(Quick Reference)

3 Tutorial - Reference Documentation

Authors: Burt Beckwith

Version: 1.1.1

3 Tutorial

First create a test application:


$ grails create-app acltest
$ cd acltest

Install the plugin:


$ grails install-plugin spring-security-acl

This will install the Spring Security Core plugin, so you'll need to configure that by running the s2-quickstart script:


$ grails s2-quickstart com.testacl User Role

The ACL support uses domain classes but to allow customizing the domain classes (e.g. to enable Hibernate 2nd-level caching) there's a script that copies the domain classes into your application, s2-create-acl-domains. This script is run when the plugin is installed (otherwise the plugin code wouldn't compile) but you can run it again to re-create the domain classes:


$ grails s2-create-acl-domains

Note that you cannot change the domain class names or packages since they're used by the plugin. The domain class mappings are configured to generate the same DDL as is required by the standard Spring Security JDBC implementation for portability.

We'll need a domain class to test with, so create a Report domain class:


$ grails create-domain-class com.testacl.Report

and add a name property for testing:

package com.testaclclass Report {
   String name
}

Next we'll create a service to test ACLs:


$ grails create-service com.testacl.Report

and add some methods that work with Reports:

package com.testaclimport org.springframework.security.access.prepost.PostFilter
import org.springframework.security.access.prepost.PreAuthorize
import org.springframework.security.acls.domain.BasePermission
import org.springframework.security.acls.model.Permission
import org.springframework.transaction.annotation.Transactional
class ReportService {
   static transactional = false
   def aclPermissionFactory
   def aclService
   def aclUtilService
   def springSecurityService
   void addPermission(Report report, String username, int permission) {
      addPermission report, username,
           aclPermissionFactory.buildFromMask(permission)
   }
   @PreAuthorize("hasPermission(#report, admin)")
   @Transactional
   void addPermission(Report report, String username,
                      Permission permission) {
      aclUtilService.addPermission report, username, permission
   }
   @Transactional
   @PreAuthorize("hasRole('ROLE_USER')")
   Report create(String name) {
      Report report = new Report(name: name)
      report.save()
      // Grant the current principal administrative permission
      addPermission report, springSecurityService.authentication.name,
                    BasePermission.ADMINISTRATION
      report
   }
   @PreAuthorize("hasPermission(#id, 'com.testacl.Report', read) or " +
                 "hasPermission(#id, 'com.testacl.Report', admin)")
   Report get(long id) {
      Report.get id
   }
   @PreAuthorize("hasRole('ROLE_USER')")
   @PostFilter("hasPermission(filterObject, read) or " +
               "hasPermission(filterObject, admin)")
   List<Report> list(Map params) {
      Report.list params
   }
   int count() {
      Report.count()
   }
   @Transactional
   @PreAuthorize("hasPermission(#report, write) or " +
                 "hasPermission(#report, admin)")
   void update(Report report, String name) {
      report.name = name
   }
   @Transactional
   @PreAuthorize("hasPermission(#report, delete) or " +
                 "hasPermission(#report, admin)")
   void delete(Report report) {
      report.delete()
      // Delete the ACL information as well
      aclUtilService.deleteAcl report
   }
   @Transactional
   @PreAuthorize("hasPermission(#report, admin)")
   void deletePermission(Report report, String username, Permission permission) {
      def acl = aclUtilService.readAcl(report)
      // Remove all permissions associated with this particular
      // recipient (string equality to KISS)
      acl.entries.eachWithIndex { entry, i ->
         if (entry.sid.equals(recipient) &&
               entry.permission.equals(permission)) {
            acl.deleteAce i
         }
      }
      aclService.updateAcl acl
   }
}

The configuration specifies these rules:

addPermission requires that the authenticated user have admin permission on the report instance to grant a permission to someone else
create requires that the authenticated user have ROLE_USER
get requires that the authenticated user have read or admin permission on the specified Report
list requires that the authenticated user have ROLE_USER and read or admin permission on each returned Report; instances that don't have granted permissions will be removed from the returned List
count has no restrictions
update requires that the authenticated user have write or admin permission on the report instance to edit it
delete requires that the authenticated user have delete or admin permission on the report instance to edit it
deletePermission requires that the authenticated user have admin permission on the report instance to delete a grant

