NAME
pwqcheck - Check passphrase quality
SYNOPSIS
pwqcheck [options]
DESCRIPTION
The pwqcheck program checks passphrase quality using the libpasswdqc
library. By default, it expects to read 3 lines from standard input:
first line is a new password,
second line is an old password, and
third line is either an existing account name or a passwd(5) entry.
There are a number of supported options, which can be used to control the
pwqcheck behavior.
pwqcheck prints OK on success. Scripts invoking pwqcheck are suggested
to check for both a zero exit status and the OK line.
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=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.
passphrase=N
(default: passphrase=3) The number of words required for a
passphrase.
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.
config=FILE
Load config FILE in the passwdqc.conf format. This file may
define any options described in passwdqc.conf(5), but only the
min, max, passphrase, match, and config options are honored by
pwqcheck.
-1 Read just 1 line (new passphrase). This is needed to use
pwqcheck as the passwordcheck program on OpenBSD - e.g., with
":passwordcheck=/usr/bin/pwqcheck -1:\" in the "default" section
in /etc/login.conf.
-2 Read just 2 lines (new and old passphrases).
--multi
Check multiple passphrases (until EOF). This option may be used
on its own or along with the -1 or -2 options. pwqcheck will
read 1, 2, or 3 lines and will output one line per passphrase to
check. The lines will start with either OK or a message
explaining why the passphrase did not pass the checks, followed
by a colon and a space, and finally followed by the passphrase.
The explanatory message is guaranteed to not include a colon.
With this option, the exit status of pwqcheck depends solely on
whether there were any errors preventing the strength of
passphrases from being fully checked or not. A primary use for
this option is to test different policies and/or different
versions of passwdqc on large passphrase lists.
--version
Output pwqcheck program version and exit.
-h, --help
Output pwqcheck help text and exit.
EXIT STATUS
pwqcheck exits with non-zero status when it encounters invalid config
file, invalid option, invalid parameter value, invalid data in standard
input, and in any case when it fails to check passphrase strength.
Without the --multi option, pwqcheck also exits with non-zero status when
it detects a weak passphrase.
FILES
/etc/passwdqc.conf.
SEE ALSO
pwqgen(1), passwd(5), passwdqc.conf(5), pam_passwdqc(8).
http://www.openwall.com/passwdqc/
AUTHORS
The pam_passwdqc module was written for Openwall GNU/*/Linux by Solar
Designer. The pwqcheck program was originally written for ALT
GNU/*/Linux by Dmitry V. Levin, indirectly reusing code from pam_passwdqc
(via libpasswdqc). This manual page (derived from the pam_passwdqc
documentation) was written for Openwall GNU/*/Linux by Dmitry V. Levin.