forked from AkkomaGang/akkoma
Oneric
ba558c0c24
Else malicious emoji packs or our EmojiStealer MRF can put payloads into the same domain as the instance itself. Sanitising the content type should prevent proper clients from acting on any potential payload. Note, this does not affect the default emoji shipped with Akkoma as they are handled by another plug. However, those are fully trusted and thus not in needed of sanitisation.
127 lines
3.3 KiB
Elixir
127 lines
3.3 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.Plugs.UploadedMedia do
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@moduledoc """
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"""
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import Plug.Conn
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import Pleroma.Web.Gettext
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require Logger
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alias Pleroma.Web.MediaProxy
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alias Pleroma.Web.Plugs.Utils
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@behaviour Plug
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# no slashes
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@path "media"
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@default_cache_control_header "public, max-age=1209600"
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def init(_opts) do
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static_plug_opts =
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[
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headers: %{"cache-control" => @default_cache_control_header},
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cache_control_for_etags: @default_cache_control_header
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]
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|> Keyword.put(:from, "__unconfigured_media_plug")
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|> Keyword.put(:at, "/__unconfigured_media_plug")
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|> Plug.Static.init()
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config = Pleroma.Config.get(Pleroma.Upload)
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allowed_mime_types = Keyword.fetch!(config, :allowed_mime_types)
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uploader = Keyword.fetch!(config, :uploader)
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%{
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static_plug_opts: static_plug_opts,
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allowed_mime_types: allowed_mime_types,
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uploader: uploader
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}
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end
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def call(
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%{request_path: <<"/", @path, "/", file::binary>>} = conn,
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%{uploader: uploader} = opts
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) do
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conn =
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case fetch_query_params(conn) do
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%{query_params: %{"name" => name}} = conn ->
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name = escape_header_value(name)
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put_resp_header(conn, "content-disposition", ~s[inline; filename="#{name}"])
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conn ->
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conn
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end
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|> merge_resp_headers([{"content-security-policy", "sandbox"}])
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with {:ok, get_method} <- uploader.get_file(file),
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false <- media_is_banned(conn, get_method) do
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get_media(conn, get_method, opts)
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else
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_ ->
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conn
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|> send_resp(:internal_server_error, dgettext("errors", "Failed"))
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|> halt()
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end
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end
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def call(conn, _opts), do: conn
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defp media_is_banned(%{request_path: path} = _conn, {:static_dir, _}) do
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MediaProxy.in_banned_urls(Pleroma.Upload.base_url() <> path)
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end
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defp media_is_banned(_, {:url, url}), do: MediaProxy.in_banned_urls(url)
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defp media_is_banned(_, _), do: false
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defp set_content_type(conn, opts, filepath) do
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real_mime = MIME.from_path(filepath)
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clean_mime = Utils.get_safe_mime_type(opts, real_mime)
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put_resp_header(conn, "content-type", clean_mime)
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end
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defp get_media(conn, {:static_dir, directory}, opts) do
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static_opts =
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Map.get(opts, :static_plug_opts)
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|> Map.put(:at, [@path])
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|> Map.put(:from, directory)
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|> Map.put(:set_content_type, false)
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conn =
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conn
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|> set_content_type(opts, conn.request_path)
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|> Pleroma.Web.Plugs.StaticNoCT.call(static_opts)
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if conn.halted do
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conn
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else
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conn
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|> send_resp(:not_found, dgettext("errors", "Not found"))
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|> halt()
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end
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end
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defp get_media(conn, {:url, url}, _) do
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conn
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|> Phoenix.Controller.redirect(external: url)
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|> halt()
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end
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defp get_media(conn, unknown, _) do
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Logger.error("#{__MODULE__}: Unknown get startegy: #{inspect(unknown)}")
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conn
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|> send_resp(:internal_server_error, dgettext("errors", "Internal Error"))
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|> halt()
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end
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defp escape_header_value(value) do
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value
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|> String.replace("\"", "\\\"")
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|> String.replace("\\r", "")
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|> String.replace("\\n", "")
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end
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end
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