To test this out we'll need some users; create those and their grants in BootStrap.groovy:

import com.testacl.Report
import com.testacl.Role
import com.testacl.User
import com.testacl.UserRoleimport static org.springframework.security.acls.domain.BasePermission.ADMINISTRATION
import static org.springframework.security.acls.domain.BasePermission.DELETE
import static org.springframework.security.acls.domain.BasePermission.READ
import static org.springframework.security.acls.domain.BasePermission.WRITE
import org.springframework.security.authentication. UsernamePasswordAuthenticationToken
import org.springframework.security.core.authority.AuthorityUtils
import org.springframework.security.core.context.SecurityContextHolder as SCH
class BootStrap {
   def aclService
   def aclUtilService
   def objectIdentityRetrievalStrategy
   def sessionFactory
   def springSecurityService
   def init = { servletContext ->
      createUsers()
      loginAsAdmin()
      grantPermissions()
      sessionFactory.currentSession.flush()
      // logout
      SCH.clearContext()
   }
   private void loginAsAdmin() {
      // have to be authenticated as an admin to create ACLs
      SCH.context.authentication = new UsernamePasswordAuthenticationToken(
            'admin', 'admin123',
            AuthorityUtils.createAuthorityList('ROLE_ADMIN'))
   }
   private void createUsers() {
      def roleAdmin = new Role(authority: 'ROLE_ADMIN').save()
      def roleUser = new Role(authority: 'ROLE_USER').save()
      3.times {
         long id = it + 1
         def user = new User(username: "user$id", enabled: true,
            password: springSecurityService.encodePassword("password$id")).save()
         UserRole.create user, roleUser
      }
      def admin = new User(username: 'admin', enabled: true,
         password: springSecurityService.encodePassword('admin123')).save()
      UserRole.create admin, roleUser
      UserRole.create admin, roleAdmin, true
   }
   private void grantPermissions() {
      def reports = []
      100.times {
         long id = it + 1
         def report = new Report(name: "report$id").save()
         reports << report
         aclService.createAcl(
               objectIdentityRetrievalStrategy.getObjectIdentity(report))
      }
      // grant user 1 admin on 11,12 and read on 1-67
      aclUtilService.addPermission reports[10], 'user1', ADMINISTRATION
      aclUtilService.addPermission reports[11], 'user1', ADMINISTRATION
      67.times {
         aclUtilService.addPermission reports[it], 'user1', READ
      }
      // grant user 2 read on 1-5, write on 5
      5.times {
         aclUtilService.addPermission reports[it], 'user2', READ
      }
      aclUtilService.addPermission reports[4], 'user2', WRITE
      // user 3 has no grants
      // grant admin admin on all
      for (report in reports) {
         aclUtilService.addPermission report, 'admin', ADMINISTRATION
      }
      // grant user 1 ownership on 1,2 to allow the user to grant
      aclUtilService.changeOwner reports[0], 'user1'
      aclUtilService.changeOwner reports[1], 'user1'
   }
}

And to have a UI to test with, let's create a Report controller and GSPs:


$ grails generate-all com.testacl.Report

But to use the controller, it will have to be reworked to use ReportService. It's a good idea to put all create/edit/delete code in a transactional service, but in this case we need to move all database access to the service to ensure that appropriate access checks are made:

package com.testaclimport org.springframework.dao.DataIntegrityViolationException
import org.springframework.security.acls.model.Permission
import grails.plugins.springsecurity.Secured
@Secured(['ROLE_USER'])
class ReportController {
   static defaultAction = 'list'
   def reportService
   def list = {
      params.max = Math.min(params.max ? params.int('max') : 10, 100)
      [reportInstanceList: reportService.list(params),
       reportInstanceTotal: reportService.count()]
   }
   def create = {
      [reportInstance: new Report(params)]
   }
   def save = {
      def report = reportService.create(params.name)
      if (!renderWithErrors('create', report)) {
         redirectShow "Report $report.id created", report.id
      }
   }
   def show = {
      def report = findInstance()
      if (!report) return
      [reportInstance: report]
   }
   def edit = {
      def report = findInstance()
      if (!report) return
      [reportInstance: report]
   }
   def update = {
      def report = findInstance()
      if (!report) return
      reportService.update report, params.name
      if (!renderWithErrors('edit', report)) {
         redirectShow "Report $report.id updated", report.id
      }
   }
   def delete = {
      def report = findInstance()
      if (!report) return
      try {
         reportService.delete report
         flash.message = "Report $params.id deleted"
         redirect action: list
      }
      catch (DataIntegrityViolationException e) {
         redirectShow "Report $params.id could not be deleted", params.id
      }
   }
   def grant = {
      def report = findInstance()
      if (!report) return
      if (!request.post) {
         return [reportInstance: report]
      }
      reportService.addPermission(report, params.recipient,
               params.int('permission'))
      redirectShow "Permission $params.permission granted on Report $report.id " +
                   "to $params.recipient", report.id
   }
   private Report findInstance() {
      def report = reportService.get(params.long('id'))
      if (!report) {
         flash.message = "Report not found with id $params.id"
         redirect action: list
      }
      report
   }
   private void redirectShow(message, id) {
      flash.message = message
      redirect action: show, id: id
   }
   private boolean renderWithErrors(String view, Report report) {
      if (report.hasErrors()) {
         render view: view, model: [reportInstance: report]
         return true
      }
      false
   }
}

Note that the controller is annotated to require either ROLE_USER or ROLE_ADMIN. Since services have nothing to do with HTTP, when access is blocked you cannot be redirected to the login page as when you try to access a URL that requires an authentication. So you need to configure URLs with similar role requirements to give the user a chance to attempt a login before calling secured service methods.

