cpython: e73627483d2f (original) (raw)

Mercurial > cpython

changeset 86467:e73627483d2f

Issue #19254: Provide an optimized Python implementation of PBKDF2_HMAC [#19254]

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--- a/Doc/library/hashlib.rst +++ b/Doc/library/hashlib.rst @@ -212,7 +212,11 @@ slow and include a salt. .. versionadded:: 3.4

• .. note:: pbkdf2_hmac is only available with OpenSSL 1.0 and newer.

• .. note:: A fast implementation of pbkdf2_hmac is only available with

•  OpenSSL 1.0 and newer. The Python implementation uses an inline[](#l1.9)

•  version of :mod:`hmac` and is about three times slower. Contrary to[](#l1.10)

•  OpenSSL's current code the length of the password has only a minimal[](#l1.11)

•  impact on the runtime of the Python implementation.[](#l1.12)

.. seealso::

--- a/Lib/hashlib.py +++ b/Lib/hashlib.py @@ -1,4 +1,4 @@ -# Copyright (C) 2005-2010 Gregory P. Smith (greg@krypto.org) +#. Copyright (C) 2005-2010 Gregory P. Smith (greg@krypto.org)

Licensed to PSF under a Contributor Agreement.

# @@ -61,7 +61,7 @@ algorithms_guaranteed = set(__always_sup algorithms_available = set(__always_supported) all = __always_supported + ('new', 'algorithms_guaranteed',

•                            'algorithms_available')[](#l2.13)

•                            'algorithms_available', 'pbkdf2_hmac')[](#l2.14)

def __get_builtin_constructor(name): @@ -147,13 +147,70 @@ except ImportError: new = __py_new __get_hash = __get_builtin_constructor -# PBKDF2 requires OpenSSL 1.0+ with HMAC and SHA try:

• OpenSSL's PKCS5_PBKDF2_HMAC requires OpenSSL 1.0+ with HMAC and SHA

  from _hashlib import pbkdf2_hmac except ImportError:

• pass

-else:

• all += ('pbkdf2_hmac',)

• _trans_5C = bytes((x ^ 0x5C) for x in range(256))
• _trans_36 = bytes((x ^ 0x36) for x in range(256))

+

• def pbkdf2_hmac(hash_name, password, salt, iterations, dklen=None):

•    """Password based key derivation function 2 (PKCS #5 v2.0)[](#l2.34)

+

•    This Python implementations based on the hmac module about as fast[](#l2.36)

•    as OpenSSL's PKCS5_PBKDF2_HMAC for short passwords and much faster[](#l2.37)

•    for long passwords.[](#l2.38)

•    """[](#l2.39)

•    if not isinstance(hash_name, str):[](#l2.40)

•        raise TypeError(hash_name)[](#l2.41)

+

•    if not isinstance(password, (bytes, bytearray)):[](#l2.43)

•        password = bytes(memoryview(password))[](#l2.44)

•    if not isinstance(salt, (bytes, bytearray)):[](#l2.45)

•        salt = bytes(memoryview(salt))[](#l2.46)

+

•    # Fast inline HMAC implementation[](#l2.48)

•    inner = new(hash_name)[](#l2.49)

•    outer = new(hash_name)[](#l2.50)

•    blocksize = getattr(inner, 'block_size', 64)[](#l2.51)

•    if len(password) > blocksize:[](#l2.52)

•        password = new(hash_name, password).digest()[](#l2.53)

•    password = password + b'\x00' * (blocksize - len(password))[](#l2.54)

•    inner.update(password.translate(_trans_36))[](#l2.55)

•    outer.update(password.translate(_trans_5C))[](#l2.56)

+

•    def prf(msg, inner=inner, outer=outer):[](#l2.58)

•        # PBKDF2_HMAC uses the password as key. We can re-use the same[](#l2.59)

•        # digest objects and and just update copies to skip initialization.[](#l2.60)

•        icpy = inner.copy()[](#l2.61)

