Linux kernel发现本地权限提升漏洞现已修正(2)

-                       ret = copy_to_user(ptr, addr + offset, bytes);

-               else

-                       ret = copy_from_user(addr + offset, ptr, bytes);

-               kunmap(page);

-               if (ret)

-                       return -EFAULT;

+               ret = copy_from_user(addr + offset, ptr, bytes);

        }

+       kunmap(page);

-       return 0;

+       return ret ? -EFAULT : 0;

 }

 EXPORT_SYMBOL_GPL(rds_page_copy_user);