Class: Federa::Saml::Metadata

Inherits:
Object
  • Object
show all
Includes:
Coding, REXML
Defined in:
lib/federa/ruby-saml/metadata.rb

Constant Summary collapse

HTTP_POST =

a few symbols for SAML class names

"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
HTTP_GET = 
"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"

Instance Method Summary collapse

Methods included from Coding

#decode, #deflate, #encode, #escape, #inflate, #unescape

Constructor Details

#initialize(settings = nil) ⇒ Metadata

Returns a new instance of Metadata.



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# File 'lib/federa/ruby-saml/metadata.rb', line 20

def initialize(settings=nil)
  if settings
    @settings = settings
  end
end

Instance Method Details

#binding_select(service) ⇒ Object

get the IdP metadata, and select the appropriate SSO binding that we can support. Currently this is HTTP-Redirect and HTTP-POST but more could be added in the future



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# File 'lib/federa/ruby-saml/metadata.rb', line 130

def binding_select(service)
  # first check if we're still using the old hard coded method for 
  # backwards compatability
  if service == "SingleSignOnService" && @settings.idp_metadata == nil && @settings.idp_sso_target_url != nil
      return @settings.idp_sso_target_url
  end
  if service == "SingleLogoutService" && @settings.idp_metadata == nil && @settings.idp_slo_target_url != nil
      return  @settings.idp_slo_target_url
  end
  
  meta_doc = get_idp_metadata
  
  return nil unless meta_doc
  # first try POST
  sso_element = REXML::XPath.first(meta_doc, "/md:EntityDescriptor/md:IDPSSODescriptor/md:#{service}[@Binding='#{HTTP_POST}']")
  if !sso_element.nil? 
    @URL = sso_element.attributes["Location"]
    #Logging.debug "binding_select: POST to #{@URL}"
    return @URL
  end
  
  # next try GET
  sso_element = REXML::XPath.first(meta_doc, "/md:EntityDescriptor/md:IDPSSODescriptor/md:#{service}[@Binding='#{HTTP_GET}']")
  if !sso_element.nil? 
    @URL = sso_element.attributes["Location"]
    Logging.debug "binding_select: GET from #{@URL}"
    return @URL
  end
  # other types we might want to add in the future:  SOAP, Artifact
end

#build_message(options = {}) ⇒ Object

Construct a SAML message using information in the IdP metadata.

:type can be either “SAMLRequest” or “SAMLResponse” :service refers to the Binding method, 

either "SingleLogoutService" or "SingleSignOnService"

:message is the SAML message itself (XML)

I’ve provided easy to use wrapper functions above



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# File 'lib/federa/ruby-saml/metadata.rb', line 121

def build_message( options = {} )
  opt = { :type => nil, :service => nil, :message => nil, :extra_parameters => nil }.merge(options)
  url = binding_select( opt[:service] )
  return message_get( opt[:type], url, opt[:message], opt[:extra_parameters] )
end

#create_slo_request(message, extra_parameters = {}) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 104

def create_slo_request(message, extra_parameters = {} )
  build_message( :type => "SAMLRequest", 
      :service => "SingleLogoutService", 
      :message => message, :extra_parameters => extra_parameters)
end

#create_slo_response(message, extra_parameters = {}) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 109

def create_slo_response(message, extra_parameters = {} )
  build_message( :type => "SAMLResponse", 
      :service => "SingleLogoutService", 
      :message => message, :extra_parameters => extra_parameters)     
end

#create_sso_request(message, extra_parameters = {}) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 94

def create_sso_request(message, extra_parameters = {} )
  build_message( :type => "SAMLRequest", 
      :service => "SingleSignOnService", 
      :message => message, :extra_parameters => extra_parameters)
end

#create_sso_response(message, extra_parameters = {}) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 99

def create_sso_response(message, extra_parameters = {} )
  build_message( :type => "SAMLResponse", 
      :service => "SingleSignOnService", 
      :message => message, :extra_parameters => extra_parameters)     
end

#extract_certificate(meta_doc) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 225

def extract_certificate(meta_doc)

  # pull out the x509 tag
  x509 = REXML::XPath.first(meta_doc, "/md:EntityDescriptor/md:IDPSSODescriptor"+"/md:KeyDescriptor"+"/ds:KeyInfo/ds:X509Data/ds:X509Certificate"
      )
  # If the IdP didn't specify the use attribute
  if x509.nil?
    x509 = REXML::XPath.first(meta_doc, 
          "/EntityDescriptor/IDPSSODescriptor" +
        "/KeyDescriptor" +
        "/ds:KeyInfo/ds:X509Data/ds:X509Certificate"
      )
  end
  @settings.idp_cert = x509.text.gsub(/\n/, "").gsub(/\t/, "")
end

#generate(settings) ⇒ Object 



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# File 'lib/federa/ruby-saml/metadata.rb', line 26

def generate(settings)
  meta_doc = REXML::Document.new
  root = meta_doc.add_element "md:EntityDescriptor", { 
      "xmlns:md"        => "urn:oasis:names:tc:SAML:2.0:metadata",
      "xmlns:xml"       => "http://www.w3.org/XML/1998/namespace",
      "cacheDuration"   => "P1M" 
  }
  if settings.issuer != nil
    root.attributes["entityID"] = settings.issuer
  end
  sp_sso = root.add_element "md:SPSSODescriptor", { 
      "protocolSupportEnumeration" => "urn:oasis:names:tc:SAML:2.0:protocol",
      "WantAssertionsSigned"       => "true"

