Ruby SAML Identity Provider (IdP)

Forked from https://github.com/lawrencepit/ruby-saml-idp

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The ruby SAML Identity Provider library is for implementing the server side of SAML authentication. It allows your application to act as an IdP (Identity Provider) using the SAML v2.0 protocol. It provides a means for managing authentication requests and confirmation responses for SPs (Service Providers).

This was originally setup by @lawrencepit to test SAML Clients. I took it closer to a real SAML IDP implementation.

Installation and Usage

Add this to your Gemfile:

gem 'saml_idp'

Not using rails?

Include SamlIdp::Controller and see the examples that use rails. It should be straightforward for you.

Basically you call decode_request(params[:SAMLRequest]) on an incoming request and then use the value saml_acs_url to determine the source for which you need to authenticate a user. How you authenticate a user is entirely up to you.

Once a user has successfully authenticated on your system send the Service Provider a SAMLReponse by posting to saml_acs_url the parameter SAMLResponse with the return value from a call to encode_response(user_email).

Using rails?

Add to your routes.rb file, for example:

get '/saml/auth' => 'saml_idp#new'
get '/saml/metadata' => 'saml_idp#show'
post '/saml/auth' => 'saml_idp#create'
match '/saml/logout' => 'saml_idp#logout', via: [:get, :post, :delete]

Create a controller that looks like this, customize to your own situation:

class SamlIdpController < SamlIdp::IdpController
  def idp_authenticate(email, password) # not using params intentionally
    user = User.by_email(email).first
    user && user.valid_password?(password) ? user : nil
  end
  private :idp_authenticate

  def idp_make_saml_response(found_user) # not using params intentionally
    # NOTE encryption is optional
    encode_response found_user, encryption: {
      cert: saml_request.service_provider.cert,
      block_encryption: 'aes256-cbc',
      key_transport: 'rsa-oaep-mgf1p'
    }
  end
  private :idp_make_saml_response

  def idp_logout
    user = User.by_email(saml_request.name_id)
    user.logout
  end
  private :idp_logout
end

Configuration

Be sure to load a file like this during your app initialization:

SamlIdp.configure do |config|
  base = "http://example.com"

  config.x509_certificate = <<-CERT
-----BEGIN CERTIFICATE-----
CERTIFICATE DATA
-----END CERTIFICATE-----
CERT

  config.secret_key = <<-CERT
-----BEGIN RSA PRIVATE KEY-----
KEY DATA
-----END RSA PRIVATE KEY-----
CERT

  # config.password = "secret_key_password"
  # config.algorithm = :sha256
  # config.organization_name = "Your Organization"
  # config.organization_url = "http://example.com"
  # config.base_saml_location = "#{base}/saml"
  # config.reference_id_generator                                 # Default: -> { UUID.generate }
  # config.attribute_service_location = "#{base}/saml/attributes"
  # config.single_service_post_location = "#{base}/saml/auth"
  # config.session_expiry = 86400                                 # Default: 0 which means never

  # Principal (e.g. User) is passed in when you `encode_response`
  #
  # config.name_id.formats # =>
  #   {                         # All 2.0
  #     email_address: -> (principal) { principal.email_address },
  #     transient: -> (principal) { principal.id },
  #     persistent: -> (p) { p.id },
  #   }
  #   OR
  #
  #   {
  #     "1.1" => {
  #       email_address: -> (principal) { principal.email_address },
  #     },
  #     "2.0" => {
  #       transient: -> (principal) { principal.email_address },
  #       persistent: -> (p) { p.id },
  #     },
  #   }

  # If Principal responds to a method called `asserted_attributes`
  # the return value of that method will be used in lieu of the
  # attributes defined here in the global space. This allows for
  # per-user attribute definitions.
  #
  ## EXAMPLE **
  # class User
  #   def asserted_attributes
  #     {
  #       phone: { getter: :phone },
  #       email: {
  #         getter: :email,
  #         name_format: Saml::XML::Namespaces::Formats::NameId::EMAIL_ADDRESS,
  #         name_id_format: Saml::XML::Namespaces::Formats::NameId::EMAIL_ADDRESS
  #       }
  #     }
  #   end
  # end
  #
  # If you have a method called `asserted_attributes` in your Principal class,
  # there is no need to define it here in the config.

