Class: Spid::Saml::Utils

Inherits:
Object
  • Object
show all
Defined in:
lib/spid/ruby-saml/utils.rb

Overview

SAML2 Auxiliary class

Constant Summary collapse

DSIG = 
"http://www.w3.org/2000/09/xmldsig#"
XENC = 
"http://www.w3.org/2001/04/xmlenc#"
@@uuid_generator = 
UUID.new

Class Method Summary collapse

Class Method Details

.build_query(params) ⇒ String

Build the Query String signature that will be used in the HTTP-Redirect binding to generate the Signature

Parameters:

  • params (Hash) —

    Parameters to build the Query String

Options Hash (params):

  • :type (String) —

    ‘SAMLRequest’ or ‘SAMLResponse’

  • :data (String) —

    Base64 encoded SAMLRequest or SAMLResponse

  • :relay_state (String) —

    The RelayState parameter

  • :sig_alg (String) —

    The SigAlg parameter

Returns:

  • (String) —

    The Query String



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# File 'lib/spid/ruby-saml/utils.rb', line 62

def self.build_query(params)
  type, data, relay_state, sig_alg = [:type, :data, :relay_state, :sig_alg].map { |k| params[k]}

  url_string = "#{type}=#{CGI.escape(data)}"
  url_string << "&RelayState=#{CGI.escape(relay_state)}" if relay_state
  url_string << "&SigAlg=#{CGI.escape(sig_alg)}"
end

.decrypt_data(encrypted_node, private_key) ⇒ String

Obtains the decrypted string from an Encrypted node element in XML

Parameters:

  • encrypted_node (REXML::Element) —

    The Encrypted element

  • private_key (OpenSSL::PKey::RSA) —

    The Service provider private key

Returns:

  • (String) —

    The decrypted data



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# File 'lib/spid/ruby-saml/utils.rb', line 105

def self.decrypt_data(encrypted_node, private_key)
  encrypt_data = REXML::XPath.first(
    encrypted_node,
    "./xenc:EncryptedData",
    { 'xenc' => XENC }
  )
  symmetric_key = retrieve_symmetric_key(encrypt_data, private_key)
  cipher_value = REXML::XPath.first(
    encrypt_data,
    "//xenc:EncryptedData/xenc:CipherData/xenc:CipherValue",
    { 'xenc' => XENC }
  )
  node = Base64.decode64(cipher_value.text)
  encrypt_method = REXML::XPath.first(
    encrypt_data,
    "//xenc:EncryptedData/xenc:EncryptionMethod",
    { 'xenc' => XENC }
  )
  algorithm = encrypt_method.attributes['Algorithm']
  retrieve_plaintext(node, symmetric_key, algorithm)
end

.element_text(element) ⇒ Object

Given a REXML::Element instance, return the concatenation of all child text nodes. Assumes that there all children other than text nodes can be ignored (e.g. comments). If nil is passed, nil will be returned.



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# File 'lib/spid/ruby-saml/utils.rb', line 218

def self.element_text(element)
  element.texts.map(&:value).join if element
end

.format_cert(cert) ⇒ String

Return a properly formatted x509 certificate

Parameters:

  • cert (String) —

    The original certificate

Returns:

  • (String) —

    The formatted certificate



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# File 'lib/spid/ruby-saml/utils.rb', line 23

def self.format_cert(cert)
  # don't try to format an encoded certificate or if is empty or nil
  return cert if cert.nil? || cert.empty? || cert.match(/\x0d/)

  cert = cert.gsub(/\-{5}\s?(BEGIN|END) CERTIFICATE\s?\-{5}/, "")
  cert = cert.gsub(/[\n\r\s]/, "")
  cert = cert.scan(/.{1,64}/)
  cert = cert.join("\n")
  "-----BEGIN CERTIFICATE-----\n#{cert}\n-----END CERTIFICATE-----"
end

.format_private_key(key) ⇒ String

Return a properly formatted private key

Parameters:

  • key (String) —

    The original private key

Returns:

  • (String) —

    The formatted private key



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# File 'lib/spid/ruby-saml/utils.rb', line 39

def self.format_private_key(key)
  # don't try to format an encoded private key or if is empty
  return key if key.nil? || key.empty? || key.match(/\x0d/)

  # is this an rsa key?
  rsa_key = key.match("RSA PRIVATE KEY")
  key = key.gsub(/\-{5}\s?(BEGIN|END)( RSA)? PRIVATE KEY\s?\-{5}/, "")
  key = key.gsub(/[\n\r\s]/, "")
  key = key.scan(/.{1,64}/)
  key = key.join("\n")
  key_label = rsa_key ? "RSA PRIVATE KEY" : "PRIVATE KEY"
  "-----BEGIN #{key_label}-----\n#{key}\n-----END #{key_label}-----"
end

.original_uri_match?(destination_url, settings_url) ⇒ Boolean

If Rails’ URI.parse can’t match to valid URL, default back to the original matching service.

