lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex

@@ -101,10 +101,19 @@ defp get_extension_if_safe(response) do
     end
   end
 
+  defp get_int_header(headers, header_name, default \\ nil) do
+    with rawval when rawval != :undefined <- :proplists.get_value(header_name, headers),
+         {int, ""} <- Integer.parse(rawval) do
+      int
+    else
+      _ -> default
+    end
+  end
+
   defp is_remote_size_within_limit?(url) do
     with {:ok, %{status: status, headers: headers} = _response} when status in 200..299 <-
            Pleroma.HTTP.request(:head, url, nil, [], []) do
-      content_length = :proplists.get_value("content-length", headers, nil)
+      content_length = get_int_header(headers, "content-length")
       size_limit = Config.get([:mrf_steal_emoji, :size_limit], @size_limit)
 
       accept_unknown =

test/pleroma/web/activity_pub/mrf/steal_emoji_policy_test.exs

@@ -202,7 +202,7 @@ test "reject unknown size", %{message: message} do
 
   test "reject too large content-size before download", %{message: message} do
     clear_config([:mrf_steal_emoji, :download_unknown_size], false)
-    mock_tesla("https://example.org/emoji/firedfox.png", 200, [{"content-length", 2 ** 30}])
+    mock_tesla("https://example.org/emoji/firedfox.png", 200, [{"content-length", "#{2 ** 30}"}])
 
     refute "firedfox" in installed()
 
@@ -216,7 +216,7 @@ test "reject too large content-size before download", %{message: message} do
 
   test "accepts content-size below limit", %{message: message} do
     clear_config([:mrf_steal_emoji, :download_unknown_size], false)
-    mock_tesla("https://example.org/emoji/firedfox.png", 200, [{"content-length", 2}])
+    mock_tesla("https://example.org/emoji/firedfox.png", 200, [{"content-length", "2"}])
 
     refute "firedfox" in installed()