Makes permit! recursive

lib/action_controller/parameters.rb

@@ -22,6 +22,11 @@ def initialize(attributes = nil)
     end
 
     def permit!
+      each_pair do |key, value|
+        convert_hashes_to_parameters(key, value)
+        self[key].permit! if self[key].respond_to? :permit!
+      end
+
       @permitted = true
       self
     end

test/parameters_taint_test.rb

@@ -58,4 +58,11 @@ class ParametersTaintTest < ActiveSupport::TestCase
     @params.permit!
     assert_equal @params.permitted?, @params.dup.permitted?
   end
+
+  test "permit is recursive" do
+    @params.permit!
+    assert @params.permitted?
+    assert @params[:person].permitted?
+    assert @params[:person][:name].permitted?
+  end
 end