440 lines
14 KiB
Python
440 lines
14 KiB
Python
# 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 SSLError
|
|
from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED
|
|
from _ssl import PROTOCOL_SSLv2, PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1
|
|
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 socket import socket, _fileobject, _delegate_methods
|
|
from socket import 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):
|
|
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._sslobj = None
|
|
else:
|
|
# yes, create the SSL object
|
|
self._sslobj = _ssl.sslwrap(self._sock, server_side,
|
|
keyfile, certfile,
|
|
cert_reqs, ssl_version, ca_certs)
|
|
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.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 socket.send(self, data, flags)
|
|
|
|
def sendto(self, data, addr, flags=0):
|
|
if self._sslobj:
|
|
raise ValueError("sendto not allowed on instances of %s" %
|
|
self.__class__)
|
|
else:
|
|
return socket.sendto(self, data, addr, flags)
|
|
|
|
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 socket.recv(self, 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 socket.recv_into(self, buffer, nbytes, flags)
|
|
|
|
def recvfrom(self, addr, buflen=1024, flags=0):
|
|
if self._sslobj:
|
|
raise ValueError("recvfrom not allowed on instances of %s" %
|
|
self.__class__)
|
|
else:
|
|
return socket.recvfrom(self, addr, 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 socket.recvfrom_into(self, 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 connect(self, addr):
|
|
|
|
"""Connects to remote ADDR, and then wraps the connection in
|
|
an SSL channel."""
|
|
|
|
# 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._sslobj:
|
|
raise ValueError("attempt to connect already-connected SSLSocket!")
|
|
socket.connect(self, addr)
|
|
self._sslobj = _ssl.sslwrap(self._sock, False, self.keyfile, self.certfile,
|
|
self.cert_reqs, self.ssl_version,
|
|
self.ca_certs)
|
|
if self.do_handshake_on_connect:
|
|
self.do_handshake()
|
|
|
|
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,
|
|
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):
|
|
|
|
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)
|
|
|
|
|
|
# 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):
|
|
if protocol_code == PROTOCOL_TLSv1:
|
|
return "TLSv1"
|
|
elif protocol_code == PROTOCOL_SSLv23:
|
|
return "SSLv23"
|
|
elif protocol_code == PROTOCOL_SSLv2:
|
|
return "SSLv2"
|
|
elif protocol_code == PROTOCOL_SSLv3:
|
|
return "SSLv3"
|
|
else:
|
|
return "<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:
|
|
# no, no connection yet
|
|
pass
|
|
else:
|
|
# yes, do the handshake
|
|
ssl_sock.do_handshake()
|
|
|
|
return ssl_sock
|