EIdOpenSSLShutdownError with Linux

[ThomasHorstmann]

I am testing OpenSSL with a simple TIdHTTPServer. It delivers only the index.htm and the favicon.ico. I am running two servers in the internet (windows and linux), without special firewalls. So there are a lot of attacks every day. Windows works fine, but sometimes linux crashses with an EIdOpenSSLShutdownError (Failed to shutdown the TLS connection.error:0A000197:SSL routines::shutdown while in init). Maybe because of an attack. This happens in "TIdOpenSSLSocket.Close". I changed the code. Now it seems to run without problems. Is this the correct way?

{ TIdOpenSSLSocket }

procedure TIdOpenSSLSocket.Close;
var
LReturnCode: TIdC_INT;
LSSLErrorCode: TIdC_INT;
begin
if not FDoNotCallShutdown then
begin
LReturnCode := SSL_shutdown(FSSL);
if LReturnCode < 0 then
begin
LSSLErrorCode := SSL_get_error(FSSL, LReturnCode);
if LSSLErrorCode <> SSL_ERROR_ZERO_RETURN then
SSL_set_shutdown(FSSL, SSL_SENT_SHUTDOWN or SSL_RECEIVED_SHUTDOWN); // <- new
// raise EIdOpenSSLShutdownError.Create(FSSL, LReturnCode, RIdOpenSSLShutdownError); // <- old
end;
end
else
SSL_set_shutdown(FSSL, SSL_SENT_SHUTDOWN or SSL_RECEIVED_SHUTDOWN);
end;