This is the pam_unix module. It has been significantly rewritten since
.51 was released (due mostly to the efforts of Cristian Gafton), and
now takes more options and correctly updates vanilla UNIX/shadow/md5
passwords.

[Please read the source and make a note of all the warnings there, as
the license suggests -- use at your own risk.]

So far as I am concerned this module is now pretty stable. If you find
any bugs, PLEASE tell me! <morgan@linux.kernel.org>

Options recognized by this module are as follows:

	debug		-	log more debugging info
	audit		-	a little more extreme than debug
	use_first_pass	-	don't prompt the user for passwords
				take them from PAM_ items instead
	try_first_pass  -	don't prompt the user for the passwords
				unless PAM_(OLD)AUTHTOK is unset
	use_authtok	-	like try_first_pass, but *fail* if the new
				PAM_AUTHTOK has not been previously set.
				(intended for stacking password modules only)
	not_set_pass    -	don't set the PAM_ items with the passwords
				used by this module.
	shadow          -       try to maintian a shadow based system.
	unix		-	when changing passwords, they are placed
				in the /etc/passwd file
	md5		-	when a user changes their password next,
				encrypt it with the md5 algorithm.
	bigcrypt	-	when a user changes their password next,
				excrypt it with the DEC C2-algorithm(0).
	nodelay		-	used to prevent failed authentication
				resulting in a delay of about 1 second.

There is some support for building a shadow file on-the-fly from an
/etc/passwd file. This is VERY alpha. If you want to play with it you
should read the source to find the appropriate #define that you will
need.

---------------------
Andrew Morgan <morgan@linux.kernel.org>