219 lines
8.5 KiB
Python
219 lines
8.5 KiB
Python
# Patch: patching of the Python stadard library's ssl module for transparent
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# use of datagram sockets.
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# Copyright 2012 Ray Brown
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# The License is also distributed with this work in the file named "LICENSE."
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Patch
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This module is used to patch the Python standard library's ssl module. Patching
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has the following effects:
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* The constant PROTOCOL_DTLSv1 is added at ssl module level
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* DTLSv1's protocol name is added to the ssl module's id-to-name dictionary
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* The constants DTLS_OPENSSL_VERSION* are added at the ssl module level
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* Instntiation of ssl.SSLSocket with sock.type == socket.SOCK_DGRAM is
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supported and leads to substitution of this module's DTLS code paths for
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that SSLSocket instance
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* Direct instantiation of SSLSocket as well as instantiation through
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ssl.wrap_socket are supported
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* Invocation of the function get_server_certificate with a value of
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PROTOCOL_DTLSv1 for the parameter ssl_version is supported
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"""
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from socket import SOCK_DGRAM, socket, _delegate_methods, error as socket_error
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from socket import AF_INET, SOCK_DGRAM, getaddrinfo
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from sslconnection import SSLConnection, PROTOCOL_DTLSv1, CERT_NONE
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from sslconnection import DTLS_OPENSSL_VERSION_NUMBER, DTLS_OPENSSL_VERSION
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from sslconnection import DTLS_OPENSSL_VERSION_INFO
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from err import raise_as_ssl_module_error
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from types import MethodType
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from weakref import proxy
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import errno
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def do_patch():
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import ssl as _ssl # import to be avoided if ssl module is never patched
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global _orig_SSLSocket_init, _orig_get_server_certificate
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global ssl
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ssl = _ssl
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if hasattr(ssl, "PROTOCOL_DTLSv1"):
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return
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ssl.PROTOCOL_DTLSv1 = PROTOCOL_DTLSv1
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ssl._PROTOCOL_NAMES[PROTOCOL_DTLSv1] = "DTLSv1"
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ssl.DTLS_OPENSSL_VERSION_NUMBER = DTLS_OPENSSL_VERSION_NUMBER
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ssl.DTLS_OPENSSL_VERSION = DTLS_OPENSSL_VERSION
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ssl.DTLS_OPENSSL_VERSION_INFO = DTLS_OPENSSL_VERSION_INFO
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_orig_SSLSocket_init = ssl.SSLSocket.__init__
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_orig_get_server_certificate = ssl.get_server_certificate
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ssl.SSLSocket.__init__ = _SSLSocket_init
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ssl.get_server_certificate = _get_server_certificate
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raise_as_ssl_module_error()
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PROTOCOL_SSLv3 = 1
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PROTOCOL_SSLv23 = 2
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def _get_server_certificate(addr, ssl_version=PROTOCOL_SSLv3, ca_certs=None):
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"""Retrieve a server certificate
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Retrieve the certificate from the server at the specified address,
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and return it as a PEM-encoded string.
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If 'ca_certs' is specified, validate the server cert against it.
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If 'ssl_version' is specified, use it in the connection attempt.
