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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2021 OpenVPN Inc <sales@openvpn.net>
* Copyright (C) 2010-2021 Fox Crypto B.V. <openvpn@foxcrypto.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* @file Control Channel Verification Module mbed TLS backend
*/
#ifndef SSL_VERIFY_MBEDTLS_H_
#define SSL_VERIFY_MBEDTLS_H_
#include "syshead.h"
#include <mbedtls/x509_crt.h>
#ifndef __OPENVPN_X509_CERT_T_DECLARED
#define __OPENVPN_X509_CERT_T_DECLARED
typedef mbedtls_x509_crt openvpn_x509_cert_t;
#endif
/** @name Function for authenticating a new connection from a remote OpenVPN peer
* @{ */
/**
* Verify that the remote OpenVPN peer's certificate allows setting up a
* VPN tunnel.
* @ingroup control_tls
*
* This callback function is called when a new TLS session is being setup to
* determine whether the remote OpenVPN peer's certificate is allowed to
* connect. It is called for once for every certificate in the chain. The
* callback functionality is configured in the \c key_state_ssl_init() function,
* which calls the mbed TLS library's \c mbedtls_ssl_conf_verify() function with
* \c verify_callback() as its callback argument.
*
* It checks *flags and registers the certificate hash. If these steps succeed,
* it calls the \c verify_cert() function, which performs OpenVPN-specific
* verification.
*
* @param session_obj - The OpenVPN \c tls_session associated with this object,
* as set during SSL session setup.
* @param cert - The certificate used by mbed TLS.
* @param cert_depth - The depth of the current certificate in the chain, with
* 0 being the actual certificate.
* @param flags - Whether the remote OpenVPN peer's certificate
* passed verification. A value of 0 means it
* verified successfully, any other value means it
* failed. \c verify_callback() is considered to have
* ok'ed this certificate if flags is 0 when it returns.
*
* @return The return value is 0 unless a fatal error occurred.
*/
int verify_callback(void *session_obj, mbedtls_x509_crt *cert, int cert_depth,
uint32_t *flags);
/** @} name Function for authenticating a new connection from a remote OpenVPN peer */
#endif /* SSL_VERIFY_MBEDTLS_H_ */
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