pam_authenticate

3 Linux-PAM Linux-PAM Manual

pam_authenticate

account authentication

          #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

8