cpython / Lib / ssl.py

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
# Wrapper module for _ssl, providing some additional facilities
# implemented in Python.  Written by Bill Janssen.

"""\
This module provides some more Pythonic support for SSL.

Object types:

  SSLSocket -- subtype of socket.socket which does SSL over the socket

Exceptions:

  SSLError -- exception raised for I/O errors

Functions:

  cert_time_to_seconds -- convert time string used for certificate
                          notBefore and notAfter functions to integer
                          seconds past the Epoch (the time values
                          returned from time.time())

  fetch_server_certificate (HOST, PORT) -- fetch the certificate provided
                          by the server running on HOST at port PORT.  No
                          validation of the certificate is performed.

Integer constants:

SSL_ERROR_ZERO_RETURN
SSL_ERROR_WANT_READ
SSL_ERROR_WANT_WRITE
SSL_ERROR_WANT_X509_LOOKUP
SSL_ERROR_SYSCALL
SSL_ERROR_SSL
SSL_ERROR_WANT_CONNECT

SSL_ERROR_EOF
SSL_ERROR_INVALID_ERROR_CODE

The following group define certificate requirements that one side is
allowing/requiring from the other side:

CERT_NONE - no certificates from the other side are required (or will
            be looked at if provided)
CERT_OPTIONAL - certificates are not required, but if provided will be
                validated, and if validation fails, the connection will
                also fail
CERT_REQUIRED - certificates are required, and will be validated, and
                if validation fails, the connection will also fail

The following constants identify various SSL protocol variants:

PROTOCOL_SSLv2
PROTOCOL_SSLv3
PROTOCOL_SSLv23
PROTOCOL_TLSv1
"""

import textwrap

import _ssl             # if we can't import it, let the error propagate

from _ssl import OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_INFO, OPENSSL_VERSION
from _ssl import SSLError
from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED
from _ssl import RAND_status, RAND_egd, RAND_add
from _ssl import \
     SSL_ERROR_ZERO_RETURN, \
     SSL_ERROR_WANT_READ, \
     SSL_ERROR_WANT_WRITE, \
     SSL_ERROR_WANT_X509_LOOKUP, \
     SSL_ERROR_SYSCALL, \
     SSL_ERROR_SSL, \
     SSL_ERROR_WANT_CONNECT, \
     SSL_ERROR_EOF, \
     SSL_ERROR_INVALID_ERROR_CODE
from _ssl import PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1
_PROTOCOL_NAMES = {
    PROTOCOL_TLSv1: "TLSv1",
    PROTOCOL_SSLv23: "SSLv23",
    PROTOCOL_SSLv3: "SSLv3",
}
try:
    from _ssl import PROTOCOL_SSLv2
    _SSLv2_IF_EXISTS = PROTOCOL_SSLv2
except ImportError:
    _SSLv2_IF_EXISTS = None
else:
    _PROTOCOL_NAMES[PROTOCOL_SSLv2] = "SSLv2"

from socket import socket, _fileobject, _delegate_methods, error as socket_error
from socket import getnameinfo as _getnameinfo
import base64        # for DER-to-PEM translation
import errno

# Disable weak or insecure ciphers by default
# (OpenSSL's default setting is 'DEFAULT:!aNULL:!eNULL')
_DEFAULT_CIPHERS = 'DEFAULT:!aNULL:!eNULL:!LOW:!EXPORT:!SSLv2'


class SSLSocket(socket):

    """This class implements a subtype of socket.socket that wraps
    the underlying OS socket in an SSL context when necessary, and
    provides read and write methods over that channel."""

    def __init__(self, sock, keyfile=None, certfile=None,
                 server_side=False, cert_reqs=CERT_NONE,
                 ssl_version=PROTOCOL_SSLv23, ca_certs=None,
                 do_handshake_on_connect=True,
                 suppress_ragged_eofs=True, ciphers=None):
        socket.__init__(self, _sock=sock._sock)
        # The initializer for socket overrides the methods send(), recv(), etc.
        # in the instancce, which we don't need -- but we want to provide the
        # methods defined in SSLSocket.
        for attr in _delegate_methods:
            try:
                delattr(self, attr)
            except AttributeError:
                pass

        if ciphers is None and ssl_version != _SSLv2_IF_EXISTS:
            ciphers = _DEFAULT_CIPHERS

        if certfile and not keyfile:
            keyfile = certfile
        # see if it's connected
        try:
            socket.getpeername(self)
        except socket_error, e:
            if e.errno != errno.ENOTCONN:
                raise
            # no, no connection yet
            self._connected = False
            self._sslobj = None
        else:
            # yes, create the SSL object
            self._connected = True
            self._sslobj = _ssl.sslwrap(self._sock, server_side,
                                        keyfile, certfile,
                                        cert_reqs, ssl_version, ca_certs,
                                        ciphers)
            if do_handshake_on_connect:
                self.do_handshake()
        self.keyfile = keyfile
        self.certfile = certfile
        self.cert_reqs = cert_reqs
        self.ssl_version = ssl_version
        self.ca_certs = ca_certs
        self.ciphers = ciphers
        self.do_handshake_on_connect = do_handshake_on_connect
        self.suppress_ragged_eofs = suppress_ragged_eofs
        self._makefile_refs = 0

    def read(self, len=1024):

