Huge refactor of security policy enforcer stuff.
This revision involves 3 cooperating classes to secure tasks considered
either 'sensitive' or 'security bug'
- SecurityPolicyListener applies an initial security policy to tasks submitted with the 'security' option set to anything other than 'none.' It will also reset the security policy if anyone tries to override the policy to 'public' or 'any user' when the security flag is set to something other than 'none', this is just a sanity check to keep someone from inadvertantly or maliciously revealing a secure task without explicitly setting the security to 'none'
- The default security policy now includes a new custom policy rule, implemented in PhabricatorPolicyRuleTaskSubscribers, which allows anyone subscribed to a task to /view + comment/ on the task. !
- WMFSecurityPolicy class contains static functions related to the implementation of the other two, whereever it's appropriate to abstract the functionality intp a less workflow-specific reusable function.
Note: The following pre-existing behavior is not changed by the new patch:
The task author, the assignee, and any member of the corresponding 'security' project will be able to view/edit the task without explicitly being subscribed.
Note2: The custom Herald action related to security policy enforcement is now deprecated
and it will now function as a no-op. The related herald rule should be removed from phabricator.