Fix Optimistic Inbox for failed signatures

When signatures fail on incoming activities we put the job into Oban to be processed later instead of doing the user fetching and validation inline which is expensive and increases latency on the incoming POST request. Unfortunately we did not retain the :method, :request_path, and :query_string parameters from the conn so the signature validation and Oban Job would always fail.

This was most obvious when Mastodon sends Deletes for users your server has never seen before.

changelog.d/optimistic-inbox-sigs.fix

@@ -0,0 +1 @@
+Fix Optimistic Inbox for failed signatures

lib/pleroma/web/activity_pub/activity_pub_controller.ex

@@ -293,8 +293,15 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
     json(conn, "ok")
   end
 
-  def inbox(%{assigns: %{valid_signature: false}, req_headers: req_headers} = conn, params) do
-    Federator.incoming_ap_doc(%{req_headers: req_headers, params: params})
+  def inbox(%{assigns: %{valid_signature: false}} = conn, params) do
+    Federator.incoming_ap_doc(%{
+      method: conn.method,
+      req_headers: conn.req_headers,
+      request_path: conn.request_path,
+      params: params,
+      query_string: conn.query_string
+    })
+
     json(conn, "ok")
   end
 

lib/pleroma/workers/receiver_worker.ex

@@ -12,13 +12,26 @@ defmodule Pleroma.Workers.ReceiverWorker do
   @impl Oban.Worker
 
   def perform(%Job{
-        args: %{"op" => "incoming_ap_doc", "req_headers" => req_headers, "params" => params}
+        args: %{
+          "op" => "incoming_ap_doc",
+          "method" => method,
+          "params" => params,
+          "req_headers" => req_headers,
+          "request_path" => request_path,
+          "query_string" => query_string
+        }
       }) do
     # Oban's serialization converts our tuple headers to lists.
     # Revert it for the signature validation.
     req_headers = Enum.into(req_headers, [], &List.to_tuple(&1))
 
-    conn_data = %{params: params, req_headers: req_headers}
+    conn_data = %{
+      method: method,
+      params: params,
+      req_headers: req_headers,
+      request_path: request_path,
+      query_string: query_string
+    }
 
     with {:ok, %User{} = _actor} <- User.get_or_fetch_by_ap_id(conn_data.params["actor"]),
          {:ok, _public_key} <- Signature.refetch_public_key(conn_data),