refactor(activitypub): handle failure finding public key in actor keys

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

lib/federation/activity_pub/utils.ex

@@ -680,19 +680,22 @@ defmodule Mobilizon.Federation.ActivityPub.Utils do
   @doc """
   Converts PEM encoded keys to a public key representation
   """
-  @spec pem_to_public_key_pem(String.t()) :: String.t()
+  @spec pem_to_public_key_pem(String.t()) :: String.t() | {:error, :no_publickey_found}
   def pem_to_public_key_pem(pem) do
-    public_key = pem_to_public_key(pem)
+    case :public_key.pem_decode(pem) do
+      [key_code] ->
+        public_key = pem_to_public_key(key_code)
         public_key = :public_key.pem_entry_encode(:RSAPublicKey, public_key)
         :public_key.pem_encode([public_key])
+
+      _ ->
+        {:error, :no_publickey_found}
+    end
   end
 
   @spec pem_to_public_key(String.t()) :: {:RSAPublicKey, any(), any()}
-  defp pem_to_public_key(pem) do
-    [key_code] = :public_key.pem_decode(pem)
-    key = :public_key.pem_entry_decode(key_code)
-
-    case key do
+  defp pem_to_public_key(key_code) do
+    case :public_key.pem_entry_decode(key_code) do
       {:RSAPrivateKey, _, modulus, exponent, _, _, _, _, _, _, _} ->
         {:RSAPublicKey, modulus, exponent}
 

lib/federation/activity_stream/converter/actor.ex

@@ -112,19 +112,11 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Actor do
       },
       "discoverable" => actor.visibility == :public,
       "openness" => actor.openness,
-      "manuallyApprovesFollowers" => actor.manually_approves_followers,
-      "publicKey" => %{
-        "id" => "#{actor.url}#main-key",
-        "owner" => actor.url,
-        "publicKeyPem" =>
-          if(is_nil(actor.domain) and not is_nil(actor.keys),
-            do: Utils.pem_to_public_key_pem(actor.keys),
-            else: actor.keys
-          )
-      }
+      "manuallyApprovesFollowers" => actor.manually_approves_followers
     }
 
     actor_data
+    |> add_keys(actor)
     |> add_endpoints(actor)
     |> maybe_add_members(actor)
     |> maybe_add_avatar_picture(actor)
@@ -132,6 +124,28 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Actor do
     |> maybe_add_physical_address(actor)
   end
 
+  @spec add_keys(map(), ActorModel.t()) :: map()
+  defp add_keys(actor_data, %ActorModel{} = actor) do
+    keys =
+      if is_nil(actor.domain) and not is_nil(actor.keys) do
+        case Utils.pem_to_public_key_pem(actor.keys) do
+          {:error, :no_publickey_found} ->
+            raise "No publickey found in private keys"
+
+          public_key when is_binary(public_key) ->
+            public_key
+        end
+      else
+        actor.keys
+      end
+
+    Map.put(actor_data, "publicKey", %{
+      "id" => "#{actor.url}#main-key",
+      "owner" => actor.url,
+      "publicKeyPem" => keys
+    })
+  end
+
   defp add_endpoints(%{"endpoints" => endpoints} = actor_data, %ActorModel{} = actor) do
     new_endpoints = %{
       "members" => actor.members_url,