NAME

       pam_sm_authenticate - PAM service function for user authentication

SYNOPSIS

       #define PAM_SM_AUTH

       #include <security/pam_modules.h>

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

DESCRIPTION

       The pam_sm_authenticate function is the service module's implementation of the
       pam_authenticate(3) interface.

       This function performs the task of authenticating the user.

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

       PAM_SILENT
           Do not emit any messages.

       PAM_DISALLOW_NULL_AUTHTOK
           Return PAM_AUTH_ERR if the database of authentication tokens for this authentication
           mechanism has a NULL entry for the user. Without this flag, such a NULL token will
           lead to a success without the user being prompted.

RETURN VALUES

       PAM_AUTH_ERR
           Authentication failure.

       PAM_CRED_INSUFFICIENT
           For some reason the application does not have sufficient credentials to authenticate
           the user.

       PAM_AUTHINFO_UNAVAIL
           The modules were not able to access the authentication information. This might be due
           to a network or hardware failure etc.

       PAM_SUCCESS
           The authentication token was successfully updated.

       PAM_USER_UNKNOWN
           The supplied username is not known to the authentication service.

       PAM_MAXTRIES
           One or more of the authentication modules has reached its limit of tries
           authenticating the user. Do not try again.

SEE ALSO

       pam(3), pam_authenticate(3), pam_sm_setcred(3), pam_strerror(3), PAM(8)