467 lines
15 KiB
Python
467 lines
15 KiB
Python
|
"""
|
||
|
|
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 16.0.0)
|
||
|
|
* cryptography (minimum 1.3.4, from pyopenssl)
|
||
|
|
* idna (minimum 2.0, from cryptography)
|
||
|
|
|
||
|
|
However, pyopenssl depends on cryptography, which depends on idna, so while we
|
||
|
|
use all three directly here we end up having relatively few packages required.
|
||
|
|
|
||
|
|
You can install them with the following command:
|
||
|
|
|
||
|
|
pip install pyopenssl cryptography idna
|
||
|
|
|
||
|
|
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.
|
||
|
|
|
||
|
|
.. _sni: https://en.wikipedia.org/wiki/Server_Name_Indication
|
||
|
|
.. _crime attack: https://en.wikipedia.org/wiki/CRIME_(security_exploit)
|
||
|
|
"""
|
||
|
|
from __future__ import absolute_import
|
||
|
|
|
||
|
|
import OpenSSL.SSL
|
||
|
|
from cryptography import x509
|
||
|
|
from cryptography.hazmat.backends.openssl import backend as openssl_backend
|
||
|
|
from cryptography.hazmat.backends.openssl.x509 import _Certificate
|
||
|
|
try:
|
||
|
|
from cryptography.x509 import UnsupportedExtension
|
||
|
|
except ImportError:
|
||
|
|
# UnsupportedExtension is gone in cryptography >= 2.1.0
|
||
|
|
class UnsupportedExtension(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
from socket import timeout, error as SocketError
|
||
|
|
from io import BytesIO
|
||
|
|
|
||
|
|
try: # Platform-specific: Python 2
|
||
|
|
from socket import _fileobject
|
||
|
|
except ImportError: # Platform-specific: Python 3
|
||
|
|
_fileobject = None
|
||
|
|
from ..packages.backports.makefile import backport_makefile
|
||
|
|
|
||
|
|
import logging
|
||
|
|
import ssl
|
||
|
|
from ..packages import six
|
||
|
|
import sys
|
||
|
|
|
||
|
|
from .. import util
|
||
|
|
|
||
|
|
__all__ = ['inject_into_urllib3', 'extract_from_urllib3']
|
||
|
|
|
||
|
|
# SNI always works.
|
||
|
|
HAS_SNI = True
|
||
|
|
|
||
|
|
# Map from urllib3 to PyOpenSSL compatible parameter-values.
|
||
|
|
_openssl_versions = {
|
||
|
|
ssl.PROTOCOL_SSLv23: OpenSSL.SSL.SSLv23_METHOD,
|
||
|
|
ssl.PROTOCOL_TLSv1: OpenSSL.SSL.TLSv1_METHOD,
|
||
|
|
}
|
||
|
|
|
||
|
|
if hasattr(ssl, 'PROTOCOL_TLSv1_1') and hasattr(OpenSSL.SSL, 'TLSv1_1_METHOD'):
|
||
|
|
_openssl_versions[ssl.PROTOCOL_TLSv1_1] = OpenSSL.SSL.TLSv1_1_METHOD
|
||
|
|
|
||
|
|
if hasattr(ssl, 'PROTOCOL_TLSv1_2') and hasattr(OpenSSL.SSL, 'TLSv1_2_METHOD'):
|
||
|
|
_openssl_versions[ssl.PROTOCOL_TLSv1_2] = OpenSSL.SSL.TLSv1_2_METHOD
|
||
|
|
|
||
|
|
try:
|
||
|
|
_openssl_versions.update({ssl.PROTOCOL_SSLv3: OpenSSL.SSL.SSLv3_METHOD})
|
||
|
|
except AttributeError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
_stdlib_to_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,
|
||
|
|
}
|
||
|
|
_openssl_to_stdlib_verify = dict(
|
||
|
|
(v, k) for k, v in _stdlib_to_openssl_verify.items()
|
||
|
|
)
|
||
|
|
|
||
|
|
# OpenSSL will only write 16K at a time
|
||
|
|
SSL_WRITE_BLOCKSIZE = 16384
|
||
|
|
|
||
|
|
orig_util_HAS_SNI = util.HAS_SNI
|
||
|
|
orig_util_SSLContext = util.ssl_.SSLContext
|
||
|
|
|
||
|
|
|
||
|
|
log = logging.getLogger(__name__)
|
||
|
|
|
||
|
|
|
||
|
|
def inject_into_urllib3():
|
||
|
|
'Monkey-patch urllib3 with PyOpenSSL-backed SSL-support.'
