From b221b640a2dd443e3c2274b16ed5b62566329d09 Mon Sep 17 00:00:00 2001
From: = <=>
Date: Mon, 13 Jul 2020 22:19:13 +0300
Subject: [PATCH] Transmogrifier: filtering weirdness in address fields

---
 lib/pleroma/web/activity_pub/transmogrifier.ex | 14 ++++++++------
 test/web/activity_pub/transmogrifier_test.exs  | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 884646ceb..f37bcab3e 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -62,15 +62,17 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def fix_summary(object), do: Map.put(object, "summary", "")
 
   def fix_addressing_list(map, field) do
-    cond do
-      is_binary(map[field]) ->
-        Map.put(map, field, [map[field]])
+    addrs = map[field]
 
-      is_nil(map[field]) ->
-        Map.put(map, field, [])
+    cond do
+      is_list(addrs) ->
+        Map.put(map, field, Enum.filter(addrs, &is_binary/1))
+
+      is_binary(addrs) ->
+        Map.put(map, field, [addrs])
 
       true ->
-        map
+        Map.put(map, field, [])
     end
   end
 
diff --git a/test/web/activity_pub/transmogrifier_test.exs b/test/web/activity_pub/transmogrifier_test.exs
index f7b7d1a9f..248b410c6 100644
--- a/test/web/activity_pub/transmogrifier_test.exs
+++ b/test/web/activity_pub/transmogrifier_test.exs
@@ -774,6 +774,29 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert [user.follower_address] == activity.data["to"]
     end
 
+    test "it correctly processes messages with weirdness in address fields" do
+      user = insert(:user)
+
+      message = %{
+        "@context" => "https://www.w3.org/ns/activitystreams",
+        "to" => [nil, user.follower_address],
+        "cc" => ["https://www.w3.org/ns/activitystreams#Public", ["¿"]],
+        "type" => "Create",
+        "object" => %{
+          "content" => "…",
+          "type" => "Note",
+          "attributedTo" => user.ap_id,
+          "inReplyTo" => nil
+        },
+        "actor" => user.ap_id
+      }
+
+      assert {:ok, activity} = Transmogrifier.handle_incoming(message)
+
+      assert ["https://www.w3.org/ns/activitystreams#Public"] == activity.data["cc"]
+      assert [user.follower_address] == activity.data["to"]
+    end
+
     test "it accepts Move activities" do
       old_user = insert(:user)
       new_user = insert(:user)