sneeuwvlok/modules/nixos/system/security/boot.nix
Chris Kruining a03240d99d
more work
2025-07-28 14:34:40 +02:00

46 lines
No EOL
1.8 KiB
Nix

{ config, namespace, inputs, ... }:
let
cfg = config.${namespace}.system.security.boot;
in
{
options.${namespace}.system.security.boot = {};
config = {
boot = {
kernelModules = [ "tcp_bbr" ];
kernel.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";
};
};
};
}