May 15, 2002 PAM_KSU 8

### NAME

pam_ksu - Kerberos 5 SU PAM module

### SYNOPSIS

[service-name] module-type control-flag ```pam_ksu` [options]

### DESCRIPTION

The Kerberos 5 SU authentication service module for PAM provides functionality for only one PAM category: authentication. In terms of the module-type parameter, this is the `````auth`'' feature. The module is specifically designed to be used with the su(1) utility.

#### Kerberos 5 SU Authentication Module

The Kerberos 5 SU authentication component provides functions to verify the identity of a user (pam_sm_authenticate(``)), and determine whether or not the user is authorized to obtain the privileges of the target account. If the target account is ``root'', then the Kerberos 5 principal used for authentication and authorization will be the ``root'' instance of the current user, e.g. `````user/root@REAL.M`''. Otherwise, the principal will simply be the current user's default principal, e.g. `````user@REAL.M`''.

The user is prompted for a password if necessary. Authorization is performed by comparing the Kerberos 5 principal with those listed in the ```.k5login` file in the target account's home directory (e.g. ```/root/.k5login` for root).

The following options may be passed to the authentication module:

debug
  syslog(3) debugging information at ```LOG_DEBUG` level.

use_first_pass
  If the authentication module is not the first in the stack, and a previous module obtained the user's password, that password is used to authenticate the user. If this fails, the authentication module returns failure without prompting the user for a password. This option has no effect if the authentication module is the first in the stack, or if no previous modules obtained the user's password.

try_first_pass
  This option is similar to the use_first_pass option, except that if the previously obtained password fails, the user is prompted for another password.

### SEE ALSO

su(1), syslog(3), pam.conf(5), pam(8)