Devise LDAP Authenticatable

Devise LDAP Authenticatable is a LDAP based authentication strategy for the Devise authentication framework.

If you are building applications for use within your organization which require authentication and you want to use LDAP, this plugin is for you.

Devise LDAP Authenticatable works in replacement of Database Authenticatable. This devise plugin has not been tested with DatabaseAuthenticatable enabled at the same time. This is meant as a drop in replacement for DatabaseAuthenticatable allowing for a semi single sign on approach.

For a screencast with an example application, please visit: http://random-rails.blogspot.com/2010/07/ldap-authentication-with-devise.html

Prerequisites

• devise ~> 2.0.0 (which requires rails ~> 3.1)
• net-ldap ~> 0.2.2

Usage

In the Gemfile for your application:

gem "devise_ldap_authenticatable"

To get the latest version, pull directly from github instead of the gem:

gem "devise_ldap_authenticatable", :git => "git://github.com/cschiewek/devise_ldap_authenticatable.git"

Setup

Run the rails generators for devise (please check the devise documents for further instructions)

rails generate devise:install
rails generate devise MODEL_NAME

Run the rails generator for devise_ldap_authenticatable

rails generate devise_ldap_authenticatable:install [options]

This will install the sample.yml, update the devise.rb initializer, and update your user model. There are some options you can pass to it:

Options:

[--user-model=USER_MODEL]  # Model to update
                           # Default: user
[--update-model]           # Update model to change from database_authenticatable to ldap_authenticatable
                           # Default: true
[--add-rescue]             # Update Application Controller with rescue_from for DeviseLdapAuthenticatable::LdapException
                           # Default: true
[--advanced]               # Add advanced config options to the devise initializer

Querying LDAP

Given that ldap_create_user is set to true and you are authenticating with username, you can query an LDAP server for other attributes.

in your user model:

before_save :get_ldap_email

def get_ldap_email self.email = Devise::LdapAdapter.get_ldap_param(self.username,"mail") end

Configuration

In initializer config/initializers/devise.rb :

• ldap_logger (default: true)

  • If set to true, will log LDAP queries to the Rails logger.

• ldap_create_user (default: false)

  • If set to true, all valid LDAP users will be allowed to login and an appropriate user record will be created. If set to false, you will have to create the user record before they will be allowed to login.

• ldap_config (default: #{Rails.root}/config/ldap.yml)

  • Where to find the LDAP config file. Commented out to use the default, change if needed.

• ldap_update_password (default: true)

  • When doing password resets, if true will update the LDAP server. Requires admin password in the ldap.yml

• ldap_check_group_membership (default: false)

  • When set to true, the user trying to login will be checked to make sure they are in all of groups specified in the ldap.yml file.

• ldap_check_attributes (default: false)

  • When set to true, the user trying to login will be checked to make sure they have all of the attributes in the ldap.yml file.

• ldap_use_admin_to_bind (default: false)

  • When set to true, the admin user will be used to bind to the LDAP server during authentication.

Advanced Configuration

These parameters will be added to config/initializers/devise.rb when you pass the --advanced switch to the generator:

• ldap_auth_username_builder (default: Proc.new() {|attribute, login, ldap| "#{attribute}=#{login},#{ldap.base}" })
  • You can pass a proc to the username option to explicitly specify the format that you search for a users' DN on your LDAP server.

Troubleshooting

Using a "username" instead of an "email": The field that is used for logins is the first key that's configured in the config/devise.rb file under config.authentication_keys, which by default is email. For help changing this, please see the Railscast that goes through how to customize Devise.

SSL certificate invalid: If you're using a test LDAP server running a self-signed SSL certificate, make sure the appropriate root certificate is installed on your system. Alternately, you may temporarily disable certificate checking for SSL by modifying your system LDAP configuration (e.g., /etc/openldap/ldap.conf or /etc/ldap/ldap.conf) to read TLS_REQCERT never.

Development guide

To contribute to devise_ldap_authentication, you should be able to run a test OpenLDAP server. Specifically, you need the slapd, ldapadd, and ldapmodify binaries.

This seems to come out of the box with Mac OS X 10.6.

On Ubuntu (tested on 12.04), you can run sudo apt-get install slapd ldap-utils. You will also likely have to add the spec/ldap directory of your local git clone to the slapd apparmor profile /etc/apparmor.d/usr.sbin.slapd if you get permissions errors.

To start hacking on devise_ldap_authentication, clone the github repository, start the test LDAP server, and run the rake test task:

git clone https://github.com/cschiewek/devise_ldap_authenticatable.git
cd devise_ldap_authenticatable
bundle install

# in a separate console or backgrounded
./spec/ldap/run-server

bundle exec rake spec

References

• OpenLDAP
• Devise
• Warden

Released under the MIT license

Copyright (c) 2012 Curtis Schiewek, Daniel McNevin, Steven Xu