115 lines
3.2 KiB
Python
115 lines
3.2 KiB
Python
"""
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Password generation for the yap_ipython notebook.
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"""
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#-----------------------------------------------------------------------------
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# Imports
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#-----------------------------------------------------------------------------
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# Stdlib
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import getpass
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import hashlib
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import random
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# Our own
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from yap_ipython.core.error import UsageError
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from yap_ipython.utils.py3compat import encode
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#-----------------------------------------------------------------------------
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# Globals
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#-----------------------------------------------------------------------------
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# Length of the salt in nr of hex chars, which implies salt_len * 4
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# bits of randomness.
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salt_len = 12
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#-----------------------------------------------------------------------------
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# Functions
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#-----------------------------------------------------------------------------
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def passwd(passphrase=None, algorithm='sha1'):
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"""Generate hashed password and salt for use in notebook configuration.
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In the notebook configuration, set `c.NotebookApp.password` to
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the generated string.
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Parameters
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----------
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passphrase : str
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Password to hash. If unspecified, the user is asked to input
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and verify a password.
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algorithm : str
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Hashing algorithm to use (e.g, 'sha1' or any argument supported
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by :func:`hashlib.new`).
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Returns
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-------
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hashed_passphrase : str
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Hashed password, in the format 'hash_algorithm:salt:passphrase_hash'.
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Examples
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--------
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>>> passwd('mypassword')
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'sha1:7cf3:b7d6da294ea9592a9480c8f52e63cd42cfb9dd12'
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"""
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if passphrase is None:
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for i in range(3):
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p0 = getpass.getpass('Enter password: ')
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p1 = getpass.getpass('Verify password: ')
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if p0 == p1:
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passphrase = p0
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break
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else:
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print('Passwords do not match.')
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else:
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raise UsageError('No matching passwords found. Giving up.')
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h = hashlib.new(algorithm)
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salt = ('%0' + str(salt_len) + 'x') % random.getrandbits(4 * salt_len)
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h.update(encode(passphrase, 'utf-8') + encode(salt, 'ascii'))
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return ':'.join((algorithm, salt, h.hexdigest()))
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def passwd_check(hashed_passphrase, passphrase):
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"""Verify that a given passphrase matches its hashed version.
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Parameters
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----------
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hashed_passphrase : str
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Hashed password, in the format returned by `passwd`.
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passphrase : str
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Passphrase to validate.
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Returns
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-------
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valid : bool
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True if the passphrase matches the hash.
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Examples
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--------
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>>> from yap_ipython.lib.security import passwd_check
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>>> passwd_check('sha1:0e112c3ddfce:a68df677475c2b47b6e86d0467eec97ac5f4b85a',
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... 'mypassword')
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True
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>>> passwd_check('sha1:0e112c3ddfce:a68df677475c2b47b6e86d0467eec97ac5f4b85a',
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... 'anotherpassword')
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False
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"""
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try:
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algorithm, salt, pw_digest = hashed_passphrase.split(':', 2)
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except (ValueError, TypeError):
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return False
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try:
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h = hashlib.new(algorithm)
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except ValueError:
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return False
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if len(pw_digest) == 0:
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return False
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h.update(encode(passphrase, 'utf-8') + encode(salt, 'ascii'))
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return h.hexdigest() == pw_digest
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