dotfiles/nixos/systems/blowhole/firewall.nix
magic_rb e055a1535e
Fix server firewall activatuon script not rolling back correctly
Signed-off-by: magic_rb <magic_rb@redalder.org>
2024-07-13 21:00:06 +02:00

406 lines
15 KiB
Nix

{
pkgs,
secret,
config,
lib,
...
}: let
inherit
(lib)
mapAttrs
const
mkForce
singleton
;
wlan = "wlp10s0";
lan = "eno1";
wan = "eno3";
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.dnscrypt-proxy2 = {
enable = true;
upstreamDefaults = true;
settings = {
listen_addresses = singleton "127.0.0.1:5353";
dnscrypt_servers = false;
doh_servers = true;
odoh_servers = false;
block_ipv6 = true;
static."mullvad".stamp = "sdns://AgcAAAAAAAAACzE5NC4yNDIuMi41ABxleHRlbmRlZC5kbnMubXVsbHZhZC5uZXQ6NDQzCi9kbnMtcXVlcnk";
sources = {};
max_clients = 1024;
cache_size = 32768;
};
};
systemd.services.dnscrypt-proxy2 = {
before = ["network-online.target"];
};
services.kea.dhcp4 = {
enable = true;
settings =
{
interfaces-config.interfaces = [
"${lan}"
];
lease-database = {
name = "/var/lib/kea/dhcp4.leases";
persist = true;
type = "memfile";
};
rebind-timer = 2000;
renew-timer = 1000;
}
// (secret.dhcp.blowhole.zones or (const {}) {inherit wlan lan;});
};
networking = {
useDHCP = false;
hostName = "blowhole";
resolvconf.useLocalResolver = false;
nameservers = singleton (secret.network.ips.blowhole.ip or "");
# Disable the in-built iptable based firewall
firewall.enable = mkForce false;
interfaces = {
# Don't do DHCP on the LAN interface
"${lan}" = {
useDHCP = false;
ipv4.addresses = [
{
address = secret.network.ips.blowhole.ip or "";
prefixLength = 24;
}
];
};
# "${wlan}" = {
# useDHCP = false;
# ipv4.addresses = [{
# address = secret.network.ips.blowhole.wlan or "";
# prefixLength = 24;
# }];
# };
# But do DHCP on the WAN interface
"${wan}".useDHCP = true;
};
wireguard = {
enable = true;
interfaces."${doVPN}" =
secret.wireguard."${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;
iifname != "${wan}" tcp dport 22 accept comment "Accept SSH traffic always"
iifname != "lo" tcp dport 5353 drop comment "Drop traffic to dnscrypt-proxy always except for localhost to localhost traffic"
# Accept WireGuard
iifname "${wan}" udp dport 6666 accept;
# Accept file-share
iifname "${wan}" tcp dport 5666 accept;
# Accept minecraft
iifname "${wan}" tcp dport 25560 accept;
# iifname "cni0" accept;
iifgroup { 99 } tcp dport { 6443, 10250, 4244 } accept
iifgroup { 99 } oifgroup { 99 } accept
iifgroup { 99 } ip saddr 10.64.48.0/21 ip daddr 10.64.48.0/21 accept
iifgroup { 99 } ip saddr 10.64.48.0/21 ip daddr != 10.0.0.0/8 ip daddr != 192.168.0.0/16 ip daddr != 172.0.0.0/12 accept
iifname { "nomad", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "nomad", "ve-monitor", "ve-klipper", "uk3s0" } 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", "mvm0", "uk3s0" } jump input_out
iifgroup 99 jump input_out
# iifname { "${doVPN}", "${lan}" } tcp dport { 6443 } accept
iifname { "${doVPN}", "${lan}" } ip daddr 10.64.2.1 tcp dport { 8833 } accept
iifname { "${doVPN}" } jump input_doVPN
# Allow containers to reach the DNS server
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } tcp dport 53 accept
iifgroup { 99 } tcp dport 53 accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } udp dport 53 accept
iifgroup { 99 } udp dport 53 accept
# Allow Nomad Containers to reach Nomad
iifname { "nomad" } tcp dport 4646 accept
# Allow proxies to reach consul
iifname { "nomad", "ve-monitor", "ve-klipper" } tcp dport 8500 accept
iifname { "ve-monitor", "ve-klipper" } tcp dport 8502 accept
# Allow containers to reach the NFS server
iifname { "docker0", "uk3s0" } tcp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
iifname { "docker0", "uk3s0" } udp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept comment "NFS traffic"
iifname { "${wan}" } udp dport 2302-2304 ip daddr == 192.168.2.20 accept
# drop pointless IoT discovery traffic explicitly
iifname { "${wan}" } ip daddr == 255.255.255.255 udp dport == 6667 drop
log prefix "[drop] nf_filter.input: " queue-threshold 1 group 2 drop
}
chain output {
type filter hook output priority 0; policy accept;
# Drop all DNS traffic if leaving through "wan"
# oifname { "${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
# log prefix "[drop] nf_filter.output: " queue-threshold 1 group 2 drop
}
chain forward {
type filter hook forward priority 10; policy drop;
# Enable flow offloading for better throughput
# ip protocol { tcp, udp } flow offload @f
ip daddr 10.64.52.130 nftrace set 1
ip saddr 10.64.52.130 nftrace set 1
# 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}", "${wlan}" } ct state established, related accept
iifgroup { 99 } oifname { "${doVPN}", "${lan}", "${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", "uk3s0" } oifname { "${wan}" } accept
iifgroup { 99 } oifname { "${wan}" } accept
iifname { "${wan}" } oifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } ct state established, related accept
iifname { "${wan}" } oifgroup { 99 } ct state established, related accept
# Allow containers to reach the DNS and NFS server
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip daddr 10.64.2.1 tcp dport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip saddr 10.64.2.1 tcp sport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip daddr 10.64.2.1 tcp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip saddr 10.64.2.1 tcp sport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip daddr 10.64.2.1 udp dport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip saddr 10.64.2.1 udp sport { 53 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0"} oifname { "${lan}" } ip daddr 10.64.2.1 udp dport { 111, 2049, 4000, 4001, 4002, 20048 } accept
iifname { "nomad", "docker0", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "${lan}" } ip saddr 10.64.2.1 udp sport { 111, 2049, 4000, 4001, 4002, 20048 } accept
# allow communication between all container interfaces
iifname { "nomad", "ve-monitor", "ve-klipper", "uk3s0" } oifname { "nomad", "ve-monitor", "ve-klipper", "uk3s0" } accept
