# Pleroma: A lightweight social networking server # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Web.ActivityPub.MRF.KeywordPolicy do require Pleroma.Constants @moduledoc "Reject or Word-Replace messages with a keyword or regex" @behaviour Pleroma.Web.ActivityPub.MRF defp string_matches?(string, _) when not is_binary(string) do false end defp string_matches?(string, pattern) when is_binary(pattern) do String.contains?(string, pattern) end defp string_matches?(string, pattern) do String.match?(string, pattern) end defp object_payload(%{} = object) do [object["content"], object["summary"], object["name"]] |> Enum.filter(& &1) |> Enum.join("\n") end defp check_reject(%{"object" => %{} = object} = message) do payload = object_payload(object) if Enum.any?(Pleroma.Config.get([:mrf_keyword, :reject]), fn pattern -> string_matches?(payload, pattern) end) do {:reject, "[KeywordPolicy] Matches with rejected keyword"} else {:ok, message} end end defp check_ftl_removal(%{"to" => to, "object" => %{} = object} = message) do payload = object_payload(object) if Pleroma.Constants.as_public() in to and Enum.any?(Pleroma.Config.get([:mrf_keyword, :federated_timeline_removal]), fn pattern -> string_matches?(payload, pattern) end) do to = List.delete(to, Pleroma.Constants.as_public()) cc = [Pleroma.Constants.as_public() | message["cc"] || []] message = message |> Map.put("to", to) |> Map.put("cc", cc) {:ok, message} else {:ok, message} end end defp check_replace(%{"object" => %{} = object} = message) do object = ["content", "name", "summary"] |> Enum.filter(fn field -> Map.has_key?(object, field) && object[field] end) |> Enum.reduce(object, fn field, object -> data = Enum.reduce( Pleroma.Config.get([:mrf_keyword, :replace]), object[field], fn {pat, repl}, acc -> String.replace(acc, pat, repl) end ) Map.put(object, field, data) end) message = Map.put(message, "object", object) {:ok, message} end @impl true def filter(%{"type" => "Create", "object" => %{"content" => _content}} = message) do with {:ok, message} <- check_reject(message), {:ok, message} <- check_ftl_removal(message), {:ok, message} <- check_replace(message) do {:ok, message} else {:reject, nil} -> {:reject, "[KeywordPolicy] "} {:reject, _} = e -> e _e -> {:reject, "[KeywordPolicy] "} end end @impl true def filter(message), do: {:ok, message} @impl true def describe do # This horror is needed to convert regex sigils to strings mrf_keyword = Pleroma.Config.get(:mrf_keyword, []) |> Enum.map(fn {key, value} -> {key, Enum.map(value, fn {pattern, replacement} -> %{ "pattern" => if not is_binary(pattern) do inspect(pattern) else pattern end, "replacement" => replacement } pattern -> if not is_binary(pattern) do inspect(pattern) else pattern end end)} end) |> Enum.into(%{}) {:ok, %{mrf_keyword: mrf_keyword}} end end