dotfiles/nixos/systems/blowhole/firewall.nix
Magic_RB eec8f409d6
Don't block outgoing DoT traffic, iifname doesn't work in output
Signed-off-by: Magic_RB <magic_rb@redalder.org>
2023-04-04 00:41:25 +02:00

333 lines
12 KiB
Nix

{ pkgs, secret, config, lib, ... }:
with lib;
let
wlan = "wlp10s0";
lan = "enp8s0f1";
wan = "enp3s0";
doVPN = "do_vpn0";
nomad = mapAttrs (const toString) {
inherit (config.services.hashicorp.nomad.settings.client)
min_dynamic_port
max_dynamic_port;
};
in
{
boot.kernel.sysctl = {
# Enable forwarding on IPv4 but disable on IPv6
"net.ipv4.conf.all.forwarding" = true;
"net.ipv6.conf.all.forwarding" = false;
# source: https://github.com/mdlayher/homelab/blob/master/nixos/routnerr-2/configuration.nix#L52
# By default, not automatically configure any IPv6 addresses.
"net.ipv6.conf.all.accept_ra" = 0;
"net.ipv6.conf.all.autoconf" = 0;
"net.ipv6.conf.all.use_tempaddr" = 0;
# On WAN, allow IPv6 autoconfiguration and tempory address use.
# "net.ipv6.conf.${name}.accept_ra" = 2;
# "net.ipv6.conf.${name}.autoconf" = 1;
};
services.stubby = {
enable = true;
logLevel = 7;
settings = {
resolution_type = "GETDNS_RESOLUTION_STUB";
dns_transport_list = [
"GETDNS_TRANSPORT_TLS"
];
tls_authentication = "GETDNS_AUTHENTICATION_REQUIRED";
tls_query_padding_blocksize = 256;
edns_client_subnet_private = 1;
idle_timeout = 10000;
listen_addresses = [
"127.0.0.1@5353"
];
dnssec_return_status = "GETDNS_EXTENSION_TRUE";
appdata_dir = "/var/cache/stubby";
round_robin_upstreams = 1;
upstream_recursive_servers = [
{
address_data = "9.9.9.9";
tls_auth_name = "dns.quad9.net";
}
{
address_data = "149.112.112.112";
tls_auth_name = "dns.quad9.net";
}
];
};
};
systemd.services.stubby = {
before = [ "network-online.target" ];
};
services.dhcpd4 = {
enable = true;
interfaces = [ "${lan}" "${wlan}" ];
extraConfig = ''
option domain-name-servers 10.64.2.1;
option subnet-mask 255.255.255.0;
subnet 10.64.2.0 netmask 255.255.255.0 {
option broadcast-address 10.64.2.255;
option routers 10.64.2.1;
interface ${lan};
range 10.64.2.128 10.64.2.254;
${secret.network.dhcpd.blowhole-lan}
}
subnet 10.64.3.0 netmask 255.255.255.0 {
option broadcast-address 10.64.3.255;
option routers 10.64.3.1;
interface ${wlan};
range 10.64.3.128 10.64.3.254;
${secret.network.dhcpd.blowhole-wlan}
}
'';
};
# systemd.services.dns-check = {
# before = [ "network-online.target"];
# serviceConfig.Type = "oneshot";
# script = ''
# '';
# };
networking = {
useDHCP = false;
hostName = "blowhole";
resolvconf.useLocalResolver = false;
nameservers = [ "10.64.2.1" ];
# Disable the in-built iptable based firewall
firewall.enable = mkForce false;
localCommands = ''
ip link add enp4s0 type dummy || true
ip link set enp4s0 up || true
ip addr add 10.64.2.1/24 dev enp4s0 || true
'';
interfaces = {
# Don't do DHCP on the LAN interface
"${lan}" = {
useDHCP = false;
ipv4.addresses = [{
address = "10.64.2.1";
prefixLength = 24;
}];
};
"${wlan}" = {
useDHCP = false;
ipv4.addresses = [{
address = "10.64.3.1";
prefixLength = 24;
}];
};
# But do DHCP on the WAN interface
"${wan}".useDHCP = true;
};
wireguard = {
enable = true;
interfaces."${doVPN}" =
config.magic_rb.secret.wireguard."${config.networking.hostName}" or {}
// {
listenPort = 6666;
privateKeyFile = "/var/secrets/${doVPN}.key";
};
};
nftables = {
enable = true;
ruleset = ''
table ip nf_filter {
chain input_out {
ct state { established, related } accept comment "Allow established traffic"
icmp type { echo-request, destination-unreachable, time-exceeded } counter accept comment "Allow select ICMP"
}
chain input_doVPN {
tcp dport { 4646, 4647, 4648 } accept comment "Nomad traffic"
tcp dport { 8600, 8500, 8502, 8300, 8301, 8302 } accept comment "Consul traffic"
tcp dport { 8200 } accept comment "Vault traffic"
tcp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
tcp dport ${nomad.min_dynamic_port}-${nomad.max_dynamic_port} accept comment "Consul Connect sidecar traffic"
tcp dport { 53 } accept comment "DNS traffic"
tcp dport { 80 } accept comment "HTTP traffic"
udp dport { 8600, 8301, 8302 } comment "Consul traffic"
udp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
udp dport ${nomad.min_dynamic_port}-${nomad.max_dynamic_port} accept comment "Consul Connect sidecar traffic"
udp dport { 53 } accept comment "DNS traffic"
}
chain input {
type filter hook input priority 0; policy drop;
tcp dport 22 accept comment "Accept SSH traffic always"
iifname != "lo" tcp dport 5353 drop comment "Drop traffic to stubby always except for localhost to localhost traffic"
iifname { "nomad", "ve-monitor", "ve-klipper" } oifname { "nomad", "ve-monitor", "ve-klipper" } accept comment "Allow Nomad to do whatever it wants in its interface"
iifname { "${wlan}", "${lan}", "lo" } accept comment "Allow local network to access the router"
