Class: XMLSecurity::SignedDocument

Inherits:
BaseDocument
  • Object
show all
Defined in:
lib/xml_security.rb

Constant Summary

Constants inherited from BaseDocument

BaseDocument::C14N, BaseDocument::DSIG, BaseDocument::NOKOGIRI_OPTIONS

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from BaseDocument

#algorithm, #canon_algorithm

Constructor Details

#initialize(response, errors = []) ⇒ SignedDocument

Returns a new instance of SignedDocument.



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# File 'lib/xml_security.rb', line 186

def initialize(response, errors = [])
  super(response)
  @errors = errors
end

Instance Attribute Details

#errors ⇒ Object

Returns the value of attribute errors.



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# File 'lib/xml_security.rb', line 184

def errors
  @errors
end

#signed_element_id ⇒ Object

Returns the value of attribute signed_element_id.



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# File 'lib/xml_security.rb', line 183

def signed_element_id
  @signed_element_id
end

Instance Method Details

#validate_document(idp_cert_fingerprint, soft = true, options = {}) ⇒ Object 



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# File 'lib/xml_security.rb', line 195

def validate_document(idp_cert_fingerprint, soft = true, options = {})
  # get cert from response
  cert_element = REXML::XPath.first(
    self,
    "//ds:X509Certificate",
    { "ds"=>DSIG }
  )

  if cert_element        
    base64_cert = cert_element.text
    cert_text = Base64.decode64(base64_cert)
    cert = OpenSSL::X509::Certificate.new(cert_text)

    if options[:fingerprint_alg]
      fingerprint_alg = XMLSecurity::BaseDocument.new.algorithm(options[:fingerprint_alg]).new
    else
      fingerprint_alg = OpenSSL::Digest::SHA1.new
    end
    fingerprint = fingerprint_alg.hexdigest(cert.to_der)

    # check cert matches registered idp cert
    if fingerprint != idp_cert_fingerprint.gsub(/[^a-zA-Z0-9]/,"").downcase
      @errors << "Fingerprint mismatch"
      return soft ? false : (raise OneLogin::RubySaml::ValidationError.new("Fingerprint mismatch"))
    end
  else
    if options[:cert]
      base64_cert = Base64.encode64(options[:cert].to_pem)
    else
      if soft
        return false
      else
        raise OneLogin::RubySaml::ValidationError.new("Certificate element missing in response (ds:X509Certificate) and not cert provided at settings")
      end          
    end
  end
  validate_signature(base64_cert, soft)
end

#validate_signature(base64_cert, soft = true) ⇒ Object 



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# File 'lib/xml_security.rb', line 234

def validate_signature(base64_cert, soft = true)

  document = Nokogiri.parse(self.to_s) do |options|
    options = XMLSecurity::BaseDocument::NOKOGIRI_OPTIONS
  end

  # create a rexml document
  @working_copy ||= REXML::Document.new(self.to_s).root

  # get signature node
  sig_element = REXML::XPath.first(
      @working_copy,
      "//ds:Signature",
      {"ds"=>DSIG}
  )

  # signature method
  sig_alg_value = REXML::XPath.first(
    sig_element,
    "./ds:SignedInfo/ds:SignatureMethod",
    {"ds"=>DSIG}
  )
  signature_algorithm = algorithm(sig_alg_value)

  # get signature
  base64_signature = REXML::XPath.first(
    sig_element,
    "./ds:SignatureValue",
    {"ds" => DSIG}
  ).text
  signature = Base64.decode64(base64_signature)

  # canonicalization method
  canon_algorithm = canon_algorithm REXML::XPath.first(
    sig_element,
    './ds:SignedInfo/ds:CanonicalizationMethod',
    'ds' => DSIG
  )

  noko_sig_element = document.at_xpath('//ds:Signature', 'ds' => DSIG)
  noko_signed_info_element = noko_sig_element.at_xpath('./ds:SignedInfo', 'ds' => DSIG)

  # Handle when no URI
  noko_signed_info_reference_element_uri_attr = noko_signed_info_element.at_xpath('./ds:Reference', 'ds' => DSIG).attributes["URI"]
  if (noko_signed_info_reference_element_uri_attr.value.empty?)
    noko_signed_info_reference_element_uri_attr.value = "##{document.root.attribute('ID')}"
  end

  canon_string = noko_signed_info_element.canonicalize(canon_algorithm)
  noko_sig_element.remove

  # get inclusive namespaces
  inclusive_namespaces = extract_inclusive_namespaces

  # check digests
  ref = REXML::XPath.first(sig_element, "//ds:Reference", {"ds"=>DSIG})
  uri = ref.attributes.get_attribute("URI").value

  hashed_element = uri.empty? ? document : document.at_xpath("//*[@ID=$uri]", nil, { 'uri' => uri[1..-1] })
  # hashed_element = document.at_xpath("//*[@ID=$uri]", nil, { 'uri' => uri[1..-1] })
  canon_algorithm = canon_algorithm REXML::XPath.first(
    ref,
    '//ds:CanonicalizationMethod',
    { "ds" => DSIG }
  )
  canon_hashed_element = hashed_element.canonicalize(canon_algorithm, inclusive_namespaces)

  digest_algorithm = algorithm(REXML::XPath.first(
    ref,
    "//ds:DigestMethod",
    { "ds" => DSIG }
  ))
  hash = digest_algorithm.digest(canon_hashed_element)
  encoded_digest_value = REXML::XPath.first(
    ref,
    "//ds:DigestValue",
    { "ds" => DSIG }
  ).text
  digest_value = Base64.decode64(encoded_digest_value)

  unless digests_match?(hash, digest_value)
    @errors << "Digest mismatch"
    return soft ? false : (raise OneLogin::RubySaml::ValidationError.new("Digest mismatch"))
  end

  # get certificate object
  cert_text = Base64.decode64(base64_cert)
  cert = OpenSSL::X509::Certificate.new(cert_text)

  # verify signature
  unless cert.public_key.verify(signature_algorithm.new, signature, canon_string)
    @errors << "Key validation error"
    return soft ? false : (raise OneLogin::RubySaml::ValidationError.new("Key validation error"))
  end

  return true
end