127 lines
		
	
	
	
		
			3.6 KiB
		
	
	
	
		
			Elixir
		
	
	
	
	
	
			
		
		
	
	
			127 lines
		
	
	
	
		
			3.6 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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| 
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| defmodule Pleroma.Web.Plugs.HTTPSignaturePlug do
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|   import Plug.Conn
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|   import Phoenix.Controller, only: [get_format: 1]
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|   alias Pleroma.Activity
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|   alias Pleroma.Web.Router
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|   alias Pleroma.Signature
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|   alias Pleroma.Instances
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|   require Logger
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| 
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|   @cachex Pleroma.Config.get([:cachex, :provider], Cachex)
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| 
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|   def init(options) do
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|     options
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|   end
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| 
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|   def call(%{assigns: %{valid_signature: true}} = conn, _opts) do
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|     conn
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|   end
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| 
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|   def call(conn, _opts) do
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|     if get_format(conn) in ["json", "activity+json"] do
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|       conn
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|       |> maybe_assign_valid_signature()
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|       |> maybe_require_signature()
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|     else
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|       conn
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|     end
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|   end
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| 
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|   def route_aliases(%{path_info: ["objects", id], query_string: query_string}) do
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|     ap_id = Router.Helpers.o_status_url(Pleroma.Web.Endpoint, :object, id)
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| 
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|     with %Activity{} = activity <- Activity.get_by_object_ap_id_with_object(ap_id) do
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|       ["/notice/#{activity.id}", "/notice/#{activity.id}?#{query_string}"]
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|     else
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|       _ -> []
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|     end
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|   end
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| 
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|   def route_aliases(_), do: []
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| 
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|   defp assign_valid_signature_on_route_aliases(conn, []), do: conn
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| 
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|   defp assign_valid_signature_on_route_aliases(%{assigns: %{valid_signature: true}} = conn, _),
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|     do: conn
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| 
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|   defp assign_valid_signature_on_route_aliases(conn, [path | rest]) do
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|     request_target = String.downcase("#{conn.method}") <> " #{path}"
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| 
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|     conn =
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|       conn
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|       |> put_req_header("(request-target)", request_target)
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|       |> case do
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|         %{assigns: %{digest: digest}} = conn -> put_req_header(conn, "digest", digest)
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|         conn -> conn
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|       end
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| 
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|     conn
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|     |> assign(:valid_signature, HTTPSignatures.validate_conn(conn))
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|     |> assign(:signature_actor_id, signature_host(conn))
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|     |> assign_valid_signature_on_route_aliases(rest)
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|   end
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| 
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|   defp maybe_assign_valid_signature(conn) do
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|     if has_signature_header?(conn) do
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|       # set (request-target) header to the appropriate value
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|       # we also replace the digest header with the one we computed
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|       possible_paths =
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|         route_aliases(conn) ++ [conn.request_path, conn.request_path <> "?#{conn.query_string}"]
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| 
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|       assign_valid_signature_on_route_aliases(conn, possible_paths)
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|     else
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|       Logger.debug("No signature header!")
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|       conn
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|     end
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|   end
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| 
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|   defp has_signature_header?(conn) do
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|     conn |> get_req_header("signature") |> Enum.at(0, false)
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|   end
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| 
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|   defp maybe_require_signature(
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|          %{assigns: %{valid_signature: true, signature_actor_id: actor_id}} = conn
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|        ) do
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|     # inboxes implicitly need http signatures for authentication
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|     # so we don't really know if the instance will have broken federation after
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|     # we turn on authorized_fetch_mode.
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|     #
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|     # to "check" this is a signed fetch, verify if method is GET
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|     if conn.method == "GET" do
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|       actor_host = URI.parse(actor_id).host
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| 
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|       case @cachex.get(:request_signatures_cache, actor_host) do
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|         {:ok, nil} ->
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|           Logger.debug("Successful signature from #{actor_host}")
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|           Instances.set_request_signatures(actor_host)
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|           @cachex.put(:request_signatures_cache, actor_host, true)
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| 
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|         {:ok, true} ->
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|           :noop
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| 
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|         any ->
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|           Logger.warn(
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|             "expected request signature cache to return a boolean, instead got #{inspect(any)}"
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|           )
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|       end
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|     end
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| 
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|     conn
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|   end
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| 
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|   defp maybe_require_signature(conn), do: conn
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| 
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|   defp signature_host(conn) do
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|     with %{"keyId" => kid} <- HTTPSignatures.signature_for_conn(conn),
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|          {:ok, actor_id} <- Signature.key_id_to_actor_id(kid) do
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|       actor_id
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|     else
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|       e ->
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|         {:error, e}
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|     end
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|   end
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| end
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