pleroma/lib/pleroma/web/plugs/http_signature_plug.ex
marcin mikołajczak ad953143bb Require HTTP signatures (if enabled) for routes used by both C2S and S2S AP API
Signed-off-by: marcin mikołajczak <git@mkljczk.pl>
2024-09-15 15:20:28 +02:00

121 lines
3.3 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.Plugs.HTTPSignaturePlug do
alias Pleroma.Helpers.InetHelper
import Plug.Conn
import Phoenix.Controller, only: [get_format: 1, text: 2]
alias Pleroma.Signature
alias Pleroma.Web.ActivityPub.MRF
require Logger
@config_impl Application.compile_env(:pleroma, [__MODULE__, :config_impl], Pleroma.Config)
def init(options) do
options
end
def call(%{assigns: %{valid_signature: true}} = conn, _opts), do: conn
# skip for C2S requests from authenticated users
def call(%{assigns: %{user: %Pleroma.User{}}} = conn, _opts) do
if get_format(conn) in ["json", "activity+json"] do
# ensure access token is provided for 2FA
Pleroma.Web.Plugs.EnsureAuthenticatedPlug.call(conn, %{})
else
conn
end
end
def call(conn, _opts) do
if get_format(conn) in ["json", "activity+json"] do
conn
|> maybe_assign_valid_signature()
|> maybe_assign_actor_id()
|> maybe_require_signature()
|> maybe_filter_requests()
else
conn
end
end
defp maybe_assign_valid_signature(conn) do
if has_signature_header?(conn) do
# we replace the digest header with the one we computed in DigestPlug
conn =
case conn do
%{assigns: %{digest: digest}} = conn -> put_req_header(conn, "digest", digest)
conn -> conn
end
assign(conn, :valid_signature, Signature.validate_signature(conn))
else
Logger.debug("No signature header!")
conn
end
end
defp maybe_assign_actor_id(%{assigns: %{valid_signature: true}} = conn) do
adapter = Application.get_env(:http_signatures, :adapter)
{:ok, actor_id} = adapter.get_actor_id(conn)
assign(conn, :actor_id, actor_id)
end
defp maybe_assign_actor_id(conn), do: conn
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(%{remote_ip: remote_ip} = conn) do
if @config_impl.get([:activitypub, :authorized_fetch_mode], false) do
exceptions =
@config_impl.get([:activitypub, :authorized_fetch_mode_exceptions], [])
|> Enum.map(&InetHelper.parse_cidr/1)
if Enum.any?(exceptions, fn x -> InetCidr.contains?(x, remote_ip) end) do
conn
else
conn
|> put_status(:unauthorized)
|> text("Request not signed")
|> halt()
end
else
conn
end
end
defp maybe_filter_requests(%{halted: true} = conn), do: conn
defp maybe_filter_requests(conn) do
if @config_impl.get([:activitypub, :authorized_fetch_mode], false) and
conn.assigns[:actor_id] do
%{host: host} = URI.parse(conn.assigns.actor_id)
if MRF.subdomain_match?(rejected_domains(), host) do
conn
|> put_status(:unauthorized)
|> halt()
else
conn
end
else
conn
end
end
defp rejected_domains do
@config_impl.get([:instance, :rejected_instances])
|> Pleroma.Web.ActivityPub.MRF.instance_list_from_tuples()
|> Pleroma.Web.ActivityPub.MRF.subdomains_regex()
end
end