Module: Tem::CA

Included in:
Session
Defined in:
lib/tem/ca.rb

Overview

Certificate Authority (CA) functionality for TEM manufacturers

Constant Summary collapse

@@dev_dir =
File.join(File.dirname(__FILE__), "..", "..", "dev_ca")

Class Method Summary collapse

Class Method Details

.ca_certObject

retrieves the TEM CA certificate



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# File 'lib/tem/ca.rb', line 54

def self.ca_cert
  cpath = Tem::Hive.path_to 'ca/ca_cert.pem'
  cpath = File.join(@@dev_dir, 'ca_cert.pem') unless File.exists? cpath
  return OpenSSL::X509::Certificate.new(File.open(cpath, 'r') { |f| f.read })
end

.ca_keyObject

retrieves the TEM CA key pair (needed for signing)



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# File 'lib/tem/ca.rb', line 61

def self.ca_key
  cpath = Tem::Hive.path_to 'ca/ca_key.pem'
  cpath = File.join(@@dev_dir, 'ca_key.pem') unless File.exists? cpath
  return OpenSSL::PKey::RSA.new(File.open(cpath, 'r') { |f| f.read })
end

.configObject

retrieves the TEM CA configuration



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# File 'lib/tem/ca.rb', line 44

def self.config
  cpath = Tem::Hive.path_to 'ca/config.yml'
  cpath = File.join(@@dev_dir, 'config.yml') unless File.exists? cpath

  # try to open it in the base folder
  scaffold_config unless File.exists? cpath
  return File.open(cpath, 'r') { |f| YAML.load f } 
end

.new_ecert(pubek) ⇒ Object

Creates an Endorsement Certificate for a TEM’s Public Endorsement Key.



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# File 'lib/tem/ca.rb', line 7

def self.new_ecert(pubek)
  ca_cert = Tem::CA.ca_cert
  ca_key = Tem::CA.ca_key
  conf = Tem::CA.config
  
  dn = OpenSSL::X509::Name.new conf[:issuer].merge(conf[:subject]).to_a
  now = Time.now
  ecert = OpenSSL::X509::Certificate.new
  ecert.issuer = ca_cert.subject
  ecert.subject = dn
  ecert.not_before = now;
  ecert.not_after = now + conf[:ecert_validity_days] * 60 * 60 * 24;
  ecert.public_key = pubek
  ecert.version = 2
  cf = OpenSSL::X509::ExtensionFactory.new
  cf.subject_certificate = ecert 
  cf.issuer_certificate = ca_cert
  ecert.add_extension cf.create_extension("basicConstraints", "CA:true", true)
  ecert.add_extension cf.create_extension("authorityKeyIdentifier",
                                          "keyid,issuer")    
  ecert.add_extension cf.create_extension("keyUsage",
     "digitalSignature,nonRepudiation,keyEncipherment,dataEncipherment," +
     "keyAgreement,keyCertSign,cRLSign")
  ecert.add_extension cf.create_extension("extendedKeyUsage",
     "serverAuth,clientAuth,codeSigning,emailProtection,timeStamping," +
     "msCodeInd,msCodeCom,msCTLSign,msSGC,msEFS,nsSGC")
  ecert.add_extension cf.create_extension("nsCertType",
     "client,server,email,objsign,sslCA,emailCA,objCA")
  ecert.add_extension cf.create_extension("subjectKeyIdentifier", "hash")
  ecert.sign ca_key, OpenSSL::Digest::SHA1.new
  
  return ecert
end

.scaffold_caObject

scaffolds the structures needed for a TEM CA



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# File 'lib/tem/ca.rb', line 68

def self.scaffold_ca
  conf = config
  
  # generate and write key
  ca_key = Tem::CryptoAbi.generate_ssl_kp
  key_path = Tem::Hive.create 'ca/ca_key.pem'
  File.open(key_path, 'w') { |f| f.write ca_key.to_pem }
  
  # create the CA certificate
  dn = OpenSSL::X509::Name.new conf[:issuer].to_a
  now = Time.now
  cert = OpenSSL::X509::Certificate.new
  cert.subject = cert.issuer = dn
  cert.not_before = now;
  cert.not_after = now + conf[:ca_validity_days] * 60 * 60 * 24;
  cert.public_key = ca_key.public_key
  cert.version = 2
  cf = OpenSSL::X509::ExtensionFactory.new
  cf.subject_certificate = cf.issuer_certificate = cert
  cert.add_extension cf.create_extension("basicConstraints", "CA:true", true)
  cert.add_extension cf.create_extension("authorityKeyIdentifier", "keyid,issuer")    
  cert.add_extension cf.create_extension("keyUsage", "cRLSign,keyCertSign")
  cert.add_extension cf.create_extension("nsCertType", "emailCA,sslCA")
  cert.add_extension cf.create_extension("subjectKeyIdentifier", "hash")
  cert.sign ca_key, OpenSSL::Digest::SHA1.new    
  
  # write the CA certificate
  cert_path = Tem::Hive.create 'ca/ca_cert.pem'
  File.open(cert_path, 'w') { |f| f.write cert.to_pem }
  cert_path = Tem::Hive.create 'ca/ca_cert.cer'
  File.open(cert_path, 'wb') { |f| f.write cert.to_der }
end

.scaffold_configObject

scaffolds a TEM CA configuration



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# File 'lib/tem/ca.rb', line 102

def self.scaffold_config
  def_config = {
    :issuer => {
      'C' => 'US', 'ST' => 'Massachusetts', 'L' => 'Cambridge',
      'O' => 'Massachusetts Insitute of Technology',
      'OU' => 'Computer Science and Artificial Intelligence Laboratory',
      'CN' => 'Trusted Execution Module Development CA'
    },
    :subject => {
      'CN' => 'Trusted Execution Module DevChip'
    },
    :ca_validity_days => 3652,
    :ecert_validity_days => 365 * 2,
  } 
  
  cpath = Tem::Hive.create 'ca/config.yml'
  File.open(cpath, 'w') { |f| YAML.dump def_config, f }
end