#fixed code
                                public static UsbDevice[] getUsbDevices() {
        // Reusable buffer for getting IO name strings
        Pointer buffer = new Memory(128); // io_name_t is char[128]
        // Build a list of devices with no parent; these will be the roots
        List<Long> usbControllers = new ArrayList<>();
        // Empty out maps
        nameMap.clear();
        vendorMap.clear();
        serialMap.clear();
        hubMap.clear();

        // Iterate over USB Controllers. All devices are children of one of
        // these controllers in the "IOService" plane
        IntByReference iter = new IntByReference();
        IOKitUtil.getMatchingServices("IOUSBController", iter);
        int device = IOKit.INSTANCE.IOIteratorNext(iter.getValue());
        while (device != 0) {
            // Unique global identifier for this device
            LongByReference id = new LongByReference();
            IOKit.INSTANCE.IORegistryEntryGetRegistryEntryID(device, id);
            usbControllers.add(id.getValue());

            // Get device name and store in map
            IOKit.INSTANCE.IORegistryEntryGetName(device, buffer);
            nameMap.put(id.getValue(), buffer.getString(0));
            // Controllers don't have vendor and serial so ignore at this level

            // Now iterate the children of this device in the "IOService" plane.
            // If devices have a parent, link to that parent, otherwise link to
            // the controller as parent
            IntByReference childIter = new IntByReference();
            IOKit.INSTANCE.IORegistryEntryGetChildIterator(device, "IOService", childIter);
            int childDevice = IOKit.INSTANCE.IOIteratorNext(childIter.getValue());
            while (childDevice != 0) {
                // Unique global identifier for this device
                LongByReference childId = new LongByReference();
                IOKit.INSTANCE.IORegistryEntryGetRegistryEntryID(childDevice, childId);

                // Get this device's parent in the "IOUSB" plane
                IntByReference parent = new IntByReference();
                IOKit.INSTANCE.IORegistryEntryGetParentEntry(childDevice, "IOUSB", parent);

                // If parent is named "Root" ignore that id and use the
                // controller's id
                LongByReference parentId = id;
                IOKit.INSTANCE.IORegistryEntryGetName(parent.getValue(), buffer);
                if (!buffer.getString(0).equals("Root")) {
                    // Unique global identifier for the parent
                    parentId = new LongByReference();
                    IOKit.INSTANCE.IORegistryEntryGetRegistryEntryID(parent.getValue(), parentId);
                }
                // Store parent in map
                if (!hubMap.containsKey(parentId.getValue())) {
                    hubMap.put(parentId.getValue(), new ArrayList<Long>());
                }
                hubMap.get(parentId.getValue()).add(childId.getValue());

                // Get device name and store in map
                IOKit.INSTANCE.IORegistryEntryGetName(childDevice, buffer);
                nameMap.put(childId.getValue(), buffer.getString(0));
                // Get vendor and store in map
                CFTypeRef vendorRef = IOKit.INSTANCE.IORegistryEntryCreateCFProperty(childDevice, cfVendor,
                        CfUtil.ALLOCATOR, 0);
                if (vendorRef != null && vendorRef.getPointer() != null) {
                    vendorMap.put(childId.getValue(), CfUtil.cfPointerToString(vendorRef.getPointer()));
                }
                CfUtil.release(vendorRef);
                // Get serial and store in map
                CFTypeRef serialRef = IOKit.INSTANCE.IORegistryEntryCreateCFProperty(childDevice, cfSerial,
                        CfUtil.ALLOCATOR, 0);
                if (serialRef != null && serialRef.getPointer() != null) {
                    serialMap.put(childId.getValue(), CfUtil.cfPointerToString(serialRef.getPointer()));
                }
                CfUtil.release(serialRef);

                IOKit.INSTANCE.IOObjectRelease(childDevice);
                childDevice = IOKit.INSTANCE.IOIteratorNext(childIter.getValue());
            }
            IOKit.INSTANCE.IOObjectRelease(childIter.getValue());

            IOKit.INSTANCE.IOObjectRelease(device);
            device = IOKit.INSTANCE.IOIteratorNext(iter.getValue());
        }
        IOKit.INSTANCE.IOObjectRelease(iter.getValue());

        // Build tree and return
        List<UsbDevice> controllerDevices = new ArrayList<UsbDevice>();
        for (Long controller : usbControllers) {
            controllerDevices.add(getDeviceAndChildren(controller));
        }
        return controllerDevices.toArray(new UsbDevice[controllerDevices.size()]);
    }
#vulnerable code 
                                public static UsbDevice[] getUsbDevices() {
        // Get heirarchical list of USB devices
        List<String> xml = ExecutingCommand.runNative("system_profiler SPUSBDataType -xml");
        // Look for <key>_items</key> which prcedes <array> ... </array>
        // Each pair of <dict> ... </dict> following is a USB device/hub
        List<String> items = new ArrayList<>();
        boolean copy = false;
        int indent = 0;
        for (String s : xml) {
            s = s.trim();
            // Read until <key>_items</key>
            if (!copy && s.equals("<key>_items</key>")) {
                copy = true;
                continue;
            }
            // If we've fond items indent with each <array> tag and copy over
            // everything with indent > 0.
            if (copy) {
                if (s.equals("</array>")) {
                    if (--indent == 0) {
                        copy = false;
                        continue;
                    }
                }
                if (indent > 0) {
                    items.add(s);
                }
                if (s.equals("<array>")) {
                    indent++;
                }
            }
        }
        // Items now contains 0 or more sets of <dict>...</dict>
        return getUsbDevices(items);
    } 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE