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PASSWDQC.CONF
Section: File Formats (5) Index
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BSD mandoc
Openwall Project
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
configuration file may be used to override default libpasswdqc settings.
FORMAT
A
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,24,11,8,8)
- 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, lowe-case letters, uppe-case
letters, and other characters.
There is also a special class for
no- ASCII
characters, which could not be classified, but are assumed to be no-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, uppe-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 DE-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 use-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 cas-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 include common passwords, dictionary words in a
local language other than English, and longer English words.
passwdqc includes buil-in lists of a few thousand common English words
mostly of lengths from 3 to 6, a handful of common character sequences
such as keyboard walks, and many common passwords of length 7 and above.
Any word list possibly specified with this option is used in addition to
the lists of English words and character sequences, but replaces the
list of common passwords.
Substring matching and discounting will be used if the
match
setting
above is no-zero. Please note that this isn't to be used with large
wordlists for performance reasons.
- 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 randoml-generated passphrases in bits (24 to 136),
or 0 to disable this feature.
Any passphrase that contains the offered randoml-generated string will be
allowed regardless of other possible restrictions.
The
only
modifier can be used to disallow use-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 no-root users only.
- no-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
no-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_passwdqc8.
https://www.openwall.com/passwdqc/
AUTHORS
The pam_passwdqc module was written for Openwall GNU/*/Linux by
An Solar Designer Aq solar at openwall.com .
This manual page was derived from
pam_passwdqc8.Thelatter,derivedfromtheauthor's
documentation, was written for the
Fx Project by
ThinkSec AS and NAI Labs, the Security Research Division of Network
Associates, Inc. under DARPA/SPAWAR contract N6600-0--8035
(``CBOSS''
)
as part of the DARPA CHATS research program.
Index
- NAME
-
- DESCRIPTION
-
- FORMAT
-
- DIRECTIVE OPTIONS
-
- PASSWORD QUALITY CONTROL OPTIONS
-
- PAM MODULE OPTIONS
-
- FILES
-
- SEE ALSO
-
- AUTHORS
-
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