86 lines
2.4 KiB
Elixir
86 lines
2.4 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2022 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.AntiFollowbotPolicy do
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alias Pleroma.User
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@moduledoc "Prevent followbots from following with a bit of heuristic"
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@behaviour Pleroma.Web.ActivityPub.MRF.Policy
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# XXX: this should become User.normalize_by_ap_id() or similar, really.
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defp normalize_by_ap_id(%{"id" => id}), do: User.get_cached_by_ap_id(id)
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defp normalize_by_ap_id(uri) when is_binary(uri), do: User.get_cached_by_ap_id(uri)
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defp normalize_by_ap_id(_), do: nil
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defp score_nickname("followbot@" <> _), do: 1.0
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defp score_nickname("federationbot@" <> _), do: 1.0
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defp score_nickname("federation_bot@" <> _), do: 1.0
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defp score_nickname(_), do: 0.0
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defp score_displayname("federation bot"), do: 1.0
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defp score_displayname("federationbot"), do: 1.0
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defp score_displayname("fedibot"), do: 1.0
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defp score_displayname(_), do: 0.0
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defp determine_if_followbot(%User{nickname: nickname, name: displayname, actor_type: actor_type}) do
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# nickname will be a binary string except when following a relay
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nick_score =
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if is_binary(nickname) do
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nickname
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|> String.downcase()
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|> score_nickname()
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else
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0.0
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end
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# displayname will either be a binary string or nil, if a displayname isn't set.
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name_score =
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if is_binary(displayname) do
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displayname
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|> String.downcase()
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|> score_displayname()
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else
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0.0
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end
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# actor_type "Service" is a Bot account
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actor_type_score =
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if actor_type == "Service" do
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1.0
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else
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0.0
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end
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nick_score + name_score + actor_type_score
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end
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defp determine_if_followbot(_), do: 0.0
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defp bot_allowed?(%{"object" => target}, bot_actor) do
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%User{} = user = normalize_by_ap_id(target)
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User.following?(user, bot_actor)
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end
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@impl true
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def filter(%{"type" => "Follow", "actor" => actor_id} = message) do
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%User{} = actor = normalize_by_ap_id(actor_id)
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score = determine_if_followbot(actor)
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if score < 0.8 || bot_allowed?(message, actor) do
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{:ok, message}
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else
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{:reject, "[AntiFollowbotPolicy] Scored #{actor_id} as #{score}"}
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end
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end
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@impl true
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def filter(message), do: {:ok, message}
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@impl true
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def describe, do: {:ok, %{}}
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end
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