security: detect object containment violations at the IR level

It is more efficient to check for object containment violations at the IR
level instead of in the protocol handlers.  OStatus containment is especially
a tricky situation, as the containment rules don't match those of IR and
ActivityPub.

Accordingly, we just always do a final containment check at the IR level
before the object is added to the IR object graph.

diff --git a/lib/pleroma/object/containment.ex b/lib/pleroma/object/containment.ex
index ada9da0bb6de7a0bdcb144b789223b939bd5deb9..f077a9f32436841f1ffb01975c970d3082fd80a7 100644 (file)
--- a/lib/pleroma/object/containment.ex
+++ b/lib/pleroma/object/containment.ex
@@ -48,6 +48,9 @@ defmodule Pleroma.Object.Containment do
     end
   end
 
+  def contain_origin(id, %{"attributedTo" => actor} = params),
+    do: contain_origin(id, Map.put(params, "actor", actor))
+
   def contain_origin_from_id(_id, %{"id" => nil}), do: :error
 
   def contain_origin_from_id(id, %{"id" => other_id} = _params) do
@@ -60,4 +63,9 @@ defmodule Pleroma.Object.Containment do
       :error
     end
   end
+
+  def contain_child(%{"object" => %{"id" => id, "attributedTo" => _} = object}),
+    do: contain_origin(id, object)
+
+  def contain_child(_), do: :ok
 end

diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index a3174a7871fc2f4d8188b26125ccf9ee8a832330..87963b691b8abafb9e7c001fb9488e4131039717 100644 (file)
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -8,6 +8,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
   alias Pleroma.Conversation
   alias Pleroma.Notification
   alias Pleroma.Object
+  alias Pleroma.Object.Containment
   alias Pleroma.Object.Fetcher
   alias Pleroma.Pagination
   alias Pleroma.Repo
@@ -126,6 +127,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
          {:ok, map} <- MRF.filter(map),
          {recipients, _, _} = get_recipients(map),
          {:fake, false, map, recipients} <- {:fake, fake, map, recipients},
+         :ok <- Containment.contain_child(map),
          {:ok, map, object} <- insert_full_object(map) do
       {:ok, activity} =
         Repo.insert(%Activity{

diff --git a/test/object/containment_test.exs b/test/object/containment_test.exs
index 1beed623646936ce43fd3bee76203ee119f2b640..61cd1b41228d896e72f4596789e331ce3e2a2f66 100644 (file)
--- a/test/object/containment_test.exs
+++ b/test/object/containment_test.exs
@@ -68,4 +68,34 @@ defmodule Pleroma.Object.ContainmentTest do
                "[error] Could not decode user at fetch https://n1u.moe/users/rye, {:error, :error}"
     end
   end
+
+  describe "containment of children" do
+    test "contain_child() catches spoofing attempts" do
+      data = %{
+        "id" => "http://example.com/whatever",
+        "type" => "Create",
+        "object" => %{
+          "id" => "http://example.net/~alyssa/activities/1234",
+          "attributedTo" => "http://example.org/~alyssa"
+        },
+        "actor" => "http://example.com/~bob"
+      }
+
+      :error = Containment.contain_child(data)
+    end
+
+    test "contain_child() allows correct origins" do
+      data = %{
+        "id" => "http://example.org/~alyssa/activities/5678",
+        "type" => "Create",
+        "object" => %{
+          "id" => "http://example.org/~alyssa/activities/1234",
+          "attributedTo" => "http://example.org/~alyssa"
+        },
+        "actor" => "http://example.org/~alyssa"
+      }
+
+      :ok = Containment.contain_child(data)
+    end
+  end
 end