access="ROLE_DELETE_USER" />

and a curl -X DELETE -u login:password 'http://example.com/users/1'

would delete the user with id 1.

By a RESTFul, since uris are either identifiers or actions, there is no use in add roles (privileges) dinamically. Since those roles are meant to be used against a new resource that should contain the xml file.

I'm afraid you cannot do this, unless you use ** wildcards. Which in my opinion if used uncarefully can lead to troubles.

Answer 2

Maybe I can add more roles like 'user_admin_add' and 'user_admin_delete'.

This is the way. Permissions are roles and generally there are people who view differentiation between them as unneeded.

I don't think there is much difference in having a role ROLE_USER_ADDER or a permission PERMISSION_ADD_USERS.

You can however use roles as a concept to group permissions if you need to. For instance you can have a role admin which can add and remove users. So the role ROLE_ADMIN will have PERMISSION_ADD_USER and PERMISSION_REMOVE_USER. Still spring will view both roles and permissions simply as authorities.

As for dynamic roles adding you can do it by loading the current user permission from your DB for instance. Have a look at the UserDetailsService of spring security. The UserDetails object it returns has a getAuthorities() method which you can populate from your DB.

/**
 * Returns the authorities granted to the user. Cannot return <code>null</code>.
 *
 * @return the authorities, sorted by natural key (never <code>null</code>)
 */
Collection<GrantedAuthority> getAuthorities();

Here is a very good example of implementing your own UserDetailsService.