iifgroup { 99 } oifgroup { 99 } accept
iifname { "${lan}" } oifgroup { 99 } accept
# allow portforwarding to lan?
iifname { "${wan}" } oifname { "${lan}" } ip daddr 10.64.2.20 udp dport 2302-2304 accept
# allow lan to access kubernetes http ingress
iifname { "${lan}" } oifname { "uk3s0" } ip daddr 172.26.96.2 tcp dport 80 accept
# allow vpn to access kubernetes http ingress
iifname { "${doVPN}" } oifname { "uk3s0" } ip saddr 10.64.0.1 ip daddr 172.26.96.2 tcp dport 80 accept
# allow kubernetes to respond to incoming traffic
iifname { "uk3s0" } oifname { "${lan}", "${doVPN}" } jump input_out
# Rules to make CNI happy
meta mark and 0x01 == 0x01 accept
log prefix "[drop] nf_filter.forward: " queue-threshold 1 group 2 drop
}
}
table ip nf_nat {
# TCP: 2344-2345, 27015, 27036
# UDP: 2302-2306, 2344, 27015, 27031-27036
chain postrouting {
type nat hook postrouting priority 100; policy accept;
oifname "${wan}" masquerade
udp dport 2302-2304 ip daddr { 192.168.2.20 } masquerade
iifname "${doVPN}" tcp dport 8344 ip daddr 172.26.96.2 masquerade
}
chain prerouting {
type nat hook prerouting priority 100; policy accept;
ip daddr { 192.168.2.20 } udp dport 2302-2304 dnat 10.64.2.20
ip daddr { ${secret.network.ips.blowhole.ip or ""} } tcp dport 8344 dnat 172.26.96.2:80
}
}
table ip6 nf_filter {
chain output {
type filter hook output priority 0; policy drop;
# meta nftrace set 1
oifname "lo" icmpv6 type { echo-request, destination-unreachable, time-exceeded } counter accept comment "Allow select ICMP"
oifname "lo" ip6 saddr "::1" ip6 daddr "::1" reject
}
chain input {
type filter hook input priority 0; policy drop;
# meta nftrace set 1
iifname "lo" icmpv6 type { echo-request, destination-unreachable, time-exceeded } counter accept comment "Allow select ICMP"
}
chain forward {
type filter hook forward priority 0; policy drop;
}
}
'';
};
};
services.ulogd = {
enable = true;
settings = {
# This one for logging to local file in emulated syslog format.
global.stack = "log2:NFLOG,base1:BASE,ifi1:IFINDEX,ip2str1:IP2STR,print1:PRINTPKT,emu1:LOGEMU";
log2.group = 2;
emu1 = {
file = "/var/log/nft_drop.log";
sync = 1;
};
};
};
systemd.services.nftables = {
path = with pkgs; [
nftables
iptables
bash
];
serviceConfig = let
rulesScript = pkgs.writeShellScript "nftables-rules" ''
set -ex
exit_code=0
dynamic_iptables_rules="$(mktemp)"
iptables-save -t filter >> $dynamic_iptables_rules
iptables-save -t nat >> $dynamic_iptables_rules
static_nftables_rules="$(mktemp)"
nft list table ip nf_filter >> $static_nftables_rules || nft create table ip nf_filter
nft list table ip nf_nat >> $static_nftables_rules || nft create table ip nf_nat
nft list table ip6 nf_filter >> $static_nftables_rules || nft create table ip6 nf_filter
nft flush ruleset
iptables-restore < $dynamic_iptables_rules
if nft -f "${pkgs.writeText "nftables-rules" config.networking.nftables.ruleset}" ; then
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
else
echo "Apply failed, restoring previous rules!"
nft -f $static_nftables_rules
exit_code=1
fi
rm $dynamic_iptables_rules $static_nftables_rules
exit $exit_code
'';
in {
ExecStart = mkForce rulesScript;
ExecReload = mkForce rulesScript;
ExecStop = mkForce (pkgs.writeShellScript "nftables-flush" ''
set -ex
tmpfile="$(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
'');
};
};
}