PHP

SSH Tunnel Authenticate with a SecureString Password and Private Key

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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<?php

use Chilkat2\SecureString;
use Chilkat2\SshKey;
use Chilkat2\SshTunnel;

// 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 = new SshTunnel();

// The tunnel forwards accepted local connections to this destination through the SSH server.
$tunnel->DestHostname = 'db.internal.example.com';
$tunnel->DestPort = 5432;

// Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
// does not authenticate yet.
$sshPort = 22;
try {
    $tunnel->Connect('ssh.example.com', $sshPort);

    // 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 = new SshKey();
    $keyText = $privKey->LoadText('qa_data/id_rsa');

    $privKey->FromOpenSshPrivateKey($keyText);

    // Place the login and password into SecureString objects.
    $secureLogin = new SecureString();
    $secureLogin->Append('mySshLogin');
    $securePassword = new SecureString();
    $securePassword->Append($password);

    $tunnel->AuthenticateSecPwPk($secureLogin, $securePassword, $privKey);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo "Authenticated.\n";

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

$waitForThreadExit = true;
try {
    $tunnel->CloseTunnel($waitForThreadExit);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}