Two factor authentication for Devise

Features

• control sms code pattern
• configure max login attempts
• per user level control if he really need two factor authentication
• your own sms logic
• configurable period where users won't be asked for 2FA again

Configuration

Initial Setup

In a Rails environment, require the gem in your Gemfile:

gem 'two_factor_authentication'

Once that's done, run:

bundle install

Automatic installation

In order to add two factor authentication to a model, run the command:

bundle exec rails g two_factor_authentication MODEL

Where MODEL is your model name (e.g. User or Admin). This generator will add :two_factor_authenticatable to your model and create a migration in db/migrate/, which will add :otp_secret_key and :second_factor_attempts_count to your table. Finally, run the migration with:

bundle exec rake db:migrate

Add the following line to your model to fully enable two-factor auth:

has_one_time_password

Set config values, if desired:

config.max_login_attempts = 3  # Maximum second factor attempts count
config.allowed_otp_drift_seconds = 30  # Allowed time drift
config.otp_length = 6  # OTP code length
config.remember_otp_session_for_seconds = 30.days  # Time before browser has to enter OTP code again

Override the method to send one-time passwords in your model, this is automatically called when a user logs in:

def send_two_factor_authentication_code
  # use Model#otp_code and send via SMS, etc.
end

Manual installation

To manually enable two factor authentication for the User model, you should add two_factor_authentication to your devise line, like:

devise :database_authenticatable, :registerable,
       :recoverable, :rememberable, :trackable, :validatable, :two_factor_authenticatable

Add the following line to your model to fully enable two-factor auth:

has_one_time_password

Set config values to devise.rb, if desired:

config.max_login_attempts = 3  # Maximum second factor attempts count
config.allowed_otp_drift_seconds = 30  # Allowed time drift
config.otp_length = 6  # OTP code length
config.remember_otp_session_for_seconds = 30.days  # Time before browser has to enter OTP code again

Override the method to send one-time passwords in your model, this is automatically called when a user logs in:

def send_two_factor_authentication_code
  # use Model#otp_code and send via SMS, etc.
end

Customisation and Usage

By default second factor authentication enabled for each user, you can change it with this method in your User model:

def need_two_factor_authentication?(request)
  request.ip != '127.0.0.1'
end

this will disable two factor authentication for local users

This gem is compatible with Google Authenticator (https://support.google.com/accounts/answer/1066447?hl=en). You can generate provisioning uris by invoking the following method on your model:

user.provisioning_uri #This assumes a user model with an email attributes

This provisioning uri can then be turned in to a QR code if desired so that users may add the app to Google Authenticator easily. Once this is done they may retrieve a one-time password directly from the Google Authenticator app as well as through whatever method you define in send_two_factor_authentication_code

Overriding the view

The default view that shows the form can be overridden by first adding a folder named: "two_factor_authentication" inside "app/views/devise", in here you want to create a "show.html.erb" view.

The full path should be "app/views/devise/two_factor_authentication/show.html.erb"

<h2>Hi, you received a code by email, please enter it below, thanks!</h2>

<%= form_tag([resource_name, :two_factor_authentication], :method => :put) do %>
  <%= text_field_tag :code %>
  <%= submit_tag "Log in!" %>
<% end %>

<%= link_to "Sign out", destroy_user_session_path, :method => :delete %>

Updating existing users with OTP secret key

If you have existing users that needs to be provided with a OTP secret key, so they can take benefit of the two factor authentication, create a rake. It could look like this one below:

desc "rake task to update users with otp secret key"
task :update_users_with_otp_secret_key  => :environment do
	users = User.all

	users.each do |user|
		key = ROTP::Base32.random_base32
		user.update_attributes(:otp_secret_key => key)
		user.save
		puts "Rake[:update_users_with_otp_secret_key] => User '#{user.email}' OTP secret key set to '#{key}'"
	end
end

Executing some code after the user signs in and before they sign out

In some cases, you might want to perform some action right after the user signs in, but before the OTP is sent, and also right before the user signs out. One scenario where you would need this is if you are requiring users to confirm their phone number first before they can receive an OTP. If they enter a wrong number, then sign out or close the browser before they confirm, they won't be able to confirm their real number. To solve this problem, we need to be able to reset their unconfirmed number before they sign out or sign in, and before the OTP code is sent.

To define this action, create a #{user.class}OtpSender class that takes the current user as its parameter, and defines a #reset_otp_state instance method. For example, if your user's class is User, you would create a UserOtpSender class, like this:

class UserOtpSender
  def initialize(user)
    @user = user
  end

  def reset_otp_state
    if @user.unconfirmed_mobile.present?
      @user.update(unconfirmed_mobile: nil)
    end
  end
end

If you have different types of users in your app (for example, User and Admin), and you need different logic for each type of user, create a second class for your admin user, such as AdminOtpSender, with its own logic for #reset_otp_state.

Example

TwoFactorAuthenticationExample