/* wolfSSL-TLS-PSK-Server.cs * * Copyright (C) 2006-2023 wolfSSL Inc. * * This file is part of wolfSSL. * * wolfSSL is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * wolfSSL 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 02110-1335, USA */ using System; using System.Runtime.InteropServices; using System.Text; using System.Threading; using System.IO; using System.Net; using System.Net.Sockets; using wolfSSL.CSharp; public class wolfSSL_TLS_PSK_Server { /// /// Example of a PSK function call back /// /// pointer to ssl structure /// identity of client connecting /// buffer to hold key /// max key size /// size of key set public static uint my_psk_server_cb(IntPtr ssl, string identity, IntPtr key, uint max_key) { /* perform a check on the identity sent across * log function must be set for print out of logging information */ wolfssl.log(wolfssl.INFO_LOG, "PSK Client Identity = " + identity); /* Use desired key, note must be a key smaller than max key size parameter Replace this with desired key. Is trivial one for testing */ if (max_key < 4) return 0; byte[] tmp = { 26, 43, 60, 77 }; Marshal.Copy(tmp, 0, key, 4); return (uint)4; } private static void clean(IntPtr ssl, IntPtr ctx) { wolfssl.free(ssl); wolfssl.CTX_free(ctx); wolfssl.Cleanup(); } public static void Main(string[] args) { IntPtr ctx; IntPtr ssl; Socket fd; wolfssl.psk_delegate psk_cb = new wolfssl.psk_delegate(my_psk_server_cb); /* These paths should be changed according to use */ string fileCert = wolfssl.setPath("server-cert.pem"); string fileKey = wolfssl.setPath("server-key.pem"); StringBuilder dhparam = new StringBuilder(wolfssl.setPath("dh2048.pem")); if (fileCert == "" || fileKey == "" || dhparam.Length == 0) { Console.WriteLine("Platform not supported"); return; } StringBuilder buff = new StringBuilder(1024); StringBuilder reply = new StringBuilder("Hello, this is the wolfSSL C# wrapper"); wolfssl.Init(); Console.WriteLine("Calling ctx Init from wolfSSL"); ctx = wolfssl.CTX_new(wolfssl.useTLSv1_2_server()); if (ctx == IntPtr.Zero) { Console.WriteLine("Error creating ctx structure"); return; } Console.WriteLine("Finished init of ctx .... now load in cert and key"); if (!File.Exists(fileCert) || !File.Exists(fileKey)) { Console.WriteLine("Could not find cert or key file"); wolfssl.CTX_free(ctx); return; } if (!File.Exists(dhparam.ToString())) { Console.WriteLine("Could not find dh file"); wolfssl.CTX_free(ctx); return; } if (wolfssl.CTX_use_certificate_file(ctx, fileCert, wolfssl.SSL_FILETYPE_PEM) != wolfssl.SUCCESS) { Console.WriteLine("Error in setting cert file"); wolfssl.CTX_free(ctx); return; } if (wolfssl.CTX_use_PrivateKey_file(ctx, fileKey, wolfssl.SSL_FILETYPE_PEM) != wolfssl.SUCCESS) { Console.WriteLine("Error in setting key file"); wolfssl.CTX_free(ctx); return; } StringBuilder ciphers = new StringBuilder(new String(' ', 4096)); wolfssl.get_ciphers(ciphers, 4096); Console.WriteLine("Ciphers : " + ciphers.ToString()); short minDhKey = 128; wolfssl.CTX_SetMinDhKey_Sz(ctx, minDhKey); Console.Write("Setting cipher suite to "); /* In order to use static PSK build wolfSSL with the preprocessor flag WOLFSSL_STATIC_PSK */ StringBuilder set_cipher = new StringBuilder("DHE-PSK-AES128-CBC-SHA256"); Console.WriteLine(set_cipher); if (wolfssl.CTX_set_cipher_list(ctx, set_cipher) != wolfssl.SUCCESS) { Console.WriteLine("Failed to set cipher suite"); return; } /* Test psk use with DHE */ StringBuilder hint = new StringBuilder("cyassl server"); if (wolfssl.CTX_use_psk_identity_hint(ctx, hint) != wolfssl.SUCCESS) { Console.WriteLine("Error setting hint"); wolfssl.CTX_free(ctx); return; } wolfssl.CTX_set_psk_server_callback(ctx, psk_cb); /* set up TCP socket */ IPAddress ip = IPAddress.Parse("0.0.0.0"); //bind to any TcpListener tcp = new TcpListener(ip, 11111); tcp.Start(); Console.WriteLine("Started TCP and waiting for a connection"); fd = tcp.AcceptSocket(); ssl = wolfssl.new_ssl(ctx); if (ssl == IntPtr.Zero) { Console.WriteLine("Error creating ssl object"); tcp.Stop(); wolfssl.CTX_free(ctx); return; } Console.WriteLine("Connection made wolfSSL_accept "); if (wolfssl.set_fd(ssl, fd) != wolfssl.SUCCESS) { /* get and print out the error */ Console.WriteLine(wolfssl.get_error(ssl)); tcp.Stop(); clean(ssl, ctx); return; } wolfssl.SetTmpDH_file(ssl, dhparam, wolfssl.SSL_FILETYPE_PEM); if (wolfssl.accept(ssl) != wolfssl.SUCCESS) { /* get and print out the error */ Console.WriteLine(wolfssl.get_error(ssl)); tcp.Stop(); clean(ssl, ctx); return; } /* print out results of TLS/SSL accept */ Console.WriteLine("SSL version is " + wolfssl.get_version(ssl)); Console.WriteLine("SSL cipher suite is " + wolfssl.get_current_cipher(ssl)); /* read and print out the message then reply */ if (wolfssl.read(ssl, buff, 1023) < 0) { Console.WriteLine("Error in read"); tcp.Stop(); clean(ssl, ctx); return; } Console.WriteLine(buff); if (wolfssl.write(ssl, reply, reply.Length) != reply.Length) { Console.WriteLine("Error in write"); tcp.Stop(); clean(ssl, ctx); return; } wolfssl.shutdown(ssl); fd.Close(); tcp.Stop(); clean(ssl, ctx); } }