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"""
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if ssl_version != PROTOCOL_DTLSv1:
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return _orig_get_server_certificate(addr, ssl_version, ca_certs)
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if (ca_certs is not None):
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cert_reqs = ssl.CERT_REQUIRED
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else:
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cert_reqs = ssl.CERT_NONE
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af = getaddrinfo(addr[0], addr[1])[0][0]
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s = ssl.wrap_socket(socket(af, SOCK_DGRAM),
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ssl_version=ssl_version,
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cert_reqs=cert_reqs, ca_certs=ca_certs)
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s.connect(addr)
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dercert = s.getpeercert(True)
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s.close()
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return ssl.DER_cert_to_PEM_cert(dercert)
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def _SSLSocket_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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do_handshake_on_connect=True,
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suppress_ragged_eofs=True, ciphers=None):
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is_connection = is_datagram = False
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if isinstance(sock, SSLConnection):
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is_connection = True
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elif hasattr(sock, "type") and sock.type == SOCK_DGRAM:
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is_datagram = True
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if not is_connection and not is_datagram:
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# Non-DTLS code path
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return _orig_SSLSocket_init(self, sock, keyfile, certfile,
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server_side, cert_reqs,
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ssl_version, ca_certs,
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do_handshake_on_connect,
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suppress_ragged_eofs, ciphers)
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# DTLS code paths: datagram socket and newly accepted DTLS connection
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if is_datagram:
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socket.__init__(self, _sock=sock._sock)
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else:
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socket.__init__(self, _sock=sock.get_socket(True)._sock)
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# Copy instance initialization from SSLSocket class
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for attr in _delegate_methods:
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try:
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delattr(self, attr)
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except AttributeError:
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pass
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if certfile and not keyfile:
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keyfile = certfile
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if is_datagram:
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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 socket_error, e:
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if e.errno != errno.ENOTCONN:
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raise
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# no, no connection yet
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self._connected = False
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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._connected = True
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self._sslobj = SSLConnection(sock, keyfile, certfile,
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server_side, cert_reqs,
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ssl_version, ca_certs,
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do_handshake_on_connect,
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suppress_ragged_eofs, ciphers)
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else:
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self._sslobj = sock
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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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self.ciphers = ciphers
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self.do_handshake_on_connect = do_handshake_on_connect
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self.suppress_ragged_eofs = suppress_ragged_eofs
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self._makefile_refs = 0
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# Perform method substitution and addition (without reference cycle)
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self._real_connect = MethodType(_SSLSocket_real_connect, proxy(self))
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self.listen = MethodType(_SSLSocket_listen, proxy(self))
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self.accept = MethodType(_SSLSocket_accept, proxy(self))
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self.get_timeout = MethodType(_SSLSocket_get_timeout, proxy(self))
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self.handle_timeout = MethodType(_SSLSocket_handle_timeout, proxy(self))
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def _SSLSocket_listen(self, ignored):
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if self._connected:
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raise ValueError("attempt to listen on connected SSLSocket!")
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if self._sslobj:
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return
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self._sslobj = SSLConnection(socket(_sock=self._sock),
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self.keyfile, self.certfile, True,
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self.cert_reqs, self.ssl_version,
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self.ca_certs,
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self.do_handshake_on_connect,
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self.suppress_ragged_eofs, self.ciphers)
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def _SSLSocket_accept(self):
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if self._connected:
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raise ValueError("attempt to accept on connected SSLSocket!")
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if not self._sslobj:
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raise ValueError("attempt to accept on SSLSocket prior to listen!")
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acc_ret = self._sslobj.accept()
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if not acc_ret:
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return
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new_conn, addr = acc_ret
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new_ssl_sock = ssl.SSLSocket(new_conn, self.keyfile, self.certfile, True,
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self.cert_reqs, self.ssl_version,
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self.ca_certs,
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self.do_handshake_on_connect,
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self.suppress_ragged_eofs, self.ciphers)
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return new_ssl_sock, addr
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def _SSLSocket_real_connect(self, addr, return_errno):
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if self._connected:
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raise ValueError("attempt to connect already-connected SSLSocket!")
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self._sslobj = SSLConnection(socket(_sock=self._sock),
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self.keyfile, self.certfile, False,
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self.cert_reqs, self.ssl_version,
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self.ca_certs,
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self.do_handshake_on_connect,
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self.suppress_ragged_eofs, self.ciphers)
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try:
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self._sslobj.connect(addr)
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except socket_error as e:
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if return_errno:
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return e.errno
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else:
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self._sslobj = None
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raise e
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self._connected = True
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return 0
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if __name__ == "__main__":
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do_patch()
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def _SSLSocket_get_timeout(self):
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return self._sslobj.get_timeout()
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def _SSLSocket_handle_timeout(self):
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return self._sslobj.handle_timeout()
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