239 lines
7.7 KiB
Python
239 lines
7.7 KiB
Python
# Wrapper module for _ssl, providing some additional facilities
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# implemented in Python. Written by Bill Janssen.
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"""\
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This module provides some more Pythonic support for SSL.
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Object types:
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sslsocket -- subtype of socket.socket which does SSL over the socket
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Exceptions:
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sslerror -- exception raised for I/O errors
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Functions:
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cert_time_to_seconds -- convert time string used for certificate
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notBefore and notAfter functions to integer
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seconds past the Epoch (the time values
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returned from time.time())
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fetch_server_certificate (HOST, PORT) -- fetch the certificate provided
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by the server running on HOST at port PORT. No
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validation of the certificate is performed.
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Integer constants:
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SSL_ERROR_ZERO_RETURN
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SSL_ERROR_WANT_READ
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SSL_ERROR_WANT_WRITE
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SSL_ERROR_WANT_X509_LOOKUP
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SSL_ERROR_SYSCALL
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SSL_ERROR_SSL
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SSL_ERROR_WANT_CONNECT
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SSL_ERROR_EOF
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SSL_ERROR_INVALID_ERROR_CODE
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The following group define certificate requirements that one side is
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allowing/requiring from the other side:
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CERT_NONE - no certificates from the other side are required (or will
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be looked at if provided)
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CERT_OPTIONAL - certificates are not required, but if provided will be
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validated, and if validation fails, the connection will
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also fail
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CERT_REQUIRED - certificates are required, and will be validated, and
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if validation fails, the connection will also fail
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The following constants identify various SSL protocol variants:
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PROTOCOL_SSLv2
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PROTOCOL_SSLv3
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PROTOCOL_SSLv23
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PROTOCOL_TLSv1
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"""
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import os, sys
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import _ssl # if we can't import it, let the error propagate
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from _ssl import sslerror
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from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED
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from _ssl import PROTOCOL_SSLv2, PROTOCOL_SSLv3, PROTOCOL_SSLv23, PROTOCOL_TLSv1
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from _ssl import \
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SSL_ERROR_ZERO_RETURN, \
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SSL_ERROR_WANT_READ, \
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SSL_ERROR_WANT_WRITE, \
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SSL_ERROR_WANT_X509_LOOKUP, \
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SSL_ERROR_SYSCALL, \
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SSL_ERROR_SSL, \
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SSL_ERROR_WANT_CONNECT, \
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SSL_ERROR_EOF, \
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SSL_ERROR_INVALID_ERROR_CODE
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from socket import socket
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from socket import getnameinfo as _getnameinfo
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class sslsocket (socket):
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"""This class implements a subtype of socket.socket that wraps
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the underlying OS socket in an SSL context when necessary, and
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provides read and write methods over that channel."""
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def __init__(self, sock, keyfile=None, certfile=None,
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server_side=False, cert_reqs=CERT_NONE,
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ssl_version=PROTOCOL_SSLv23, ca_certs=None):
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socket.__init__(self, _sock=sock._sock)
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if certfile and not keyfile:
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keyfile = certfile
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# see if it's connected
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try:
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socket.getpeername(self)
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except:
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# no, no connection yet
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self._sslobj = None
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else:
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# yes, create the SSL object
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self._sslobj = _ssl.sslwrap(self._sock, server_side,
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keyfile, certfile,
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cert_reqs, ssl_version, ca_certs)
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self.keyfile = keyfile
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self.certfile = certfile
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self.cert_reqs = cert_reqs
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self.ssl_version = ssl_version
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self.ca_certs = ca_certs
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def read(self, len=1024):
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"""Read up to LEN bytes and return them.
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Return zero-length string on EOF."""
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return self._sslobj.read(len)
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def write(self, data):
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"""Write DATA to the underlying SSL channel. Returns
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number of bytes of DATA actually transmitted."""
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return self._sslobj.write(data)
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def getpeercert(self):
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"""Returns a formatted version of the data in the
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certificate provided by the other end of the SSL channel.
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Return None if no certificate was provided, {} if a
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certificate was provided, but not validated."""
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return self._sslobj.peer_certificate()
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def send (self, data, flags=0):
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if self._sslobj:
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if flags != 0:
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raise ValueError(
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"non-zero flags not allowed in calls to send() on %s" %
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self.__class__)
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return self._sslobj.write(data)
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else:
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return socket.send(self, data, flags)
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def send_to (self, data, addr, flags=0):
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if self._sslobj:
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raise ValueError("send_to not allowed on instances of %s" %
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self.__class__)
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else:
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return socket.send_to(self, data, addr, flags)
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def sendall (self, data, flags=0):
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if self._sslobj:
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if flags != 0:
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raise ValueError(
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"non-zero flags not allowed in calls to sendall() on %s" %
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self.__class__)
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return self._sslobj.write(data)
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else:
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return socket.sendall(self, data, flags)
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def recv (self, buflen=1024, flags=0):
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if self._sslobj:
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if flags != 0:
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raise ValueError(
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"non-zero flags not allowed in calls to sendall() on %s" %
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self.__class__)
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return self._sslobj.read(data, buflen)
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else:
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return socket.recv(self, buflen, flags)
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def recv_from (self, addr, buflen=1024, flags=0):
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if self._sslobj:
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raise ValueError("recv_from not allowed on instances of %s" %
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self.__class__)
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else:
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return socket.recv_from(self, addr, buflen, flags)
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def ssl_shutdown(self):
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"""Shuts down the SSL channel over this socket (if active),
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without closing the socket connection."""
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if self._sslobj:
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self._sslobj.shutdown()
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self._sslobj = None
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def shutdown(self, how):
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self.ssl_shutdown()
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socket.shutdown(self, how)
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def close(self):
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self.ssl_shutdown()
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socket.close(self)
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def connect(self, addr):
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"""Connects to remote ADDR, and then wraps the connection in
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an SSL channel."""
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# Here we assume that the socket is client-side, and not
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# connected at the time of the call. We connect it, then wrap it.
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if self._sslobj:
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raise ValueError("attempt to connect already-connected sslsocket!")
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socket.connect(self, addr)
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self._sslobj = _ssl.sslwrap(self._sock, False, self.keyfile, self.certfile,
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self.cert_reqs, self.ssl_version,
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self.ca_certs)
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def accept(self):
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"""Accepts a new connection from a remote client, and returns
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a tuple containing that new connection wrapped with a server-side
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SSL channel, and the address of the remote client."""
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newsock, addr = socket.accept(self)
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return (sslsocket(newsock, True, self.keyfile, self.certfile,
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self.cert_reqs, self.ssl_version,
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self.ca_certs), addr)
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# some utility functions
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def cert_time_to_seconds(cert_time):
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"""Takes a date-time string in standard ASN1_print form
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("MON DAY 24HOUR:MINUTE:SEC YEAR TIMEZONE") and return
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a Python time value in seconds past the epoch."""
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import time
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return time.mktime(time.strptime(cert_time, "%b %d %H:%M:%S %Y GMT"))
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# a replacement for the old socket.ssl function
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def sslwrap_simple (sock, keyfile=None, certfile=None):
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"""A replacement for the old socket.ssl function. Designed
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for compability with Python 2.5 and earlier. Will disappear in
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Python 3.0."""
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return _ssl.sslwrap(sock._sock, 0, keyfile, certfile, CERT_NONE,
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PROTOCOL_SSLv23, None)
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