|
||
|
|
|
||
|
|
_validate_dependencies_met()
|
||
|
|
|
||
|
|
util.ssl_.SSLContext = PyOpenSSLContext
|
||
|
|
util.HAS_SNI = HAS_SNI
|
||
|
|
util.ssl_.HAS_SNI = HAS_SNI
|
||
|
|
util.IS_PYOPENSSL = True
|
||
|
|
util.ssl_.IS_PYOPENSSL = True
|
||
|
|
|
||
|
|
|
||
|
|
def extract_from_urllib3():
|
||
|
|
'Undo monkey-patching by :func:`inject_into_urllib3`.'
|
||
|
|
|
||
|
|
util.ssl_.SSLContext = orig_util_SSLContext
|
||
|
|
util.HAS_SNI = orig_util_HAS_SNI
|
||
|
|
util.ssl_.HAS_SNI = orig_util_HAS_SNI
|
||
|
|
util.IS_PYOPENSSL = False
|
||
|
|
util.ssl_.IS_PYOPENSSL = False
|
||
|
|
|
||
|
|
|
||
|
|
def _validate_dependencies_met():
|
||
|
|
"""
|
||
|
|
Verifies that PyOpenSSL's package-level dependencies have been met.
|
||
|
|
Throws `ImportError` if they are not met.
|
||
|
|
"""
|
||
|
|
# Method added in `cryptography==1.1`; not available in older versions
|
||
|
|
from cryptography.x509.extensions import Extensions
|
||
|
|
if getattr(Extensions, "get_extension_for_class", None) is None:
|
||
|
|
raise ImportError("'cryptography' module missing required functionality. "
|
||
|
|
"Try upgrading to v1.3.4 or newer.")
|
||
|
|
|
||
|
|
# pyOpenSSL 0.14 and above use cryptography for OpenSSL bindings. The _x509
|
||
|
|
# attribute is only present on those versions.
|
||
|
|
from OpenSSL.crypto import X509
|
||
|
|
x509 = X509()
|
||
|
|
if getattr(x509, "_x509", None) is None:
|
||
|
|
raise ImportError("'pyOpenSSL' module missing required functionality. "
|
||
|
|
"Try upgrading to v0.14 or newer.")
|
||
|
|
|
||
|
|
|
||
|
|
def _dnsname_to_stdlib(name):
|
||
|
|
"""
|
||
|
|
Converts a dNSName SubjectAlternativeName field to the form used by the
|
||
|
|
standard library on the given Python version.
|
||
|
|
|
||
|
|
Cryptography produces a dNSName as a unicode string that was idna-decoded
|
||
|
|
from ASCII bytes. We need to idna-encode that string to get it back, and
|
||
|
|
then on Python 3 we also need to convert to unicode via UTF-8 (the stdlib
|
||
|
|
uses PyUnicode_FromStringAndSize on it, which decodes via UTF-8).
|
||
|
|
|
||
|
|
If the name cannot be idna-encoded then we return None signalling that
|
||
|
|
the name given should be skipped.
|
||
|
|
"""
|
||
|
|
def idna_encode(name):
|
||
|
|
"""
|
||
|
|
Borrowed wholesale from the Python Cryptography Project. It turns out
|
||
|
|
that we can't just safely call `idna.encode`: it can explode for
|
||
|
|
wildcard names. This avoids that problem.
