Delphi DLL

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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Delphi DLL

var
success: Boolean;
tunnel: HCkSshTunnel;
sshPort: Integer;
password: PWideChar;
privKey: HCkSshKey;
keyText: PWideChar;
secureLogin: HCkSecureString;
securePassword: HCkSecureString;
waitForThreadExit: Boolean;

begin
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) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    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 := CkSshKey_Create();
keyText := CkSshKey__loadText(privKey,'qa_data/id_rsa');
if (CkSshKey_getLastMethodSuccess(privKey) = False) then
  begin
    Memo1.Lines.Add(CkSshKey__lastErrorText(privKey));
    Exit;
  end;
success := CkSshKey_FromOpenSshPrivateKey(privKey,keyText);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshKey__lastErrorText(privKey));
    Exit;
  end;

//  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) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;
Memo1.Lines.Add('Authenticated.');

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

waitForThreadExit := True;
success := CkSshTunnel_CloseTunnel(tunnel,waitForThreadExit);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;

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