buffym / libsaml

A Ruby gem to easily create SAML 2.0 messages.

libsaml

Libsaml is a Ruby gem to easily create SAML 2.0 messages. This gem was written because other SAML gems were missing functionality such as XML signing.

Libsaml's features include:

• Multiple bindings:
  • HTTP-Post
  • HTTP-Redirect
  • HTTP-Artifact
  • SOAP
• XML signing and verification
• Pluggable backend for providers (FileStore backend included)

Copyright Digidentity B.V., released under the MIT license. This gem was written by Benoist Claassen.

Installation

Place in your Gemfile:

gem 'libsaml', require: 'saml'

Usage

Below follows how to configure the SAML gem in a service provider.

Store the private key in: config/ssl/key.pem

Store the public key of the identity provider in: config/ssl/trust-federate.cert

Add the Identity Provider web container configuration file to config/metadata/service_provider.xml.

This contains an encoded version of the public key, generate this in the ruby console by typing:

require 'openssl'
require 'base64'

pem = File.open("config/ssl/trust-federate.cert").read
cert = OpenSSL::X509::Certificate.new(pem)
output = Base64.encode64(cert.to_der).gsub("\n", "")

Add the Service Provider configuration file to: config/metadata/service_provider.xml:

<?xml version="1.0" encoding="UTF-8"?>
<md:EntityDescriptor ID="_052c51476c9560a429e1171e8c9528b96b69fb57" entityID="my:very:original:entityid" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata">
  <md:SPSSODescriptor>
    <md:KeyDescriptor use="signing">
      <ds:KeyInfo>
        <ds:X509Data>
          <ds:X509Certificate>SAME_KEY_AS_GENERATED_IN_THE_CONSOLE_BEFORE</ds:X509Certificate>
        </ds:X509Data>
      </ds:KeyInfo>
    </md:KeyDescriptor>
    <md:AssertionConsumerService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Post" Location="http://localhost:3000/saml/receive_response" index="0" isDefault="true"/>
  </md:SPSSODescriptor>
</md:EntityDescriptor>

Set up an intializer in config/initializers/saml_config.rb:

Saml.setup do |config|
  config.register_store :file, Saml::ProviderStores::File.new("config/metadata", "config/ssl/key.pem"), default: true
end

By default this will use a SamlProvider model that uses the filestore, if you want a database driven model comment out the #provider_store function in the initializer and make a model that defines #find_by_entity_id:

class SamlProvider < ActiveRecord::Base
  include Saml::Provider

  def self.find_by_entity_id(entity_id)
    find_by entity_id: entity_id
  end
end

Now you can make a SAML controller in app/controllers/saml_controller.rb:

class SamlController < ApplicationController
  extend Saml::Rails::ControllerHelper
  current_provider "entity_id"

  def request_authentication
    provider = Saml.provider("my:very:original:entityid")
    destination = provider.single_sign_on_service_url(Saml::ProtocolBindings::HTTP_POST)

    authn_request = Saml::AuthnRequest.new(:destination => destination)

    @saml_attributes = Saml::Bindings::HTTPPost.create_form_attributes(authn_request)

    render text: @saml_attributes.to_yaml
  end

  def receive_response
  end
end

Don't forget to define the routes in config/routes.rb:

  get "/saml/request_authentication" => "saml#request_authentication"
  get "/saml/receive_response" => "saml#receive_response"

Contributing

• Fork the project
• Contribute your changes. Please make sure your changes are properly documented and covered by tests.
• Send a pull request