.

modules/system/security.nix

@@ -0,0 +1,62 @@
+{ pkgs, ... }:
+{
+  environment.systemPackages = with pkgs; [
+    kdePackages.kwallet-pam
+    bitwarden
+  ];
+
+  security = {
+    sudo.execWheelOnly = true;
+    acme.acceptTerms = true;
+    polkit.enable = true;
+    pam.services.kwallet = {
+      name = "kwallet";
+      enableKwallet = true;
+    };
+  };
+
+  networking.firewall.enable = true;
+  programs.gnupg.agent.enable = true;
+
+  boot = {
+    loader.systemd-boot = {
+      editor = false;
+      configurationLimit = 50;
+    };
+
+    kernalModules = [ "tcp_bbr" ];
+    kernal.sysctl = {
+      ## 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 on 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
+      # Enable TCP Fast Open for 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";
+    };
+  };
+}