•        ocpy = outer.copy()[](#l2.62)

•        icpy.update(msg)[](#l2.63)

•        ocpy.update(icpy.digest())[](#l2.64)

•        return ocpy.digest()[](#l2.65)

+

•    if iterations < 1:[](#l2.67)

•        raise ValueError(iterations)[](#l2.68)

•    if dklen is None:[](#l2.69)

•        dklen = outer.digest_size[](#l2.70)

•    if dklen < 1:[](#l2.71)

•        raise ValueError(dklen)[](#l2.72)

+

•    dkey = b''[](#l2.74)

•    loop = 1[](#l2.75)

•    from_bytes = int.from_bytes[](#l2.76)

•    while len(dkey) < dklen:[](#l2.77)

•        prev = prf(salt + loop.to_bytes(4, 'big'))[](#l2.78)

•        # endianess doesn't matter here as long to / from use the same[](#l2.79)

•        rkey = int.from_bytes(prev, 'big')[](#l2.80)

•        for i in range(iterations - 1):[](#l2.81)

•            prev = prf(prev)[](#l2.82)

•            # rkey = rkey ^ prev[](#l2.83)

•            rkey ^= from_bytes(prev, 'big')[](#l2.84)

•        loop += 1[](#l2.85)

•        dkey += rkey.to_bytes(inner.digest_size, 'big')[](#l2.86)

+

•    return dkey[:dklen][](#l2.88)

+ for __func_name in __always_supported: # try them all, some may not work due to the OpenSSL

--- a/Lib/test/test_hashlib.py +++ b/Lib/test/test_hashlib.py @@ -18,11 +18,13 @@ except ImportError: import unittest import warnings from test import support -from test.support import _4G, bigmemtest +from test.support import _4G, bigmemtest, import_fresh_module

Were we compiled --with-pydebug or with #define Py_DEBUG?

COMPILED_WITH_PYDEBUG = hasattr(sys, 'gettotalrefcount') +c_hashlib = import_fresh_module('hashlib', fresh=['_hashlib']) +py_hashlib = import_fresh_module('hashlib', blocked=['_hashlib']) def hexstr(s): assert isinstance(s, bytes), repr(s) @@ -545,6 +547,10 @@ class HashLibTestCase(unittest.TestCase) self.assertEqual(expected_hash, hasher.hexdigest()) + +class KDFTests:

• hashlibmod = None

+ pbkdf2_test_vectors = [ (b'password', b'salt', 1, None), (b'password', b'salt', 2, None), @@ -594,10 +600,8 @@ class HashLibTestCase(unittest.TestCase) (bytes.fromhex('9d9e9c4cd21fe4be24d5b8244c759665'), None),], }

• @unittest.skipUnless(hasattr(hashlib, 'pbkdf2_hmac'),

•                     'pbkdf2_hmac required for this test.')[](#l3.34)

  def test_pbkdf2_hmac(self):

•    pbkdf2 = hashlib.pbkdf2_hmac[](#l3.36)

•    pbkdf2 = self.hashlibmod.pbkdf2_hmac[](#l3.37)

for digest_name, results in self.pbkdf2_results.items(): for i, vector in enumerate(self.pbkdf2_test_vectors): @@ -628,5 +632,13 @@ class HashLibTestCase(unittest.TestCase) pbkdf2('unknown', b'pass', b'salt', 1) +class PyKDFTests(KDFTests, unittest.TestCase):

• hashlibmod = py_hashlib

+ + +class CKDFTests(KDFTests, unittest.TestCase):

• hashlibmod = c_hashlib

+ + if name == "main": unittest.main()

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -57,6 +57,8 @@ Core and Builtins Library ------- +- Issue #19254: Provide an optimized Python implementation of PBKDF2_HMAC. +

• Issues #19201, #19222, #19223: Add "x" mode (exclusive creation) in opening file to bz2, gzip and lzma modules. Patches by Tim Heaney and Vajrasky Kok.