Delphi DLL

Continue SSH Tunnel Keyboard-Interactive Authentication

Demonstrates the Chilkat SshTunnel.ContinueKeyboardAuth method, which submits a response to a keyboard-interactive prompt. The only argument is the response text; for a request with multiple prompts, an XML response is supplied instead. It returns XML indicating the next prompt or the final result.

Background: This is the second half of the exchange started by StartKeyboardAuth. A server may issue several rounds of prompts, so a robust client loops: submit answers, read the returned XML, and continue until it sees success or failure. On success, BeginAccepting still must be called before the tunnel forwards traffic.

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var
success: Boolean;
tunnel: HCkSshTunnel;
sshPort: Integer;
infoRequestXml: PWideChar;
password: PWideChar;
result: PWideChar;
waitForThreadExit: Boolean;

begin
success := False;

//  Demonstrates the SshTunnel.ContinueKeyboardAuth method, which submits a response to a
//  keyboard-interactive prompt.  The only argument is the response.  For multiple prompts, an XML
//  response is supplied instead.

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;

//  Begin keyboard-interactive authentication to receive the server's prompt(s).
infoRequestXml := CkSshTunnel__startKeyboardAuth(tunnel,'mySshLogin');
if (CkSshTunnel_getLastMethodSuccess(tunnel) = 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';

//  Submit the response (typically the password).  The returned XML indicates the next prompt or
//  the final result.
result := CkSshTunnel__continueKeyboardAuth(tunnel,password);
if (CkSshTunnel_getLastMethodSuccess(tunnel) = False) then
  begin
    Memo1.Lines.Add(CkSshTunnel__lastErrorText(tunnel));
    Exit;
  end;
Memo1.Lines.Add(result);

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

CkSshTunnel_Dispose(tunnel);