zapi: Harden more dispatch to prevent invalid data and fix MLK

The previous change (85e13a7)
introduced a MLK, and it passed reviews :)

That said the risk to leak is low because it is not supposed to happend

Origin: #132
Bug-SiliconLabs: UIC-3668
Relate-to: SLVDBBP-3169975
Relate-to: SiliconLabsSoftware/z-wave-engine-application-layer#42
Relate-to: #124
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

applications/zpc/components/zwave_api/src/zwapi_init.c

@@ -136,8 +136,10 @@ bool zwapi_poll()
   zwapi_session_enqueue_rx_frames();
   bool more_frames = zwapi_session_dequeue_frame(&frame, &len);
 
-  if (frame && len >=1) {
-    zwave_api_protocol_rx_dispatch(frame, len);
+  if (frame) {
+    if (len >= 1) {
+      zwave_api_protocol_rx_dispatch(frame, len);
+    }
     free(frame);
   }
 

applications/zpc/components/zwave_command_handler/src/zwave_command_handler.cpp

@@ -87,6 +87,9 @@ sl_status_t zwave_command_handler_dispatch(
   const uint8_t *frame_data,
   uint16_t frame_length)
 {
+  assert(connection);
+  assert(frame_data);
+  assert(frame_length);
   zwave_command_handler_t handler_to_invoke = {};
   handler_to_invoke.command_class           = frame_data[0];
   sl_status_t rc                            = SL_STATUS_NOT_SUPPORTED;
@@ -313,4 +316,4 @@ void zwave_command_handler_print_info(int fd)
   } else {
     dprintf(fd, "%s", ss.str().c_str());
   }
-}
+}