Add ability to obfuscate domains in MRF transparency

[akkoma] / lib / pleroma / web / activity_pub / mrf / simple_policy.ex

diff --git a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
index 2f26fc3a01104373f9d4c08d33cfcfba8446d693..415c5d2ddb87937605684f547bba6fe457426f03 100644 (file)
--- a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
@@ -256,16 +256,71 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicy do
 
   def filter(object), do: {:ok, object}
 
+  defp obfuscate(string) when is_binary(string) do
+    string
+    |> to_charlist()
+    |> Enum.with_index()
+    |> Enum.map(fn
+      {?., _index} ->
+        ?.
+
+      {char, index} ->
+        if 3 <= index && index < String.length(string) - 3, do: ?*, else: char
+    end)
+    |> to_string()
+  end
+
+  defp maybe_obfuscate(host, obfuscations) do
+    if MRF.subdomain_match?(obfuscations, host) do
+      obfuscate(host)
+    else
+      host
+    end
+  end
+
   @impl true
   def describe do
     exclusions = Config.get([:mrf, :transparency_exclusions]) |> MRF.instance_list_from_tuples()
 
-    mrf_simple =
+    obfuscations =
+      Config.get([:mrf, :transparency_obfuscate_domains], []) |> MRF.subdomains_regex()
+
+    mrf_simple_excluded =
       Config.get(:mrf_simple)
-      |> Enum.map(fn {k, v} -> {k, Enum.reject(v, fn {v, _} -> v in exclusions end)} end)
-      |> Enum.into(%{})
+      |> Enum.map(fn {rule, instances} ->
+        {rule, Enum.reject(instances, fn {host, _} -> host in exclusions end)}
+      end)
 
-    {:ok, %{mrf_simple: mrf_simple}}
+    mrf_simple =
+      mrf_simple_excluded
+      |> Enum.map(fn {rule, instances} ->
+        {rule, Enum.map(instances, fn {host, _} -> maybe_obfuscate(host, obfuscations) end)}
+      end)
+      |> Map.new()
+
+    # This is for backwards compatibility. We originally didn't sent
+    # extra info like a reason why an instance was rejected/quarantined/etc.
+    # Because we didn't want to break backwards compatibility it was decided
+    # to add an extra "info" key.
+    mrf_simple_info =
+      mrf_simple_excluded
+      |> Enum.map(fn {rule, instances} ->
+        {rule, Enum.reject(instances, fn {_, reason} -> reason == "" end)}
+      end)
+      |> Enum.reject(fn {_, instances} -> instances == [] end)
+      |> Enum.map(fn {rule, instances} ->
+        instances =
+          instances
+          |> Enum.map(fn {host, reason} ->
+            {maybe_obfuscate(host, obfuscations), %{"reason" => reason}}
+          end)
+          |> Map.new()
+
+        {rule, instances}
+      end)
+      |> Map.new()
+
+    {:ok, %{mrf_simple: mrf_simple, mrf_simple_info: mrf_simple_info}}
   end
 
   @impl true