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nix-config-ryan4yin/hardening/README.md
2024-09-06 00:03:46 +08:00

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# Linux Hardening
## Goal
- **System Level**: Protect critical files from being accessed by untrusted applications.
1. Such as browser cookies, SSH keys, etc.
- **Per-App Level**: Prevent untrusted applications(such as closed-source apps) from:
1. Accessing files they shouldn't.
- Such as a malicious application accessing your browser's cookies, SSH Keys, etc.
1. Accessing the network when they don't need to.
1. Accessing hardware devices they don't need.
## Current Status
1. **System Level**:
- [ ] AppArmor
- [ ] Kernel & System Hardening
1. **Per-App Level**:
- Nixpak (Bubblewrap)
- [x] QQ
- [ ] Firefox (Nvidia GPU support issue)
- [ ] Firejail (risk? not enabled yet)
## Kernel Hardening
- NixOS Kernel Config:
https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/os-specific/linux/kernel/hardened/config.nix
## System Hardening
- NixOS Profile:
https://github.com/NixOS/nixpkgs/blob/nixos-unstable/nixos/modules/profiles/hardened.nix
- Apparmor: [roddhjav/apparmor.d)](https://github.com/roddhjav/apparmor.d)
- https://gitlab.com/apparmor/apparmor/-/wikis/Documentation
- AppArmor.d is a set of over 1500 AppArmor profiles whose aim is to confine most Linux based
applications and processes.
- Nix Package:
[roddhjav-apparmor-rules](https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/by-name/ro/roddhjav-apparmor-rules/package.nix#L33)
- https://github.com/NixOS/nixpkgs/issues/331645
- SELinux: too complex, not recommended for personal use.
## Application Sandboxing
- [Firejail](https://github.com/netblue30/firejail/tree/master/etc): A SUID security sandbox with
hundreds of security profiles for many common applications in the default installation.
- https://wiki.nixos.org/wiki/Firejail
- Firejail needs SUID to work, which is considered a security risk -
[Does firejail improve the security of my system?](https://github.com/netblue30/firejail/discussions/4601)
- [Bubblewrap](https://github.com/containers/bubblewrap):
[nixpak](https://github.com/nixpak/nixpak), more secure than firejail, but no batteries included.
- NixOS's FHSEnv is implemented using bubblewrap by default.
- [Systemd/Hardening](https://wiki.nixos.org/wiki/Systemd/Hardening): Systemd also provides some
sandboxing features.
## NOTE
**Running untrusted code is never safe, kernel hardening & sandboxing cannot change this**.
If you want to run untrusted code, please use a VM & an isolated network environment, which will
provide a much higher level of security.
## References
- [Harden your NixOS workstation - dataswamp](https://dataswamp.org/~solene/2022-01-13-nixos-hardened.html)
- [Linux Insecurities - Madaidans](https://madaidans-insecurities.github.io/linux.html)
- [Sandboxing all programs by default - NixOS Discourse](https://discourse.nixos.org/t/sandboxing-all-programs-by-default/7792)
- [在 Firejail 中运行 Steam](https://imbearchild.cyou/archives/2021/11/steam-in-firejail/)
- [Firejail - Arch Linux Wiki](https://wiki.archlinux.org/title/Firejail)
- nixpak configs:
- https://github.com/pokon548/OysterOS/tree/b97604d89953373d6316286b96f6a964af2c398d/desktop/application
- https://github.com/segment-tree/my-nixos/tree/ceb6041f73bd9edcb78a8818b27a28f7c629193b/hm/me/apps/nixpak
- https://github.com/Keksgesicht/nixos-config/tree/91cc77d8d6b598da7c4dbed143e0009c2dea6940/packages/nixpak
- https://github.com/bluskript/nix-config/blob/7ecb6a7254c1ac4969072f4c4febdc19f8b83b30/pkgs/nixpak/default.nix
- firejail configs:
- https://github.com/stelcodes/nixos-config/blob/f8967c82a5e5f3d128eb1aaf7498b5f918f719ec/packages/overlay.nix#L261
- apparmor configs:
- https://github.com/sukhmancs/nixos-configs/blob/7fcf737c506ad843113cd5b94796b49d4d4dfad2/modules/shared/security/apparmor/default.nix#L8
- https://github.com/zramctl/dotfiles/blob/4fe177f6984154960942bb47d5a375098ec6ed6a/modules/nixos/security/apparmor.nix#L4
- Others:
- Directly via `buildFHSUserEnvBubblewrap`:
https://github.com/xddxdd/nur-packages/blob/master/pkgs/uncategorized/wechat-uos/default.nix