61 lines
1.8 KiB
Nix
61 lines
1.8 KiB
Nix
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{
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config,
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lib,
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...
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}: let
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cfg = config.gen.system.hardening;
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in {
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options.gen.system.hardening = {
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hardenBpf = lib.mkEnableOption "place heavier restrictions on BPF";
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fullRpFilter = lib.mkEnableOption "enable full reverse path filtering. breaks dynamic routing, probably";
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ignoreIcmpEcho = lib.mkEnableOption "ignore icmp echos. obviously, this makes pings unresponsive";
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disableSack = lib.mkEnableOption "disable tcp sack";
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disableConsole = lib.mkEnableOption "disable console. not recommended for test machines";
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};
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config = {
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### Sysctls ###
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boot.kernel.sysctl =
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{
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"kernel.kptr_restrict" = 1;
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"kernel.dmesg_restrict" = 1;
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"kernel.printk" = "3 3 3 3";
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"dev.tty.ldisc_autoload" = 0;
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"vm.unprivileged_userfaultfd" = 0;
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"kernel.kexec_load_disabled" = 1;
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"kernel.sysrq" = 0; # ignore sysrq key
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"kernel.perf_event_paranoid" = 3;
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"net.ipv4.tcp_rfc1337" = 1; # drop RSTs during time-wait state
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}
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// lib.mkIf cfg.ignoreIcmpEcho {
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"net.ipv4.icmp_echo_ignore_all" = 1;
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}
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// lib.mkIf cfg.hardenBpf {
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"kernel.unprivileged_bpf_disabled" = 1;
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"net.core.bpf_jit_harden" = 2;
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}
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// lib.mkIf cfg.fullRpFilter {
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"net.ipv4.conf.all.rp_filter" = 1;
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"net.ipv4.conf.default.rp_filter" = 1;
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}
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// lib.mkIf cfg.disableSack {
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"net.ipv4.tcp_sack" = 0;
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"net.ipv4.tcp_dsack" = 0;
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"net.ipv4.tcp_fack" = 0;
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};
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### Security options ###
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security.protectKernelImage = true;
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### Disable emergency access ###
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systemd.enableEmergencyMode = false;
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boot.initrd.systemd.emergencyAccess = false;
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### Disable tty login ###
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console = {
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earlySetup = true;
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enable = !cfg.disableConsole;
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};
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};
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}
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