|
||
|
|
"""
|
||
|
|
import idna
|
||
|
|
|
||
|
|
try:
|
||
|
|
for prefix in [u'*.', u'.']:
|
||
|
|
if name.startswith(prefix):
|
||
|
|
name = name[len(prefix):]
|
||
|
|
return prefix.encode('ascii') + idna.encode(name)
|
||
|
|
return idna.encode(name)
|
||
|
|
except idna.core.IDNAError:
|
||
|
|
return None
|
||
|
|
|
||
|
|
name = idna_encode(name)
|
||
|
|
if name is None:
|
||
|
|
return None
|
||
|
|
elif sys.version_info >= (3, 0):
|
||
|
|
name = name.decode('utf-8')
|
||
|
|
return name
|
||
|
|
|
||
|
|
|
||
|
|
def get_subj_alt_name(peer_cert):
|
||
|
|
"""
|
||
|
|
Given an PyOpenSSL certificate, provides all the subject alternative names.
|
||
|
|
"""
|
||
|
|
# Pass the cert to cryptography, which has much better APIs for this.
|
||
|
|
if hasattr(peer_cert, "to_cryptography"):
|
||
|
|
cert = peer_cert.to_cryptography()
|
||
|
|
else:
|
||
|
|
# This is technically using private APIs, but should work across all
|
||
|
|
# relevant versions before PyOpenSSL got a proper API for this.
|
||
|
|
cert = _Certificate(openssl_backend, peer_cert._x509)
|
||
|
|
|
||
|
|
# We want to find the SAN extension. Ask Cryptography to locate it (it's
|
||
|
|
# faster than looping in Python)
|
||
|
|
try:
|
||
|
|
ext = cert.extensions.get_extension_for_class(
|
||
|
|
x509.SubjectAlternativeName
|
||
|
|
).value
|
||
|
|
except x509.ExtensionNotFound:
|
||
|
|
# No such extension, return the empty list.
|
||
|
|
return []
|
||
|
|
except (x509.DuplicateExtension, UnsupportedExtension,
|
||
|
|
x509.UnsupportedGeneralNameType, UnicodeError) as e:
|
||
|
|
# A problem has been found with the quality of the certificate. Assume
|
||
|
|
# no SAN field is present.
|
||
|
|
log.warning(
|
||
|
|
"A problem was encountered with the certificate that prevented "
|
||
|
|
"urllib3 from finding the SubjectAlternativeName field. This can "
|
||
|
|
"affect certificate validation. The error was %s",
|
||
|
|
e,
|
||
|
|
)
|
||
|
|
return []
