static int au1200fb_ioctl(struct fb_info *info, unsigned int cmd,
                          unsigned long arg)
{
	struct au1200fb_device *fbdev = info->par;
	int plane;
	int val;

	plane = fbinfo2index(info);
	print_dbg("au1200fb: ioctl %d on plane %d\n", cmd, plane);

	if (cmd == AU1200_LCD_FB_IOCTL) {
		struct au1200_lcd_iodata_t iodata;

		if (copy_from_user(&iodata, (void __user *) arg, sizeof(iodata)))
			return -EFAULT;

		print_dbg("FB IOCTL called\n");

		switch (iodata.subcmd) {
		case AU1200_LCD_SET_SCREEN:
			print_dbg("AU1200_LCD_SET_SCREEN\n");
			set_global(cmd, &iodata.global);
			break;

		case AU1200_LCD_GET_SCREEN:
			print_dbg("AU1200_LCD_GET_SCREEN\n");
			get_global(cmd, &iodata.global);
			break;

		case AU1200_LCD_SET_WINDOW:
			print_dbg("AU1200_LCD_SET_WINDOW\n");
			set_window(plane, &iodata.window);
			break;

		case AU1200_LCD_GET_WINDOW:
			print_dbg("AU1200_LCD_GET_WINDOW\n");
			get_window(plane, &iodata.window);
			break;

		case AU1200_LCD_SET_PANEL:
			print_dbg("AU1200_LCD_SET_PANEL\n");
			if ((iodata.global.panel_choice >= 0) &&
					(iodata.global.panel_choice <
					 NUM_PANELS))
			{
				struct panel_settings *newpanel;
				panel_index = iodata.global.panel_choice;
				newpanel = &known_lcd_panels[panel_index];
				au1200_setpanel(newpanel, fbdev->pd);
			}
			break;

		case AU1200_LCD_GET_PANEL:
			print_dbg("AU1200_LCD_GET_PANEL\n");
			iodata.global.panel_choice = panel_index;
			break;

		default:
			return -EINVAL;
		}

		val = copy_to_user((void __user *) arg, &iodata, sizeof(iodata));
		if (val) {
			print_dbg("error: could not copy %d bytes\n", val);
			return -EFAULT;
		}
	}

	return 0;
}

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.