NAME

     passwdqc.conf — libpasswdqc configuration file

DESCRIPTION

     libpasswdqc is a simple password strength checking library.  In addition to checking regular
     passwords, it offers support for passphrases and can provide randomly generated ones.  A
     passwdqc.conf configuration file may be used to override default libpasswdqc settings.

FORMAT

     A passwdqc.conf file consists of 0 or more lines of the following format:
           option=value

     Empty lines and lines beginning with “#” are ignored.  Whitespace characters between the
     option, “=”, and value are not allowed.

DIRECTIVE OPTIONS

     config=FILE
             Load the specified configuration FILE in the passwdqc.conf format.  This file may
             define any options described in this manual, including load of yet another
             configuration file, but loops are not allowed.

PASSWORD QUALITY CONTROL OPTIONS

     min=N0,N1,N2,N3,N4
             (default: min=disabled,24,11,8,7) 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 character 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 classified, but are assumed to be non-digits.

             N1 is used for passwords consisting of characters from two character classes that do
             not meet the requirements for a passphrase.

             N2 is used for passphrases.  Note that besides meeting this length requirement, a
             passphrase must also consist of a sufficient number of 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 letters 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   (default: max=72) The maximum allowed password length.  This can be used to prevent
             users from setting passwords that 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 to be used with the traditional DES-based
             password hashes, which truncate the password at 8 characters.

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

     passphrase=N
             (default: passphrase=3) The number of words required for a passphrase, or 0 to
             disable the support for user-chosen passphrases.

     match=N
             (default: 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 partially discounted.

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

     similar=permit|deny
             (default: 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 password with the substring partially discounted would
             be weak.

     wordlist=FILE
             Deny passwords that are based on lines of the tiny external text FILE, which can
             reasonably be e.g. a list of a few thousand common passwords.  Common dictionary
             words may also reasonably be included, especially in a local language other than
             English, or longer yet common English words.  (passwdqc includes a list of a few
             thousand common English words of lengths from 3 to 6 built in.  Any word list
             possibly specified with this option is used in addition to the built-in word list.)

             Substring matching and discounting will be used if the match setting above is non-
             zero.  Please note that this is very inefficient, and isn't to be used with large
             wordlists.

     denylist=FILE
             Deny passwords or passphrases directly appearing in the tiny external text FILE.
             That file can reasonably be e.g. a list of common passwords if only a relaxed policy
             is desired and stricter checks are thus disabled (using their separate options).
             Such policy would only be somewhat effective against online/remote attacks, but not
             against offline attacks on hashed passwords.

     filter=FILE
             Deny passwords or passphrases directly appearing in a maybe huge binary filter FILE
             created with pwqfilter.  This is very efficient, needing at most two random disk
             reads per query.  A filter created from millions of leaked passwords can reasonably
             be used on top of passwdqc's other checks to further reduce the number of passing
             yet weak passwords without causing unreasonable inconvenience (as e.g. higher
             minimum lengths and character set requirements could).

     random=N[,only]
             (default: random=47) The size of randomly-generated passphrases in bits (24 to 136),
             or 0 to disable this feature.  Any passphrase that contains the offered randomly-
             generated string will be allowed regardless of other possible restrictions.

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

PAM MODULE OPTIONS

     enforce=none|users|everyone
             (default: enforce=everyone) The PAM module can be configured to warn of weak
             passwords only, but not actually enforce strong passwords.  The users setting is
             like everyone for all PAM services except chpasswd and passwd.  For these two PAM
             services users will enforce strong passwords for invocations by non-root users only.

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

     retry=N
             (default: retry=3) The number of times the PAM module will ask for a new password 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, the PAM module leaves this task for
             subsequent modules.  With no argument, the ask_oldauthtok option will cause the PAM
             module to ask for the old password during the preliminary check phase. If the
             ask_oldauthtok option is specified with the update argument, the PAM module will do
             that during the update phase.

     check_oldauthtok
             This tells the PAM module to validate the old password before giving a new password
             prompt.  Normally, this task is left for subsequent modules.

             The primary use for this option is when ask_oldauthtok=update is also specified, in
             which case no other module 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 other modules stacked before the PAM module.  This
             disables user interaction within the PAM module.  The only difference between
             use_first_pass and use_authtok is that the former is incompatible with
             ask_oldauthtok.

     noaudit
             If audit is enabled at build time, the PAM module logs audit events once user tries
             to change their credentials.  This option disables that audit logging.

FILES

     /etc/passwdqc.conf (not read unless this suggested file location is specified with the
     config=/etc/passwdqc.conf option).

SEE ALSO

     getpwnam(3), libpasswdqc(3), pam_passwdqc(8).

     https://www.openwall.com/passwdqc/

AUTHORS

     The pam_passwdqc module was written for Openwall GNU/*/Linux by Solar Designer <solar at
     openwall.com>.  This manual page was derived from pam_passwdqc(8). The latter, derived from
     the author's documentation, 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.