리눅스 패스워드 정책 설정 (CentOS 6.6 기준)

This option makes the module write information to syslog(3) indicating the behavior of the module (this option does not write password information to the log file).

authtok_type=XXX
The default action is for the module to use the following prompts when requesting passwords: “New UNIX password: ” and “Retype UNIX password: “. The example word UNIX can be replaced with this option, by default it is empty.

retry=N
Prompt user at most N times before returning with error. The default is 1.

difok=N
This argument will change the default of 5 for the number of character changes in the new password that differentiate it from the old password.

minlen=N
The minimum acceptable size for the new password (plus one if credits are not disabled which is the default). In addition to the number of characters in the new password, credit (of +1 in length) is given for each different kind of character (other, upper, lower and digit). The default for this parameter is 9 which is good for a old style UNIX password all of the same type of character but may be too low to exploit the added security of a md5 system. Note that there is a pair of length limits in Cracklib itself, a “way too short” limit of 4 which is hard coded in and a defined limit (6) that will be checked without reference to minlen. If you want to allow passwords as short as 5 characters you should not use this module.

dcredit=N
(N >= 0) This is the maximum credit for having digits in the new password. If you have less than or N digits, each digit will count +1 towards meeting the current minlen value. The default for dcredit is 1 which is the recommended value for minlen less than 10.
(N < 0) This is the minimum number of digits that must be met for a new password. ucredit=N (N >= 0) This is the maximum credit for having upper case letters in the new password. If you have less than or N upper case letters each letter will count +1 towards meeting the current minlen value. The default for ucredit is 1 which is the recommended value for minlen less than 10.
(N < 0) This is the minimum number of upper case letters that must be met for a new password. lcredit=N (N >= 0) This is the maximum credit for having lower case letters in the new password. If you have less than or N lower case letters, each letter will count +1 towards meeting the current minlen value. The default for lcredit is 1 which is the recommended value for minlen less than 10.
(N < 0) This is the minimum number of lower case letters that must be met for a new password. ocredit=N (N >= 0) This is the maximum credit for having other characters in the new password. If you have less than or N other characters, each character will count +1 towards meeting the current minlen value. The default for ocredit is 1 which is the recommended value for minlen less than 10.
(N < 0) This is the minimum number of other characters that must be met for a new password.

minclass=N
The minimum number of required classes of characters for the new password. The default number is zero. The four classes are digits, upper and lower letters and other characters. The difference to the credit check is that a specific class if of characters is not required. Instead N out of four of the classes are required.

maxrepeat=N
Reject passwords which contain more than N same consecutive characters. The default is 0 which means that this check is disabled.

maxsequence=N
Reject passwords which contain monotonic character sequences longer than N. The default is 0 which means that this check is disabled. Examples of such sequence are ‘12345’ or ‘fedcb’. Note that most such passwords will not pass the simplicity check unless the sequence is only a minor part of the password.

maxclassrepeat=N
Reject passwords which contain more than N consecutive characters of the same class. The default is 0 which means that this check is disabled.

reject_username
Check whether the name of the user in straight or reversed form is contained in the new password. If it is found the new password is rejected.

gecoscheck
Check whether the words from the GECOS field (usualy full name of the user) longer than 3 characters in straight or reversed form are contained in the new password. If any such word is found the new password is rejected.

enforce_for_root
The module will return error on failed check also if the user changing the password is root. This option is off by default which means that just the message about the failed check is printed but root can change the password anyway.

use_authtok
This argument is used to force the module to not prompt the user for a new password but use the one provided by the previously stacked password module.

dictpath=/path/to/dict
Path to the cracklib dictionaries.