NAME

       pam_authenticate - account authentication

SYNOPSIS

       #include <security/pam_appl.h>

       int pam_authenticate(pam_handle_t *pamh, int flags);

DESCRIPTION

       The pam_authenticate function is used to authenticate the user. The user is required to provide an
       authentication token depending upon the authentication service, usually this is a password, but could
       also be a finger print.

       The PAM service module may request that the user enter their username via the conversation mechanism (see
       pam_start(3) and pam_conv(3)). The name of the authenticated user will be present in the PAM item
       PAM_USER. This item may be recovered with a call to pam_get_item(3).

       The pamh argument is an authentication handle obtained by a prior call to pam_start(). The flags argument
       is the binary or of zero or more of the following values:

       PAM_SILENT
           Do not emit any messages.

       PAM_DISALLOW_NULL_AUTHTOK
           The PAM module service should return PAM_AUTH_ERR if the user does not have a registered
           authentication token.

RETURN VALUES

       PAM_ABORT
           The application should exit immediately after calling pam_end(3) first.

       PAM_AUTH_ERR
           The user was not authenticated.

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

       PAM_SUCCESS
           The user was successfully authenticated.

       PAM_USER_UNKNOWN
           User unknown to authentication service.

SEE ALSO

       pam_start(3), pam_setcred(3), pam_chauthtok(3), pam_strerror(3), pam(7)

Linux-PAM Manual                                   06/08/2020                                PAM_AUTHENTICATE(3)