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PAM_PASSWDQC(8)		FreeBSD	System Manager's Manual	       PAM_PASSWDQC(8)

NAME
     pam_passwdqc -- Password quality-control PAM module

SYNOPSIS
     [service-name] module-type	control-flag pam_passwdqc [options]

DESCRIPTION
     The pam_passwdqc module is	a simple password strength checking module for
     PAM.  In addition to checking regular passwords, it offers	support	for
     passphrases and can provide randomly generated passwords.

     The pam_passwdqc module provides functionality for	only one PAM category:
     password changing.	 In terms of the module-type parameter,	this is	the
     ``password'' feature.

     The pam_chauthtok() service function will ask the user for	a new pass-
     word, and verify that it meets certain minimum standards.	If the chosen
     password is unsatisfactory, the service function returns PAM_AUTHTOK_ERR.

     The following options may be passed to the	authentication module:

     min=N0,N1,N2,N3,N4
	     (min=disabled,24,12,8,7) The minimum allowed password lengths for
	     different kinds of	passwords/passphrases.	The keyword disabled
	     can be used to disallow passwords of a given kind regardless of
	     their length.  Each subsequent number is required to be no	larger
	     than the preceding	one.

	     N0	is used	for passwords consisting of characters from one	char-
	     acter class only.	The character classes are: digits, lower-case
	     letters, upper-case letters, and other characters.	 There is also
	     a special class for non-ASCII characters which could not be clas-
	     sified, but are assumed to	be non-digits.

	     N1	is used	for passwords consisting of characters from two	char-
	     acter classes, which do not meet the requirements for a
	     passphrase.

	     N2	is used	for passphrases.  A passphrase must consist of suffi-
	     cient words (see the passphrase option below).

	     N3	and N4 are used	for passwords consisting of characters from
	     three and four character classes, respectively.

	     When calculating the number of character classes, upper-case let-
	     ters used as the first character and digits used as the last
	     character of a password are not counted.

	     In	addition to being sufficiently long, passwords are required to
	     contain enough different characters for the character classes and
	     the minimum length	they have been checked against.

     max=N   (max=40) The maximum allowed password length.  This can be	used
	     to	prevent	users from setting passwords which may be too long for
	     some system services.  The	value 8	is treated specially: if max
	     is	set to 8, passwords longer than	8 characters will not be
	     rejected, but will	be truncated to	8 characters for the strength
	     checks and	the user will be warned.  This is for compatibility
	     with the traditional DES password hashes, which truncate the
	     password at 8 characters.

	     It	is important that you do set max=8 if you are using the	tradi-
	     tional hashes, or some weak passwords will	pass the checks.

     passphrase=N
	     (passphrase=3) The	number of words	required for a passphrase, or
	     0 to disable passphrase support.

     match=N
	     (match=4) The length of common substring required to conclude
	     that a password is	at least partially based on information	found
	     in	a character string, or 0 to disable the	substring search.
	     Note that the password will not be	rejected once a	weak substring
	     is	found; it will instead be subjected to the usual strength
	     requirements with the weak	substring removed.

	     The substring search is case-insensitive and is able to detect
	     and remove	a common substring spelled backwards.

     similar=permit|deny
	     (similar=deny) Whether a new password is allowed to be similar to
	     the old one.  The passwords are considered	to be similar when
	     there is a	sufficiently long common substring and the new pass-
	     word with the substring removed would be weak.

     random=N[,only]
	     (random=42) The size of randomly-generated	passwords in bits, or
	     0 to disable this feature.	 Passwords that	contain	the offered
	     randomly-generated	string will be allowed regardless of other
	     possible restrictions.

	     The only modifier can be used to disallow user-chosen passwords.

     enforce=none|users|everyone
	     (enforce=everyone)	The module can be configured to	warn of	weak
	     passwords only, but not actually enforce strong passwords.	 The
	     users setting will	enforce	strong passwords for non-root users
	     only.

     non-unix
	     Normally, pam_passwdqc uses getpwnam(3) to	obtain the user's per-
	     sonal login information and use that during the password strength
	     checks.  This behavior can	be disabled with the non-unix option.

     retry=N
	     (retry=3) The number of times the module will ask for a new pass-
	     word if the user fails to provide a sufficiently strong password
	     and enter it twice	the first time.

     ask_oldauthtok[=update]
	     Ask for the old password as well.	Normally, pam_passwdqc leaves
	     this task for subsequent modules.	With no	argument, the
	     ask_oldauthtok option will	cause pam_passwdqc to ask for the old
	     password during the preliminary check phase.  If the
	     ask_oldauthtok option is specified	with the update	argument,
	     pam_passwdqc will do that during the update phase.

     check_oldauthtok
	     This tells	pam_passwdqc to	validate the old password before giv-
	     ing a new password	prompt.	 Normally, this	task is	left for sub-
	     sequent modules.

	     The primary use for this option is	when ask_oldauthtok=update is
	     also specified, in	which case no other modules gets a chance to
	     ask for and validate the password.	 Of course, this will only
	     work with UNIX passwords.

     use_first_pass, use_authtok
	     Use the new password obtained by modules stacked before
	     pam_passwdqc.  This disables user interaction within
	     pam_passwdqc.  The	only difference	between	use_first_pass and
	     use_authtok is that the former is incompatible with
	     ask_oldauthtok.

SEE ALSO
     getpwnam(3), pam.conf(5), pam(8)

AUTHORS
     The pam_passwdqc module was written by Solar Designer
     <solar@openwall.com>.  This manual	page, derived from the author's	docu-
     mentation,	was written for	the FreeBSD Project by ThinkSec	AS and NAI
     Labs, the Security	Research Division of Network Associates, Inc. under
     DARPA/SPAWAR contract N66001-01-C-8035 (``CBOSS''), as part of the	DARPA
     CHATS research program.

FreeBSD	9.2			April 15, 2002			   FreeBSD 9.2

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHORS

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