iifname { "${wan}", "${doVPN}", "nomad", "docker0", "ve-monitor", "ve-klipper" } jump input_out
iifname { "${doVPN}" } jump input_doVPN
# Allow containers to reach the DNS server
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } tcp dport 53 accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } udp dport 53 accept
# Allow proxies to reach consul
iifname { "nomad", "ve-monitor", "ve-klipper" } tcp dport 8500 accept
iifname { "ve-monitor", "ve-klipper" } tcp dport 8502 accept
# Allow containers to reach the NFS server
iifname { "docker0" } tcp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
iifname { "docker0" } udp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
meta nftrace set 1
}
chain output {
type filter hook output priority 0; policy accept;
# Drop all DNS traffic if leaving through "wan"
oifname { "${wan}" } tcp dport 53 drop
oifname { "${wan}" } udp dport 53 drop
# Allow DoT traffic to leave through "wan" if it comes from "lo"
# iifname != { "lo" } oifname { "${wan}" } tcp dport 853 drop
}
chain forward {
type filter hook forward priority 10; policy drop;
# Enable flow offloading for better throughput
# ip protocol { tcp, udp } flow offload @f
# Drop all DNS or DoT traffic if forwarded through "wan"
oifname { "${wan}" } tcp dport 853 drop
oifname { "${wan}" } tcp dport 53 drop
oifname { "${wan}" } udp dport 53 drop
# Allow trusted LAN to WAN"
iifname { "${lan}", "${wlan}" } oifname { "${wan}" } accept
iifname { "${wan}" } oifname { "${lan}", "${wlan}" } ct state established, related accept
iifname { "nomad" } oifname { "${doVPN}", "${lan}", "${wlan}" } accept
iifname { "${doVPN}", "${lan}", "${wlan}" } oifname { "nomad" } accept
iifname { "${doVPN}" } oifname { "${lan}", "${wlan}" } accept
iifname { "${lan}", "${wlan}" } oifname { "${doVPN}" } accept
# Allow containers to reach WAN
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${wan}" } accept
iifname { "${wan}" } oifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } ct state established, related accept
# Allow containers to reach the DNS and NFS server
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip daddr 10.64.2.1 tcp dport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip saddr 10.64.2.1 tcp sport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip daddr 10.64.2.1 tcp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip saddr 10.64.2.1 tcp sport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip daddr 10.64.2.1 udp dport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip saddr 10.64.2.1 udp sport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip daddr 10.64.2.1 udp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper" } oifname { "${lan}" } ip saddr 10.64.2.1 udp sport { 111, 2049, 4000, 4001, 4002, 20048 } accept
# Rules to make CNI happy
meta mark and 0x01 == 0x01 accept
meta nftrace set 1
}
}
table ip nf_nat {
chain postrouting {
type nat hook postrouting priority 100; policy accept;
oifname "${wan}" masquerade
}
chain prerouting {
type nat hook prerouting priority 100; policy accept;
}
}
table ip6 nf_filter {
chain output {
type filter hook output priority 0; policy drop;
meta nftrace set 1
oifname "lo" icmpv6 type { echo-request, destination-unreachable, time-exceeded } counter accept comment "Allow select ICMP"
oifname "lo" ip6 saddr "::1" ip6 daddr "::1" reject
}
chain input {
type filter hook input priority 0; policy drop;
meta nftrace set 1
iifname "lo" icmpv6 type { echo-request, destination-unreachable, time-exceeded } counter accept comment "Allow select ICMP"
}
chain forward {
type filter hook forward priority 0; policy drop;
}
}
'';
};
};
systemd.services.nftables = {
serviceConfig =
let
rulesScript = pkgs.writeShellScript "nftables-rules" ''
set -ex
export PATH=${pkgs.nftables}/bin:${pkgs.iptables}/bin:${pkgs.bash}/bin:$PATH
tmpfile="$(mktemp)"
iptables-save -t filter >> $tmpfile
iptables-save -t nat >> $tmpfile
nft flush ruleset
cat $tmpfile | iptables-restore
nft -f "${pkgs.writeText "nftables-rules" config.networking.nftables.ruleset}"
rm $tmpfile
iptables -D FORWARD -j MARK --set-mark 0x01 || true
iptables -D FORWARD -j MARK --set-mark 0x00 || true
iptables -I FORWARD -j MARK --set-mark 0x01
iptables -A FORWARD -j MARK --set-mark 0x00
'';
in {
ExecStart = mkForce rulesScript;
ExecReload = mkForce rulesScript;
ExecStop = mkForce (pkgs.writeShellScript "nftables-flush" ''
set -ex
export PATH=${pkgs.nftables}/bin:${pkgs.iptables}/bin:${pkgs.bash}/bin:$PATH
tmpfile="$(mktemp)"
iptables-save -t filter >> $tmpfile
iptables-save -t nat >> $tmpfile
nft flush ruleset
cat $tmpfile | iptables-restore
rm $tmpfile
iptables -D FORWARD -j MARK --set-mark 0x01 || true
iptables -D FORWARD -j MARK --set-mark 0x00 || true
iptables -I FORWARD -j MARK --set-mark 0x01
iptables -A FORWARD -j MARK --set-mark 0x00
'');
};
};
}