Securing NixOS services with systemd

NixOS, with the nix package manager, provides different services that can be installed and configured in a reproducible, declarative way. But how does one know whether software sticks to what it is supposed to do, and prevent a malicious application to spy on others?

Systemd provides users with ways to specify fine-grained sandboxing options for their running service, taking advantage of the Linux kernel's security facilities. This project will improve the default configuration of the services that are available in NixOS using systemd, so that users may deploy services without granting them too much trust: the services would only have access to the parts of the system they require. From a security point of view, this limits the attack surface of the system and improves a lot of defense in depth. This also means that services wouldn't be able to snoop on all of the user's system.

To gain long-term benefits from this project, we will develop automated tools to help with finding the right configuration for a given service, and we will write documentation to help people who will want to secure other services with their task.