You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
407 lines
14 KiB
407 lines
14 KiB
from __future__ import absolute_import
|
|
import errno
|
|
import warnings
|
|
import hmac
|
|
import sys
|
|
|
|
from binascii import hexlify, unhexlify
|
|
from hashlib import md5, sha1, sha256
|
|
|
|
from .url import IPV4_RE, BRACELESS_IPV6_ADDRZ_RE
|
|
from ..exceptions import SSLError, InsecurePlatformWarning, SNIMissingWarning
|
|
from ..packages import six
|
|
|
|
|
|
SSLContext = None
|
|
HAS_SNI = False
|
|
IS_PYOPENSSL = False
|
|
IS_SECURETRANSPORT = False
|
|
|
|
# Maps the length of a digest to a possible hash function producing this digest
|
|
HASHFUNC_MAP = {32: md5, 40: sha1, 64: sha256}
|
|
|
|
|
|
def _const_compare_digest_backport(a, b):
|
|
"""
|
|
Compare two digests of equal length in constant time.
|
|
|
|
The digests must be of type str/bytes.
|
|
Returns True if the digests match, and False otherwise.
|
|
"""
|
|
result = abs(len(a) - len(b))
|
|
for l, r in zip(bytearray(a), bytearray(b)):
|
|
result |= l ^ r
|
|
return result == 0
|
|
|
|
|
|
_const_compare_digest = getattr(hmac, "compare_digest", _const_compare_digest_backport)
|
|
|
|
try: # Test for SSL features
|
|
import ssl
|
|
from ssl import wrap_socket, CERT_REQUIRED
|
|
from ssl import HAS_SNI # Has SNI?
|
|
except ImportError:
|
|
pass
|
|
|
|
try: # Platform-specific: Python 3.6
|
|
from ssl import PROTOCOL_TLS
|
|
|
|
PROTOCOL_SSLv23 = PROTOCOL_TLS
|
|
except ImportError:
|
|
try:
|
|
from ssl import PROTOCOL_SSLv23 as PROTOCOL_TLS
|
|
|
|
PROTOCOL_SSLv23 = PROTOCOL_TLS
|
|
except ImportError:
|
|
PROTOCOL_SSLv23 = PROTOCOL_TLS = 2
|
|
|
|
|
|
try:
|
|
from ssl import OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION
|
|
except ImportError:
|
|
OP_NO_SSLv2, OP_NO_SSLv3 = 0x1000000, 0x2000000
|
|
OP_NO_COMPRESSION = 0x20000
|
|
|
|
|
|
# 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 and ChaCha20 over any AES-CBC for better performance and
|
|
# security,
|
|
# - prefer AES-GCM over ChaCha20 because hardware-accelerated AES is common,
|
|
# - disable NULL authentication, MD5 MACs, DSS, and other
|
|
# insecure ciphers for security reasons.
|
|
# - NOTE: TLS 1.3 cipher suites are managed through a different interface
|
|
# not exposed by CPython (yet!) and are enabled by default if they're available.
|
|
DEFAULT_CIPHERS = ":".join(
|
|
[
|
|
"ECDHE+AESGCM",
|
|
"ECDHE+CHACHA20",
|
|
"DHE+AESGCM",
|
|
"DHE+CHACHA20",
|
|
"ECDH+AESGCM",
|
|
"DH+AESGCM",
|
|
"ECDH+AES",
|
|
"DH+AES",
|
|
"RSA+AESGCM",
|
|
"RSA+AES",
|
|
"!aNULL",
|
|
"!eNULL",
|
|
"!MD5",
|
|
"!DSS",
|
|
]
|
|
)
|
|
|
|
try:
|
|
from ssl import SSLContext # Modern SSL?
