duo3

Usage

Overview

The duo API provides access to the Duo two-factor authentication service.

duo_open() is used to obtain a handle to the Duo service. ikey and skey are the required integration and secret keys, respectively, for a Duo customer account. progname identifies the program to the Duo service. cafile should be NULL or the pathname of a PEM-format CA certificate to override the default.

duo_set_conv_funcs() may be used to override the internal user conversation functions. conv_prompt is called to present the user a login menu and prompt, and gather their response, returning buf or NULL on error. It may be set to NULL if automatic login is specified with DUO_FLAG_AUTO. conv_status is called to display status messages to the user, and may be NULL if no status display is needed. conv_arg is passed as the first argument to these conversation functions.

duo_set_host() may be used to override the default Duo API host.

duo_set_ssl_verify() may be used to override SSL certificate verification (enabled by default).

duo_login() performs secondary authentication via the Duo service for the specified username. client_ip is the source IP address of the connection to be authenticated, or NULL to specify the local host. The following bitmask values are defined for flags:

DUO_FLAG_AUTO

Attempt authentication without prompting the user, using their default out-of-band authentication factor.

DUO_FLAG_SYNC

Do not report incremental status during authentication (e.g. voice callback progress) - only issue one status message per authentication attempt.

If not NULL, the command to be authorized will be displayed during push authentication.

duo_geterr() returns a description of the last-seen error on the specified Duo API handle. The returned constant string should not be modified or freed by the caller.

duo_close() closes and frees the specified Duo API handle.

Return values

duo_open() returns a pointer to the configured Duo API handle, or NULL on failure.

duo_login() returns status codes of type duo_code_t, which may have the following values:

DUO_OK

User authenticated

DUO_FAIL

User failed to authenticate

DUO_ABORT

User denied by policy

DUO_LIB_ERROR

Unexpected library error

DUO_CONN_ERROR

Duo service unreachable

DUO_CLIENT_ERROR

Invalid client parameters to API call

DUO_SERVER_ERROR

Duo service error

In the event of a DUO_*_ERROR return, duo_geterr may be called to recover a human-readable error message.

duo_geterr() returns a constant string which should not be modified or freed by the caller.