| # 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 | |
| except ImportError: | |
| pass | |
| 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 | |
| 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 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: | |
| socket.connect(self, addr) | |
| if self.do_handshake_on_connect: | |
| self.do_handshake() | |
| except socket_error as e: | |
| if return_errno: | |
| return e.errno | |
| else: | |
| self._sslobj = None | |
| raise e | |
| self._connected = True | |
| return 0 | |
| 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 |