3 files changed, 22 insertions, 3 deletions
diff --git a/lib/pleroma/web/activity_pub/object_validator.ex b/lib/pleroma/web/activity_pub/object_validator.ex
index 11432ef38..14c3e8531 100644
--- a/lib/pleroma/web/activity_pub/object_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validator.ex
@@ -17,6 +17,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   alias Pleroma.Object.Containment
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.ObjectValidators.AcceptRejectValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.AddRemoveValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.AnnounceValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.AnswerValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.ArticleNoteValidator
@@ -30,7 +31,6 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   alias Pleroma.Web.ActivityPub.ObjectValidators.EventValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.FollowValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.LikeValidator
-  alias Pleroma.Web.ActivityPub.ObjectValidators.PinValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.QuestionValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.UndoValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.UpdateValidator
@@ -238,7 +238,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   def validate(%{"type" => type} = object, meta) when type in ~w(Add Remove) do
     with {:ok, object} <-
            object
-           |> PinValidator.cast_and_validate()
+           |> AddRemoveValidator.cast_and_validate()
            |> Ecto.Changeset.apply_action(:insert) do
       object = stringify_keys(object)
       {:ok, object, meta}
diff --git a/lib/pleroma/web/activity_pub/object_validators/pin_validator.ex b/lib/pleroma/web/activity_pub/object_validators/add_remove_validator.ex
index dca8cba6f..73d1c03f0 100644
--- a/lib/pleroma/web/activity_pub/object_validators/pin_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/add_remove_validator.ex
@@ -2,7 +2,7 @@
 # Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
 # SPDX-License-Identifier: AGPL-3.0-only
 
-defmodule Pleroma.Web.ActivityPub.ObjectValidators.PinValidator do
+defmodule Pleroma.Web.ActivityPub.ObjectValidators.AddRemoveValidator do
   use Ecto.Schema
 
   import Ecto.Changeset
@@ -37,6 +37,17 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.PinValidator do
     |> validate_required([:id, :target, :object, :actor, :type, :to, :cc])
     |> validate_inclusion(:type, ~w(Add Remove))
     |> validate_actor_presence()
+    |> validate_collection_belongs_to_actor()
     |> validate_object_presence()
   end
+
+  defp validate_collection_belongs_to_actor(changeset) do
+    validate_change(changeset, :target, fn :target, target ->
+      if String.starts_with?(target, changeset.changes[:actor]) do
+        []
+      else
+        [target: "collection doesn't belong to actor"]
+      end
+    end)
+  end
 end
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_validations.ex b/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
index 093549a45..940430588 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_validations.ex
@@ -9,6 +9,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
   alias Pleroma.Object
   alias Pleroma.User
 
+  @spec validate_any_presence(Ecto.Changeset.t(), [atom()]) :: Ecto.Changeset.t()
   def validate_any_presence(cng, fields) do
     non_empty =
       fields
@@ -29,6 +30,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     end
   end
 
+  @spec validate_actor_presence(Ecto.Changeset.t(), keyword()) :: Ecto.Changeset.t()
   def validate_actor_presence(cng, options \\ []) do
     field_name = Keyword.get(options, :field_name, :actor)
 
@@ -47,6 +49,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     end)
   end
 
+  @spec validate_object_presence(Ecto.Changeset.t(), keyword()) :: Ecto.Changeset.t()
   def validate_object_presence(cng, options \\ []) do
     field_name = Keyword.get(options, :field_name, :object)
     allowed_types = Keyword.get(options, :allowed_types, false)
@@ -68,6 +71,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     end)
   end
 
+  @spec validate_object_or_user_presence(Ecto.Changeset.t(), keyword()) :: Ecto.Changeset.t()
   def validate_object_or_user_presence(cng, options \\ []) do
     field_name = Keyword.get(options, :field_name, :object)
     options = Keyword.put(options, :field_name, field_name)
@@ -83,6 +87,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     if actor_cng.valid?, do: actor_cng, else: object_cng
   end
 
+  @spec validate_host_match(Ecto.Changeset.t(), [atom()]) :: Ecto.Changeset.t()
   def validate_host_match(cng, fields \\ [:id, :actor]) do
     if same_domain?(cng, fields) do
       cng
@@ -95,6 +100,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     end
   end
 
+  @spec validate_fields_match(Ecto.Changeset.t(), [atom()]) :: Ecto.Changeset.t()
   def validate_fields_match(cng, fields) do
     if map_unique?(cng, fields) do
       cng
@@ -122,12 +128,14 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonValidations do
     end)
   end
 
+  @spec same_domain?(Ecto.Changeset.t(), [atom()]) :: boolean()
   def same_domain?(cng, fields \\ [:actor, :object]) do
     map_unique?(cng, fields, fn value -> URI.parse(value).host end)
   end
 
   # This figures out if a user is able to create, delete or modify something
   # based on the domain and superuser status
+  @spec validate_modification_rights(Ecto.Changeset.t()) :: Ecto.Changeset.t()
   def validate_modification_rights(cng) do
     actor = User.get_cached_by_ap_id(get_field(cng, :actor))