AppPkg/Applications/Python/Python-2.7.2/Lib/ssl.py

   1 # Wrapper module for _ssl, providing some additional facilities
   2 # implemented in Python.  Written by Bill Janssen.
   3
   4 """\
   5 This module provides some more Pythonic support for SSL.
   6
   7 Object types:
   8
   9   SSLSocket -- subtype of socket.socket which does SSL over the socket
  10
  11 Exceptions:
  12
  13   SSLError -- exception raised for I/O errors
  14
  15 Functions:
  16
  17   cert_time_to_seconds -- convert time string used for certificate
  18                           notBefore and notAfter functions to integer
  19                           seconds past the Epoch (the time values
  20                           returned from time.time())
  21
  22   fetch_server_certificate (HOST, PORT) -- fetch the certificate provided
  23                           by the server running on HOST at port PORT.  No
  24                           validation of the certificate is performed.
  25
  26 Integer constants:
  27
  28 SSL_ERROR_ZERO_RETURN
  29 SSL_ERROR_WANT_READ
  30 SSL_ERROR_WANT_WRITE
  31 SSL_ERROR_WANT_X509_LOOKUP
  32 SSL_ERROR_SYSCALL
  33 SSL_ERROR_SSL
  34 SSL_ERROR_WANT_CONNECT
  35
  36 SSL_ERROR_EOF
  37 SSL_ERROR_INVALID_ERROR_CODE
  38
  39 The following group define certificate requirements that one side is
  40 allowing/requiring from the other side:
  41
  42 CERT_NONE - no certificates from the other side are required (or will
  43             be looked at if provided)
  44 CERT_OPTIONAL - certificates are not required, but if provided will be
  45                 validated, and if validation fails, the connection will
  46                 also fail
  47 CERT_REQUIRED - certificates are required, and will be validated, and
  48                 if validation fails, the connection will also fail
  49
  50 The following constants identify various SSL protocol variants:
  51
  52 PROTOCOL_SSLv2
  53 PROTOCOL_SSLv3
  54 PROTOCOL_SSLv23
  55 PROTOCOL_TLSv1
  56 """
  57
  58 import textwrap
  59
  60 import _ssl             # if we can't import it, let the error propagate
  61
  62 from _ssl import OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_INFO, OPENSSL_VERSION
  63 from _ssl import SSLError
  64 from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED
  65 from _ssl import RAND_status, RAND_egd, RAND_add
  66 from _ssl import \
  67      SSL_ERROR_ZERO_RETURN, \
  68      SSL_ERROR_WANT_READ, \
  69      SSL_ERROR_WANT_WRITE, \
  70      SSL_ERROR_WANT_X509_LOOKUP, \
  71      SSL_ERROR_SYSCALL, \
  72      SSL_ERROR_SSL, \
  73      SSL_ERROR_WANT_CONNECT, \
  74      SSL_ERROR_EOF, \
  75      SSL_ERROR_INVALID_ERROR_CODE
  76 from _ssl import PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1
  77 _PROTOCOL_NAMES = {
  78     PROTOCOL_TLSv1: "TLSv1",
  79     PROTOCOL_SSLv23: "SSLv23",
  80     PROTOCOL_SSLv3: "SSLv3",
  81 }
  82 try:
  83     from _ssl import PROTOCOL_SSLv2
  84 except ImportError:
  85     pass
  86 else:
  87     _PROTOCOL_NAMES[PROTOCOL_SSLv2] = "SSLv2"
  88
  89 from socket import socket, _fileobject, _delegate_methods, error as socket_error
  90 from socket import getnameinfo as _getnameinfo
  91 import base64        # for DER-to-PEM translation
  92 import errno
  93
  94 class SSLSocket(socket):
  95
  96     """This class implements a subtype of socket.socket that wraps
  97     the underlying OS socket in an SSL context when necessary, and
  98     provides read and write methods over that channel."""
  99
 100     def __init__(self, sock, keyfile=None, certfile=None,
 101                  server_side=False, cert_reqs=CERT_NONE,
 102                  ssl_version=PROTOCOL_SSLv23, ca_certs=None,
 103                  do_handshake_on_connect=True,
 104                  suppress_ragged_eofs=True, ciphers=None):
 105         socket.__init__(self, _sock=sock._sock)
 106         # The initializer for socket overrides the methods send(), recv(), etc.