        """Read up to LEN bytes and return them.
        Return zero-length string on EOF."""

        try:
            return self._sslobj.read(len)
        except SSLError, x:
            if x.args[0] == SSL_ERROR_EOF and self.suppress_ragged_eofs:
                return ''
            else:
                raise

    def write(self, data):

        """Write DATA to the underlying SSL channel.  Returns
        number of bytes of DATA actually transmitted."""

        return self._sslobj.write(data)

    def getpeercert(self, binary_form=False):

        """Returns a formatted version of the data in the
        certificate provided by the other end of the SSL channel.
        Return None if no certificate was provided, {} if a
        certificate was provided, but not validated."""

        return self._sslobj.peer_certificate(binary_form)

    def cipher(self):

        if not self._sslobj:
            return None
        else:
            return self._sslobj.cipher()

    def send(self, data, flags=0):
        if self._sslobj:
            if flags != 0:
                raise ValueError(
                    "non-zero flags not allowed in calls to send() on %s" %
                    self.__class__)
            while True:
                try:
                    v = self._sslobj.write(data)
                except SSLError, x:
                    if x.args[0] == SSL_ERROR_WANT_READ:
                        return 0
                    elif x.args[0] == SSL_ERROR_WANT_WRITE:
                        return 0
                    else:
                        raise
                else:
                    return v
        else:
            return self._sock.send(data, flags)

    def sendto(self, data, flags_or_addr, addr=None):
        if self._sslobj:
            raise ValueError("sendto not allowed on instances of %s" %
                             self.__class__)
        elif addr is None:
            return self._sock.sendto(data, flags_or_addr)
        else:
            return self._sock.sendto(data, flags_or_addr, addr)

    def sendall(self, data, flags=0):
        if self._sslobj:
            if flags != 0:
                raise ValueError(
                    "non-zero flags not allowed in calls to sendall() on %s" %
                    self.__class__)
            amount = len(data)
            count = 0
            while (count < amount):
                v = self.send(data[count:])
                count += v
            return amount
        else:
            return socket.sendall(self, data, flags)

    def recv(self, buflen=1024, flags=0):
        if self._sslobj:
            if flags != 0:
                raise ValueError(
                    "non-zero flags not allowed in calls to recv() on %s" %
                    self.__class__)
            return self.read(buflen)
        else:
            return self._sock.recv(buflen, flags)

    def recv_into(self, buffer, nbytes=None, flags=0):
        if buffer and (nbytes is None):
            nbytes = len(buffer)
        elif nbytes is None:
            nbytes = 1024
        if self._sslobj:
            if flags != 0:
                raise ValueError(
                  "non-zero flags not allowed in calls to recv_into() on %s" %
                  self.__class__)
            tmp_buffer = self.read(nbytes)
            v = len(tmp_buffer)
            buffer[:v] = tmp_buffer
            return v
        else:
            return self._sock.recv_into(buffer, nbytes, flags)

    def recvfrom(self, buflen=1024, flags=0):
        if self._sslobj:
            raise ValueError("recvfrom not allowed on instances of %s" %
                             self.__class__)
        else:
            return self._sock.recvfrom(buflen, flags)

    def recvfrom_into(self, buffer, nbytes=None, flags=0):
        if self._sslobj:
            raise ValueError("recvfrom_into not allowed on instances of %s" %
                             self.__class__)
        else:
            return self._sock.recvfrom_into(buffer, nbytes, flags)

    def pending(self):
        if self._sslobj:
            return self._sslobj.pending()
        else:
            return 0

    def unwrap(self):
        if self._sslobj:
            s = self._sslobj.shutdown()
            self._sslobj = None
            return s
        else:
            raise ValueError("No SSL wrapper around " + str(self))

    def shutdown(self, how):
        self._sslobj = None
        socket.shutdown(self, how)

    def close(self):
        if self._makefile_refs < 1:
            self._sslobj = None
            socket.close(self)
        else:
            self._makefile_refs -= 1

    def do_handshake(self):

        """Perform a TLS/SSL handshake."""

        self._sslobj.do_handshake()

    def _real_connect(self, addr, return_errno):
        # Here we assume that the socket is client-side, and not
        # connected at the time of the call.  We connect it, then wrap it.
        if self._connected:
            raise ValueError("attempt to connect already-connected SSLSocket!")
        self._sslobj = _ssl.sslwrap(self._sock, False, self.keyfile, self.certfile,
                                    self.cert_reqs, self.ssl_version,
                                    self.ca_certs, self.ciphers)
        try:
            if return_errno:
                rc = socket.connect_ex(self, addr)
            else:
                rc = None
                socket.connect(self, addr)
            if not rc:
                if self.do_handshake_on_connect:
                    self.do_handshake()
                self._connected = True
            return rc
        except socket_error:
            self._sslobj = None
            raise

    def connect(self, addr):
        """Connects to remote ADDR, and then wraps the connection in
        an SSL channel."""
        self._real_connect(addr, False)

    def connect_ex(self, addr):
        """Connects to remote ADDR, and then wraps the connection in
        an SSL channel."""
        return self._real_connect(addr, True)

    def accept(self):

