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C

SSH Tunnel Authenticate with a SecureString Password and Private Key

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Demonstrates the Chilkat SshTunnel.AuthenticateSecPwPk method, which authenticates using SecureString login and password objects together with a private key. The third argument is the SshKey private key.

Note: The private-key path is relative to the application's current working directory. Absolute paths may also be used. Supply the path to your own key file.

Background: This is the SecureString form of two-factor tunnel authentication: the password is held encrypted in memory and combined with a private key for servers that require both. It is the most protective option when a deployment mandates two-factor SSH and you also want to minimize plaintext credential exposure in a long-running process.

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C
#include <C_CkSshTunnel.h>
#include <C_CkSshKey.h>
#include <C_CkSecureString.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSshTunnel tunnel;
    int sshPort;
    const char *password;
    HCkSshKey privKey;
    const char *keyText;
    HCkSecureString secureLogin;
    HCkSecureString securePassword;
    BOOL waitForThreadExit;

    success = FALSE;

    //  Demonstrates the SshTunnel.AuthenticateSecPwPk method, which authenticates using SecureString
    //  login and password objects together with a private key.  The 1st argument is the username, the
    //  2nd is the password, and the 3rd is an SshKey private key.

    tunnel = CkSshTunnel_Create();

    //  The tunnel forwards accepted local connections to this destination through the SSH server.
    CkSshTunnel_putDestHostname(tunnel,"db.internal.example.com");
    CkSshTunnel_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 = CkSshTunnel_Connect(tunnel,"ssh.example.com",sshPort);
    if (success == FALSE) {
        printf("%s\n",CkSshTunnel_lastErrorText(tunnel));
        CkSshTunnel_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 = "mySshPassword";

    //  Load the SSH private key.  LoadText reads the file's text, which is then imported.
    privKey = CkSshKey_Create();
    keyText = CkSshKey_loadText(privKey,"qa_data/id_rsa");
    if (CkSshKey_getLastMethodSuccess(privKey) == FALSE) {
        printf("%s\n",CkSshKey_lastErrorText(privKey));
        CkSshTunnel_Dispose(tunnel);
        CkSshKey_Dispose(privKey);
        return;
    }

    success = CkSshKey_FromOpenSshPrivateKey(privKey,keyText);
    if (success == FALSE) {
        printf("%s\n",CkSshKey_lastErrorText(privKey));
        CkSshTunnel_Dispose(tunnel);
        CkSshKey_Dispose(privKey);
        return;
    }

    //  Place the login and password into SecureString objects.
    secureLogin = CkSecureString_Create();
    CkSecureString_Append(secureLogin,"mySshLogin");
    securePassword = CkSecureString_Create();
    CkSecureString_Append(securePassword,password);

    success = CkSshTunnel_AuthenticateSecPwPk(tunnel,secureLogin,securePassword,privKey);
    if (success == FALSE) {
        printf("%s\n",CkSshTunnel_lastErrorText(tunnel));
        CkSshTunnel_Dispose(tunnel);
        CkSshKey_Dispose(privKey);
        CkSecureString_Dispose(secureLogin);
        CkSecureString_Dispose(securePassword);
        return;
    }

    printf("Authenticated.\n");

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

    waitForThreadExit = TRUE;
    success = CkSshTunnel_CloseTunnel(tunnel,waitForThreadExit);
    if (success == FALSE) {
        printf("%s\n",CkSshTunnel_lastErrorText(tunnel));
        CkSshTunnel_Dispose(tunnel);
        CkSshKey_Dispose(privKey);
        CkSecureString_Dispose(secureLogin);
        CkSecureString_Dispose(securePassword);
        return;
    }



    CkSshTunnel_Dispose(tunnel);
    CkSshKey_Dispose(privKey);
    CkSecureString_Dispose(secureLogin);
    CkSecureString_Dispose(securePassword);

    }