akkoma/lib/pleroma/web/plugs/http_signature_plug.ex

92 lines
2.5 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.Plugs.HTTPSignaturePlug do
import Plug.Conn
import Phoenix.Controller, only: [get_format: 1, text: 2]
alias Pleroma.Activity
alias Pleroma.Web.Router
require Logger
def init(options) do
options
end
def call(%{assigns: %{valid_signature: true}} = conn, _opts) do
conn
end
def call(conn, _opts) do
if get_format(conn) == "activity+json" do
conn
|> maybe_assign_valid_signature()
|> maybe_require_signature()
else
conn
end
end
def route_aliases(%{path_info: ["objects", id]} = conn) do
ap_id = Router.Helpers.o_status_url(Pleroma.Web.Endpoint, :object, id)
with %Activity{} = activity <- Activity.get_by_object_ap_id_with_object(ap_id) do
["/notice/#{activity.id}"]
else
_ -> []
end
end
def route_aliases(_), do: []
defp assign_valid_signature_on_route_aliases(conn, []), do: conn
defp assign_valid_signature_on_route_aliases(%{assigns: %{valid_signature: true}} = conn, _),
do: conn
defp assign_valid_signature_on_route_aliases(conn, [path | rest]) do
request_target = String.downcase("#{conn.method}") <> " #{path}"
conn =
conn
|> put_req_header("(request-target)", request_target)
|> case do
%{assigns: %{digest: digest}} = conn -> put_req_header(conn, "digest", digest)
conn -> conn
end
conn
|> assign(:valid_signature, HTTPSignatures.validate_conn(conn))
|> assign_valid_signature_on_route_aliases(rest)
end
defp maybe_assign_valid_signature(conn) do
if has_signature_header?(conn) do
# set (request-target) header to the appropriate value
# we also replace the digest header with the one we computed
possible_paths = route_aliases(conn) ++ [conn.request_path]
assign_valid_signature_on_route_aliases(conn, possible_paths)
else
Logger.debug("No signature header!")
conn
end
end
defp has_signature_header?(conn) do
conn |> get_req_header("signature") |> Enum.at(0, false)
end
defp maybe_require_signature(%{assigns: %{valid_signature: true}} = conn), do: conn
defp maybe_require_signature(conn) do
if Pleroma.Config.get([:activitypub, :authorized_fetch_mode], false) do
conn
|> put_status(:unauthorized)
|> text("Request not signed")
|> halt()
else
conn
end
end
end