Integrate ActiveModel::ForbiddenAttributesProtection from StrongParam…

…eters gem

activemodel/lib/active_model.rb

@@ -34,6 +34,7 @@ module ActiveModel
   autoload :Conversion
   autoload :Dirty
   autoload :EachValidator, 'active_model/validator'
+  autoload :ForbiddenAttributesProtection
   autoload :Lint
   autoload :MassAssignmentSecurity
   autoload :Model

activemodel/lib/active_model/forbidden_attributes_protection.rb

@@ -0,0 +1,14 @@
+module ActiveModel
+  class ForbiddenAttributes < StandardError
+  end
+
+  module ForbiddenAttributesProtection
+    def sanitize_for_mass_assignment(new_attributes, options = {})
+      if !new_attributes.respond_to?(:permitted?) || (new_attributes.respond_to?(:permitted?) && new_attributes.permitted?)
+        super
+      else
+        raise ActiveModel::ForbiddenAttributes
+      end
+    end
+  end
+end

activemodel/test/cases/forbidden_attributes_protection_test.rb

@@ -0,0 +1,32 @@
+require 'cases/helper'
+require 'models/mass_assignment_specific'
+
+class ActiveModelMassUpdateProtectionTest < ActiveSupport::TestCase
+  test "forbidden attributes cannot be used for mass updating" do
+    params = { "a" => "b" }
+    class << params
+      define_method(:permitted?) { false }
+    end
+    assert_raises(ActiveModel::ForbiddenAttributes) do
+      SpecialPerson.new.sanitize_for_mass_assignment(params)
+    end
+  end
+
+  test "permitted attributes can be used for mass updating" do
+    params = { "a" => "b" }
+    class << params
+      define_method(:permitted?) { true }
+    end
+    assert_nothing_raised do
+      assert_equal({ "a" => "b" },
+        SpecialPerson.new.sanitize_for_mass_assignment(params))
+    end
+  end
+
+  test "regular attributes should still be allowed" do
+    assert_nothing_raised do
+      assert_equal({ a: "b" },
+        SpecialPerson.new.sanitize_for_mass_assignment(a: "b"))
+    end
+  end
+end

activemodel/test/models/mass_assignment_specific.rb

@@ -20,6 +20,13 @@ class Person
   public :sanitize_for_mass_assignment
 end
 
+class SpecialPerson
+  include ActiveModel::MassAssignmentSecurity
+  include ActiveModel::ForbiddenAttributesProtection
+
+  public :sanitize_for_mass_assignment
+end
+
 class Account
   include ActiveModel::MassAssignmentSecurity
   attr_accessible :name, :email, :as => [:default, :admin]