{ inputs, outputs, lib, config, pkgs, ... }: { environment.systemPackages = with pkgs; [ /* ------------------------- Essential Applications ------------------------- */ git wine bottles onlyoffice-bin google-chrome microsoft-edge /* ---------------------------- System Utilities ---------------------------- */ gnupg ffmpeg unzip mpv gparted libappindicator-gtk3 pavucontrol hyfetch ]; programs.firefox.enable = true; /* ----------------------------- Security Tweaks ---------------------------- */ # sets hidepid=2 on /proc (make process info visible only to owning user) # NOTE Was removed on nixpkgs-unstable because it doesn't do anything # security.hideProcessInformation = true; # tmpfs = /tmp is mounted in ram. Doing so makes temp file management speedy # on ssd systems and more secure (and volatile)! Because it's wiped on reboot. boot.tmp.useTmpfs = lib.mkDefault true; # If not using tmpfs, which is naturally purged on reboot, we must clean it # /tmp ourselves. /tmp should be volatile storage! boot.tmp.cleanOnBoot = lib.mkDefault (!config.boot.tmp.useTmpfs); # Fix a security hole in place for backwards compatibility. See desc in # nixpkgs/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix boot.loader.systemd-boot.editor = lib.mkDefault false; boot.kernel.sysctl = { # The Magic SysRq key is a key combo that allows users connected to the # system console of a Linux kernel to perform some low-level commands. # Disable it, since we don't need it, and is a potential security concern. "kernel.sysrq" = 0; ## TCP hardening # Prevent bogus ICMP errors from filling up logs. "net.ipv4.icmp_ignore_bogus_error_responses" = 1; # Reverse path filtering causes the kernel to do source validation of # packets received from all interfaces. This can mitigate IP spoofing. "net.ipv4.conf.default.rp_filter" = 1; "net.ipv4.conf.all.rp_filter" = 1; # Do not accept IP source route packets (we're not a router) "net.ipv4.conf.all.accept_source_route" = 0; "net.ipv6.conf.all.accept_source_route" = 0; # Don't send ICMP redirects (again, we're not a router) "net.ipv4.conf.all.send_redirects" = 0; "net.ipv4.conf.default.send_redirects" = 0; # Refuse ICMP redirects (MITM mitigations) "net.ipv4.conf.all.accept_redirects" = 0; "net.ipv4.conf.default.accept_redirects" = 0; "net.ipv4.conf.all.secure_redirects" = 0; "net.ipv4.conf.default.secure_redirects" = 0; "net.ipv6.conf.all.accept_redirects" = 0; "net.ipv6.conf.default.accept_redirects" = 0; # Protects against SYN flood attacks "net.ipv4.tcp_syncookies" = 1; # Incomplete protection again TIME-WAIT assassination "net.ipv4.tcp_rfc1337" = 1; ## TCP optimization # TCP Fast Open is a TCP extension that reduces network latency by packing # data in the sender’s initial TCP SYN. Setting 3 = enable TCP Fast Open for # both incoming and outgoing connections: "net.ipv4.tcp_fastopen" = 3; # Bufferbloat mitigations + slight improvement in throughput & latency "net.ipv4.tcp_congestion_control" = "bbr"; "net.core.default_qdisc" = "cake"; }; boot.kernelModules = [ "tcp_bbr" ]; # Harden SSH client programs.ssh = { # Known vulnerability. See # https://security.stackexchange.com/questions/110639/how-exploitable-is-the-recent-useroaming-ssh-vulnerability extraConfig = '' Host * UseRoaming no ''; }; }