Provided by: passwdqc_2.0.2-1_amd64 
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 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.