154 lines
4.4 KiB
Elixir
154 lines
4.4 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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defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
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require Logger
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alias Pleroma.Config
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@moduledoc "Detect new emojis by their shortcode and steals them"
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@behaviour Pleroma.Web.ActivityPub.MRF.Policy
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defp accept_host?(host), do: host in Config.get([:mrf_steal_emoji, :hosts], [])
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defp shortcode_matches?(shortcode, pattern) when is_binary(pattern) do
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shortcode == pattern
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end
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defp shortcode_matches?(shortcode, pattern) do
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String.match?(shortcode, pattern)
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end
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defp steal_emoji({shortcode, url}, emoji_dir_path) do
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url = Pleroma.Web.MediaProxy.url(url)
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with {:ok, %{status: status} = response} when status in 200..299 <- Pleroma.HTTP.get(url) do
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size_limit = Config.get([:mrf_steal_emoji, :size_limit], 50_000)
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if byte_size(response.body) <= size_limit do
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extension =
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url
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|> URI.parse()
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|> Map.get(:path)
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|> Path.basename()
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|> Path.extname()
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file_path = Path.join(emoji_dir_path, shortcode <> (extension || ".png"))
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case File.write(file_path, response.body) do
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:ok ->
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shortcode
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e ->
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Logger.warning("MRF.StealEmojiPolicy: Failed to write to #{file_path}: #{inspect(e)}")
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nil
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end
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else
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Logger.debug(
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"MRF.StealEmojiPolicy: :#{shortcode}: at #{url} (#{byte_size(response.body)} B) over size limit (#{size_limit} B)"
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)
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nil
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end
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else
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e ->
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Logger.warning("MRF.StealEmojiPolicy: Failed to fetch #{url}: #{inspect(e)}")
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nil
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end
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end
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@impl true
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def filter(%{"object" => %{"emoji" => foreign_emojis, "actor" => actor}} = message) do
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host = URI.parse(actor).host
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if host != Pleroma.Web.Endpoint.host() and accept_host?(host) do
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installed_emoji = Pleroma.Emoji.get_all() |> Enum.map(fn {k, _} -> k end)
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emoji_dir_path =
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Config.get(
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[:mrf_steal_emoji, :path],
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Path.join(Config.get([:instance, :static_dir]), "emoji/stolen")
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)
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File.mkdir_p(emoji_dir_path)
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new_emojis =
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foreign_emojis
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|> Enum.reject(fn {shortcode, _url} -> shortcode in installed_emoji end)
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|> Enum.filter(fn {shortcode, _url} ->
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reject_emoji? =
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[:mrf_steal_emoji, :rejected_shortcodes]
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|> Config.get([])
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|> Enum.find(false, fn pattern -> shortcode_matches?(shortcode, pattern) end)
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!reject_emoji?
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end)
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|> Enum.map(&steal_emoji(&1, emoji_dir_path))
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|> Enum.filter(& &1)
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if !Enum.empty?(new_emojis) do
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Logger.info("Stole new emojis: #{inspect(new_emojis)}")
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Pleroma.Emoji.reload()
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end
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end
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{:ok, message}
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end
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def filter(message), do: {:ok, message}
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@impl true
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@spec config_description :: %{
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children: [
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%{
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description: <<_::272, _::_*256>>,
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key: :hosts | :rejected_shortcodes | :size_limit,
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suggestions: [any(), ...],
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type: {:list, :string} | {:list, :string} | :integer
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},
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...
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],
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description: <<_::448>>,
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key: :mrf_steal_emoji,
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label: <<_::80>>,
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related_policy: <<_::352>>
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}
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def config_description do
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%{
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key: :mrf_steal_emoji,
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related_policy: "Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy",
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label: "MRF Emojis",
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description: "Steals emojis from selected instances when it sees them.",
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children: [
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%{
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key: :hosts,
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type: {:list, :string},
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description: "List of hosts to steal emojis from",
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suggestions: [""]
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},
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%{
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key: :rejected_shortcodes,
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type: {:list, :string},
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description: """
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A list of patterns or matches to reject shortcodes with.
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Each pattern can be a string or [Regex](https://hexdocs.pm/elixir/Regex.html) in the format of `~r/PATTERN/`.
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""",
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suggestions: ["foo", ~r/foo/]
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},
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%{
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key: :size_limit,
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type: :integer,
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description: "File size limit (in bytes), checked before an emoji is saved to the disk",
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suggestions: ["100000"]
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}
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]
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}
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end
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@impl true
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def describe do
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{:ok, %{}}
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end
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end
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