levoleague / protected_attributes_continued

Community continued version of protected_attributes, now with Rails 5 support!

Protected Attributes Continued

This is the community continued version of protected_attributes. It works with Rails 5 only and I recommend you only use it to support legacy portions of your application that you do not want to upgrade. Note that this feature was dropped by the Rails team and switched to strong_parameters because of security issues, just so you understand your risks. This is in use successfully in some of my Rails 5 apps in which security like this is a non-issue. For people who would like to continue using this feature in their Rails 5 apps lets continue the work here.

Protect attributes from mass-assignment in Active Record models.

This plugin adds the class methods attr_accessible and attr_protected to your models to be able to declare white or black lists of attributes.

Installation

Add this line to your application's Gemfile:

gem 'protected_attributes_continued'

And then execute:

bundle install

Usage

Mass assignment security provides an interface for protecting attributes from end-user injection. This plugin provides two class methods in Active Record classes to control access to their attributes. The attr_protected method takes a list of attributes that will be ignored in mass-assignment.

For example:

attr_protected :admin

attr_protected also optionally takes a role option using :as which allows you to define multiple mass-assignment groupings. If no role is defined then attributes will be added to the :default role.

attr_protected :last_login, as: :admin

A much better way, because it follows the whitelist-principle, is the attr_accessible method. It is the exact opposite of attr_protected, because it takes a list of attributes that will be mass-assigned if present. Any other attributes will be ignored. This way you won’t forget to protect attributes when adding new ones in the course of development. Here is an example:

attr_accessible :name
attr_accessible :name, :is_admin, as: :admin

If you want to set a protected attribute, you will have to assign it individually:

params[:user] # => {name: "owned", is_admin: true}
@user = User.new(params[:user])
@user.is_admin # => false, not mass-assigned
@user.is_admin = true
@user.is_admin # => true

When assigning attributes in Active Record using attributes= the :default role will be used. To assign attributes using different roles you should use assign_attributes which accepts an optional :as options parameter. If no :as option is provided then the :default role will be used.

You can also bypass mass-assignment security by using the :without_protection option. Here is an example:

@user = User.new

@user.assign_attributes(name: 'Josh', is_admin: true)
@user.name # => Josh
@user.is_admin # => false

@user.assign_attributes({ name: 'Josh', is_admin: true }, as: :admin)
@user.name # => Josh
@user.is_admin # => true

@user.assign_attributes({ name: 'Josh', is_admin: true }, without_protection: true)
@user.name # => Josh
@user.is_admin # => true

In a similar way, new, create, create!, update_attributes and update_attributes! methods all respect mass-assignment security and accept either :as or :without_protection options. For example:

@user = User.new({ name: 'Sebastian', is_admin: true }, as: :admin)
@user.name # => Sebastian
@user.is_admin # => true

@user = User.create({ name: 'Sebastian', is_admin: true }, without_protection: true)
@user.name # => Sebastian
@user.is_admin # => true

By default the gem will use the strong parameters protection when assigning attribute, unless your model has attr_accessible or attr_protected calls.

Errors

By default, attributes in the params hash which are not allowed to be updated are just ignored. If you prefer an exception to be raised configure:

config.active_record.mass_assignment_sanitizer = :strict

Any protected attributes violation raises ActiveModel::MassAssignmentSecurity::Error then.

Credits

Created and Maintained by Weston Ganger - @westonganger

Originally forked from the dead/unmaintained protected_attributes gem by the Rails team.