/usr/lib/python2.7/dist-packages/cryptography/hazmat/bindings/openssl/binding.py is in python-cryptography 1.2.3-1.
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import collections
import os
import threading
import types
import warnings
from cryptography.exceptions import InternalError
from cryptography.hazmat.bindings._openssl import ffi, lib
from cryptography.hazmat.bindings.openssl._conditional import CONDITIONAL_NAMES
_OpenSSLError = collections.namedtuple("_OpenSSLError",
["code", "lib", "func", "reason"])
def _consume_errors(lib):
errors = []
while True:
code = lib.ERR_get_error()
if code == 0:
break
err_lib = lib.ERR_GET_LIB(code)
err_func = lib.ERR_GET_FUNC(code)
err_reason = lib.ERR_GET_REASON(code)
errors.append(_OpenSSLError(code, err_lib, err_func, err_reason))
return errors
def _openssl_assert(lib, ok):
if not ok:
errors = _consume_errors(lib)
raise InternalError(
"Unknown OpenSSL error. Please file an issue at https://github.com"
"/pyca/cryptography/issues with information on how to reproduce "
"this. ({0!r})".format(errors),
errors
)
def ffi_callback(signature, name, **kwargs):
"""Callback dispatcher
The ffi_callback() dispatcher keeps callbacks compatible between dynamic
and static callbacks.
"""
def wrapper(func):
if lib.Cryptography_STATIC_CALLBACKS:
# def_extern() returns a decorator that sets the internal
# function pointer and returns the original function unmodified.
ffi.def_extern(name=name, **kwargs)(func)
callback = getattr(lib, name)
else:
# callback() wraps the function in a cdata function.
callback = ffi.callback(signature, **kwargs)(func)
return callback
return wrapper
@ffi_callback("int (*)(unsigned char *, int)",
name="Cryptography_rand_bytes",
error=-1)
def _osrandom_rand_bytes(buf, size):
signed = ffi.cast("char *", buf)
result = os.urandom(size)
signed[0:size] = result
return 1
@ffi_callback("int (*)(void)", name="Cryptography_rand_status")
def _osrandom_rand_status():
return 1
def build_conditional_library(lib, conditional_names):
conditional_lib = types.ModuleType("lib")
excluded_names = set()
for condition, names in conditional_names.items():
if not getattr(lib, condition):
excluded_names |= set(names)
for attr in dir(lib):
if attr not in excluded_names:
setattr(conditional_lib, attr, getattr(lib, attr))
return conditional_lib
class Binding(object):
"""
OpenSSL API wrapper.
"""
lib = None
ffi = ffi
_lib_loaded = False
_locks = None
_lock_cb_handle = None
_init_lock = threading.Lock()
_lock_init_lock = threading.Lock()
_osrandom_engine_id = ffi.new("const char[]", b"osrandom")
_osrandom_engine_name = ffi.new("const char[]", b"osrandom_engine")
_osrandom_method = ffi.new(
"RAND_METHOD *",
dict(bytes=_osrandom_rand_bytes,
pseudorand=_osrandom_rand_bytes,
status=_osrandom_rand_status)
)
def __init__(self):
self._ensure_ffi_initialized()
@classmethod
def _register_osrandom_engine(cls):
_openssl_assert(cls.lib, cls.lib.ERR_peek_error() == 0)
engine = cls.lib.ENGINE_new()
_openssl_assert(cls.lib, engine != cls.ffi.NULL)
try:
result = cls.lib.ENGINE_set_id(engine, cls._osrandom_engine_id)
_openssl_assert(cls.lib, result == 1)
result = cls.lib.ENGINE_set_name(engine, cls._osrandom_engine_name)
_openssl_assert(cls.lib, result == 1)
result = cls.lib.ENGINE_set_RAND(engine, cls._osrandom_method)
_openssl_assert(cls.lib, result == 1)
result = cls.lib.ENGINE_add(engine)
if result != 1:
errors = _consume_errors(cls.lib)
_openssl_assert(
cls.lib,
errors[0].reason == cls.lib.ENGINE_R_CONFLICTING_ENGINE_ID
)
finally:
result = cls.lib.ENGINE_free(engine)
_openssl_assert(cls.lib, result == 1)
@classmethod
def _ensure_ffi_initialized(cls):
with cls._init_lock:
if not cls._lib_loaded:
cls.lib = build_conditional_library(lib, CONDITIONAL_NAMES)
cls._lib_loaded = True
# initialize the SSL library
cls.lib.SSL_library_init()
# adds all ciphers/digests for EVP
cls.lib.OpenSSL_add_all_algorithms()
# loads error strings for libcrypto and libssl functions
cls.lib.SSL_load_error_strings()
cls._register_osrandom_engine()
@classmethod
def init_static_locks(cls):
with cls._lock_init_lock:
cls._ensure_ffi_initialized()
if not cls._lock_cb_handle:
wrapper = ffi_callback(
"void(int, int, const char *, int)",
name="Cryptography_locking_cb",
)
cls._lock_cb_handle = wrapper(cls._lock_cb)
# Use Python's implementation if available, importing _ssl triggers
# the setup for this.
__import__("_ssl")
if cls.lib.CRYPTO_get_locking_callback() != cls.ffi.NULL:
return
# If nothing else has setup a locking callback already, we set up
# our own
num_locks = cls.lib.CRYPTO_num_locks()
cls._locks = [threading.Lock() for n in range(num_locks)]
cls.lib.CRYPTO_set_locking_callback(cls._lock_cb_handle)
@classmethod
def _lock_cb(cls, mode, n, file, line):
lock = cls._locks[n]
if mode & cls.lib.CRYPTO_LOCK:
lock.acquire()
elif mode & cls.lib.CRYPTO_UNLOCK:
lock.release()
else:
raise RuntimeError(
"Unknown lock mode {0}: lock={1}, file={2}, line={3}.".format(
mode, n, file, line
)
)
# OpenSSL is not thread safe until the locks are initialized. We call this
# method in module scope so that it executes with the import lock. On
# Pythons < 3.4 this import lock is a global lock, which can prevent a race
# condition registering the OpenSSL locks. On Python 3.4+ the import lock
# is per module so this approach will not work.
Binding.init_static_locks()
if Binding.lib.SSLeay() < 0x10001000:
warnings.warn(
"OpenSSL versions less than 1.0.1 are no longer supported by the "
"OpenSSL project, please upgrade. A future version of cryptography "
"will drop support for these versions.",
DeprecationWarning
)
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