[Help-gnutls] Problem with anonymous authentication

[Alexei Boyarchenko]

Sorry for my bad English!

I am trying to make server with anonymous authentication:

gnutls_anon_server_credentials anon_serv_cred;
static gnutls_dh_params dh_params;

gnutls_session initialize_tls_session()
{
	int ret = 0;
    gnutls_session session;
    ret = gnutls_init(&session, GNUTLS_SERVER);
   
   
   
	 ret = gnutls_set_default_priority( session);   
       const int KX_PRIOR[] = {GNUTLS_KX_ANON_DH,0};
	 ret = gnutls_kx_set_priority(session,KX_PRIOR);

   ret = gnutls_credentials_set(session, GNUTLS_CRD_ANON,&anon_serv_cred);
   gnutls_certificate_server_set_request( session, GNUTLS_CERT_IGNORE);
   gnutls_dh_set_prime_bits( session, DH_BITS);

   return session;
}



static int generate_dh_params(void) {

   /* Generate Diffie Hellman parameters - for use with DHE
    * kx algorithms. These should be discarded and regenerated
    * once a day, once a week or once a month. Depending on the
    * security requirements.
    */
   gnutls_dh_params_init( &dh_params);
   gnutls_dh_params_generate2( dh_params, DH_BITS);
   
   return 0;
}

int main()
{
   int err, listen_sd, i;
   int sd, ret;
   struct sockaddr_in sa_serv;
   struct sockaddr_in sa_cli;
   int client_len;
   char topbuf[512];
   gnutls_session session;
   char buffer[MAX_BUF + 1];
   const char optval = 1;

   /* this must be called once in the program
    */
   gnutls_global_init();

   ret = gnutls_anon_allocate_server_credentials(&anon_serv_cred); // ret = 0

   ret = generate_dh_params();  // ret = 0 
   gnutls_anon_set_server_dh_params (anon_serv_cred,dh_params);
  //   anon_serv_cred->dh_params   ara set and not NULL both
   /* Socket operations
    */
    ........................................
    */

   printf("Server ready. Listening to port '%d'.\n\n", PORT);

   client_len = sizeof(sa_cli);
   for (;;) {
      session = initialize_tls_session();

      sd = accept(listen_sd, (SA *) & sa_cli, &client_len);

      printf("- connection from %s, port %d\n",
             inet_ntoa(sa_cli.sin_addr), ntohs(sa_cli.sin_port));

      gnutls_transport_set_ptr( session, (gnutls_transport_ptr)sd);
      ret = gnutls_handshake( session); 
      if (ret < 0) {  // ret =  -21
         closesocket(sd);
         gnutls_deinit(session);
         fprintf(stderr, "*** Handshake has failed (%s)\n\n",
                 gnutls_strerror(ret));
         continue;
       }

      gnutls_bye( session, GNUTLS_SHUT_WR); //do not wait for
                                 // the peer to close the connection.
                                 

      close(sd);
      gnutls_deinit(session);

   }
   closesocket(listen_sd);

   gnutls_anon_free_server_credentials(anon_serv_cred);

   gnutls_global_deinit();

   return 0;

}

While testing  I got mistake -"Could not negotiate a supported cipher suite"

When I tryed to debug server i've found that handshaking failed because of all 
ciphersuites was removed during  _gnutls_remove_unwanted_ciphersuites function in 
gnutls_handshake.c 

Ciphersuits was removed because  check_server_params failed .  

...........

 else if ( cred_type == GNUTLS_CRD_ANON) {
		anon_cred =
		    _gnutls_get_cred(session->key, cred_type, NULL);
	
		if (anon_cred != NULL) {
			dh_params = anon_cred->dh_params;
		}
	} else return 0; /* no need for params */


	/* If the key exchange method needs RSA or DH params,
	 * but they are not set then remove it.
	 */
	if (_gnutls_kx_needs_rsa_params( kx) != 0) {
		/* needs rsa params. */
		if (_gnutls_get_rsa_params( rsa_params)==NULL)
			return 1;
	}
	
	if (_gnutls_kx_needs_dh_params( kx) != 0) {
		/* needs DH params. */
		if (_gnutls_get_dh_params( dh_params)==NULL)
			return 1;
	}
..........

I got  _gnutls_get_dh_params( dh_params)  =  NULL 
(dh_params != NULL ,dh_params->params[0]  != NULL  but dh_params->params[1] = 0)
and all ciphersuites was removed.  (((::::

After I call gnutls_anon_set_server_dh_params(anon_serv_cred,dh_params)
anon_serv_cred->dh_params->params[0] != NULL and 
anon_serv_cred->dh_params->params[1] != NULL


Please help me find my mistake!!!!!!!!!!!!!!