|
|
except ImportError:
|
|
|
|
class SSLContext(object): # Platform-specific: Python 2
|
|
def __init__(self, protocol_version):
|
|
self.protocol = protocol_version
|
|
# Use default values from a real SSLContext
|
|
self.check_hostname = False
|
|
self.verify_mode = ssl.CERT_NONE
|
|
self.ca_certs = None
|
|
self.options = 0
|
|
self.certfile = None
|
|
self.keyfile = None
|
|
self.ciphers = None
|
|
|
|
def load_cert_chain(self, certfile, keyfile):
|
|
self.certfile = certfile
|
|
self.keyfile = keyfile
|
|
|
|
def load_verify_locations(self, cafile=None, capath=None):
|
|
self.ca_certs = cafile
|
|
|
|
if capath is not None:
|
|
raise SSLError("CA directories not supported in older Pythons")
|
|
|
|
def set_ciphers(self, cipher_suite):
|
|
self.ciphers = cipher_suite
|
|
|
|
def wrap_socket(self, socket, server_hostname=None, server_side=False):
|
|
warnings.warn(
|
|
"A true SSLContext object is not available. This prevents "
|
|
"urllib3 from configuring SSL appropriately and may cause "
|
|
"certain SSL connections to fail. You can upgrade to a newer "
|
|
"version of Python to solve this. For more information, see "
|
|
"https://urllib3.readthedocs.io/en/latest/advanced-usage.html"
|
|
"#ssl-warnings",
|
|
InsecurePlatformWarning,
|
|
)
|
|
kwargs = {
|
|
"keyfile": self.keyfile,
|
|
"certfile": self.certfile,
|
|
"ca_certs": self.ca_certs,
|
|
"cert_reqs": self.verify_mode,
|
|
"ssl_version": self.protocol,
|
|
"server_side": server_side,
|
|
}
|
|
return wrap_socket(socket, ciphers=self.ciphers, **kwargs)
|
|
|
|
|
|
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.
|
|
"""
|
|
|
|
fingerprint = fingerprint.replace(":", "").lower()
|
|
digest_length = len(fingerprint)
|
|
hashfunc = HASHFUNC_MAP.get(digest_length)
|
|
if not hashfunc:
|
|
raise SSLError("Fingerprint of invalid length: {0}".format(fingerprint))
|
|
|
|
# We need encode() here for py32; works on py2 and p33.
|
|
fingerprint_bytes = unhexlify(fingerprint.encode())
|
|
|
|
cert_digest = hashfunc(cert).digest()
|
|
|
|
if not _const_compare_digest(cert_digest, fingerprint_bytes):
|
|
raise SSLError(
|
|
'Fingerprints did not match. Expected "{0}", got "{1}".'.format(
|
|
fingerprint, 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_REQUIRED`.
|
|
If given a string it is assumed to be the name of the constant in the
|
|
:mod:`ssl` module or its abbreviation.
|
|
(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_REQUIRED
|
|
|
|
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_TLS
|
|
|
|
if isinstance(candidate, str):
|
|
res = getattr(ssl, candidate, None)
|
|
if res is None:
|
|
res = getattr(ssl, "PROTOCOL_" + candidate)
|
|
return res
|
|
|
|
return candidate
|
|
|
|
|
|
def create_urllib3_context(
|
|
ssl_version=None, cert_reqs=None, options=None, ciphers=None
|
|
):
|
|
"""All arguments have the same meaning as ``ssl_wrap_socket``.
|
|
|
|
By default, this function does a lot of the same work that
|
|
``ssl.create_default_context`` does on Python 3.4+. It:
|
|
|
|
- Disables SSLv2, SSLv3, and compression
|
|
- Sets a restricted set of server ciphers
|
|
|
|
If you wish to enable SSLv3, you can do::
|
|
|
|
from urllib3.util import ssl_
|
|
context = ssl_.create_urllib3_context()
|
|
context.options &= ~ssl_.OP_NO_SSLv3
|
|
|
|
You can do the same to enable compression (substituting ``COMPRESSION``
|
|
for ``SSLv3`` in the last line above).
