141 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
			
		
		
	
	
			141 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
| # Pleroma: A lightweight social networking server
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| # Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
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| # SPDX-License-Identifier: AGPL-3.0-only
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| 
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| defmodule Pleroma.Web.ActivityPub.MRF.ObjectAgePolicy do
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|   alias Pleroma.Config
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|   alias Pleroma.User
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| 
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|   require Pleroma.Constants
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| 
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|   @moduledoc "Filter activities depending on their age"
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|   @behaviour Pleroma.Web.ActivityPub.MRF.Policy
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| 
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|   defp check_date(%{"object" => %{"published" => published}} = message) do
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|     with %DateTime{} = now <- DateTime.utc_now(),
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|          {:ok, %DateTime{} = then, _} <- DateTime.from_iso8601(published),
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|          max_ttl <- Config.get([:mrf_object_age, :threshold]),
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|          {:ttl, false} <- {:ttl, DateTime.diff(now, then) > max_ttl} do
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|       {:ok, message}
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|     else
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|       {:ttl, true} ->
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|         {:reject, nil}
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| 
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|       e ->
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|         {:error, e}
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|     end
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|   end
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| 
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|   defp check_reject(message, actions) do
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|     if :reject in actions do
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|       {:reject, "[ObjectAgePolicy]"}
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|     else
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|       {:ok, message}
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|     end
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|   end
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| 
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|   defp check_delist(message, actions) do
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|     if :delist in actions do
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|       with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
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|         to =
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|           List.delete(message["to"] || [], Pleroma.Constants.as_public()) ++
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|             [user.follower_address]
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| 
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|         cc =
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|           List.delete(message["cc"] || [], user.follower_address) ++
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|             [Pleroma.Constants.as_public()]
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| 
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|         message =
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|           message
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|           |> Map.put("to", to)
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|           |> Map.put("cc", cc)
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|           |> Kernel.put_in(["object", "to"], to)
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|           |> Kernel.put_in(["object", "cc"], cc)
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| 
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|         {:ok, message}
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|       else
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|         _e ->
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|           {:reject, "[ObjectAgePolicy] Unhandled error"}
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|       end
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|     else
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|       {:ok, message}
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|     end
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|   end
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| 
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|   defp check_strip_followers(message, actions) do
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|     if :strip_followers in actions do
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|       with %User{} = user <- User.get_cached_by_ap_id(message["actor"]) do
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|         to = List.delete(message["to"] || [], user.follower_address)
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|         cc = List.delete(message["cc"] || [], user.follower_address)
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| 
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|         message =
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|           message
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|           |> Map.put("to", to)
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|           |> Map.put("cc", cc)
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|           |> Kernel.put_in(["object", "to"], to)
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|           |> Kernel.put_in(["object", "cc"], cc)
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| 
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|         {:ok, message}
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|       else
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|         _e ->
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|           {:reject, "[ObjectAgePolicy] Unhandled error"}
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|       end
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|     else
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|       {:ok, message}
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|     end
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|   end
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| 
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|   @impl true
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|   def filter(%{"type" => "Create", "object" => %{"published" => _}} = message) do
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|     with actions <- Config.get([:mrf_object_age, :actions]),
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|          {:reject, _} <- check_date(message),
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|          {:ok, message} <- check_reject(message, actions),
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|          {:ok, message} <- check_delist(message, actions),
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|          {:ok, message} <- check_strip_followers(message, actions) do
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|       {:ok, message}
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|     else
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|       # check_date() is allowed to short-circuit the pipeline
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|       e -> e
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|     end
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|   end
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| 
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|   @impl true
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|   def filter(message), do: {:ok, message}
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| 
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|   @impl true
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|   def describe do
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|     mrf_object_age =
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|       Config.get(:mrf_object_age)
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|       |> Enum.into(%{})
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| 
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|     {:ok, %{mrf_object_age: mrf_object_age}}
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|   end
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| 
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|   @impl true
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|   def config_description do
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|     %{
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|       key: :mrf_object_age,
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|       related_policy: "Pleroma.Web.ActivityPub.MRF.ObjectAgePolicy",
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|       label: "MRF Object Age",
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|       description:
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|         "Rejects or delists posts based on their timestamp deviance from your server's clock.",
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|       children: [
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|         %{
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|           key: :threshold,
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|           type: :integer,
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|           description: "Required age (in seconds) of a post before actions are taken.",
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|           suggestions: [172_800]
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|         },
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|         %{
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|           key: :actions,
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|           type: {:list, :atom},
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|           description:
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|             "A list of actions to apply to the post. `:delist` removes the post from public timelines; " <>
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|               "`:strip_followers` removes followers from the ActivityPub recipient list ensuring they won't be delivered to home timelines; " <>
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|               "`:reject` rejects the message entirely",
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|           suggestions: [:delist, :strip_followers, :reject]
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|         }
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|       ]
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|     }
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|   end
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| end
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