Properly send empty EAP-TLS messages

src/charon/plugins/eap_tls/eap_tls.c

@@ -215,6 +215,8 @@ static eap_payload_t *read_buf(private_eap_tls_t *this, u_int8_t identifier)
 	pkt->type = EAP_TLS;
 	pkt->flags = 0;
 
+	if (this->output.len)
+	{
 		start = (char*)(pkt + 1);
 		if (this->outpos == 0)
 		{	/* first fragment */
@@ -239,6 +241,7 @@ static eap_payload_t *read_buf(private_eap_tls_t *this, u_int8_t identifier)
 			chunk_free(&this->output);
 			this->outpos = 0;
 		}
+	}
 	htoun16(&pkt->length, pkt_len);
 	return eap_payload_create_data(chunk_create(buf, pkt_len));
 }