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     passwdqc.conf - libpasswdqc configuration file


     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.


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

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


             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.


             (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

             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=40) 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.

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

             (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

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

             (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

             (default: random=47) The size of randomly-generated passphrases
             in bits (26 to 81), 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.


             (default: enforce=everyone) The PAM module can be configured to
             warn of weak passwords only, but not actually enforce strong
             passwords.  The users setting will enforce strong passwords for
             invocations by non-root users only.

             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

             (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 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.

             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




     getpwnam(3), pam_passwdqc(8).


     The pam_passwdqc module was written for Openwall GNU/*/Linux by Solar
     Designer 〈solar at〉.  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.