Class: Federa::Saml::Authrequest

Inherits:
Object
  • Object
show all
Defined in:
lib/federa/ruby-saml/authrequest.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 Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(settings) ⇒ Authrequest

Returns a new instance of Authrequest.



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# File 'lib/federa/ruby-saml/authrequest.rb', line 19

def initialize( settings )
  @settings = settings
  @request_params = Hash.new
end

Instance Attribute Details

#request ⇒ Object

Returns the value of attribute request.



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# File 'lib/federa/ruby-saml/authrequest.rb', line 17

def request
  @request
end

#uuid ⇒ Object

Returns the value of attribute uuid.



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# File 'lib/federa/ruby-saml/authrequest.rb', line 17

def uuid
  @uuid
end

Instance Method Details

#binding_select ⇒ 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/authrequest.rb', line 108

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

#content_get ⇒ Object

construct the the parameter list on the URL and return



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# File 'lib/federa/ruby-saml/authrequest.rb', line 140

def content_get
  # compress GET requests to try and stay under that 8KB request limit
  deflated_request  = Zlib::Deflate.deflate(@request, 9)[2..-5]
  # strict_encode64() isn't available?  sub out the newlines
  @request_params["SAMLRequest"] = Base64.encode64(deflated_request).gsub(/\n/, "")
  
  Logging.debug "SAMLRequest=#{@request_params["SAMLRequest"]}"
  uri = Addressable::URI.parse(@URL)
  if uri.query_values == nil
    uri.query_values = @request_params
  else
    # solution to stevenwilkin's parameter merge
    uri.query_values = @request_params.merge(uri.query_values)
  end
  url = uri.to_s
  #Logging.debug "Sending to URL #{url}"
  return url
end

#content_post ⇒ Object

construct an HTML form (POST) and return the content



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# File 'lib/federa/ruby-saml/authrequest.rb', line 159

def content_post
  # POST requests seem to bomb out when they're deflated
  # and they probably don't need to be compressed anyway
  @request_params["SAMLRequest"] = Base64.encode64(@request).gsub(/\n/, "")
  
  #Logging.debug "SAMLRequest=#{@request_params["SAMLRequest"]}"
  # kind of a cheesy method of building an HTML, form since we can't rely on Rails too much,
  # and REXML doesn't work well with quote characters
  str = "<html><body onLoad=\"document.getElementById('form').submit();\">\n"
  str += "<form id='form' name='form' method='POST' action=\"#{@URL}\">\n"
  # we could change this in the future to associate a temp auth session ID
  str += "<input name='RelayState' value='ruby-saml' type='hidden' />\n"
  @request_params.each_pair do |key, value|
    str += "<input name=\"#{key}\" value=\"#{value}\" type='hidden' />\n"
    #str += "<input name=\"#{key}\" value=\"#{CGI.escape(value)}\" type='hidden' />\n"
  end
  str += "</form></body></html>\n"
  
  #Logging.debug "Created form:\n#{str}"
  return str
end

#create(params = {}) ⇒ Object 



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# File 'lib/federa/ruby-saml/authrequest.rb', line 24

def create(params = {})
  uuid = "_" + UUID.new.generate
  self.uuid = uuid
  time = Time.now.utc.strftime("%Y-%m-%dT%H:%M:%SZ")
  # Create AuthnRequest root element using REXML 
  request_doc = REXML::Document.new
  request_doc.context[:attribute_quote] = :quote
  root = request_doc.add_element "saml2p:AuthnRequest", { "xmlns:saml2p" => "urn:oasis:names:tc:SAML:2.0:protocol" }
  root.attributes['ID'] = uuid
  root.attributes['IssueInstant'] = time
  root.attributes['Version'] = "2.0"
  root.attributes['ProtocolBinding'] = "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
  #root.attributes['AttributeConsumingServiceIndex'] = "2"
  root.attributes['ForceAuthn'] = "false"
  root.attributes['IsPassive'] = "false"

  # Conditionally defined elements based on settings
  if @settings.assertion_consumer_service_url != nil
    root.attributes["AssertionConsumerServiceURL"] = @settings.assertion_consumer_service_url
  end

   if @settings.destination_service_url != nil
    root.attributes["Destination"] = @settings.destination_service_url
  end

  if @settings.issuer != nil
    issuer = root.add_element "saml2:Issuer", { "xmlns:saml2" => "urn:oasis:names:tc:SAML:2.0:assertion" }
    issuer.text = @settings.issuer
  end
  if @settings.name_identifier_format != nil
    root.add_element "saml2p:NameIDPolicy", { 
        # Might want to make AllowCreate a setting?
        "AllowCreate"     => "true",
        "Format"          => @settings.name_identifier_format[1],
        "SPNameQualifier" => @settings.sp_name_qualifier
    }
  end

  # BUG fix here -- if an authn_context is defined, add the tags with an "exact"
  # match required for authentication to succeed.  If this is not defined, 
  # the IdP will choose default rules for authentication.  (Shibboleth IdP)
  if @settings.authn_context != nil
    requested_context = root.add_element "saml2p:RequestedAuthnContext", { 
      "Comparison" => "exact"
    }
    context_class = []
    @settings.authn_context.each_with_index{ |context, index|
      context_class[index] = requested_context.add_element "saml2:AuthnContextClassRef", {
        "xmlns:saml2" => "urn:oasis:names:tc:SAML:2.0:assertion"
      }
      context_class[index].text = context
    }
    
  end

  if @settings.requester_identificator != nil
    requester_identificator = root.add_element "saml2p:Scoping", { 
      "ProxyCount" => "1"
    }
    identificators = []
    @settings.requester_identificator.each_with_index{ |requester, index|
      identificators[index] = requester_identificator.add_element "saml2p:RequesterID"
      identificators[index].text = requester
    }
    
  end

  request_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
  request_doc.write(ret, 1)

  @request = ""
  request_doc.write(@request)

  #Logging.debug "Created AuthnRequest: #{@request}"

  return self

end