aboutsummaryrefslogtreecommitdiff
path: root/requests/packages/urllib3/contrib/pyopenssl.py
blob: 5c4c6d8d31052b88426dd83aaf50ccea33f51126 (plain)
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
'''SSL with SNI-support for Python 2.

This needs the following packages installed:

* pyOpenSSL (tested with 0.13)
* ndg-httpsclient (tested with 0.3.2)
* pyasn1 (tested with 0.1.6)

To activate it call :func:`~urllib3.contrib.pyopenssl.inject_into_urllib3`.
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.
'''

from ndg.httpsclient.ssl_peer_verification import (ServerSSLCertVerification,
                                                   SUBJ_ALT_NAME_SUPPORT)
from ndg.httpsclient.subj_alt_name import SubjectAltName
import OpenSSL.SSL
from pyasn1.codec.der import decoder as der_decoder
from socket import _fileobject
import ssl

from .. import connectionpool
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_SSLv3: OpenSSL.SSL.SSLv3_METHOD,
    ssl.PROTOCOL_TLSv1: OpenSSL.SSL.TLSv1_METHOD,
}
_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,
}


orig_util_HAS_SNI = util.HAS_SNI
orig_connectionpool_ssl_wrap_socket = connectionpool.ssl_wrap_socket


def inject_into_urllib3():
    'Monkey-patch urllib3 with PyOpenSSL-backed SSL-support.'

    connectionpool.ssl_wrap_socket = ssl_wrap_socket
    util.HAS_SNI = HAS_SNI


def extract_from_urllib3():
    'Undo monkey-patching by :func:`inject_into_urllib3`.'

    connectionpool.ssl_wrap_socket = orig_connectionpool_ssl_wrap_socket
    util.HAS_SNI = orig_util_HAS_SNI


### 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.'''

    def __init__(self, connection, socket):
        self.connection = connection
        self.socket = socket

    def makefile(self, mode, bufsize=-1):
        return _fileobject(self.connection, mode, bufsize)

    def settimeout(self, timeout):
        return self.socket.settimeout(timeout)

    def sendall(self, data):
        return self.connection.sendall(data)

    def getpeercert(self, binary_form=False):
        x509 = self.connection.get_peer_certificate()
        if not x509:
            raise ssl.SSLError('')

        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 _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)

    cnx = OpenSSL.SSL.Connection(ctx, sock)
    cnx.set_tlsext_host_name(server_hostname)
    cnx.set_connect_state()
    try:
        cnx.do_handshake()
    except OpenSSL.SSL.Error as e:
        raise ssl.SSLError('bad handshake', e)

    return WrappedSocket(cnx, sock)