RDKBWIFI-203: wifi_ctrl_wifiapi_handlers: add null check for dev_array (rdkcentral#696)

The changes in this PR were automatically generated by the Permanence AI
Coder and reviewed by @fwph. This change moves the deallocation of
dev_array outside of the for loop to prvent a null pointer dereference
when num_devs > 1. In addition, it adds a null check for dev_array
after the call to wifi_getApAssociatedDeviceDiagnosticResult3. If dev_array
is null, an error message is written to result_buf and the  function returns
early to prevent null pointer deferecnces.

on-behalf-of: @permanence-ai <[email protected]>

Author: Permanence-AI-Coder

source/core/wifi_ctrl_wifiapi_handlers.c

@@ -622,6 +622,10 @@ static void wifiapi_handle_get_ApAssocDeviceDiagnosticResult(char **args, unsign
          }
          return;
       }
+    if (dev_array == NULL) {
+        snprintf(result_buf, result_buf_size, "Error: dev_array is NULL\n");
+        return;
+    }
 		char* to_sta_key(uint8_t *mac_address, sta_key_t sta_key) {
     snprintf(sta_key, STA_KEY_LEN, "%02x:%02x:%02x:%02x:%02x:%02x",
              mac_address[0], mac_address[1], mac_address[2],
@@ -660,11 +664,11 @@ static void wifiapi_handle_get_ApAssocDeviceDiagnosticResult(char **args, unsign
               dev_array[i].cli_MultipleRetryCount, dev_array[i].cli_MaxDownlinkRate,
               dev_array[i].cli_MaxUplinkRate, dev_array[i].cli_activeNumSpatialStreams,
               dev_array[i].cli_TxFrames, dev_array[i].cli_RxRetries, dev_array[i].cli_RxErrors);
+      }
       if (dev_array != NULL) {
         free(dev_array);
         dev_array = NULL;
     }
-      }
 }
 
 void process_wifiapi_command(char *command, unsigned int len)