Returns:

  • (Boolean) 


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# File 'lib/spid/ruby-saml/utils.rb', line 211

def self.original_uri_match?(destination_url, settings_url)
  destination_url == settings_url
end

.retrieve_plaintext(cipher_text, symmetric_key, algorithm) ⇒ String

Obtains the deciphered text

Parameters:

  • cipher_text (String) —

    The ciphered text

  • symmetric_key (String) —

    The symetric key used to encrypt the text

  • algorithm (String) —

    The encrypted algorithm

Returns:

  • (String) —

    The deciphered text



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# File 'lib/spid/ruby-saml/utils.rb', line 158

def self.retrieve_plaintext(cipher_text, symmetric_key, algorithm)
  case algorithm
    when 'http://www.w3.org/2001/04/xmlenc#tripledes-cbc' then cipher = OpenSSL::Cipher.new('DES-EDE3-CBC').decrypt
    when 'http://www.w3.org/2001/04/xmlenc#aes128-cbc' then cipher = OpenSSL::Cipher.new('AES-128-CBC').decrypt
    when 'http://www.w3.org/2001/04/xmlenc#aes192-cbc' then cipher = OpenSSL::Cipher.new('AES-192-CBC').decrypt
    when 'http://www.w3.org/2001/04/xmlenc#aes256-cbc' then cipher = OpenSSL::Cipher.new('AES-256-CBC').decrypt
    when 'http://www.w3.org/2001/04/xmlenc#rsa-1_5' then rsa = symmetric_key
    when 'http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p' then oaep = symmetric_key
  end

  if cipher
    iv_len = cipher.iv_len
    data = cipher_text[iv_len..-1]
    cipher.padding, cipher.key, cipher.iv = 0, symmetric_key, cipher_text[0..iv_len-1]
    assertion_plaintext = cipher.update(data)
    assertion_plaintext << cipher.final
  elsif rsa
    rsa.private_decrypt(cipher_text)
  elsif oaep
    oaep.private_decrypt(cipher_text, OpenSSL::PKey::RSA::PKCS1_OAEP_PADDING)
  else
    cipher_text
  end
end

.retrieve_symmetric_key(encrypt_data, private_key) ⇒ String

Obtains the symmetric key from the EncryptedData element

Parameters:

  • encrypt_data (REXML::Element) —

    The EncryptedData element

  • private_key (OpenSSL::PKey::RSA) —

    The Service provider private key

Returns:

  • (String) —

    The symmetric key



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# File 'lib/spid/ruby-saml/utils.rb', line 131

def self.retrieve_symmetric_key(encrypt_data, private_key)
  encrypted_key = REXML::XPath.first(
    encrypt_data,
    "//xenc:EncryptedData/ds:KeyInfo/xenc:EncryptedKey or \
     //xenc:EncryptedKey[@Id=substring-after(//xenc:EncryptedData/ds:KeyInfo/ds:RetrievalMethod/@URI, '#')]",
    { "ds" => DSIG, "xenc" => XENC }
  )
  encrypted_symmetric_key_element = REXML::XPath.first(
    encrypted_key,
    "./xenc:CipherData/xenc:CipherValue",
    { "ds" => DSIG, "xenc" => XENC }
  )
  cipher_text = Base64.decode64(encrypted_symmetric_key_element.text)
  encrypt_method = REXML::XPath.first(
    encrypted_key,
    "./xenc:EncryptionMethod",
    {"ds" => DSIG,  "xenc" => XENC }
  )
  algorithm = encrypt_method.attributes['Algorithm']
  retrieve_plaintext(cipher_text, private_key, algorithm)
end

.status_error_msg(error_msg, status_code = nil, status_message = nil) ⇒ String

Build the status error message

Parameters:

  • status_code (String) (defaults to: nil) —

    StatusCode value

  • status_message (Strig) (defaults to: nil) —

    StatusMessage value

Returns:

  • (String) —

    The status error message



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# File 'lib/spid/ruby-saml/utils.rb', line 88

def self.status_error_msg(error_msg, status_code = nil, status_message = nil)
  unless status_code.nil?
    printable_code = status_code.split(':').last
    error_msg << ', was ' + printable_code
  end

  unless status_message.nil?
    error_msg << ' -> ' + status_message
  end

  error_msg
end

.uri_match?(destination_url, settings_url) ⇒ Boolean

Given two strings, attempt to match them as URIs using Rails’ parse method. If they can be parsed, then the fully-qualified domain name and the host should performa a case-insensitive match, per the RFC for URIs. If Rails can not parse the string in to URL pieces, return a boolean match of the two strings. This maintains the previous functionality.

Returns:

  • (Boolean) 


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# File 'lib/spid/ruby-saml/utils.rb', line 193

def self.uri_match?(destination_url, settings_url)
  dest_uri = URI.parse(destination_url)
  acs_uri = URI.parse(settings_url)

  if dest_uri.scheme.nil? || acs_uri.scheme.nil? || dest_uri.host.nil? || acs_uri.host.nil?
    raise URI::InvalidURIError
  else
    dest_uri.scheme.downcase == acs_uri.scheme.downcase &&
      dest_uri.host.downcase == acs_uri.host.downcase &&
      dest_uri.path == acs_uri.path &&
      dest_uri.query == acs_uri.query
  end
rescue URI::InvalidURIError
  original_uri_match?(destination_url, settings_url)
end

.uuid ⇒ Object 



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# File 'lib/spid/ruby-saml/utils.rb', line 183

def self.uuid
  RUBY_VERSION < '1.9' ? "_#{@@uuid_generator.generate}" : "_#{SecureRandom.uuid}"
end

.verify_signature(params) ⇒ Boolean

Validate the Signature parameter sent on the HTTP-Redirect binding

Parameters:

  • params (Hash) —

    Parameters to be used in the validation process

Options Hash (params):

  • cert (OpenSSL::X509::Certificate) —

    The Identity provider public certtificate

  • sig_alg (String) —

    The SigAlg parameter

  • signature (String) —

    The Signature parameter (base64 encoded)

  • query_string (String) —

    The full GET Query String to be compared

Returns:

  • (Boolean) —

    True if the Signature is valid, False otherwise



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# File 'lib/spid/ruby-saml/utils.rb', line 78

def self.verify_signature(params)
  cert, sig_alg, signature, query_string = [:cert, :sig_alg, :signature, :query_string].map { |k| params[k]}
  signature_algorithm = Spid::XMLSecurityNew::BaseDocument.new.algorithm(sig_alg)
  return cert.public_key.verify(signature_algorithm.new, Base64.decode64(signature), query_string)
end