        """Accepts a new connection from a remote client, and returns
        a tuple containing that new connection wrapped with a server-side
        SSL channel, and the address of the remote client."""

        newsock, addr = socket.accept(self)
        return (SSLSocket(newsock,
                          keyfile=self.keyfile,
                          certfile=self.certfile,
                          server_side=True,
                          cert_reqs=self.cert_reqs,
                          ssl_version=self.ssl_version,
                          ca_certs=self.ca_certs,
                          ciphers=self.ciphers,
                          do_handshake_on_connect=self.do_handshake_on_connect,
                          suppress_ragged_eofs=self.suppress_ragged_eofs),
                addr)

    def makefile(self, mode='r', bufsize=-1):

        """Make and return a file-like object that
        works with the SSL connection.  Just use the code
        from the socket module."""

        self._makefile_refs += 1
        # close=True so as to decrement the reference count when done with
        # the file-like object.
        return _fileobject(self, mode, bufsize, close=True)



def wrap_socket(sock, keyfile=None, certfile=None,
                server_side=False, cert_reqs=CERT_NONE,
                ssl_version=PROTOCOL_SSLv23, ca_certs=None,
                do_handshake_on_connect=True,
                suppress_ragged_eofs=True, ciphers=None):

    return SSLSocket(sock, keyfile=keyfile, certfile=certfile,
                     server_side=server_side, cert_reqs=cert_reqs,
                     ssl_version=ssl_version, ca_certs=ca_certs,
                     do_handshake_on_connect=do_handshake_on_connect,
                     suppress_ragged_eofs=suppress_ragged_eofs,
                     ciphers=ciphers)


# some utility functions

def cert_time_to_seconds(cert_time):

    """Takes a date-time string in standard ASN1_print form
    ("MON DAY 24HOUR:MINUTE:SEC YEAR TIMEZONE") and return
    a Python time value in seconds past the epoch."""

    import time
    return time.mktime(time.strptime(cert_time, "%b %d %H:%M:%S %Y GMT"))

PEM_HEADER = "-----BEGIN CERTIFICATE-----"
PEM_FOOTER = "-----END CERTIFICATE-----"

def DER_cert_to_PEM_cert(der_cert_bytes):

    """Takes a certificate in binary DER format and returns the
    PEM version of it as a string."""

    if hasattr(base64, 'standard_b64encode'):
        # preferred because older API gets line-length wrong
        f = base64.standard_b64encode(der_cert_bytes)
        return (PEM_HEADER + '\n' +
                textwrap.fill(f, 64) + '\n' +
                PEM_FOOTER + '\n')
    else:
        return (PEM_HEADER + '\n' +
                base64.encodestring(der_cert_bytes) +
                PEM_FOOTER + '\n')

def PEM_cert_to_DER_cert(pem_cert_string):

    """Takes a certificate in ASCII PEM format and returns the
    DER-encoded version of it as a byte sequence"""

    if not pem_cert_string.startswith(PEM_HEADER):
        raise ValueError("Invalid PEM encoding; must start with %s"
                         % PEM_HEADER)
    if not pem_cert_string.strip().endswith(PEM_FOOTER):
        raise ValueError("Invalid PEM encoding; must end with %s"
                         % PEM_FOOTER)
    d = pem_cert_string.strip()[len(PEM_HEADER):-len(PEM_FOOTER)]
    return base64.decodestring(d)

def get_server_certificate(addr, ssl_version=PROTOCOL_SSLv3, ca_certs=None):

    """Retrieve the certificate from the server at the specified address,
    and return it as a PEM-encoded string.
    If 'ca_certs' is specified, validate the server cert against it.
    If 'ssl_version' is specified, use it in the connection attempt."""

    host, port = addr
    if (ca_certs is not None):
        cert_reqs = CERT_REQUIRED
    else:
        cert_reqs = CERT_NONE
    s = wrap_socket(socket(), ssl_version=ssl_version,
                    cert_reqs=cert_reqs, ca_certs=ca_certs)
    s.connect(addr)
    dercert = s.getpeercert(True)
    s.close()
    return DER_cert_to_PEM_cert(dercert)

def get_protocol_name(protocol_code):
    return _PROTOCOL_NAMES.get(protocol_code, '<unknown>')


# a replacement for the old socket.ssl function

def sslwrap_simple(sock, keyfile=None, certfile=None):

    """A replacement for the old socket.ssl function.  Designed
    for compability with Python 2.5 and earlier.  Will disappear in
    Python 3.0."""

    if hasattr(sock, "_sock"):
        sock = sock._sock

    ssl_sock = _ssl.sslwrap(sock, 0, keyfile, certfile, CERT_NONE,
                            PROTOCOL_SSLv23, None)
    try:
        sock.getpeername()
    except socket_error:
        # no, no connection yet
        pass
    else:
        # yes, do the handshake
        ssl_sock.do_handshake()

    return ssl_sock
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.