Delphi ActiveX

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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var
success: Integer;
tunnel: TChilkatSshTunnel;
sshPort: Integer;
password: WideString;
privKey: TChilkatSshKey;
keyText: WideString;
secureLogin: TChilkatSecureString;
securePassword: TChilkatSecureString;
waitForThreadExit: Integer;

begin
success := 0;

//  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 := TChilkatSshTunnel.Create(Self);

//  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;
success := tunnel.Connect('ssh.example.com',sshPort);
if (success = 0) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;

//  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 := TChilkatSshKey.Create(Self);
keyText := privKey.LoadText('qa_data/id_rsa');
if (privKey.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;
success := privKey.FromOpenSshPrivateKey(keyText);
if (success = 0) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;

//  Place the login and password into SecureString objects.
secureLogin := TChilkatSecureString.Create(Self);
secureLogin.Append('mySshLogin');
securePassword := TChilkatSecureString.Create(Self);
securePassword.Append(password);

success := tunnel.AuthenticateSecPwPk(secureLogin.ControlInterface,securePassword.ControlInterface,privKey.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add('Authenticated.');

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

waitForThreadExit := 1;
success := tunnel.CloseTunnel(waitForThreadExit);
if (success = 0) then
  begin
    Memo1.Lines.Add(tunnel.LastErrorText);
    Exit;
  end;