akkoma/lib/pleroma/object/containment.ex
Oneric 59a142e0b0 Never fetch resource from ourselves
If it’s not already in the database,
it must be counterfeit (or just not exists at all)

Changed test URLs were only ever used from "local: false" users anyway.
2024-03-25 14:05:05 -01:00

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# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Object.Containment do
@moduledoc """
This module contains some useful functions for containing objects to specific
origins and determining those origins. They previously lived in the
ActivityPub `Transmogrifier` module.
Object containment is an important step in validating remote objects to prevent
spoofing, therefore removal of object containment functions is NOT recommended.
"""
def get_actor(%{"actor" => actor}) when is_binary(actor) do
actor
end
def get_actor(%{"actor" => actor}) when is_list(actor) do
if is_binary(Enum.at(actor, 0)) do
Enum.at(actor, 0)
else
Enum.find(actor, fn %{"type" => type} -> type in ["Person", "Service", "Application"] end)
|> Map.get("id")
end
end
def get_actor(%{"actor" => %{"id" => id}}) when is_bitstring(id) do
id
end
def get_actor(%{"actor" => nil, "attributedTo" => actor}) when not is_nil(actor) do
get_actor(%{"actor" => actor})
end
def get_object(%{"object" => id}) when is_binary(id) do
id
end
def get_object(%{"object" => %{"id" => id}}) when is_binary(id) do
id
end
def get_object(_) do
nil
end
defp compare_uris(%URI{host: host} = _id_uri, %URI{host: host} = _other_uri), do: :ok
defp compare_uris(_id_uri, _other_uri), do: :error
@doc """
Checks whether an URL to fetch from is from the local server.
We never want to fetch from ourselves; if its not in the database
it cant be authentic and must be a counterfeit.
"""
def contain_local_fetch(id) do
case compare_uris(URI.parse(id), Pleroma.Web.Endpoint.struct_url()) do
:ok -> :error
_ -> :ok
end
end
@doc """
Checks that an imported AP object's actor matches the host it came from.
"""
def contain_origin(_id, %{"actor" => nil}), do: :error
def contain_origin(id, %{"actor" => _actor} = params) do
id_uri = URI.parse(id)
actor_uri = URI.parse(get_actor(params))
compare_uris(actor_uri, id_uri)
end
def contain_origin(id, %{"attributedTo" => actor} = params),
do: contain_origin(id, Map.put(params, "actor", actor))
def contain_origin(_id, _data), do: :ok
@doc """
Check whether the object id is from the same host as another id
"""
def contain_origin_from_id(id, %{"id" => other_id} = _params) when is_binary(other_id) do
id_uri = URI.parse(id)
other_uri = URI.parse(other_id)
compare_uris(id_uri, other_uri)
end
# Mastodon pin activities don't have an id, so we check the object field, which will be pinned.
def contain_origin_from_id(id, %{"object" => object}) when is_binary(object) do
id_uri = URI.parse(id)
object_uri = URI.parse(object)
compare_uris(id_uri, object_uri)
end
def contain_origin_from_id(_id, _data), do: :error
def contain_child(%{"object" => %{"id" => id, "attributedTo" => _} = object}),
do: contain_origin(id, object)
def contain_child(_), do: :ok
end