Lora: Check for valid ABP params

Check that ABP dev_addr and nwk_id is non-zero and keys are not null.

Author: Kimmo Vaisanen

features/lorawan/lorastack/mac/LoRaMac.cpp

@@ -1381,6 +1381,13 @@ lorawan_status_t LoRaMac::prepare_join(const lorawan_connect_t *params, bool is_
             // Reset variable JoinRequestTrials
             _params.join_request_trial_counter = 0;
         } else {
+            if ((params->connection_u.abp.dev_addr == 0)
+                    || (params->connection_u.abp.nwk_id == 0)
+                    || (params->connection_u.abp.nwk_skey == NULL)
+                    || (params->connection_u.abp.app_skey == NULL)) {
+                return LORAWAN_STATUS_PARAMETER_INVALID;
+            }
+
             _params.net_id = params->connection_u.abp.nwk_id;
             _params.dev_addr = params->connection_u.abp.dev_addr;