|
|
|
|
:param ssl_version:
|
|
The desired protocol version to use. This will default to
|
|
PROTOCOL_SSLv23 which will negotiate the highest protocol that both
|
|
the server and your installation of OpenSSL support.
|
|
:param cert_reqs:
|
|
Whether to require the certificate verification. This defaults to
|
|
``ssl.CERT_REQUIRED``.
|
|
:param options:
|
|
Specific OpenSSL options. These default to ``ssl.OP_NO_SSLv2``,
|
|
``ssl.OP_NO_SSLv3``, ``ssl.OP_NO_COMPRESSION``.
|
|
:param ciphers:
|
|
Which cipher suites to allow the server to select.
|
|
:returns:
|
|
Constructed SSLContext object with specified options
|
|
:rtype: SSLContext
|
|
"""
|
|
context = SSLContext(ssl_version or PROTOCOL_TLS)
|
|
|
|
context.set_ciphers(ciphers or DEFAULT_CIPHERS)
|
|
|
|
# Setting the default here, as we may have no ssl module on import
|
|
cert_reqs = ssl.CERT_REQUIRED if cert_reqs is None else cert_reqs
|
|
|
|
if options is None:
|
|
options = 0
|
|
# SSLv2 is easily broken and is considered harmful and dangerous
|
|
options |= OP_NO_SSLv2
|
|
# SSLv3 has several problems and is now dangerous
|
|
options |= OP_NO_SSLv3
|
|
# Disable compression to prevent CRIME attacks for OpenSSL 1.0+
|
|
# (issue #309)
|
|
options |= OP_NO_COMPRESSION
|
|
|
|
context.options |= options
|
|
|
|
# Enable post-handshake authentication for TLS 1.3, see GH #1634. PHA is
|
|
# necessary for conditional client cert authentication with TLS 1.3.
|
|
# The attribute is None for OpenSSL <= 1.1.0 or does not exist in older
|
|
# versions of Python. We only enable on Python 3.7.4+ or if certificate
|
|
# verification is enabled to work around Python issue #37428
|
|
# See: https://bugs.python.org/issue37428
|
|
if (cert_reqs == ssl.CERT_REQUIRED or sys.version_info >= (3, 7, 4)) and getattr(
|
|
context, "post_handshake_auth", None
|
|
) is not None:
|
|
context.post_handshake_auth = True
|
|
|
|
context.verify_mode = cert_reqs
|
|
if (
|
|
getattr(context, "check_hostname", None) is not None
|
|
): # Platform-specific: Python 3.2
|
|
# We do our own verification, including fingerprints and alternative
|
|
# hostnames. So disable it here
|
|
context.check_hostname = False
|
|
return context
|
|
|
|
|
|
def ssl_wrap_socket(
|
|
sock,
|
|
keyfile=None,
|
|
certfile=None,
|
|
cert_reqs=None,
|
|
ca_certs=None,
|
|
server_hostname=None,
|
|
ssl_version=None,
|
|
ciphers=None,
|
|
ssl_context=None,
|
|
ca_cert_dir=None,
|
|
key_password=None,
|
|
):
|
|
"""
|
|
All arguments except for server_hostname, ssl_context, and ca_cert_dir have
|
|
the same meaning as they do when using :func:`ssl.wrap_socket`.
|
|
|
|
:param server_hostname:
|
|
When SNI is supported, the expected hostname of the certificate
|
|
:param ssl_context:
|
|
A pre-made :class:`SSLContext` object. If none is provided, one will
|
|
be created using :func:`create_urllib3_context`.
|
|
:param ciphers:
|
|
A string of ciphers we wish the client to support.
|
|
:param ca_cert_dir:
|
|
A directory containing CA certificates in multiple separate files, as
|
|
supported by OpenSSL's -CApath flag or the capath argument to
|
|
SSLContext.load_verify_locations().