Finally, we'll make a few adjustments so errors are handled gracefully.

First, edit grails-app/conf/UrlMappings.groovy and add some error code mappings:

import org.springframework.security.access.AccessDeniedException
import org.springframework.security.acls.model.NotFoundExceptionclass UrlMappings {
   static mappings = {
      "/$controller/$action?/$id?"{
         constraints {}
      }
      "/"(view:"/index")
      "403"(controller: "errors", action: "error403")
      "404"(controller: "errors", action: "error404")
      "500"(controller: "errors", action: "error500")
      "500"(controller: "errors", action: "error403",
            exception: AccessDeniedException)
      "500"(controller: "errors", action: "error403",
            exception: NotFoundException)
   }
}

Then create the ErrorsController that these reference:


$ grails create-controller com.testacl.Errors

and add this code:

package com.testaclimport grails.plugins.springsecurity.Secured
@Secured(['permitAll'])
class ErrorsController {
   def error403 = {}
   def error404 = {}
   def error500 = {
      render view: '/error'
   }
}

and create the GSPs:

Add this to grails-app/views/errors/error403.gsp:

<html>
<head>
<title>Access denied!</title>
<meta name='layout' content='main' />
</head><body>
<h1>Access Denied</h1>
<p>We're sorry, but you are not authorized
   to perform the requested operation.</p>
</body>
</html>

and this to grails-app/views/errors/error404.gsp:

<html>
<head>
<title>Not Found</title>
<meta name='layout' content='main' />
</head><body>
<h1>Not Found</h1>
<p>We're sorry, but that page doesn't exist.</p>
</body>
</html>

actionSubmit issues

Grails has a convenient feature where it supports multiple submit actions per form. This is done by posting to the index action but with a special parameter that indicates which action to invoke. This is a problem in general for security since any URL rules for edit, delete, save, etc. will be bypassed. It's an even more significant issue with ACLs because of the way that the access denied exception interacts with the actionSubmit processing. If you don't make any adjustments for this, your users will see a blank page when they attempt to submit a form and the action is disallowed. The solution is to remove actionSubmit buttons and replace them with regular submit buttons. This requires one form per button, and without adjusting the CSS the buttons will look differently than if they were in-line actionSubmit buttons, but that is fixable with the appropriate CSS changes.

It's simple to adjust the actionSubmit buttons; in grails-app/views/report/show.gsp, replace the two actionSubmit buttons with these two forms (maintain the g:message tags; the strings are hard-coded here to reduce clutter):

<div class="buttons">
    <g:form action='edit'>
        <g:hiddenField name="id" value="${reportInstance?.id}" />
        <span class="button">
            <g:submitButton class="edit" name="Edit" />
        </span>
    </g:form>
    <g:form action='delete'>
        <g:hiddenField name="id" value="${reportInstance?.id}" />
        <span class="button">
            <g:submitButton class="delete" name="Delete"
                            onclick="return confirm('Are you sure?');" />
        </span>
    </g:form>
</div>

In grails-app/views/report/edit.gsp, change the <form> tag to

<g:form action='update'>

and convert the update button to a regular submit button:

<div class="buttons">
    <span class="button"><g:submitButton class="save" name="Update" /></span>
</div>

and move the delete button out of the form into its own form just below the main form:

<g:form action='delete'>
    <g:hiddenField name="id" value="${reportInstance?.id}" />
    <div class="buttons">
        <span class="button">
            <g:submitButton class="delete" name="Delete"
                            onclick="return confirm('Are you sure?');" />
        </span>
    </div>
</g:form>

list.gsp and show.gsp are fine as they are.

Testing

Now start the app:


$ grails run-app

and open http://localhost:8080/acltest/report/list

Login as user1/password1 and you should see the first page of results. But if you click on page 7 or higher, you'll see that you can only see a subset of the Reports. This illustrates one issue with using ACLs to restrict view access to instances; you would have to add joins in your query to the ACL database tables to get an accurate count of the total number of visible instances.

Click on any of the report instance links (e.g. http://localhost:8080/acltest/report/show/63) to verify that you can view the instance. You can test that you have no view access to the filtered instances by navigating to http://localhost:8080/acltest/report/show/83.

Verify that user1 has admin permission on report #11 by editing it and deleting it.

Verify that user1 doesn't have admin permission on report #13 by trying to editing or delete it and you should see the error page when you submit the form.

Logout (by navigating to http://localhost:8080/acltest/logout) and login as user2/password2. You should only see the first five reports. Verify that you can edit #5 but not any of the others, and that you can't delete any.

Finally. logout and login as admin/admin123. You should be able to view, edit, and delete all instances.

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