NAME

       pam_sm_chauthtok - PAM service function for authentication token management

SYNOPSIS

       #include <security/pam_modules.h>

       int pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const char **argv);

DESCRIPTION

       The pam_sm_chauthtok function is the service module's implementation of the
       pam_chauthtok(3) interface.

       This function is used to (re-)set the authentication token of the user.

       Valid flags, which may be logically OR'd with PAM_SILENT, are:

       PAM_SILENT
           Do not emit any messages.

       PAM_CHANGE_EXPIRED_AUTHTOK
           This argument indicates to the module that the user's authentication token (password)
           should only be changed if it has expired. This flag is optional and must be combined
           with one of the following two flags. Note, however, the following two options are
           mutually exclusive.

       PAM_PRELIM_CHECK
           This indicates that the modules are being probed as to their ready status for altering
           the user's authentication token. If the module requires access to another system over
           some network it should attempt to verify it can connect to this system on receiving
           this flag. If a module cannot establish it is ready to update the user's
           authentication token it should return PAM_TRY_AGAIN, this information will be passed
           back to the application.

           If the control value sufficient is used in the password stack, the PAM_PRELIM_CHECK
           section of the modules following that control value is not always executed.

       PAM_UPDATE_AUTHTOK
           This informs the module that this is the call it should change the authorization
           tokens. If the flag is logically OR'd with PAM_CHANGE_EXPIRED_AUTHTOK, the token is
           only changed if it has actually expired.

       The PAM library calls this function twice in succession. The first time with
       PAM_PRELIM_CHECK and then, if the module does not return PAM_TRY_AGAIN, subsequently with
       PAM_UPDATE_AUTHTOK. It is only on the second call that the authorization token is
       (possibly) changed.

RETURN VALUES

       PAM_AUTHTOK_ERR
           The module was unable to obtain the new authentication token.

       PAM_AUTHTOK_RECOVERY_ERR
           The module was unable to obtain the old authentication token.

       PAM_AUTHTOK_LOCK_BUSY
           Cannot change the authentication token since it is currently locked.

       PAM_AUTHTOK_DISABLE_AGING
           Authentication token aging has been disabled.

       PAM_PERM_DENIED
           Permission denied.

       PAM_TRY_AGAIN
           Preliminary check was unsuccessful. Signals an immediate return to the application is
           desired.

       PAM_SUCCESS
           The authentication token was successfully updated.

       PAM_USER_UNKNOWN
           User unknown to password service.

SEE ALSO

       pam(3), pam_chauthtok(3), pam_sm_chauthtok(3), pam_strerror(3), PAM(8)