|
||
|
|
|
||
|
|
# We want to return dNSName and iPAddress fields. We need to cast the IPs
|
||
|
|
# back to strings because the match_hostname function wants them as
|
||
|
|
# strings.
|
||
|
|
# Sadly the DNS names need to be idna encoded and then, on Python 3, UTF-8
|
||
|
|
# decoded. This is pretty frustrating, but that's what the standard library
|
||
|
|
# does with certificates, and so we need to attempt to do the same.
|
||
|
|
# We also want to skip over names which cannot be idna encoded.
|
||
|
|
names = [
|
||
|
|
('DNS', name) for name in map(_dnsname_to_stdlib, ext.get_values_for_type(x509.DNSName))
|
||
|
|
if name is not None
|
||
|
|
]
|
||
|
|
names.extend(
|
||
|
|
('IP Address', str(name))
|
||
|
|
for name in ext.get_values_for_type(x509.IPAddress)
|
||
|
|
)
|
||
|
|
|
||
|
|
return names
|
||
|
|
|
||
|
|
|
||
|
|
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
|
||
|
|
self._closed = False
|
||
|
|
|
||
|
|
def fileno(self):
|
||
|
|
return self.socket.fileno()
|
||
|
|
|
||
|
|
# Copy-pasted from Python 3.5 source code
|
||
|
|
def _decref_socketios(self):
|
||
|
|
if self._makefile_refs > 0:
|
||
|
|
self._makefile_refs -= 1
|
||
|
|
if self._closed:
|
||
|
|
self.close()
|
||
|
|
|
||
|
|
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 SocketError(str(e))
|
||
|
|
except OpenSSL.SSL.ZeroReturnError as e:
|
||
|
|
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
|
||
|
|
return b''
|
||
|
|
else:
|
||
|
|
raise
|
||
|
|
except OpenSSL.SSL.WantReadError:
|
||
|
|
if not util.wait_for_read(self.socket, self.socket.gettimeout()):
|
||
|
|
raise timeout('The read operation timed out')
|
||
|
|
else:
|
||
|
|
return self.recv(*args, **kwargs)
|
||
|
|
else:
|
||
|
|
return data
|
||
|
|
|
||
|
|
def recv_into(self, *args, **kwargs):
|
||
|
|
try:
|
||
|
|
return self.connection.recv_into(*args, **kwargs)
|
||
|
|
except OpenSSL.SSL.SysCallError as e:
|
||
|
|
if self.suppress_ragged_eofs and e.args == (-1, 'Unexpected EOF'):
|
||
|
|
return 0
|
||
|
|
else:
|
||
|
|
raise SocketError(str(e))
|
||
|
|
except OpenSSL.SSL.ZeroReturnError as e:
|
||
|
|
if self.connection.get_shutdown() == OpenSSL.SSL.RECEIVED_SHUTDOWN:
|
||
|
|
return 0
|
||
|
|
else:
|
||
|
|
raise
|
||
|
|
except OpenSSL.SSL.WantReadError:
|
||
|
|
if not util.wait_for_read(self.socket, self.socket.gettimeout()):
|
||
|
|
raise timeout('The read operation timed out')
|
||
|
|
else:
|
||
|
|
return self.recv_into(*args, **kwargs)
|
||
|
|
|
||
|
|
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:
|
||
|
|
if not util.wait_for_write(self.socket, self.socket.gettimeout()):
|
||
|
|
raise timeout()
|
||
|
|
continue
|
||
|
|
except OpenSSL.SSL.SysCallError as e:
|
||
|
|
raise SocketError(str(e))
|
||
|
|
|
||
|
|
def sendall(self, data):
|
||
|
|
total_sent = 0
|
||
|
|
while total_sent < len(data):
|
||
|
|
sent = self._send_until_done(data[total_sent:total_sent + SSL_WRITE_BLOCKSIZE])
|
||
|
|
total_sent += sent
|
||
|
|
|
||
|
|
def shutdown(self):
|
||
|
|
# FIXME rethrow compatible exceptions should we ever use this
|
||
|
|
self.connection.shutdown()
|
||
|
|
|
||
|
|
def close(self):
|
||
|
|
if self._makefile_refs < 1:
|
||
|
|
try:
|
||
|
|
self._closed = True
|
||
|
|
return self.connection.close()
|
||
|
|
except OpenSSL.SSL.Error:
|
||
|
|
return
|
||
|
|
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': 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
|
||
|
|
|
||
|
|
|
||
|
|
if _fileobject: # Platform-specific: Python 2
|
||
|
|
def makefile(self, mode, bufsize=-1):
|
||
|
|
self._makefile_refs += 1
|
||
|
|
return _fileobject(self, mode, bufsize, close=True)
|
||
|
|
else: # Platform-specific: Python 3
|
||
|
|
makefile = backport_makefile
|
||
|
|
|
||
|
|
WrappedSocket.makefile = makefile
|
||
|
|
|
||
|
|
|
||
|
|
class PyOpenSSLContext(object):
|
||
|
|
"""
|
||
|
|
I am a wrapper class for the PyOpenSSL ``Context`` object. I am responsible
|
||
|
|
for translating the interface of the standard library ``SSLContext`` object
|
||
|
|
to calls into PyOpenSSL.
