diff options
Diffstat (limited to 'requests/packages/urllib3/contrib/pyopenssl.py')
| -rw-r--r-- | requests/packages/urllib3/contrib/pyopenssl.py | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/requests/packages/urllib3/contrib/pyopenssl.py b/requests/packages/urllib3/contrib/pyopenssl.py new file mode 100644 index 0000000..b2c34a8 --- /dev/null +++ b/requests/packages/urllib3/contrib/pyopenssl.py @@ -0,0 +1,293 @@ +'''SSL with SNI_-support for Python 2. Follow these instructions if you would +like to verify SSL certificates in Python 2. Note, the default libraries do +*not* do certificate checking; you need to do additional work to validate +certificates yourself. + +This needs the following packages installed: + +* pyOpenSSL (tested with 0.13) +* ndg-httpsclient (tested with 0.3.2) +* pyasn1 (tested with 0.1.6) + +You can install them with the following command: + + pip install pyopenssl ndg-httpsclient pyasn1 + +To activate certificate checking, call +:func:`~urllib3.contrib.pyopenssl.inject_into_urllib3` from your Python code +before you begin making HTTP requests. This can be done in a ``sitecustomize`` +module, or at any other time before your application begins using ``urllib3``, +like this:: + + try: + import urllib3.contrib.pyopenssl + urllib3.contrib.pyopenssl.inject_into_urllib3() + except ImportError: + pass + +Now you can use :mod:`urllib3` as you normally would, and it will support SNI +when the required modules are installed. + +Activating this module also has the positive side effect of disabling SSL/TLS +compression in Python 2 (see `CRIME attack`_). + +If you want to configure the default list of supported cipher suites, you can +set the ``urllib3.contrib.pyopenssl.DEFAULT_SSL_CIPHER_LIST`` variable. + +Module Variables +---------------- + +:var DEFAULT_SSL_CIPHER_LIST: The list of supported SSL/TLS cipher suites. + +.. _sni: https://en.wikipedia.org/wiki/Server_Name_Indication +.. _crime attack: https://en.wikipedia.org/wiki/CRIME_(security_exploit) + +''' + +try: + from ndg.httpsclient.ssl_peer_verification import SUBJ_ALT_NAME_SUPPORT + from ndg.httpsclient.subj_alt_name import SubjectAltName as BaseSubjectAltName +except SyntaxError as e: + raise ImportError(e) + +import OpenSSL.SSL +from pyasn1.codec.der import decoder as der_decoder +from pyasn1.type import univ, constraint +from socket import _fileobject, timeout +import ssl +import select + +from .. import connection +from .. import util + +__all__ = ['inject_into_urllib3', 'extract_from_urllib3'] + +# SNI only *really* works if we can read the subjectAltName of certificates. +HAS_SNI = SUBJ_ALT_NAME_SUPPORT + +# Map from urllib3 to PyOpenSSL compatible parameter-values. +_openssl_versions = { + ssl.PROTOCOL_SSLv23: OpenSSL.SSL.SSLv23_METHOD, + ssl.PROTOCOL_TLSv1: OpenSSL.SSL.TLSv1_METHOD, +} + +try: + _openssl_versions.update({ssl.PROTOCOL_SSLv3: OpenSSL.SSL.SSLv3_METHOD}) +except AttributeError: + pass + +_openssl_verify = { + ssl.CERT_NONE: OpenSSL.SSL.VERIFY_NONE, + ssl.CERT_OPTIONAL: OpenSSL.SSL.VERIFY_PEER, + ssl.CERT_REQUIRED: OpenSSL.SSL.VERIFY_PEER + + OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT, +} + +DEFAULT_SSL_CIPHER_LIST = util.ssl_.DEFAULT_CIPHERS + + +orig_util_HAS_SNI = util.HAS_SNI +orig_connection_ssl_wrap_socket = connection.ssl_wrap_socket + + +def inject_into_urllib3(): + 'Monkey-patch urllib3 with PyOpenSSL-backed SSL-support.' + + connection.ssl_wrap_socket = ssl_wrap_socket + util.HAS_SNI = HAS_SNI + + +def extract_from_urllib3(): + 'Undo monkey-patching by :func:`inject_into_urllib3`.' + + connection.ssl_wrap_socket = orig_connection_ssl_wrap_socket + util.HAS_SNI = orig_util_HAS_SNI + + +### Note: This is a slightly bug-fixed version of same from ndg-httpsclient. +class SubjectAltName(BaseSubjectAltName): + '''ASN.1 implementation for subjectAltNames support''' + + # There is no limit to how many SAN certificates a certificate may have, + # however this needs to have some limit so we'll set an arbitrarily high + # limit. + sizeSpec = univ.SequenceOf.sizeSpec + \ + constraint.ValueSizeConstraint(1, 1024) + + +### Note: This is a slightly bug-fixed version of same from ndg-httpsclient. +def get_subj_alt_name(peer_cert): + # Search through extensions + dns_name = [] + if not SUBJ_ALT_NAME_SUPPORT: + return dns_name + + general_names = SubjectAltName() + for i in range(peer_cert.get_extension_count()): + ext = peer_cert.get_extension(i) + ext_name = ext.get_short_name() + if ext_name != 'subjectAltName': + continue + + # PyOpenSSL returns extension data in ASN.1 encoded form + ext_dat = ext.get_data() + decoded_dat = der_decoder.decode(ext_dat, + asn1Spec=general_names) + + for name in decoded_dat: + if not isinstance(name, SubjectAltName): + continue + for entry in range(len(name)): + component = name.getComponentByPosition(entry) + if component.getName() != 'dNSName': + continue + dns_name.append(str(component.getComponent())) + + return dns_name + + +class WrappedSocket(object): + '''API-compatibility wrapper for Python OpenSSL's Connection-class. + + Note: _makefile_refs, _drop() and _reuse() are needed for the garbage + collector of pypy. + ''' + + def __init__(self, connection, socket, suppress_ragged_eofs=True): + self.connection = connection + self.socket = socket + self.suppress_ragged_eofs = suppress_ragged_eofs + self._makefile_refs = 0 + + def fileno(self): + return self.socket.fileno() + + def makefile(self, mode, bufsize=-1): + self._makefile_refs += 1 + return _fileobject(self, mode, bufsize, close=True) + + def recv(self, *args, **kwargs): + try: + data = self.connection.recv(*args, **kwargs) + except OpenSSL.SSL.SysCallError as e: + if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'): + return b'' + else: + raise + except OpenSSL.SSL.ZeroReturnError as e: + if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN: + return b'' + else: + raise + except OpenSSL.SSL.WantReadError: + rd, wd, ed = select.select( + [self.socket], [], [], self.socket.gettimeout()) + if not rd: + raise timeout('The read operation timed out') + else: + return self.recv(*args, **kwargs) + else: + return data + + def settimeout(self, timeout): + return self.socket.settimeout(timeout) + + def _send_until_done(self, data): + while True: + try: + return self.connection.send(data) + except OpenSSL.SSL.WantWriteError: + _, wlist, _ = select.select([], [self.socket], [], + self.socket.gettimeout()) + if not wlist: + raise timeout() + continue + + def sendall(self, data): + while len(data): + sent = self._send_until_done(data) + data = data[sent:] + + def close(self): + if self._makefile_refs < 1: + return self.connection.shutdown() + else: + self._makefile_refs -= 1 + + def getpeercert(self, binary_form=False): + x509 = self.connection.get_peer_certificate() + + if not x509: + return x509 + + if binary_form: + return OpenSSL.crypto.dump_certificate( + OpenSSL.crypto.FILETYPE_ASN1, + x509) + + return { + 'subject': ( + (('commonName', x509.get_subject().CN),), + ), + 'subjectAltName': [ + ('DNS', value) + for value in get_subj_alt_name(x509) + ] + } + + def _reuse(self): + self._makefile_refs += 1 + + def _drop(self): + if self._makefile_refs < 1: + self.close() + else: + self._makefile_refs -= 1 + + +def _verify_callback(cnx, x509, err_no, err_depth, return_code): + return err_no == 0 + + +def ssl_wrap_socket(sock, keyfile=None, certfile=None, cert_reqs=None, + ca_certs=None, server_hostname=None, + ssl_version=None): + ctx = OpenSSL.SSL.Context(_openssl_versions[ssl_version]) + if certfile: + keyfile = keyfile or certfile # Match behaviour of the normal python ssl library + ctx.use_certificate_file(certfile) + if keyfile: + ctx.use_privatekey_file(keyfile) + if cert_reqs != ssl.CERT_NONE: + ctx.set_verify(_openssl_verify[cert_reqs], _verify_callback) + if ca_certs: + try: + ctx.load_verify_locations(ca_certs, None) + except OpenSSL.SSL.Error as e: + raise ssl.SSLError('bad ca_certs: %r' % ca_certs, e) + else: + ctx.set_default_verify_paths() + + # Disable TLS compression to migitate CRIME attack (issue #309) + OP_NO_COMPRESSION = 0x20000 + ctx.set_options(OP_NO_COMPRESSION) + + # Set list of supported ciphersuites. + ctx.set_cipher_list(DEFAULT_SSL_CIPHER_LIST) + + cnx = OpenSSL.SSL.Connection(ctx, sock) + cnx.set_tlsext_host_name(server_hostname) + cnx.set_connect_state() + while True: + try: + cnx.do_handshake() + except OpenSSL.SSL.WantReadError: + rd, _, _ = select.select([sock], [], [], sock.gettimeout()) + if not rd: + raise timeout('select timed out') + continue + except OpenSSL.SSL.Error as e: + raise ssl.SSLError('bad handshake', e) + break + + return WrappedSocket(cnx, sock) |