  # config.attributes # =>
  #   {
  #     <friendly_name> => {                                                  # required (ex "eduPersonAffiliation")
  #       "name" => <attrname>                                                # required (ex "urn:oid:1.3.6.1.4.1.5923.1.1.1.1")
  #       "name_format" => "urn:oasis:names:tc:SAML:2.0:attrname-format:uri", # not required
  #       "getter" => ->(principal) {                                         # not required
  #         principal.get_eduPersonAffiliation                                # If no "getter" defined, will try
  #       }                                                                   # `principal.eduPersonAffiliation`, or no values will
  #    }                                                                      # be output
  #
  ## EXAMPLE ##
  # config.attributes = {
  #   GivenName: {
  #     getter: :first_name,
  #   },
  #   SurName: {
  #     getter: :last_name,
  #   },
  # }
  ## EXAMPLE ##

  # config.technical_contact.company = "Example"
  # config.technical_contact.given_name = "Jonny"
  # config.technical_contact.sur_name = "Support"
  # config.technical_contact.telephone = "55555555555"
  # config.technical_contact.email_address = "[email protected]"

  service_providers = {
    "some-issuer-url.com/saml" => {
      fingerprint: "9E:65:2E:03:06:8D:80:F2:86:C7:6C:77:A1:D9:14:97:0A:4D:F4:4D",
      metadata_url: "http://some-issuer-url.com/saml/metadata"
    },
  }

  # `identifier` is the entity_id or issuer of the Service Provider,
  # settings is an IncomingMetadata object which has a to_h method that needs to be persisted
  config.service_provider. = ->(identifier, settings) {
    fname = identifier.to_s.gsub(/\/|:/,"_")
    `mkdir -p #{Rails.root.join("cache/saml/metadata")}`
    File.open Rails.root.join("cache/saml/metadata/#{fname}"), "r+b" do |f|
      Marshal.dump settings.to_h, f
    end
  }

  # `identifier` is the entity_id or issuer of the Service Provider,
  # `service_provider` is a ServiceProvider object. Based on the `identifier` or the
  # `service_provider` you should return the settings.to_h from above
  config.service_provider. = ->(identifier, service_provider){
    fname = identifier.to_s.gsub(/\/|:/,"_")
    `mkdir -p #{Rails.root.join("cache/saml/metadata")}`
    full_filename = Rails.root.join("cache/saml/metadata/#{fname}")
    if File.file?(full_filename)
      File.open full_filename, "rb" do |f|
        Marshal.load f
      end
    end
  }

  # Find ServiceProvider metadata_url and fingerprint based on our settings
  config.service_provider.finder = ->(issuer_or_entity_id) do
    service_providers[issuer_or_entity_id]
  end
end

Keys and Secrets

To generate the SAML Response it uses a default X.509 certificate and secret key... which isn't so secret. You can find them in SamlIdp::Default. The X.509 certificate is valid until year 2032. Obviously you shouldn't use these if you intend to use this in production environments. In that case, within the controller set the properties x509_certificate and secret_key using a prepend_before_action callback within the current request context or set them globally via the SamlIdp.config.x509_certificate and SamlIdp.config.secret_key properties.

The fingerprint to use, if you use the default X.509 certificate of this gem, is:

9E:65:2E:03:06:8D:80:F2:86:C7:6C:77:A1:D9:14:97:0A:4D:F4:4D

Service Providers

To act as a Service Provider which generates SAML Requests and can react to SAML Responses use the excellent ruby-saml gem.

Author

Jon Phenow, [email protected]

Lawrence Pit, [email protected], lawrencepit.com, @lawrencepit

Copyright

Copyright (c) 2012 Sport Ngin. Portions Copyright (c) 2010 OneLogin, LLC Portions Copyright (c) 2012 Lawrence Pit (http://lawrencepit.com)

See LICENSE for details.