From f8310114a6a4154118e54ebaac6f4a96941be4a6 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sat, 10 Nov 2018 12:04:09 +0000
Subject: [PATCH 1/3] activitypub: object view: sanitize both the activity and
 the object when an activity is given for rendering

---
 lib/pleroma/web/activity_pub/views/object_view.ex | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/pleroma/web/activity_pub/views/object_view.ex b/lib/pleroma/web/activity_pub/views/object_view.ex
index df734a871..1911ddfb7 100644
--- a/lib/pleroma/web/activity_pub/views/object_view.ex
+++ b/lib/pleroma/web/activity_pub/views/object_view.ex
@@ -1,11 +1,23 @@
 defmodule Pleroma.Web.ActivityPub.ObjectView do
   use Pleroma.Web, :view
+  alias Pleroma.{Object, Activity}
   alias Pleroma.Web.ActivityPub.Transmogrifier
 
-  def render("object.json", %{object: object}) do
+  def render("object.json", %{object: %Object{} = object}) do
     base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header()
 
     additional = Transmogrifier.prepare_object(object.data)
     Map.merge(base, additional)
   end
+
+  def render("object.json", %{object: %Activity{} = activity}) do
+    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header()
+    object = Object.normalize(activity.data["object"])
+
+    additional =
+      Transmogrifier.prepare_object(activity.data)
+      |> Map.put("object", Transmogrifier.prepare_object(object.data))
+
+    Map.merge(base, additional)
+  end
 end

From 97e50f3191f6ea8479729b639921180fcadccf73 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sat, 10 Nov 2018 12:08:53 +0000
Subject: [PATCH 2/3] activitypub: transmogrifier: sanitize internal
 representation details from outgoing objects

this causes JSON-LD parsers to get upset and has also lead to developer confusion from outside
projects which tried to parse our internal data.  accordingly, it seems better to just remove
it.
---
 .../web/activity_pub/transmogrifier.ex        | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 6a0fdb433..d51d8626b 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -589,6 +589,8 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     |> prepare_attachments
     |> set_conversation
     |> set_reply_to_uri
+    |> strip_internal_fields
+    |> strip_internal_tags
   end
 
   #  @doc
@@ -755,6 +757,29 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     |> Map.put("attachment", attachments)
   end
 
+  defp strip_internal_fields(object) do
+    object
+    |> Map.drop([
+      "likes",
+      "like_count",
+      "announcements",
+      "announcement_count",
+      "emoji",
+      "context_id"
+    ])
+  end
+
+  defp strip_internal_tags(%{"tag" => tags} = object) do
+    tags =
+      tags
+      |> Enum.filter(fn x -> is_map(x) end)
+
+    object
+    |> Map.put("tag", tags)
+  end
+
+  defp strip_internal_tags(object), do: object
+
   defp user_upgrade_task(user) do
     old_follower_address = User.ap_followers(user)
 

From 69b8c0e299c9d4ec16bd056adf2fede326de7f69 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Sat, 10 Nov 2018 12:16:10 +0000
Subject: [PATCH 3/3] tests: add test for internal data stripping

---
 test/web/activity_pub/transmogrifier_test.exs | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/test/web/activity_pub/transmogrifier_test.exs b/test/web/activity_pub/transmogrifier_test.exs
index 6e4820dbc..0278ef5d1 100644
--- a/test/web/activity_pub/transmogrifier_test.exs
+++ b/test/web/activity_pub/transmogrifier_test.exs
@@ -743,6 +743,39 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
 
       assert modified["object"]["inReplyTo"] == "http://gs.example.org:4040/index.php/notice/29"
     end
+
+    test "it strips internal hashtag data" do
+      user = insert(:user)
+
+      {:ok, activity} = CommonAPI.post(user, %{"status" => "#2hu"})
+
+      expected_tag = %{
+        "href" => Pleroma.Web.Endpoint.url() <> "/tags/2hu",
+        "type" => "Hashtag",
+        "name" => "#2hu"
+      }
+
+      {:ok, modified} = Transmogrifier.prepare_outgoing(activity.data)
+
+      assert modified["object"]["tag"] == [expected_tag]
+    end
+
+    test "it strips internal fields" do
+      user = insert(:user)
+
+      {:ok, activity} = CommonAPI.post(user, %{"status" => "#2hu :moominmamma:"})
+
+      {:ok, modified} = Transmogrifier.prepare_outgoing(activity.data)
+
+      assert length(modified["object"]["tag"]) == 2
+
+      assert is_nil(modified["object"]["emoji"])
+      assert is_nil(modified["object"]["likes"])
+      assert is_nil(modified["object"]["like_count"])
+      assert is_nil(modified["object"]["announcements"])
+      assert is_nil(modified["object"]["announcement_count"])
+      assert is_nil(modified["object"]["context_id"])
+    end
   end
 
   describe "user upgrade" do