 107         # in the instancce, which we don't need -- but we want to provide the
 108         # methods defined in SSLSocket.
 109         for attr in _delegate_methods:
 110             try:
 111                 delattr(self, attr)
 112             except AttributeError:
 113                 pass
 114
 115         if certfile and not keyfile:
 116             keyfile = certfile
 117         # see if it's connected
 118         try:
 119             socket.getpeername(self)
 120         except socket_error, e:
 121             if e.errno != errno.ENOTCONN:
 122                 raise
 123             # no, no connection yet
 124             self._connected = False
 125             self._sslobj = None
 126         else:
 127             # yes, create the SSL object
 128             self._connected = True
 129             self._sslobj = _ssl.sslwrap(self._sock, server_side,
 130                                         keyfile, certfile,
 131                                         cert_reqs, ssl_version, ca_certs,
 132                                         ciphers)
 133             if do_handshake_on_connect:
 134                 self.do_handshake()
 135         self.keyfile = keyfile
 136         self.certfile = certfile
 137         self.cert_reqs = cert_reqs
 138         self.ssl_version = ssl_version
 139         self.ca_certs = ca_certs
 140         self.ciphers = ciphers
 141         self.do_handshake_on_connect = do_handshake_on_connect
 142         self.suppress_ragged_eofs = suppress_ragged_eofs
 143         self._makefile_refs = 0
 144
 145     def read(self, len=1024):
 146
 147         """Read up to LEN bytes and return them.
 148         Return zero-length string on EOF."""
 149
 150         try:
 151             return self._sslobj.read(len)
 152         except SSLError, x:
 153             if x.args[0] == SSL_ERROR_EOF and self.suppress_ragged_eofs:
 154                 return ''
 155             else:
 156                 raise
 157
 158     def write(self, data):
 159
 160         """Write DATA to the underlying SSL channel.  Returns
 161         number of bytes of DATA actually transmitted."""
 162
 163         return self._sslobj.write(data)
 164
 165     def getpeercert(self, binary_form=False):
 166
 167         """Returns a formatted version of the data in the
 168         certificate provided by the other end of the SSL channel.
 169         Return None if no certificate was provided, {} if a
 170         certificate was provided, but not validated."""
 171
 172         return self._sslobj.peer_certificate(binary_form)
 173
 174     def cipher(self):
 175
 176         if not self._sslobj:
 177             return None
 178         else:
 179             return self._sslobj.cipher()
 180
 181     def send(self, data, flags=0):
 182         if self._sslobj:
 183             if flags != 0:
 184                 raise ValueError(
 185                     "non-zero flags not allowed in calls to send() on %s" %
 186                     self.__class__)
 187             while True:
 188                 try:
 189                     v = self._sslobj.write(data)
 190                 except SSLError, x:
 191                     if x.args[0] == SSL_ERROR_WANT_READ:
 192                         return 0
 193                     elif x.args[0] == SSL_ERROR_WANT_WRITE:
 194                         return 0
 195                     else:
 196                         raise
 197                 else:
 198                     return v
 199         else:
 200             return self._sock.send(data, flags)
 201
 202     def sendto(self, data, flags_or_addr, addr=None):
 203         if self._sslobj:
 204             raise ValueError("sendto not allowed on instances of %s" %
 205                              self.__class__)
 206         elif addr is None:
 207             return self._sock.sendto(data, flags_or_addr)
 208         else:
 209             return self._sock.sendto(data, flags_or_addr, addr)
 210
 211     def sendall(self, data, flags=0):
 212         if self._sslobj:
 213             if flags != 0:
 214                 raise ValueError(
 215                     "non-zero flags not allowed in calls to sendall() on %s" %
 216                     self.__class__)
 217             amount = len(data)
 218             count = 0
 219             while (count < amount):
 220                 v = self.send(data[count:])
 221                 count += v
 222             return amount
 223         else:
 224             return socket.sendall(self, data, flags)
 225
 226     def recv(self, buflen=1024, flags=0):
 227         if self._sslobj:
 228             if flags != 0:
 229                 raise ValueError(
 230                     "non-zero flags not allowed in calls to recv() on %s" %
 231                     self.__class__)
 232             return self.read(buflen)
 233         else:
