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46 lines
1.7 KiB
TeX
46 lines
1.7 KiB
TeX
\section{\module{crypt} ---
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Function to check \UNIX{} passwords}
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\declaremodule{builtin}{crypt}
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\platform{Unix}
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\modulesynopsis{The \cfunction{crypt()} function used to check
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\UNIX\ passwords.}
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\moduleauthor{Steven D. Majewski}{sdm7g@virginia.edu}
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\sectionauthor{Steven D. Majewski}{sdm7g@virginia.edu}
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\sectionauthor{Peter Funk}{pf@artcom-gmbh.de}
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This module implements an interface to the
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\manpage{crypt}{3}\index{crypt(3)} routine, which is a one-way hash
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function based upon a modified DES\indexii{cipher}{DES} algorithm; see
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the \UNIX{} man page for further details. Possible uses include
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allowing Python scripts to accept typed passwords from the user, or
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attempting to crack \UNIX{} passwords with a dictionary.
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\begin{funcdesc}{crypt}{word, salt}
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\var{word} will usually be a user's password as typed at a prompt or
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in a graphical interface. \var{salt} is usually a random
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two-character string which will be used to perturb the DES algorithm
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in one of 4096 ways. The characters in \var{salt} must be in the
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set \regexp{[./a-zA-Z0-9]}. Returns the hashed password as a
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string, which will be composed of characters from the same alphabet
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as the salt (the first two characters represent the salt itself).
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\end{funcdesc}
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A simple example illustrating typical use:
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\begin{verbatim}
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import crypt, getpass, pwd
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def login():
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username = raw_input('Python login:')
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cryptedpasswd = pwd.getpwnam(username)[1]
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if cryptedpasswd:
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if cryptedpasswd == 'x' or cryptedpasswd == '*':
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raise "Sorry, currently no support for shadow passwords"
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cleartext = getpass.getpass()
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return crypt.crypt(cleartext, cryptedpasswd[:2]) == cryptedpasswd
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else:
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return 1
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\end{verbatim}
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