  }
    name_identifier_formats = settings.name_identifier_format
    if name_identifier_formats != nil
      name_id = []
      name_identifier_formats.each_with_index{ |format, index|
        name_id[index] = sp_sso.add_element "md:NameIDFormat"
        name_id[index].text = format
      }
      
    end
    if settings.sp_cert != nil
      keyDescriptor = sp_sso.add_element "md:KeyDescriptor", {
        "use" => "signing"
      }
      keyInfo = keyDescriptor.add_element "ds:KeyInfo", {
        "xmlns:ds" => "http://www.w3.org/2000/09/xmldsig#"
      }
      x509Data = keyInfo.add_element "ds:X509Data"
      x509Certificate = x509Data.add_element "ds:X509Certificate"
      file = ""
      File.foreach(settings.sp_cert){ |line|
                                   file  += line unless (line.include?("RSA PUBLIC KEY") || line.include?("CERTIFICATE")) 
                                 }
      x509Certificate.text = file                            
    end
    if settings.assertion_consumer_service_url != nil
      sp_sso.add_element "md:AssertionConsumerService", {
          # Add this as a setting to create different bindings?
          "Binding" => "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST",
          "Location" => settings.assertion_consumer_service_url,
          "index" => "1"
      }
    end
    if settings.single_logout_service_url != nil
      sp_sso.add_element "md:SingleLogoutService", {
          "Binding" => "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect",
          "Location" => settings.single_logout_service_url
      }
      sp_sso.add_element "md:SingleLogoutService", {
          "Binding" => "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST",
          "Location" => settings.single_logout_service_url
      }
    end
  meta_doc << REXML::XMLDecl.new(version='1.0', encoding='UTF-8')
  ret = ""
  # pretty print the XML so IdP administrators can easily see what the SP supports
  meta_doc.write(ret, 1)

  #Logging.debug "Generated metadata:\n#{ret}"

  return ret

end

#get_idp_metadata ⇒ Object

Retrieve the remote IdP metadata from the URL or a cached copy returns a REXML document of the metadata



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# File 'lib/federa/ruby-saml/metadata.rb', line 163

def get_idp_metadata
  return false if @settings.idp_metadata.nil?

  # Look up the metdata in cache first
  id = Digest::MD5.hexdigest(@settings.idp_metadata)

  uri = URI.parse(@settings.idp_metadata)
  if uri.scheme == "http"
    response = Net::HTTP.get_response(uri)
    meta_text = response.body
  elsif uri.scheme == "https"
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    # Most IdPs will probably use self signed certs
    #http.verify_mode = OpenSSL::SSL::VERIFY_PEER
    http.verify_mode = OpenSSL::SSL::VERIFY_NONE
    get = Net::HTTP::Get.new(uri.request_uri)
    response = http.request(get)
    meta_text = response.body
  end
  testo_response = meta_text.sub!(' xmlns:xml="http://www.w3.org/XML/1998/namespace"', '')
  doc = REXML::Document.new(testo_response)
  extract_certificate(doc)
  return doc

  # USE OF CACHE WITH CERTIFICATE
  # lookup = @cache.read(id)
  # if lookup != nil
  #   Logging.debug "IdP metadata cached lookup for #{@settings.idp_metadata}"
  #   doc = REXML::Document.new( lookup )
  #   extract_certificate( doc )
  #   return doc
  # end
  
  # Logging.debug "IdP metadata cache miss on #{@settings.idp_metadata}"
  # # cache miss
  # if File.exists?(@settings.idp_metadata)
  #   fp = File.open( @settings.idp_metadata, "r")
  #   meta_text = fp.read
  # else
  #   uri = URI.parse(@settings.idp_metadata)
  #   if uri.scheme == "http"
  #     response = Net::HTTP.get_response(uri)
  #     meta_text = response.body
  #   elsif uri.scheme == "https"
  #     http = Net::HTTP.new(uri.host, uri.port)
  #     http.use_ssl = true
  #     # Most IdPs will probably use self signed certs
  #     #http.verify_mode = OpenSSL::SSL::VERIFY_PEER
  #     http.verify_mode = OpenSSL::SSL::VERIFY_NONE
  #     get = Net::HTTP::Get.new(uri.request_uri)
  #     response = http.request(get)
  #     meta_text = response.body
  #   end
  # end
  # # Add it to the cache
  # @cache.write(id, meta_text, @settings.idp_metadata_ttl )
  # doc = REXML::Document.new( meta_text )
  # extract_certificate(doc)
  # return doc
end

#message_get(type, url, message, extra_parameters = {}) ⇒ Object

construct the parameter list on the URL and return



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# File 'lib/federa/ruby-saml/metadata.rb', line 242

def message_get( type, url, message, extra_parameters = {} )
  params = Hash.new
  if extra_parameters
    params.merge!(extra_parameters)
  end
  # compress GET requests to try and stay under that 8KB request limit
  #deflate of samlrequest
  params[type] = encode( deflate( message ) )
  #Logging.debug "#{type}=#{params[type]}"
  
  uri = Addressable::URI.parse(url)
  if uri.query_values == nil
    uri.query_values = params
  else
    # solution to stevenwilkin's parameter merge
    uri.query_values = params.merge(uri.query_values)
  end
  url = uri.to_s
  #Logging.debug "Sending to URL #{url}"
  return url
end