 234             return self._sock.recv(buflen, flags)
 235
 236     def recv_into(self, buffer, nbytes=None, flags=0):
 237         if buffer and (nbytes is None):
 238             nbytes = len(buffer)
 239         elif nbytes is None:
 240             nbytes = 1024
 241         if self._sslobj:
 242             if flags != 0:
 243                 raise ValueError(
 244                   "non-zero flags not allowed in calls to recv_into() on %s" %
 245                   self.__class__)
 246             tmp_buffer = self.read(nbytes)
 247             v = len(tmp_buffer)
 248             buffer[:v] = tmp_buffer
 249             return v
 250         else:
 251             return self._sock.recv_into(buffer, nbytes, flags)
 252
 253     def recvfrom(self, buflen=1024, flags=0):
 254         if self._sslobj:
 255             raise ValueError("recvfrom not allowed on instances of %s" %
 256                              self.__class__)
 257         else:
 258             return self._sock.recvfrom(buflen, flags)
 259
 260     def recvfrom_into(self, buffer, nbytes=None, flags=0):
 261         if self._sslobj:
 262             raise ValueError("recvfrom_into not allowed on instances of %s" %
 263                              self.__class__)
 264         else:
 265             return self._sock.recvfrom_into(buffer, nbytes, flags)
 266
 267     def pending(self):
 268         if self._sslobj:
 269             return self._sslobj.pending()
 270         else:
 271             return 0
 272
 273     def unwrap(self):
 274         if self._sslobj:
 275             s = self._sslobj.shutdown()
 276             self._sslobj = None
 277             return s
 278         else:
 279             raise ValueError("No SSL wrapper around " + str(self))
 280
 281     def shutdown(self, how):
 282         self._sslobj = None
 283         socket.shutdown(self, how)
 284
 285     def close(self):
 286         if self._makefile_refs < 1:
 287             self._sslobj = None
 288             socket.close(self)
 289         else:
 290             self._makefile_refs -= 1
 291
 292     def do_handshake(self):
 293
 294         """Perform a TLS/SSL handshake."""
 295
 296         self._sslobj.do_handshake()
 297
 298     def _real_connect(self, addr, return_errno):
 299         # Here we assume that the socket is client-side, and not
 300         # connected at the time of the call.  We connect it, then wrap it.
 301         if self._connected:
 302             raise ValueError("attempt to connect already-connected SSLSocket!")
 303         self._sslobj = _ssl.sslwrap(self._sock, False, self.keyfile, self.certfile,
 304                                     self.cert_reqs, self.ssl_version,
 305                                     self.ca_certs, self.ciphers)
 306         try:
 307             socket.connect(self, addr)
 308             if self.do_handshake_on_connect:
 309                 self.do_handshake()
 310         except socket_error as e:
 311             if return_errno:
 312                 return e.errno
 313             else:
 314                 self._sslobj = None
 315                 raise e
 316         self._connected = True
 317         return 0
 318
 319     def connect(self, addr):
 320         """Connects to remote ADDR, and then wraps the connection in
 321         an SSL channel."""
 322         self._real_connect(addr, False)
 323
 324     def connect_ex(self, addr):
 325         """Connects to remote ADDR, and then wraps the connection in
 326         an SSL channel."""
 327         return self._real_connect(addr, True)
 328
 329     def accept(self):
 330
 331         """Accepts a new connection from a remote client, and returns
 332         a tuple containing that new connection wrapped with a server-side
 333         SSL channel, and the address of the remote client."""
 334
 335         newsock, addr = socket.accept(self)
 336         return (SSLSocket(newsock,
 337                           keyfile=self.keyfile,
 338                           certfile=self.certfile,
 339                           server_side=True,
 340                           cert_reqs=self.cert_reqs,
 341                           ssl_version=self.ssl_version,
 342                           ca_certs=self.ca_certs,
 343                           ciphers=self.ciphers,
 344                           do_handshake_on_connect=self.do_handshake_on_connect,
 345                           suppress_ragged_eofs=self.suppress_ragged_eofs),
 346                 addr)
 347
 348     def makefile(self, mode='r', bufsize=-1):
 349
 350         """Make and return a file-like object that
 351         works with the SSL connection.  Just use the code
 352         from the socket module."""
 353
 354         self._makefile_refs += 1
 355         # close=True so as to decrement the reference count when done with
 356         # the file-like object.
