repetitive ssl send

[Attila Csosz]

I have a state machine with the following states: create, connect, send,
receive.

When the state sequence is the following: create, connect, send, receive
everything is ok (with my code, sent in the previous email). However when
there is a receive code after connect there is a problem. There is no data
after this receive phase (maybe is not problem) but after that: send
executed successfully and the receive returns with no data.

create
connect
receive : no data, maybe ok
send: ok
receive : no data here !!


create: calls CreateSSL
connect: calls ConnectSSL
send: calls SendSSL
receive: calls ReceiveSSL

What may the problem?

Attila



On Mon, Jun 22, 2020 at 7:35 PM Viktor Dukhovni <openssl-users at dukhovni.org>
wrote:

> On Mon, Jun 22, 2020 at 03:17:41PM +0200, Attila Csosz wrote:
>
> > char HEADERS[] = "GET /search?q=arduino HTTP/1.1\r\nHost: www.google.com\r\nConnection:
> close\r\n\r\n";
> > char HOST_NAME_PORT[] = "www.google.com:443";
>
> Note the "Connection: close" in the HTTP request header!
>
> > void init_openssl()
> > {
> >     SSL_load_error_strings();
> >     SSL_library_init();
> > }
> >
> > void CreateSSL()
> > {
> >  // Create SSL context
> >  meth = SSLv23_client_method();
> >  if (!meth) throw Exception("SSL: method");
> >
> >  ctx = SSL_CTX_new(meth);
> >  if (!ctx) throw Exception("SSL: SSL_CTX_new");
> >  old_opts = SSL_CTX_set_options(ctx, SSL_OP_ALL);
>
> The SSL_CTX need only be created once, not once per connection.
> You've made no provision for verifying the server certificate.
> Typically you would load trusted CA certificate locations into
> the SSL_CTX.
>
> >  web = BIO_new_ssl_connect(ctx);
> >  if (!web) throw Exception("SSL: BIO_new_ssl_connect");
> > }
>
> This code belows in the ConnectSSL function.
>
> >
> > void ConnectSSL()
> > {
> >  // Connect
> >  res = BIO_set_conn_hostname(web, HOST_NAME_PORT);
> >  if (!res) throw Exception("SSL: BIO_ctrl");
> >
> >  res = BIO_get_ssl(web, &ssl);
> >  if (!res) throw Exception("SSL: BIO_ctrl");
> >
> >  res = SSL_set_cipher_list(ssl, PREFERRED_CIPHERS);
> >  if (!res) throw Exception("SSL: SSL_set_cipher_list");
> >
> >  res = BIO_do_connect(web);
> >  if (res <= 0) throw Exception("SSL: BIO_do_connect");
> >
> >  res = BIO_do_handshake(web);
> >  if (res <= 0) throw Exception("SSL: BIO_do_handshake");
>
> This connection is unauthenticated.  Perhaps that's OK, but often it is
> not.
>
> > }
> >
> > void SendSSL()
> > {
> >  // Send
> >  err = BIO_puts(web, HEADERS);
> >  if (err <= 0) throw Exception("SSL: BIO_puts");
> > }
> >
> > void ReceiveSSL()
> > {
> >  // Read
> >  sResult = "";
> >  for (;;) {
> >   len = BIO_read(web, buf, sizeof(buf));
> >   sResult += buf;
> >   if (len <= 0)
> >    break;
> >  }
>
> The server closes the connection after returning its reply.
> You need to close the SSL BIO to avoid a memory leak.
>
> > ---------
> > It is ok for one request.
> >
> > My problem when I trying to send a new search request to google it works
> > only when I call
> >  CreateSSL();
> >  ConnectSSL();
> > again
>
> Naturally, you're not doing HTTP/1.1 connection keep-alive, and in any
> case would need to be prepared for the server to close the connection
> now and then.  You need an actual HTTPS library, naive open-coding of an
> HTTP client over SSL is unlikely to be correct.  Something like libcurl
> or similar is the way to go.
>
> > What may the problem?
>
> You're writing a naïve HTTPS client from scratch.  A correct
> implementation would understand "Content-Length" and chunked
> trasfer encoding, handle server-initiated disconnects, be
> prepared to receive multi-record responses, ...
>
> --
>     Viktor.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mta.openssl.org/pipermail/openssl-users/attachments/20200623/cd350791/attachment.html>