|
||
|
|
"""
|
||
|
|
def __init__(self, protocol):
|
||
|
|
self.protocol = _openssl_versions[protocol]
|
||
|
|
self._ctx = OpenSSL.SSL.Context(self.protocol)
|
||
|
|
self._options = 0
|
||
|
|
self.check_hostname = False
|
||
|
|
|
||
|
|
@property
|
||
|
|
def options(self):
|
||
|
|
return self._options
|
||
|
|
|
||
|
|
@options.setter
|
||
|
|
def options(self, value):
|
||
|
|
self._options = value
|
||
|
|
self._ctx.set_options(value)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def verify_mode(self):
|
||
|
|
return _openssl_to_stdlib_verify[self._ctx.get_verify_mode()]
|
||
|
|
|
||
|
|
@verify_mode.setter
|
||
|
|
def verify_mode(self, value):
|
||
|
|
self._ctx.set_verify(
|
||
|
|
_stdlib_to_openssl_verify[value],
|
||
|
|
_verify_callback
|
||
|
|
)
|
||
|
|
|
||
|
|
def set_default_verify_paths(self):
|
||
|
|
self._ctx.set_default_verify_paths()
|
||
|
|
|
||
|
|
def set_ciphers(self, ciphers):
|
||
|
|
if isinstance(ciphers, six.text_type):
|
||
|
|
ciphers = ciphers.encode('utf-8')
|
||
|
|
self._ctx.set_cipher_list(ciphers)
|
||
|
|
|
||
|
|
def load_verify_locations(self, cafile=None, capath=None, cadata=None):
|
||
|
|
if cafile is not None:
|
||
|
|
cafile = cafile.encode('utf-8')
|
||
|
|
if capath is not None:
|
||
|
|
capath = capath.encode('utf-8')
|
||
|
|
self._ctx.load_verify_locations(cafile, capath)
|
||
|
|
if cadata is not None:
|
||
|
|
self._ctx.load_verify_locations(BytesIO(cadata))
|
||
|
|
|
||
|
|
def load_cert_chain(self, certfile, keyfile=None, password=None):
|
||
|
|
self._ctx.use_certificate_chain_file(certfile)
|
||
|
|
if password is not None:
|
||
|
|
self._ctx.set_passwd_cb(lambda max_length, prompt_twice, userdata: password)
|
||
|
|
self._ctx.use_privatekey_file(keyfile or certfile)
|
||
|
|
|
||
|
|
def wrap_socket(self, sock, server_side=False,
|
||
|
|
do_handshake_on_connect=True, suppress_ragged_eofs=True,
|
||
|
|
server_hostname=None):
|
||
|
|
cnx = OpenSSL.SSL.Connection(self._ctx, sock)
|
||
|
|
|
||
|
|
if isinstance(server_hostname, six.text_type): # Platform-specific: Python 3
|
||
|
|
server_hostname = server_hostname.encode('utf-8')
|
||
|
|
|
||
|
|
if server_hostname is not None:
|
||
|
|
cnx.set_tlsext_host_name(server_hostname)
|
||
|
|
|
||
|
|
cnx.set_connect_state()
|
||
|
|
|
||
|
|
while True:
|
||
|
|
try:
|
||
|
|
cnx.do_handshake()
|
||
|
|
except OpenSSL.SSL.WantReadError:
|
||
|
|
if not util.wait_for_read(sock, sock.gettimeout()):
|
||
|
|
raise timeout('select timed out')
|
||
|
|
continue
|
||
|
|
except OpenSSL.SSL.Error as e:
|
||
|
|
raise ssl.SSLError('bad handshake: %r' % e)
|
||
|
|
break
|
||
|
|
|
||
|
|
return WrappedSocket(cnx, sock)
|
||
|
|
|
||
|
|
|
||
|
|
def _verify_callback(cnx, x509, err_no, err_depth, return_code):
|
||
|
|
return err_no == 0
|