nix/module/Kernel.nix

89 lines
2.2 KiB
Nix

{ pkgs, config, lib, ... }: with lib; let
cfg = config.module.kernel;
in {
options = {
module.kernel = {
enable = mkEnableOption "Enable kernel tweaks.";
hardening = mkOption {
default = false;
type = types.bool;
};
hotspotTtlBypass = mkOption {
default = false;
type = types.bool;
};
latest = mkOption {
default = false;
type = types.bool;
};
};
};
config = mkIf cfg.enable (mkMerge [
{
boot.kernel.sysctl = {
# Allow sysrq.
"kernel.sysrq" = 1;
# Increase file watchers.
"fs.inotify.max_user_instances" = 9999999;
"fs.inotify.max_user_watches" = 9999999;
"fs.inotify.max_user_event" = 9999999;
# "fs.file-max" = 999999;
};
}
(mkIf cfg.hardening {
boot.kernel.sysctl = {
# Spoof protection.
"net.ipv4.conf.all.rp_filter" = 1;
"net.ipv4.conf.default.rp_filter" = 1;
# Packet forwarding.
"net.ipv4.ip_forward" = 0;
"net.ipv6.conf.all.forwarding" = 1;
# MITM protection.
"net.ipv4.conf.all.accept_redirects" = 0;
"net.ipv6.conf.all.accept_redirects" = 0;
# Do not send ICMP redirects (we are not a router).
"net.ipv4.conf.all.send_redirects" = 0;
# Do not accept IP source route packets (we are not a router).
"net.ipv4.conf.all.accept_source_route" = 0;
"net.ipv6.conf.all.accept_source_route" = 0;
# Protect filesystem links.
"fs.protected_hardlinks" = 0;
"fs.protected_symlinks" = 0;
# Lynis config.
"kernel.core_uses_pid" = 1;
"kernel.kptr_restrict" = 2;
# IP hardening.
"net.ipv4.conf.all.log_martians" = 1;
"net.ipv4.conf.default.accept_redirects" = 0;
"net.ipv4.conf.default.accept_source_route" = 0;
"net.ipv4.conf.default.log_martians" = 0;
"net.ipv4.tcp_timestamps" = 0;
"net.ipv6.conf.default.accept_redirects" = 0;
# Disable ipv6.
"net.ipv6.conf.all.disable_ipv6" = 1;
"net.ipv6.conf.default.disable_ipv6" = 1;
"net.ipv6.conf.lo.disable_ipv6" = 1;
};
})
(mkIf cfg.hotspotTtlBypass {
boot.kernel.sysctl."net.ipv4.ip_default_ttl" = 65;
})
(mkIf cfg.latest {
boot.kernelPackages = pkgs.linuxPackages_latest;
})
]);
}