Pascal (Lazarus/Delphi)

Examine Client Certificates for an Accepted TLS Connection

See more Socket/SSL/TLS Examples

Demonstrates how to access the client certificates for a TLS connection accepted by your application acting as the server. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Cert,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  listenSslSocket: TSocket;
  cert: TCert;
  myPort: Integer;
  backLog: Integer;
  maxWaitMillisec: Integer;
  clientSock: TSocket;
  numClientCerts: Integer;
  clientCert: TCert;
  i: Integer;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  listenSslSocket := TSocket.Create;

  //  An SSL/TLS server needs a digital certificate.  This example loads it from a PFX file.
  //  This is the server's certificate.

  cert := TCert.Create;
  success := cert.LoadPfxFile('qa_data/serverCert/myServerCert.pfx','pfx_password');
  if (success = False) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  //  To accept client client certificates in the TLS handshake,
  //  we must indicate a list of acceptable client certificate root CA DN's
  //  that are allowed.  (DN is an acronym for Distinguished Name.)
  //  Call AddSslAcceptableClientCaDn once for each acceptable CA DN.
  //  Here are a few examples so you can see the general format of a DN.
  listenSslSocket.AddSslAcceptableClientCaDn('C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root');
  listenSslSocket.AddSslAcceptableClientCaDn('O=Digital Signature Trust Co., CN=DST Root CA X3');

  //  Initialize with our server's TLS certificate.
  success := listenSslSocket.InitSslServer(cert);
  if (success = False) then
    begin
      WriteLn(listenSslSocket.LastErrorText);
      Exit;
    end;

  //  Bind and listen on a port:
  myPort := 8123;
  //  Allow for a max of 5 queued connect requests.
  backLog := 5;
  success := listenSslSocket.BindAndListen(myPort,backLog);
  if (success = False) then
    begin
      WriteLn(listenSslSocket.LastErrorText);
      Exit;
    end;

  //  Accept the next incoming connection.
  maxWaitMillisec := 20000;

  clientSock := TSocket.Create;
  success := listenSslSocket.AcceptNext(maxWaitMillisec,clientSock);
  if (success = False) then
    begin
      WriteLn(listenSslSocket.LastErrorText);
      Exit;
    end;

  //  Examine the client certs chain.  The 1st cert will be the client certificate, and
  //  the subsequent certs will be the certs in the chain of authentication.
  numClientCerts := clientSock.NumReceivedClientCerts;
  WriteLn('numClientCerts = ' + numClientCerts);

  clientCert := TCert.Create;
  i := 0;
  while i < numClientCerts do
    begin
      clientSock.GetRcvdClientCert(i,clientCert);
      WriteLn(clientCert.SubjectDN);
      i := i + 1;
    end;

  //  Close the connection with the client
  success := clientSock.Close(1000);


  listenSslSocket.Free;
  cert.Free;
  clientSock.Free;
  clientCert.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.