Add ActivityPub secure mode (#11269)

* Add HTTP signature requirement for served ActivityPub resources

* Change `SECURE_MODE` to `AUTHORIZED_FETCH`

* Add 'Signature' to 'Vary' header and improve code style

* Improve code style by adding `public_fetch_mode?` method

4 files changed, 22 insertions, 14 deletions

diff --git a/app/controllers/activitypub/collections_controller.rb b/app/controllers/activitypub/collections_controller.rb
index dd2f111b0..035467f41 100644
--- a/app/controllers/activitypub/collections_controller.rb
+++ b/app/controllers/activitypub/collections_controller.rb
@@ -4,12 +4,13 @@ class ActivityPub::CollectionsController < Api::BaseController
   include SignatureVerification
   include AccountOwnedConcern
 
+  before_action :require_signature!, if: :authorized_fetch_mode?
   before_action :set_size
   before_action :set_statuses
   before_action :set_cache_headers
 
   def show
-    expires_in 3.minutes, public: true
+    expires_in 3.minutes, public: public_fetch_mode?
     render json: collection_presenter, content_type: 'application/activity+json', serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, skip_activities: true
   end
 
diff --git a/app/controllers/activitypub/inboxes_controller.rb b/app/controllers/activitypub/inboxes_controller.rb
index 9be0676e1..7cfd9a25e 100644
--- a/app/controllers/activitypub/inboxes_controller.rb
+++ b/app/controllers/activitypub/inboxes_controller.rb
@@ -5,23 +5,24 @@ class ActivityPub::InboxesController < Api::BaseController
   include JsonLdHelper
   include AccountOwnedConcern
 
+  before_action :skip_unknown_actor_delete
+  before_action :require_signature!
+
   def create
-    if unknown_deleted_account?
-      head 202
-    elsif signed_request_account
-      upgrade_account
-      process_payload
-      head 202
-    else
-      render plain: signature_verification_failure_reason, status: 401
-    end
+    upgrade_account
+    process_payload
+    head 202
   end
 
   private
 
+  def skip_unknown_actor_delete
+    head 202 if unknown_deleted_account?
+  end
+
   def unknown_deleted_account?
     json = Oj.load(body, mode: :strict)
-    json['type'] == 'Delete' && json['actor'].present? && json['actor'] == value_or_id(json['object']) && !Account.where(uri: json['actor']).exists?
+    json.is_a?(Hash) && json['type'] == 'Delete' && json['actor'].present? && json['actor'] == value_or_id(json['object']) && !Account.where(uri: json['actor']).exists?
   rescue Oj::ParseError
     false
   end
@@ -32,8 +33,12 @@ class ActivityPub::InboxesController < Api::BaseController
 
   def body
     return @body if defined?(@body)
-    @body = request.body.read.force_encoding('UTF-8')
+
+    @body = request.body.read
+    @body.force_encoding('UTF-8') if @body.present?
+
     request.body.rewind if request.body.respond_to?(:rewind)
+
     @body
   end
 
diff --git a/app/controllers/activitypub/outboxes_controller.rb b/app/controllers/activitypub/outboxes_controller.rb
index 4c0b769f0..cdfd28ba8 100644
--- a/app/controllers/activitypub/outboxes_controller.rb
+++ b/app/controllers/activitypub/outboxes_controller.rb
@@ -6,12 +6,12 @@ class ActivityPub::OutboxesController < Api::BaseController
   include SignatureVerification
   include AccountOwnedConcern
 
+  before_action :require_signature!, if: :authorized_fetch_mode?
   before_action :set_statuses
   before_action :set_cache_headers
 
   def show
-    expires_in 1.minute, public: true unless page_requested?
-
+    expires_in(page_requested? ? 0 : 3.minutes, public: public_fetch_mode?)
     render json: outbox_presenter, serializer: ActivityPub::OutboxSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json'
   end
 
diff --git a/app/controllers/activitypub/replies_controller.rb b/app/controllers/activitypub/replies_controller.rb
index 99b7b310f..020c077ab 100644
--- a/app/controllers/activitypub/replies_controller.rb
+++ b/app/controllers/activitypub/replies_controller.rb
@@ -7,11 +7,13 @@ class ActivityPub::RepliesController < Api::BaseController
 
   DESCENDANTS_LIMIT = 60
 
+  before_action :require_signature!, if: :authorized_fetch_mode?
   before_action :set_status
   before_action :set_cache_headers
   before_action :set_replies
 
   def index
+    expires_in 0, public: public_fetch_mode?
     render json: replies_collection_presenter, serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter, content_type: 'application/activity+json', skip_activities: true
   end