OpenSSL session reuse does not work with TLS_client_method()

[Matt Caswell]

Was the original connection that you obtained the session from cleanly 
closed down? From the man pages:

"A session will be automatically removed from the session cache and 
marked as non-resumable if the connection is not closed down cleanly, 
e.g. if a fatal error occurs on the connection or L<SSL_shutdown(3)> is 
not called prior to L<SSL_free(3)>."

https://www.openssl.org/docs/man1.1.1/man3/SSL_get_session.html


You can check whether a session is valid for resumption using 
SSL_SESSION_is_resumable():

https://www.openssl.org/docs/man1.1.1/man3/SSL_SESSION_is_resumable.html


mATT

On 15/09/2021 12:56, Jaya Muthiah wrote:
> I am trying to reuse SSL_SESSION as below, it works fine when I use 
> TLSv1_2_client_method() to create context. However, it does not work 
> when I use TLS_client_method().
> 
>      if (!SSL_set_session(ssl, ssl_session)) {
>              //code never reaches here so SSL_set_session is successful
>      }
> 
>      if (SSL_connect(ssl) != 1) {
>       return -1;
>      }
> 
>      int reused = SSL_session_reused(ssl); <-- always returns zero for 
> TLS_client_method().
> 
>      ssl_session = SSL_get1_session(ssl); // for future connections
> 
> Above code works fine with TLSv1_2_client_method() and 
> SSL_session_reused() returns 1, handshake time is also reduced 
> considerably. However, if I use TLS_client_method(), reuse does not work 
> and SSL_session_reused() returns zero.
> 
> Any idea what is wrong? OpenSSL version is 1.1.1.g