Make sure only group moderators can update/delete events, posts

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/federation/activity_pub/utils.ex

@@ -287,15 +287,41 @@ defmodule Mobilizon.Federation.ActivityPub.Utils do
   def origin_check_from_id?(id, %{"id" => other_id} = _params) when is_binary(other_id),
     do: origin_check_from_id?(id, other_id)
 
-  def activity_actor_is_group_member?(%Actor{id: actor_id, url: actor_url}, object) do
-    Logger.debug(
-      "Checking if activity actor #{actor_url} is a member from group from #{object.url}"
-    )
-
+  def activity_actor_is_group_member?(
+        %Actor{id: actor_id, url: actor_url},
+        object,
+        role \\ :member
+      ) do
     case Ownable.group_actor(object) do
-      %Actor{type: :Group, id: group_id} ->
-        Logger.debug("Group object ID is #{group_id}")
-        Actors.is_member?(actor_id, group_id)
+      %Actor{type: :Group, id: group_id, url: group_url} ->
+        Logger.debug("Group object url is #{group_url}")
+
+        case role do
+          :moderator ->
+            Logger.debug(
+              "Checking if activity actor #{actor_url} is a moderator from group from #{
+                object.url
+              }"
+            )
+
+            Actors.is_moderator?(actor_id, group_id)
+
+          :administrator ->
+            Logger.debug(
+              "Checking if activity actor #{actor_url} is an administrator from group from #{
+                object.url
+              }"
+            )
+
+            Actors.is_administrator?(actor_id, group_id)
+
+          _ ->
+            Logger.debug(
+              "Checking if activity actor #{actor_url} is a member from group from #{object.url}"
+            )
+
+            Actors.is_member?(actor_id, group_id)
+        end
 
       _ ->
         false
@@ -633,4 +659,39 @@ defmodule Mobilizon.Federation.ActivityPub.Utils do
 
     :ok
   end
+
+  def can_update_group_object?(%Actor{} = actor, object) do
+    can_manage_group_object?(:role_needed_to_update, actor, object)
+  end
+
+  def can_delete_group_object?(%Actor{} = actor, object) do
+    can_manage_group_object?(:role_needed_to_delete, actor, object)
+  end
+
+  @spec can_manage_group_object?(
+          :role_needed_to_update | :role_needed_to_delete,
+          Actor.t(),
+          any()
+        ) :: boolean()
+  defp can_manage_group_object?(action_function, %Actor{url: actor_url} = actor, object) do
+    if Ownable.group_actor(object) != nil do
+      case apply(Ownable, action_function, [object]) do
+        role when role in [:member, :moderator, :administrator] ->
+          activity_actor_is_group_member?(actor, object, role)
+
+        _ ->
+          case action_function do
+            :role_needed_to_update ->
+              Logger.warn("Actor #{actor_url} can't update #{object.url}")
+
+            :role_needed_to_delete ->
+              Logger.warn("Actor #{actor_url} can't delete #{object.url}")
+          end
+
+          false
+      end
+    else
+      true
+    end
+  end
 end