cam/ca.py

   1 import errno
   2 import fcntl
   3 import logging
   4 import re
   5 import os
   6 import getpass
   7 import random
   8 import shutil
   9 import tempfile
  10 import time
  11 from cam import openssl_wrap
  12 from cam import utils
  13
  14 log = logging.getLogger(__name__)
  15
  16
  17 class _CAFiles(object):
  18
  19     def __init__(self, basedir, **attrs):
  20         for key, value in attrs.items():
  21             setattr(self, key, os.path.join(basedir, value))
  22
  23
  24 class CA(object):
  25
  26     def __init__(self, basedir, config, password=None):
  27         self._pw = password
  28         self.basedir = basedir
  29         self.config = {'basedir': basedir, 'default_days': '365', 'ou': 'CA',
  30                        'days': '3650', 'country': 'XX', 'crl_url': '',
  31                        'bits': '4096'}
  32         self.config.update(config)
  33         self.files = _CAFiles(basedir,
  34                               conf='conf/ca.conf',
  35                               public_key='public/ca.pem',
  36                               private_key='private/ca.key',
  37                               crl='public/ca.crl',
  38                               serial='serial',
  39                               crlnumber='crlnumber',
  40                               index='index')
  41         self._lock()
  42
  43     def _getpw(self):
  44         if self._pw is None:
  45             self._pw = getpass.getpass(prompt='CA Password: ')
  46         return self._pw
  47
  48     def _lock(self):
  49         self._lockfd = open(os.path.join(self.basedir, '_lock'), 'w+')
  50         n = 3
  51         while True:
  52             try:
  53                 fcntl.lockf(self._lockfd, fcntl.LOCK_EX | fcntl.LOCK_NB)
  54                 break
  55             except IOError, e:
  56                 if e.errno in (errno.EACCES, errno.EAGAIN):
  57                     n -= 1
  58                     if n == 0:
  59                         log.error('another instance is running')
  60                         raise
  61                     time.sleep(1)
  62                     continue
  63                 raise
  64
  65     def _unlock(self):
  66         fcntl.lockf(self._lockfd, fcntl.LOCK_UN)
  67         self._lockfd.close()
  68
  69     def close(self):
  70         self._unlock()
  71
  72     def create(self):
  73         old_umask = os.umask(077)
  74
  75         for pathext in ('', 'conf', 'public', 'public/certs',
  76                         'public/crl', 'private', 'newcerts'):
  77             fullpath = os.path.join(self.basedir, pathext)
  78             if not os.path.isdir(fullpath):
  79                 os.mkdir(fullpath)
  80
  81         if not os.path.exists(self.files.index):
  82             log.info('creating new index file')
  83             open(self.files.index, 'w').close()
  84
  85         if not os.path.exists(self.files.serial):
  86             serial = random.randint(1, 1000000000)
  87             log.info('initializing serial number (%d)', serial)
  88             with open(self.files.serial, 'w') as fd:
  89                 fd.write('%08X\n' % serial)
  90
  91         if not os.path.exists(self.files.crlnumber):
  92             with open(self.files.crlnumber, 'w') as fd:
  93                 fd.write('01\n')
  94
  95         # Create the OpenSSL configuration file.
  96         utils.render(self.files.conf, 'openssl_config', self.config)
  97
  98         # Generate keys if they do not exist.
  99         if not os.path.exists(self.files.public_key):
 100             tmpdir = tempfile.mkdtemp()
 101             csr_file = os.path.join(tmpdir, 'ca.csr')
 102             log.info('creating new RSA CA CSR')
 103             openssl_wrap.run_with_config(
 104                 self.basedir, self.files.conf,
 105                 'req', '-new',
 106                 '-passout', 'pass:%s' % self._getpw(),
 107                 '-keyout', self.files.private_key, '-out', csr_file)
 108             log.info('self-signing RSA CA certificate')
 109             openssl_wrap.run_with_config(
 110                 self.basedir, self.files.conf,
 111                 'ca', '-keyfile', self.files.private_key,
 112                 '-key', self._getpw(),
 113                 '-extensions', 'v3_ca', '-out', self.files.public_key,
 114                 '-days', self.config.get('days', self.config['default_days']),
 115                 '-selfsign', '-infiles', csr_file)
 116             shutil.rmtree(tmpdir)
 117
 118         os.umask(old_umask)
 119
 120         # Make some files public.
 121         for path in (os.path.join(self.basedir, 'public'),
 122                      os.path.join(self.basedir, 'public/certs'),
 123                      self.files.public_key):
 124             if os.path.isdir(path):
 125                 os.chmod(path, 0755)
 126             else:
 127                 os.chmod(path, 0644)
 128
 129     def gencrl(self):
 130         log.info('generating CRL')
 131         # Write the CRL in PEM format to a temporary file.
 132         tmpf = self.files.crl + '.tmp'
 133         openssl_wrap.run_with_config(
 134             self.basedir, self.files.conf,
 135             'ca', '-gencrl', '-out', tmpf,
 136             '-key', self._getpw())
 137         # Convert to DER format for distribution.
 138         openssl_wrap.run(
 139             'crl', '-inform', 'PEM', '-outform', 'DER',
 140             '-in', tmpf, '-out', self.files.crl)
 141         os.remove(tmpf)
 142         os.chmod(self.files.crl, 0644)
 143
 144     def revoke(self, cert):
 145         log.info('revoking certificate %s', cert.name)
 146         openssl_wrap.run_with_config(
 147             self.basedir, self.files.conf,
 148             'ca', '-revoke', cert.public_key_file,
 149             '-key', self._getpw())
 150         self.gencrl()
 151
 152     def generate(self, cert):
 153         expiry = cert.get_expiration_date()
 154         if expiry and expiry > time.time():
 155             log.warn('certificate is still valid, revoking previous version')
 156             self.revoke(cert)
 157
 158         log.info('generating new certificate %s', cert.name)
 159         tmpdir = tempfile.mkdtemp()
 160         try:
 161             csr_file = os.path.join(tmpdir, '%s.csr' % cert.name)
 162             conf_file = os.path.join(tmpdir, '%s.conf' % cert.name)
 163             ext_file = os.path.join(tmpdir, '%s-ext.conf' % cert.name)
 164             conf = {}
 165             conf.update(self.config)
 166             conf['cn'] = cert.cn
 167             conf['days'] = cert.days or self.config['default_days']
 168             if cert.ou:
 169                 conf['ou'] = cert.ou
 170             conf['alt_names'] = ''.join(
 171                 ['DNS.%d=%s\n' % (idx + 1, x)
 172                  for idx, x in enumerate(cert.alt_names)])
 173             utils.render(conf_file, 'openssl_config', conf)
 174             utils.render(ext_file, 'ext_config', conf)
 175             openssl_wrap.run_with_config(
 176                 self.basedir, conf_file,
 177                 'req', '-new', '-keyout', cert.private_key_file,
 178                 '-nodes', '-out', csr_file)
 179             os.chmod(cert.private_key_file, 0600)
 180             openssl_wrap.run_with_config(
 181                 self.basedir, conf_file,
 182                 'ca', '-days', conf['days'],
 183                 '-key', self._getpw(),
 184                 '-policy', 'policy_anything', '-out', cert.public_key_file,
 185                 '-extfile', ext_file, '-infiles', csr_file)
 186         finally:
 187             shutil.rmtree(tmpdir)
 188