fix(federation): prevent fetching own relay actor

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

lib/federation/http_signatures/signature.ex

@@ -12,6 +12,7 @@ defmodule Mobilizon.Federation.HTTPSignatures.Signature do
 
   alias Mobilizon.Actors.Actor
   alias Mobilizon.Federation.ActivityPub.Actor, as: ActivityPubActor
+  alias Mobilizon.Federation.ActivityPub.Relay
 
   require Logger
 
@@ -94,13 +95,19 @@ defmodule Mobilizon.Federation.HTTPSignatures.Signature do
     %{"keyId" => kid} = HTTPSignatures.signature_for_conn(conn)
     actor_url = key_id_to_actor_url(kid)
     Logger.debug("Refetching public key for #{actor_url}")
+    relay = Relay.get_actor()
 
-    # In this specific case we don't sign object fetches because
-    # this would cause infinite recursion when servers both need
-    # to fetch each other's keys
-    with {:ok, %Actor{} = actor} <-
-           ActivityPubActor.make_actor_from_url(actor_url, ignore_sign_object_fetches: true) do
-      get_actor_public_key(actor)
+    if actor_url == relay.url do
+      # Special case if ever it's our own actor fetching ourselves
+      get_actor_public_key(relay)
+    else
+      # In this specific case we don't sign object fetches because
+      # this would cause infinite recursion when servers both need
+      # to fetch each other's keys
+      with {:ok, %Actor{} = actor} <-
+             ActivityPubActor.make_actor_from_url(actor_url, ignore_sign_object_fetches: true) do
+        get_actor_public_key(actor)
+      end
     end
   end