How to set a permission using drupal ACL?
There is a example and information on the hook here.  Throw the hook into your custom module and it should work.  The below example includes a version check that you likely won't need.

function civimonitor_civicrm_permission(&amp;$permissions) {
  $version = CRM_Utils_System::version();
  if (version_compare($version, '4.6.1') &gt;= 0) {
    $permissions += array(
      'access CiviMonitor' =&gt; array(
        ts('Access CiviMonitor', array('domain' =&gt; 'com.aghstrategies.civimonitor')),
        ts('Grants the necessary API permissions for a monitoring user without Administer CiviCRM', array('domain' =&gt; 'com.aghstrategies.civimonitor')),
      ),
    );
  }
  else {
    $permissions += array(
      'access CiviMonitor' =&gt; ts('Access CiviMonitor', array('domain' =&gt; 'com.aghstrategies.civimonitor')),
    );
  }
}