5 files changed, 32 insertions, 1 deletions
diff --git a/lib/pleroma/object/fetcher.ex b/lib/pleroma/object/fetcher.ex
index 69a5f3268..c85a8b09f 100644
--- a/lib/pleroma/object/fetcher.ex
+++ b/lib/pleroma/object/fetcher.ex
@@ -145,6 +145,7 @@ defmodule Pleroma.Object.Fetcher do
     Logger.debug("Fetching object #{id} via AP")
 
     with {:scheme, true} <- {:scheme, String.starts_with?(id, "http")},
+         {_, true} <- {:mrf, MRF.id_filter(id)},
          {:ok, body} <- get_object(id),
          {:ok, data} <- safe_json_decode(body),
          :ok <- Containment.contain_origin_from_id(id, data) do
@@ -160,6 +161,9 @@ defmodule Pleroma.Object.Fetcher do
       {:error, e} ->
         {:error, e}
 
+      {:mrf, false} ->
+        {:error, {:reject, "Filtered by id"}}
+
       e ->
         {:error, e}
     end
diff --git a/lib/pleroma/web/activity_pub/mrf.ex b/lib/pleroma/web/activity_pub/mrf.ex
index bc418d908..51ab476b7 100644
--- a/lib/pleroma/web/activity_pub/mrf.ex
+++ b/lib/pleroma/web/activity_pub/mrf.ex
@@ -108,6 +108,14 @@ defmodule Pleroma.Web.ActivityPub.MRF do
 
   def filter(%{} = object), do: get_policies() |> filter(object)
 
+  def id_filter(policies, id) when is_binary(id) do
+    policies
+    |> Enum.filter(&function_exported?(&1, :id_filter, 1))
+    |> Enum.all?(& &1.id_filter(id))
+  end
+
+  def id_filter(id) when is_binary(id), do: get_policies() |> id_filter(id)
+
   @impl true
   def pipeline_filter(%{} = message, meta) do
     object = meta[:object_data]
diff --git a/lib/pleroma/web/activity_pub/mrf/drop_policy.ex b/lib/pleroma/web/activity_pub/mrf/drop_policy.ex
index e4fcc9935..cf07db7f3 100644
--- a/lib/pleroma/web/activity_pub/mrf/drop_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/drop_policy.ex
@@ -14,5 +14,11 @@ defmodule Pleroma.Web.ActivityPub.MRF.DropPolicy do
   end
 
   @impl true
+  def id_filter(id) do
+    Logger.debug("REJECTING #{id}")
+    false
+  end
+
+  @impl true
   def describe, do: {:ok, %{}}
 end
diff --git a/lib/pleroma/web/activity_pub/mrf/policy.ex b/lib/pleroma/web/activity_pub/mrf/policy.ex
index 54ca4b735..08bcac08a 100644
--- a/lib/pleroma/web/activity_pub/mrf/policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/policy.ex
@@ -4,6 +4,7 @@
 
 defmodule Pleroma.Web.ActivityPub.MRF.Policy do
   @callback filter(Pleroma.Activity.t()) :: {:ok | :reject, Pleroma.Activity.t()}
+  @callback id_filter(String.t()) :: boolean()
   @callback describe() :: {:ok | :error, map()}
   @callback config_description() :: %{
               optional(:children) => [map()],
@@ -13,5 +14,5 @@ defmodule Pleroma.Web.ActivityPub.MRF.Policy do
               description: String.t()
             }
   @callback history_awareness() :: :auto | :manual
-  @optional_callbacks config_description: 0, history_awareness: 0
+  @optional_callbacks config_description: 0, history_awareness: 0, id_filter: 1
 end
diff --git a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
index ae7f18bfe..a97e8db7b 100644
--- a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
@@ -192,6 +192,18 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicy do
   end
 
   @impl true
+  def id_filter(id) do
+    host_info = URI.parse(id)
+
+    with {:ok, _} <- check_accept(host_info, %{}),
+         {:ok, _} <- check_reject(host_info, %{}) do
+      true
+    else
+      _ -> false
+    end
+  end
+
+  @impl true
   def filter(%{"type" => "Delete", "actor" => actor} = activity) do
     %{host: actor_host} = URI.parse(actor)