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brettcannonbrettcannon
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Make Lib/crypt.py meet PEP 8 standards. This also led to a tweak in the new API
by making methods() into a module attribute as it is statically calculated.
1 parent 543b7f3 commit daa5799

3 files changed

Lines changed: 60 additions & 58 deletions

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‎Doc/library/crypt.rst‎

Lines changed: 14 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -60,6 +60,20 @@ are available on all platforms):
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.. versionadded:: 3.3
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Module Attributes
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-----------------
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.. attribute:: methods
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A list of available password hashing algorithms, as
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``crypt.METHOD_*`` objects. This list is sorted from strongest to
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weakest, and is guaranteed to have at least ``crypt.METHOD_CRYPT``.
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.. versionadded:: 3.3
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Module Functions
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----------------
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@@ -98,13 +112,6 @@ The :mod:`crypt` module defines the following functions:
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Before version 3.3, *salt* must be specified as a string and cannot
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accept ``crypt.METHOD_*`` values (which don't exist anyway).
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.. function:: methods()
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Return a list of available password hashing algorithms, as
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``crypt.METHOD_*`` objects. This list is sorted from strongest to
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weakest, and is guaranteed to have at least ``crypt.METHOD_CRYPT``.
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.. versionadded:: 3.3
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.. function:: mksalt(method=None)
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‎Lib/crypt.py‎

Lines changed: 40 additions & 44 deletions
Original file line numberDiff line numberDiff line change
@@ -1,61 +1,57 @@
1-
'''Wrapper to the POSIX crypt library call and associated functionality.
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'''
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"""Wrapper to the POSIX crypt library call and associated functionality."""
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import _crypt
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import string
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from random import choice
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from collections import namedtuple
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6-
saltchars = 'abcdefghijklmnopqrstuvwxyz'
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saltchars += saltchars.upper()
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saltchars += '0123456789./'
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_saltchars = string.ascii_letters + string.digits + './'
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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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20-
def __repr__(self):
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return '<crypt.METHOD_%s>' % self.name
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class _Method(namedtuple('_Method', 'name ident salt_chars total_size')):
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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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# 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 __repr__(self):
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return '<crypt.METHOD_{}>'.format(self.name)
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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.
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42-
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 not specified, the strongest available method will be used.
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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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"""
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if method is None:
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method = methods[0]
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s = '${}$'.format(method.ident) if method.ident else ''
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s += ''.join(choice(_saltchars) for _ 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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def crypt(word, salt=None):
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"""Return a string representing the one-way hash of a password, with a salt
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prepended.
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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))
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returned by ``crypt.mksalt()``.
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"""
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if salt is None or isinstance(salt, _Method):
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salt = mksalt(salt)
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return _crypt.crypt(word, salt)
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# available salting/crypto methods
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METHOD_CRYPT = _Method('CRYPT', None, 2, 13)
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METHOD_MD5 = _Method('MD5', '1', 8, 34)
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METHOD_SHA256 = _Method('SHA256', '5', 16, 63)
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METHOD_SHA512 = _Method('SHA512', '6', 16, 106)
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methods = [METHOD_SHA512, METHOD_SHA256, METHOD_MD5, METHOD_CRYPT]
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methods[:-1] = [m for m in methods[:-1] if len(crypt('', m)) == m.total_size]

‎Lib/test/test_crypt.py‎

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Original file line numberDiff line numberDiff line change
@@ -11,24 +11,23 @@ def test_crypt(self):
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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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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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2020
def test_saltedcrypt(self):
21-
for method in crypt.methods():
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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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# Gurantee that METHOD_CRYPT is the last method in crypt.methods().
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methods = crypt.methods()
30-
self.assertTrue(len(methods) >= 1)
31-
self.assertEqual(crypt.METHOD_CRYPT, methods[-1])
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# Gurantee that METHOD_CRYPT is the last method in crypt.methods.
29+
self.assertTrue(len(crypt.methods) >= 1)
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self.assertEqual(crypt.METHOD_CRYPT, crypt.methods[-1])
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3332
def test_main():
3433
support.run_unittest(CryptTestCase)

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