/usr/lib/python2.7/dist-packages/urllib3/contrib/pyopenssl.py is in python-urllib3 1.9.1-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 | '''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.
Default: ``ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:
ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS``
.. _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,
}
# A secure default.
# Sources for more information on TLS ciphers:
#
# - https://wiki.mozilla.org/Security/Server_Side_TLS
# - https://www.ssllabs.com/projects/best-practices/index.html
# - https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/
#
# The general intent is:
# - Prefer cipher suites that offer perfect forward secrecy (DHE/ECDHE),
# - prefer ECDHE over DHE for better performance,
# - prefer any AES-GCM over any AES-CBC for better performance and security,
# - use 3DES as fallback which is secure but slow,
# - disable NULL authentication, MD5 MACs and DSS for security reasons.
DEFAULT_SSL_CIPHER_LIST = "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:" + \
"ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:" + \
"!aNULL:!MD5:!DSS"
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.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 sendall(self, data):
return self.connection.sendall(data)
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:
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:
select.select([sock], [], [])
continue
except OpenSSL.SSL.Error as e:
raise ssl.SSLError('bad handshake', e)
break
return WrappedSocket(cnx, sock)
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