pam_unix2 - Standard PAM module for traditional password authentication

The pam_unix2 PAM module is for traditional password authentication. It uses standard calls from the glibc NSS libraries to retrieve and set account information as well as authentication. Usually this is obtained from the the local files /etc/passwd and /etc/shadow, from a NIS map, from the NIS+ passwd.org_dir table or from a LDAP database.

The options can be added in the PAM configuration files for every single service or global in /etc/security/pam_unix2.conf. /etc/default/passwd defines, which password encryption algorithm should be used in case of a password change.

The following options may be passed to all types of management groups except session:

debug

A lot of debug informations are printed with syslog(3).

nullok

Normally the account is disabled if no password is set or if the length of the password is zero. With this option the user is allowed to change the password for such accounts. This option does not overwrite a hardcoded default by the calling process.

not_set_pass

If this option is given, pam_unix2 will not make the new password available for other modules.

use_first_pass

The default is, that pam_unix2 tries to get the authentication token from a previous module. If no token is available, the user is asked for the old password. With this option, pam_unix2 aborts with an error if no authentication token from a previous module is available.

call_modules=x,y,z

With this list of PAM modules names, pam_unix2 tries to load every module and check, if this knows about the user. This is important, if you have some users in a LDAP database and wishes to fallback to traditional password authentication for the other accounts. For example call_modules=winbind,ldap will try to authenticate the user at first against a running winbindd(8). If the winbind daemon does not know the user, an authentication with pam_ldap is tried. If the user is also not known to the LDAP database, an authentiation against the normal password database is done.

The following additional options may be passed to the auth rules of this module:

set_secrpc

If SecureRPC is in use, the secret key of a user needs to be make known to keyserv(8). This option will set the secret key.

The following additional options may be passed to the passwd rules of this modules:

nisdir=<path>

This options specifies a path to the source files for NIS maps on a NIS master server. If this option is given, the passwords of NIS accounts will not be changed with yppasswd(1), instead the local passwd and shadow files below <path> will be modified. In conjunction with rpasswdd(8) and pam_make rpc.yppasswdd(8) can be replaced with a more secure solution on the NIS master server.

use_authtok

Set the new password to the one provided by the previously stacked password module. If this option is not set, pam_unix2 would ask the user for the new password.

One of the following options may be passed to the session rules of this modules:

debug

Some messages (login time, logout time) are logged to syslog with priority LOG_DEBUG.

trace

Some messages (login time, logout time) are logged to syslog with priority LOG_NOTICE.

none

No messages are logged. This is the default.

The acct management does not recognize any additional options. For root, password and login expire are ignored, only on aging warning is printed. If no shadow information exists, it always returns success.

/etc/security/pam_unix2.conf

/etc/default/passwd

This manual page is far from complete, most options are missing. Please read the README and look at the source package.

login(1), passwd(1), pam.conf(8), pam.d(8), pam_pwcheck(8), pam(8), rpasswd(1), rpasswdd(8), rpc.yppasswdd(8), yppasswd(1)