All the attacker has to do is: touch /tmp/pubkey.pem chmod a+w /tmp/pubkey.pem before the victim runs the code. No sticky bit, no restrictive umask, also

All the attacker has to do is: touch /tmp/pubkey.pem chmod a+w /tmp/pubkey.pem before the victim runs the code. No sticky bit, no restrictive umask, also no protected_hardlinks/protected_symlinks is going to save you.