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Diffstat (limited to 'requests/packages/urllib3/util/ssl_.py')
-rw-r--r-- | requests/packages/urllib3/util/ssl_.py | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/requests/packages/urllib3/util/ssl_.py b/requests/packages/urllib3/util/ssl_.py new file mode 100644 index 0000000..dee4b87 --- /dev/null +++ b/requests/packages/urllib3/util/ssl_.py @@ -0,0 +1,133 @@ +from binascii import hexlify, unhexlify +from hashlib import md5, sha1 + +from ..exceptions import SSLError + + +try: # Test for SSL features + SSLContext = None + HAS_SNI = False + + import ssl + from ssl import wrap_socket, CERT_NONE, PROTOCOL_SSLv23 + from ssl import SSLContext # Modern SSL? + from ssl import HAS_SNI # Has SNI? +except ImportError: + pass + + +def assert_fingerprint(cert, fingerprint): + """ + Checks if given fingerprint matches the supplied certificate. + + :param cert: + Certificate as bytes object. + :param fingerprint: + Fingerprint as string of hexdigits, can be interspersed by colons. + """ + + # Maps the length of a digest to a possible hash function producing + # this digest. + hashfunc_map = { + 16: md5, + 20: sha1 + } + + fingerprint = fingerprint.replace(':', '').lower() + + digest_length, rest = divmod(len(fingerprint), 2) + + if rest or digest_length not in hashfunc_map: + raise SSLError('Fingerprint is of invalid length.') + + # We need encode() here for py32; works on py2 and p33. + fingerprint_bytes = unhexlify(fingerprint.encode()) + + hashfunc = hashfunc_map[digest_length] + + cert_digest = hashfunc(cert).digest() + + if not cert_digest == fingerprint_bytes: + raise SSLError('Fingerprints did not match. Expected "{0}", got "{1}".' + .format(hexlify(fingerprint_bytes), + hexlify(cert_digest))) + + +def resolve_cert_reqs(candidate): + """ + Resolves the argument to a numeric constant, which can be passed to + the wrap_socket function/method from the ssl module. + Defaults to :data:`ssl.CERT_NONE`. + If given a string it is assumed to be the name of the constant in the + :mod:`ssl` module or its abbrevation. + (So you can specify `REQUIRED` instead of `CERT_REQUIRED`. + If it's neither `None` nor a string we assume it is already the numeric + constant which can directly be passed to wrap_socket. + """ + if candidate is None: + return CERT_NONE + + if isinstance(candidate, str): + res = getattr(ssl, candidate, None) + if res is None: + res = getattr(ssl, 'CERT_' + candidate) + return res + + return candidate + + +def resolve_ssl_version(candidate): + """ + like resolve_cert_reqs + """ + if candidate is None: + return PROTOCOL_SSLv23 + + if isinstance(candidate, str): + res = getattr(ssl, candidate, None) + if res is None: + res = getattr(ssl, 'PROTOCOL_' + candidate) + return res + + return candidate + + +if SSLContext is not None: # Python 3.2+ + def ssl_wrap_socket(sock, keyfile=None, certfile=None, cert_reqs=None, + ca_certs=None, server_hostname=None, + ssl_version=None): + """ + All arguments except `server_hostname` have the same meaning as for + :func:`ssl.wrap_socket` + + :param server_hostname: + Hostname of the expected certificate + """ + context = SSLContext(ssl_version) + context.verify_mode = cert_reqs + + # Disable TLS compression to migitate CRIME attack (issue #309) + OP_NO_COMPRESSION = 0x20000 + context.options |= OP_NO_COMPRESSION + + if ca_certs: + try: + context.load_verify_locations(ca_certs) + # Py32 raises IOError + # Py33 raises FileNotFoundError + except Exception as e: # Reraise as SSLError + raise SSLError(e) + if certfile: + # FIXME: This block needs a test. + context.load_cert_chain(certfile, keyfile) + if HAS_SNI: # Platform-specific: OpenSSL with enabled SNI + return context.wrap_socket(sock, server_hostname=server_hostname) + return context.wrap_socket(sock) + +else: # Python 3.1 and earlier + def ssl_wrap_socket(sock, keyfile=None, certfile=None, cert_reqs=None, + ca_certs=None, server_hostname=None, + ssl_version=None): + return wrap_socket(sock, keyfile=keyfile, certfile=certfile, + ca_certs=ca_certs, cert_reqs=cert_reqs, + ssl_version=ssl_version) |