Merge branch 'pleroma-ensure-authorized-fetch' into security-2.9

changelog.d/ensure-authorized-fetch.security

@@ -0,0 +1 @@
+Require HTTP signatures (if enabled) for routes used by both C2S and S2S AP API

config/config.exs

@@ -359,7 +359,8 @@ config :pleroma, :activitypub,
   follow_handshake_timeout: 500,
   note_replies_output_limit: 5,
   sign_object_fetches: true,
-  authorized_fetch_mode: false
+  authorized_fetch_mode: false,
+  client_api_enabled: true
 
 config :pleroma, :streamer,
   workers: 3,

config/description.exs

@@ -1772,6 +1772,11 @@ config :pleroma, :config_description, [
         type: :integer,
         description: "Following handshake timeout",
         suggestions: [500]
+      },
+      %{
+        key: :client_api_enabled,
+        type: :boolean,
+        description: "Allow client to server ActivityPub interactions"
       }
     ]
   },

lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex

@@ -0,0 +1,34 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Plugs.APClientApiEnabledPlug do
+  import Plug.Conn
+  import Phoenix.Controller, only: [text: 2]
+
+  @config_impl Application.compile_env(:pleroma, [__MODULE__, :config_impl], Pleroma.Config)
+  @enabled_path [:activitypub, :client_api_enabled]
+
+  def init(options \\ []), do: Map.new(options)
+
+  def call(conn, %{allow_server: true}) do
+    if @config_impl.get(@enabled_path, false) do
+      conn
+    else
+      conn
+      |> assign(:user, nil)
+      |> assign(:token, nil)
+    end
+  end
+
+  def call(conn, _) do
+    if @config_impl.get(@enabled_path, false) do
+      conn
+    else
+      conn
+      |> put_status(:forbidden)
+      |> text("C2S not enabled")
+      |> halt()
+    end
+  end
+end

lib/pleroma/web/plugs/http_signature_plug.ex

@@ -19,8 +19,16 @@ defmodule Pleroma.Web.Plugs.HTTPSignaturePlug do
     options
   end
 
-  def call(%{assigns: %{valid_signature: true}} = conn, _opts) do
-    conn
+  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

lib/pleroma/web/router.ex

@@ -907,22 +907,37 @@ defmodule Pleroma.Web.Router do
   # Client to Server (C2S) AP interactions
   pipeline :activitypub_client do
     plug(:ap_service_actor)
+    plug(Pleroma.Web.Plugs.APClientApiEnabledPlug)
     plug(:fetch_session)
     plug(:authenticate)
     plug(:after_auth)
   end
 
+  # AP interactions used by both S2S and C2S
+  pipeline :activitypub_server_or_client do
+    plug(:ap_service_actor)
+    plug(:fetch_session)
+    plug(:authenticate)
+    plug(Pleroma.Web.Plugs.APClientApiEnabledPlug, allow_server: true)
+    plug(:after_auth)
+    plug(:http_signature)
+  end
+
   scope "/", Pleroma.Web.ActivityPub do
     pipe_through([:activitypub_client])
 
     get("/api/ap/whoami", ActivityPubController, :whoami)
     get("/users/:nickname/inbox", ActivityPubController, :read_inbox)
 
-    get("/users/:nickname/outbox", ActivityPubController, :outbox)
     post("/users/:nickname/outbox", ActivityPubController, :update_outbox)
     post("/api/ap/upload_media", ActivityPubController, :upload_media)
+  end
+
+  scope "/", Pleroma.Web.ActivityPub do
+    pipe_through([:activitypub_server_or_client])
+
+    get("/users/:nickname/outbox", ActivityPubController, :outbox)
 
-    # The following two are S2S as well, see `ActivityPub.fetch_follow_information_for_user/1`:
     get("/users/:nickname/followers", ActivityPubController, :followers)
     get("/users/:nickname/following", ActivityPubController, :following)
     get("/users/:nickname/collections/featured", ActivityPubController, :pinned)

test/pleroma/web/activity_pub/activity_pub_controller_test.exs

@@ -1344,6 +1344,11 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
   end
 
   describe "GET /users/:nickname/outbox" do
+    setup do
+      Mox.stub_with(Pleroma.StaticStubbedConfigMock, Pleroma.Config)
+      :ok
+    end
+
     test "it paginates correctly", %{conn: conn} do
       user = insert(:user)
       conn = assign(conn, :user, user)
@@ -1432,6 +1437,22 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
       assert %{"orderedItems" => []} = resp
     end
 
+    test "it does not return a local note activity when C2S API is disabled", %{conn: conn} do
+      clear_config([:activitypub, :client_api_enabled], false)
+      user = insert(:user)
+      reader = insert(:user)
+      {:ok, _note_activity} = CommonAPI.post(user, %{status: "mew mew", visibility: "local"})
+
+      resp =
+        conn
+        |> assign(:user, reader)
+        |> put_req_header("accept", "application/activity+json")
+        |> get("/users/#{user.nickname}/outbox?page=true")
+        |> json_response(200)
+
+      assert %{"orderedItems" => []} = resp
+    end
+
     test "it returns a note activity in a collection", %{conn: conn} do
       note_activity = insert(:note_activity)
       note_object = Object.normalize(note_activity, fetch: false)
@@ -1483,6 +1504,35 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
       assert [answer_outbox] = outbox_get["orderedItems"]
       assert answer_outbox["id"] == activity.data["id"]
     end
+
+    test "it works with authorized fetch forced when authenticated" do
+      clear_config([:activitypub, :authorized_fetch_mode], true)
+
+      user = insert(:user)
+      outbox_endpoint = user.ap_id <> "/outbox"
+
+      conn =
+        build_conn()
+        |> assign(:user, user)
+        |> put_req_header("accept", "application/activity+json")
+        |> get(outbox_endpoint)
+
+      assert json_response(conn, 200)
+    end
+
+    test "it fails with authorized fetch forced when unauthenticated", %{conn: conn} do
+      clear_config([:activitypub, :authorized_fetch_mode], true)
+
+      user = insert(:user)
+      outbox_endpoint = user.ap_id <> "/outbox"
+
+      conn =
+        conn
+        |> put_req_header("accept", "application/activity+json")
+        |> get(outbox_endpoint)
+
+      assert response(conn, 401)
+    end
   end
 
   describe "POST /users/:nickname/outbox (C2S)" do
@@ -2153,6 +2203,30 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubControllerTest do
       |> post("/api/ap/upload_media", %{"file" => image, "description" => desc})
       |> json_response(403)
     end
+
+    test "they don't work when C2S API is disabled", %{conn: conn} do
+      clear_config([:activitypub, :client_api_enabled], false)
+
+      user = insert(:user)
+
+      assert conn
+             |> assign(:user, user)
+             |> get("/api/ap/whoami")
+             |> response(403)
+
+      desc = "Description of the image"
+
+      image = %Plug.Upload{
+        content_type: "image/jpeg",
+        path: Path.absname("test/fixtures/image.jpg"),
+        filename: "an_image.jpg"
+      }
+
+      assert conn
+             |> assign(:user, user)
+             |> post("/api/ap/upload_media", %{"file" => image, "description" => desc})
+             |> response(403)
+    end
   end
 
   test "pinned collection", %{conn: conn} do