Issues and security concerns

An important consideration, for the budding driver author, is security. The trouble is, naive usage of even the very common copy_[from|to]_user() functions within your driver can let a malicious user quite easily – and illegally – overwrite memory to their advantage in both user and kernel spaces. How? The following section explains this in some detail; then, we will even show you a (bit contrived, but nevertheless, working) hack.