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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
	     (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
	     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 5.4			April 15, 2002			   FreeBSD 5.4

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