 357         return _fileobject(self, mode, bufsize, close=True)
 358
 359
 360
 361 def wrap_socket(sock, keyfile=None, certfile=None,
 362                 server_side=False, cert_reqs=CERT_NONE,
 363                 ssl_version=PROTOCOL_SSLv23, ca_certs=None,
 364                 do_handshake_on_connect=True,
 365                 suppress_ragged_eofs=True, ciphers=None):
 366
 367     return SSLSocket(sock, keyfile=keyfile, certfile=certfile,
 368                      server_side=server_side, cert_reqs=cert_reqs,
 369                      ssl_version=ssl_version, ca_certs=ca_certs,
 370                      do_handshake_on_connect=do_handshake_on_connect,
 371                      suppress_ragged_eofs=suppress_ragged_eofs,
 372                      ciphers=ciphers)
 373
 374
 375 # some utility functions
 376
 377 def cert_time_to_seconds(cert_time):
 378
 379     """Takes a date-time string in standard ASN1_print form
 380     ("MON DAY 24HOUR:MINUTE:SEC YEAR TIMEZONE") and return
 381     a Python time value in seconds past the epoch."""
 382
 383     import time
 384     return time.mktime(time.strptime(cert_time, "%b %d %H:%M:%S %Y GMT"))
 385
 386 PEM_HEADER = "-----BEGIN CERTIFICATE-----"
 387 PEM_FOOTER = "-----END CERTIFICATE-----"
 388
 389 def DER_cert_to_PEM_cert(der_cert_bytes):
 390
 391     """Takes a certificate in binary DER format and returns the
 392     PEM version of it as a string."""
 393
 394     if hasattr(base64, 'standard_b64encode'):
 395         # preferred because older API gets line-length wrong
 396         f = base64.standard_b64encode(der_cert_bytes)
 397         return (PEM_HEADER + '\n' +
 398                 textwrap.fill(f, 64) + '\n' +
 399                 PEM_FOOTER + '\n')
 400     else:
 401         return (PEM_HEADER + '\n' +
 402                 base64.encodestring(der_cert_bytes) +
 403                 PEM_FOOTER + '\n')
 404
 405 def PEM_cert_to_DER_cert(pem_cert_string):
 406
 407     """Takes a certificate in ASCII PEM format and returns the
 408     DER-encoded version of it as a byte sequence"""
 409
 410     if not pem_cert_string.startswith(PEM_HEADER):
 411         raise ValueError("Invalid PEM encoding; must start with %s"
 412                          % PEM_HEADER)
 413     if not pem_cert_string.strip().endswith(PEM_FOOTER):
 414         raise ValueError("Invalid PEM encoding; must end with %s"
 415                          % PEM_FOOTER)
 416     d = pem_cert_string.strip()[len(PEM_HEADER):-len(PEM_FOOTER)]
 417     return base64.decodestring(d)
 418
 419 def get_server_certificate(addr, ssl_version=PROTOCOL_SSLv3, ca_certs=None):
 420
 421     """Retrieve the certificate from the server at the specified address,
 422     and return it as a PEM-encoded string.
 423     If 'ca_certs' is specified, validate the server cert against it.
 424     If 'ssl_version' is specified, use it in the connection attempt."""
 425
 426     host, port = addr
 427     if (ca_certs is not None):
 428         cert_reqs = CERT_REQUIRED
 429     else:
 430         cert_reqs = CERT_NONE
 431     s = wrap_socket(socket(), ssl_version=ssl_version,
 432                     cert_reqs=cert_reqs, ca_certs=ca_certs)
 433     s.connect(addr)
 434     dercert = s.getpeercert(True)
 435     s.close()
 436     return DER_cert_to_PEM_cert(dercert)
 437
 438 def get_protocol_name(protocol_code):
 439     return _PROTOCOL_NAMES.get(protocol_code, '<unknown>')
 440
 441
 442 # a replacement for the old socket.ssl function
 443
 444 def sslwrap_simple(sock, keyfile=None, certfile=None):
 445
 446     """A replacement for the old socket.ssl function.  Designed
 447     for compability with Python 2.5 and earlier.  Will disappear in
 448     Python 3.0."""
 449
 450     if hasattr(sock, "_sock"):
 451         sock = sock._sock
 452
 453     ssl_sock = _ssl.sslwrap(sock, 0, keyfile, certfile, CERT_NONE,
 454                             PROTOCOL_SSLv23, None)
 455     try:
 456         sock.getpeername()
 457     except socket_error:
 458         # no, no connection yet
 459         pass
 460     else:
 461         # yes, do the handshake
 462         ssl_sock.do_handshake()
 463
 464     return ssl_sock