u2fh_devs_discover (u2fh_devs * devs, unsigned *max_index)
{
  struct hid_device_info *di, *cur_dev;
  u2fh_rc res = U2FH_NO_U2F_DEVICE;
  struct u2fdevice *dev;

  di = hid_enumerate (0, 0);
  for (cur_dev = di; cur_dev; cur_dev = cur_dev->next)
    {
      int found = 0;
      unsigned short usage_page = 0, usage = 0;

      /* check if we already opened this device */
      for (dev = devs->first; dev != NULL; dev = dev->next)
	{
	  if (strcmp (dev->device_path, cur_dev->path) == 0)
	    {
	      if (ping_device (devs, dev->id) == U2FH_OK)
		{
		  found = 1;
		  res = U2FH_OK;
		}
	      else
		{
		  if (debug)
		    {
		      fprintf (stderr, "Device %s failed ping, dead.\n",
			       dev->device_path);
		    }
		  close_device (devs, dev);
		}
	      break;
	    }
	}
      if (found)
	{
	  continue;
	}

      get_usages (cur_dev, &usage_page, &usage);
      if (usage_page == FIDO_USAGE_PAGE && usage == FIDO_USAGE_U2FHID)
	{
	  dev = new_device (devs);
	  dev->devh = hid_open_path (cur_dev->path);
	  if (dev->devh != NULL)
	    {
	      dev->device_path = strdup (cur_dev->path);
	      if (dev->device_path == NULL)
		{
		  close_device (devs, dev);
		  goto out;
		}
	      if (init_device (devs, dev) == U2FH_OK)
		{
		  if (cur_dev->product_string)
		    {
		      size_t len =
			wcstombs (NULL, cur_dev->product_string, 0);
		      dev->device_string = malloc (len + 1);
		      if (dev->device_string == NULL)
			{
			  close_device (devs, dev);
			  goto out;
			}
		      memset (dev->device_string, 0, len + 1);
		      wcstombs (dev->device_string, cur_dev->product_string,
				len);
		      if (debug)
			{
			  fprintf (stderr, "device %s discovered as '%s'\n",
				   dev->device_path, dev->device_string);
			  fprintf (stderr,
				   "  version (Interface, Major, "
				   "Minor, Build): %d, %d, "
				   "%d, %d  capFlags: %d\n",
				   dev->versionInterface,
				   dev->versionMajor,
				   dev->versionMinor,
				   dev->versionBuild, dev->capFlags);
			}
		    }
		  res = U2FH_OK;
		  continue;
		}
	    }
	  close_device (devs, dev);
	}
    }


  /* loop through all open devices and make sure we find them in the enumeration */
  dev = devs->first;
  while (dev)
    {
      int found = 0;

      for (cur_dev = di; cur_dev; cur_dev = cur_dev->next)
	{
	  if (strcmp (cur_dev->path, dev->device_path) == 0)
	    {
	      found = 1;
	      dev = dev->next;
	      break;
	    }
	}
      if (!found)
	{
	  if (debug)
	    {
	      fprintf (stderr, "device %s looks dead.\n", dev->device_path);
	    }
	  dev = close_device (devs, dev);
	}
    }

out:
  hid_free_enumeration (di);
  if (res == U2FH_OK && max_index)
    *max_index = devs->max_id - 1;

  return res;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.