Class: InformationCard::SamlToken

Inherits:
IdentityToken
  • Object
show all
Defined in:
lib/vendor/information_card/saml_token.rb

Instance Method Summary collapse

Instance Method Details

#errors ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 34

def errors
  return @errors
end

#get_X509Certificate(certificate) ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 129

def get_X509Certificate(certificate)
  encoding = "-----BEGIN CERTIFICATE-----\n"
  offset = 0;
  # strip out the newlines
  certificate.delete!("=\n") 
  while (segment = certificate[offset, 64])
     encoding = encoding + segment + "\n"
     offset += 64
  end
  encoding = encoding + "-----END CERTIFICATE-----\n"        
  OpenSSL::X509::Certificate.new(encoding)
end

#process_claims ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 111

def process_claims            
  attribute_nodes = XPath.match(@doc, "//saml:AttributeStatement/saml:Attribute", {"saml" => Namespaces::SAML_ASSERTION})
  attribute_nodes.each do |node|
    key = ClaimTypes.lookup(node.attributes['AttributeNamespace'], node.attributes['AttributeName'])      
    value_nodes = XPath.match(node, "saml:AttributeValue", "saml" => Namespaces::SAML_ASSERTION)
    
    if (value_nodes.length < 2 or value_nodes.empty?)
        @claims[key] = value_nodes[0].text
    else
      claim_values = []
      value_nodes.each{ |value_node|
          claim_values << value_node.text
      }
      @claims[key] = claim_values
    end
  end
end

#validate_conditions ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 98

def validate_conditions
  conditions = XPath.first(@doc, "//saml:Conditions", "saml" => Namespaces::SAML_ASSERTION)
  
  condition_errors = {}
  not_before_time = Time.parse(conditions.attributes['NotBefore'])
  condition_errors[:not_before] = "Time is before #{not_before_time}" if Time.now.utc < not_before_time 
  
  not_on_or_after_time = Time.parse(conditions.attributes['NotOnOrAfter'])
  condition_errors[:not_on_or_after] = "Time is on or after #{not_on_or_after_time}" if Time.now.utc >= not_on_or_after_time

  @errors[:conditions] = condition_errors unless condition_errors.empty?    
end

#verify_digest ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 38

def verify_digest     
  working_doc = REXML::Document.new(@doc.to_s)
  
  assertion_node = XPath.first(working_doc, "saml:Assertion", {"saml" => Namespaces::SAML_ASSERTION}) 
  signature_node =  XPath.first(assertion_node, "ds:Signature", {"ds" => Namespaces::DS}) 
  signed_info_node = XPath.first(signature_node, "ds:SignedInfo", {"ds" => Namespaces::DS})    
  digest_value_node = XPath.first(signed_info_node, "ds:Reference/ds:DigestValue", {"ds" => Namespaces::DS})
  
  digest_value = digest_value_node.text

  signature_node.remove
  digest_errors = []
  canonicalizer = InformationCard::XmlCanonicalizer.new
  
  reference_nodes = XPath.match(signed_info_node, "ds:Reference", {"ds" => Namespaces::DS})
  # TODO: Check specification to see if digest is required.
  @errors[:digest] = "No reference nodes to check digest" and return if reference_nodes.nil? or reference_nodes.empty?
  
  reference_nodes.each do |node|
    uri = node.attributes['URI']
    nodes_to_verify = XPath.match(working_doc, "saml:Assertion[@AssertionID='#{uri[1..uri.size]}']", {"saml" => Namespaces::SAML_ASSERTION})
  
    nodes_to_verify.each do |node|
      canonicalized_signed_info = canonicalizer.canonicalize(node)
      signed_node_hash_sha1 = Base64.encode64(Digest::SHA1.digest(canonicalized_signed_info)).chomp                    
      signed_node_hash_sha256 = Base64.encode64(Digest::SHA256.digest(canonicalized_signed_info)).chomp                              
      unless signed_node_hash_sha1 == digest_value
        unless signed_node_hash_sha256 == digest_value
          digest_errors << "Invalid Digest for #{uri}. Expected #{signed_node_hash} but was #{digest_value}"
        end
      end
    end
                   
    @errors[:digest] = digest_errors unless digest_errors.empty?
  end  
end

#verify_signature ⇒ Object 



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# File 'lib/vendor/information_card/saml_token.rb', line 75

def verify_signature    
  working_doc = REXML::Document.new(@doc.to_s)

  assertion_node = XPath.first(working_doc, "saml:Assertion", {"saml" => Namespaces::SAML_ASSERTION})
  signature_node =  XPath.first(assertion_node, "ds:Signature", {"ds" => Namespaces::DS})            
  certificate_value_node = XPath.first(signature_node, "KeyInfo/X509Data/X509Certificate")
  certificate = get_X509Certificate(certificate_value_node.text)

  # TODO: here you should validate that the presented certificate is valid

  public_key_string = certificate.public_key      
  signed_info_node = XPath.first(signature_node, "ds:SignedInfo", {"ds" => Namespaces::DS})
  signature_value_node = XPath.first(signature_node, "ds:SignatureValue", {"ds" => Namespaces::DS})
  canonicalized_signed_info = InformationCard::XmlCanonicalizer.new.canonicalize(signed_info_node)
  signature = Base64.decode64(signature_value_node.text)
  
  unless public_key_string.verify(OpenSSL::Digest::SHA1.new, signature, canonicalized_signed_info) 
    unless public_key_string.verify(OpenSSL::Digest::SHA256.new, signature, canonicalized_signed_info) 
      @errors[:signature] = "Invalid Signature" 
    end
  end
end