|
|
:param key_password:
|
|
Optional password if the keyfile is encrypted.
|
|
"""
|
|
context = ssl_context
|
|
if context is None:
|
|
# Note: This branch of code and all the variables in it are no longer
|
|
# used by urllib3 itself. We should consider deprecating and removing
|
|
# this code.
|
|
context = create_urllib3_context(ssl_version, cert_reqs, ciphers=ciphers)
|
|
|
|
if ca_certs or ca_cert_dir:
|
|
try:
|
|
context.load_verify_locations(ca_certs, ca_cert_dir)
|
|
except IOError as e: # Platform-specific: Python 2.7
|
|
raise SSLError(e)
|
|
# Py33 raises FileNotFoundError which subclasses OSError
|
|
# These are not equivalent unless we check the errno attribute
|
|
except OSError as e: # Platform-specific: Python 3.3 and beyond
|
|
if e.errno == errno.ENOENT:
|
|
raise SSLError(e)
|
|
raise
|
|
|
|
elif ssl_context is None and hasattr(context, "load_default_certs"):
|
|
# try to load OS default certs; works well on Windows (require Python3.4+)
|
|
context.load_default_certs()
|
|
|
|
# Attempt to detect if we get the goofy behavior of the
|
|
# keyfile being encrypted and OpenSSL asking for the
|
|
# passphrase via the terminal and instead error out.
|
|
if keyfile and key_password is None and _is_key_file_encrypted(keyfile):
|
|
raise SSLError("Client private key is encrypted, password is required")
|
|
|
|
if certfile:
|
|
if key_password is None:
|
|
context.load_cert_chain(certfile, keyfile)
|
|
else:
|
|
context.load_cert_chain(certfile, keyfile, key_password)
|
|
|
|
# If we detect server_hostname is an IP address then the SNI
|
|
# extension should not be used according to RFC3546 Section 3.1
|
|
# We shouldn't warn the user if SNI isn't available but we would
|
|
# not be using SNI anyways due to IP address for server_hostname.
|
|
if (
|
|
server_hostname is not None and not is_ipaddress(server_hostname)
|
|
) or IS_SECURETRANSPORT:
|
|
if HAS_SNI and server_hostname is not None:
|
|
return context.wrap_socket(sock, server_hostname=server_hostname)
|
|
|
|
warnings.warn(
|
|
"An HTTPS request has been made, but the SNI (Server Name "
|
|
"Indication) extension to TLS is not available on this platform. "
|
|
"This may cause the server to present an incorrect TLS "
|
|
"certificate, which can cause validation failures. You can upgrade to "
|
|
"a newer version of Python to solve this. For more information, see "
|
|
"https://urllib3.readthedocs.io/en/latest/advanced-usage.html"
|
|
"#ssl-warnings",
|
|
SNIMissingWarning,
|
|
)
|
|
|
|
return context.wrap_socket(sock)
|
|
|
|
|
|
def is_ipaddress(hostname):
|
|
"""Detects whether the hostname given is an IPv4 or IPv6 address.
|
|
Also detects IPv6 addresses with Zone IDs.
|
|
|
|
:param str hostname: Hostname to examine.
|
|
:return: True if the hostname is an IP address, False otherwise.
|
|
"""
|
|
if not six.PY2 and isinstance(hostname, bytes):
|
|
# IDN A-label bytes are ASCII compatible.
|
|
hostname = hostname.decode("ascii")
|
|
return bool(IPV4_RE.match(hostname) or BRACELESS_IPV6_ADDRZ_RE.match(hostname))
|
|
|
|
|
|
def _is_key_file_encrypted(key_file):
|
|
"""Detects if a key file is encrypted or not."""
|
|
with open(key_file, "r") as f:
|
|
for line in f:
|
|
# Look for Proc-Type: 4,ENCRYPTED
|
|
if "ENCRYPTED" in line:
|
|
return True
|
|
|
|
return False
|
|
|