3 files changed, 61 insertions, 4 deletions
diff --git a/lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex b/lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex
new file mode 100644
index 000000000..6807673f9
--- /dev/null
+++ b/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
diff --git a/lib/pleroma/web/plugs/http_signature_plug.ex b/lib/pleroma/web/plugs/http_signature_plug.ex
index 67974599a..2e16212ce 100644
--- a/lib/pleroma/web/plugs/http_signature_plug.ex
+++ b/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
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index 0423ca9e2..d78a6aef4 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -902,22 +902,37 @@ 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)