Issue #10924: Adding salt and Modular Crypt Format to crypt library. · pythoncapi/cpython@e2dfefb · GitHub
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Sean Reifscheider
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Issue python#10924: Adding salt and Modular Crypt Format to crypt library.
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Lines changed: 183 additions & 13 deletions

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‎Doc/library/crypt.rst‎

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‎Lib/crypt.py‎

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'''Wrapper to the POSIX crypt library call and associated functionality.
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'''
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import _crypt
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saltchars = 'abcdefghijklmnopqrstuvwxyz'
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saltchars += saltchars.upper()
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saltchars += '0123456789./'
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class _MethodClass:
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'''Class representing a salt method per the Modular Crypt Format or the
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legacy 2-character crypt method.'''
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def __init__(self, name, ident, salt_chars, total_size):
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self.name = name
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self.ident = ident
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self.salt_chars = salt_chars
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self.total_size = total_size
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def __repr__(self):
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return '<crypt.METHOD_%s>' % self.name
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# available salting/crypto methods
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METHOD_CRYPT = _MethodClass('CRYPT', None, 2, 13)
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METHOD_MD5 = _MethodClass('MD5', '1', 8, 34)
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METHOD_SHA256 = _MethodClass('SHA256', '5', 16, 63)
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METHOD_SHA512 = _MethodClass('SHA512', '6', 16, 106)
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def methods():
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'''Return a list of methods that are available in the platform ``crypt()``
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library, sorted from strongest to weakest. This is guaranteed to always
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return at least ``[METHOD_CRYPT]``'''
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method_list = [ METHOD_SHA512, METHOD_SHA256, METHOD_MD5 ]
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ret = [ method for method in method_list
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if len(crypt('', method)) == method.total_size ]
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ret.append(METHOD_CRYPT)
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return ret
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def mksalt(method = None):
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'''Generate a salt for the specified method. If not specified, the
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strongest available method will be used.'''
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import random
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if method == None: method = methods()[0]
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s = '$%s$' % method.ident if method.ident else ''
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s += ''.join([ random.choice(saltchars) for x in range(method.salt_chars) ])
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return(s)
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def crypt(word, salt = None):
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'''Return a string representing the one-way hash of a password, preturbed
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by a salt. If ``salt`` is not specified or is ``None``, the strongest
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available method will be selected and a salt generated. Otherwise,
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``salt`` may be one of the ``crypt.METHOD_*`` values, or a string as
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returned by ``crypt.mksalt()``.'''
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if salt == None: salt = mksalt()
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elif isinstance(salt, _MethodClass): salt = mksalt(salt)
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return(_crypt.crypt(word, salt))

‎Lib/test/test_crypt.py‎

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if support.verbose:
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print('Test encryption: ', c)
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def test_salt(self):
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self.assertEqual(len(crypt.saltchars), 64)
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for method in crypt.methods():
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salt = crypt.mksalt(method)
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self.assertEqual(len(salt),
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method.salt_chars + (3 if method.ident else 0))
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def test_saltedcrypt(self):
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for method in crypt.methods():
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pw = crypt.crypt('assword', method)
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self.assertEqual(len(pw), method.total_size)
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pw = crypt.crypt('assword', crypt.mksalt(method))
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self.assertEqual(len(pw), method.total_size)
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def test_methods(self):
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self.assertTrue(len(crypt.methods()) > 1)
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def test_main():
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support.run_unittest(CryptTestCase)
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‎Misc/NEWS‎

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Library
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-------
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- Issue #10924: Adding salt and Modular Crypt Format to crypt library.
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Moved old C wrapper to _crypt, and added a Python wrapper with
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enhanced salt generation and simpler API for password generation.
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- Issue #11074: Make 'tokenize' so it can be reloaded.
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- Issue #11085: Moved collections abstract base classes into a separate

‎Modules/Setup.dist‎

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#
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# First, look at Setup.config; configure may have set this for you.
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#crypt cryptmodule.c # -lcrypt # crypt(3); needs -lcrypt on some systems
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#_crypt _cryptmodule.c # -lcrypt # crypt(3); needs -lcrypt on some systems
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# Some more UNIX dependent modules -- off by default, since these

Modules/cryptmodule.c renamed to Modules/_cryptmodule.c

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@@ -45,7 +45,7 @@ static PyMethodDef crypt_methods[] = {
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static struct PyModuleDef cryptmodule = {
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PyModuleDef_HEAD_INIT,
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"crypt",
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"_crypt",
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NULL,
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-1,
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crypt_methods,
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};
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PyMODINIT_FUNC
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PyInit_crypt(void)
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PyInit__crypt(void)
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{
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return PyModule_Create(&cryptmodule);
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}

‎setup.py‎

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