Send no_renegotiation alert as required by spec.

CHANGES

@@ -863,6 +863,17 @@
 
  Changes between 0.9.8l (?) and 0.9.8m (?)  [xx XXX xxxx]
 
+  *) If client attempts to renegotiate and doesn't support RI respond with
+     a no_renegotiation alert as required by draft-ietf-tls-renegotiation.
+     Some renegotiating TLS clients will continue a connection gracefully
+     when they receive the alert. Unfortunately OpenSSL mishandled
+     this alert and would hang waiting for a server hello which it will never
+     receive. Now we treat a received no_renegotiation alert as a fatal 
+     error. This is because applications requesting a renegotiation might well
+     expect it to succeed and would have no code in place to handle the server
+     denying it so the only safe thing to do is to terminate the connection.
+     [Steve Henson]
+
   *) Add ctrl macro SSL_get_secure_renegotiation_support() which returns 1 if
      peer supports secure renegotiation and 0 otherwise. Print out peer
      renegotiation support in s_client/s_server.

ssl/s3_pkt.c

@@ -1139,7 +1139,25 @@ start:
 		 * now try again to obtain the (application) data we were asked for */
 		goto start;
 		}
-
+	/* If we are a server and get a client hello when renegotiation isn't
+	 * allowed send back a no renegotiation alert and carry on.
+	 * WARNING: experimental code, needs reviewing (steve)
+	 */
+	if (s->server &&
+		SSL_is_init_finished(s) &&
+    		!s->s3->send_connection_binding &&
+		(s->version > SSL3_VERSION) &&
+		(s->s3->handshake_fragment_len >= 4) &&
+		(s->s3->handshake_fragment[0] == SSL3_MT_CLIENT_HELLO) &&
+		(s->session != NULL) && (s->session->cipher != NULL) &&
+		!(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
+		
+		{
+		/*s->s3->handshake_fragment_len = 0;*/
+		rr->length = 0;
+		ssl3_send_alert(s,SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
+		goto start;
+		}
 	if (s->s3->alert_fragment_len >= 2)
 		{
 		int alert_level = s->s3->alert_fragment[0];
@@ -1169,6 +1187,21 @@ start:
 				s->shutdown |= SSL_RECEIVED_SHUTDOWN;
 				return(0);
 				}
+			/* This is a warning but we receive it if we requested
+			 * renegotiation and the peer denied it. Terminate with
+			 * a fatal alert because if application tried to
+			 * renegotiatie it presumably had a good reason and
+			 * expects it to succeed.
+			 *
+			 * In future we might have a renegotiation where we
+			 * don't care if the peer refused it where we carry on.
+			 */
+			else if (alert_descr == SSL_AD_NO_RENEGOTIATION)
+				{
+				al = SSL_AD_HANDSHAKE_FAILURE;
+				SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_NO_RENEGOTIATION);
+				goto f_err;
+				}
 			}
 		else if (alert_level == 2) /* fatal */
 			{