Unicode C

SSH Tunnel Authenticate with a SecureString Password

Demonstrates the Chilkat SshTunnel.AuthenticateSecPw method, which authenticates using SecureString login and password objects. The first argument is the login and the second is the password.

Background: Because a tunnel process is long-lived and holds its SSH credentials for its entire lifetime, protecting them in memory is worthwhile. A SecureString keeps the value encrypted under a randomly generated session key. Populate it from a value obtained at runtime rather than a hard-coded literal.

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#include <C_CkSshTunnelW.h>
#include <C_CkSecureStringW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSshTunnelW tunnel;
    int sshPort;
    const wchar_t *password;
    HCkSecureStringW secureLogin;
    HCkSecureStringW securePassword;
    BOOL waitForThreadExit;

    success = FALSE;

    //  Demonstrates the SshTunnel.AuthenticateSecPw method, which authenticates using SecureString
    //  login and password objects.  The 1st argument is the login and the 2nd is the password.

    tunnel = CkSshTunnelW_Create();

    //  The tunnel forwards accepted local connections to this destination through the SSH server.
    CkSshTunnelW_putDestHostname(tunnel,L"db.internal.example.com");
    CkSshTunnelW_putDestPort(tunnel,5432);

    //  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
    //  does not authenticate yet.
    sshPort = 22;
    success = CkSshTunnelW_Connect(tunnel,L"ssh.example.com",sshPort);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshTunnelW_lastErrorText(tunnel));
        CkSshTunnelW_Dispose(tunnel);
        return;
    }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    password = L"mySshPassword";

    //  Place the login and password into SecureString objects.
    secureLogin = CkSecureStringW_Create();
    CkSecureStringW_Append(secureLogin,L"mySshLogin");
    securePassword = CkSecureStringW_Create();
    CkSecureStringW_Append(securePassword,password);

    success = CkSshTunnelW_AuthenticateSecPw(tunnel,secureLogin,securePassword);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshTunnelW_lastErrorText(tunnel));
        CkSshTunnelW_Dispose(tunnel);
        CkSecureStringW_Dispose(secureLogin);
        CkSecureStringW_Dispose(securePassword);
        return;
    }

    wprintf(L"Authenticated with secure strings.\n");

    //  After authenticating, call BeginAccepting to start listening for local connections to forward.

    waitForThreadExit = TRUE;
    success = CkSshTunnelW_CloseTunnel(tunnel,waitForThreadExit);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshTunnelW_lastErrorText(tunnel));
        CkSshTunnelW_Dispose(tunnel);
        CkSecureStringW_Dispose(secureLogin);
        CkSecureStringW_Dispose(securePassword);
        return;
    }



    CkSshTunnelW_Dispose(tunnel);
    CkSecureStringW_Dispose(secureLogin);
    CkSecureStringW_Dispose(securePassword);

    }