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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 OpenSSL backend
*/
#ifndef SSL_VERIFY_OPENSSL_H_
#define SSL_VERIFY_OPENSSL_H_
#include <openssl/x509.h>
#ifndef __OPENVPN_X509_CERT_T_DECLARED
#define __OPENVPN_X509_CERT_T_DECLARED
typedef X509 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 every time 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 init_ssl() function, which
* calls the OpenSSL library's \c SSL_CTX_set_verify() function with \c
* verify_callback() as its callback argument.
*
* It checks preverify_ok, and registers the certificate hash. If these steps
* succeed, it calls the \c verify_cert() function, which performs
* OpenVPN-specific verification.
*
* @param preverify_ok - Whether the remote OpenVPN peer's certificate
* past verification. A value of 1 means it
* verified successfully, 0 means it failed.
* @param ctx - The complete context used by the OpenSSL library
* to verify the certificate chain.
*
* @return The return value indicates whether the supplied certificate is
* allowed to set up a VPN tunnel. The following values can be
* returned:
* - \c 0: failure, this certificate is not allowed to connect.
* - \c 1: success, this certificate is allowed to connect.
*/
int verify_callback(int preverify_ok, X509_STORE_CTX *ctx);
/** @} name Function for authenticating a new connection from a remote OpenVPN peer */
#endif /* SSL_VERIFY_OPENSSL_H_ */
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