PAM_UNIX_NG(8)

NAME
pam_unix_ng - PAM module for traditional password authentication

SYNOPSIS

pam_unix_ng.so [...]

DESCRIPTION

This is a standard UNIX authentication PAM module which delegates tasks requiring access to /etc/shadow to pwaccessd(8), which allows one to use this module in environments without setuid binaries. If pwaccessd is not running, it tries at first to start it via D-Bus. If this fails, it tries to read the local files as fallback itself.

OPTIONS

debug
    Print debug information via syslog(3).

quiet
    Avoid all messages except errors.

nullok
    The default action of this module is to not permit the user access to a service if their official password is blank. The nullok argument overrides this default.

    If the application sets the PAM_DISALLOW_NULL_AUTHTOK flag, nullok is ignored in the auth module type.

try_first_pass
    The module first attempts to use the password from the previously stacked modules to see if it is also suitable for this module before prompting the user to enter their password again.

use_first_pass
    The module only attempts to use the password from the previously stacked modules and never prompts the user for input. If no password is available or the password does not match, the user is denied access.

use_authtok
    When a password is changed, the module will set the new password to the one provided by a previously stacked password module.

authtok_type=type
    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.

minlen=<number>
    Minimal length of new password. The default is 8 characters.

crypt_prefix=<prefix>
    Prefix of the hash algorithm to use. See crypt(5) for valid values.

crypt_count=<number>
    This option controls the processing cost of the hash. See crypt(5) for valid values.

fail_delay=<milliseconds>
    The module requests by default a delay of 2000 milliseconds should the authentication as a whole fail. This argument can be used to adjust the delay or disable it (fail_delay=0).

MODULE TYPES PROVIDED

All module types (account, auth, password, session) are provided.

RETURN VALUES

PAM_SUCCESS
    Everything was successful.

PAM_SERVICE_ERR
    Internal service module error.

PAM_USER_UNKNOWN
    User not known.

PAM_IGNORE
    Returned by service types which do nothing.

NOTES

The shadow(5) Minimum Password Age field (sp_min) get's ignored if pam_unix_ng.so cannot connect with pwaccessd(8).

EXAMPLES

An example for a full /etc/pam.d/login:

    	account   required   pam_unix_ng.so
    	auth      required   pam_unix_ng.so
    	password  requisite  pam_pwquality.so
    	password  requisite  pam_pwhistory.so use_authtok
    	password  required   pam_unix_ng.so   use_authtok
    	session   optional   pam_wtmpdb.so
    	session   optional   pam_lastlog2.so
    	session   required   pam_unix_ng.so

In this case login(1) verifies the password and that the account is not expired, logs login and logout time to syslog(8) and makes sure, that the password has some kind of quality and the last 10 passwords cannot be reused.

SEE ALSO

pwaccessd(8), pam.conf(5), pam.d(5), pam(8)

AUTHOR

pam_unix_ng was written by Thorsten Kukuk <kukuk@suse.com>.