graphene-os-server-infrastr.../nftables-attestation.conf
2024-04-05 19:14:05 -04:00

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#!/usr/bin/nft -f
flush ruleset
table inet filter {
define ip-allowlist-ssh = {
127.0.0.1,
}
define ip6-allowlist-ssh = {
::1,
}
set ip-connlimit-ssh {
type ipv4_addr
flags dynamic
}
set ip6-connlimit-ssh {
type ipv6_addr
flags dynamic
}
set ip-connlimit-http {
type ipv4_addr
flags dynamic
}
set ip6-connlimit-http {
type ipv6_addr
flags dynamic
}
chain prerouting-raw {
type filter hook prerouting priority raw
# drop packets without a reverse path (strict reverse path filtering)
fib saddr . iif oif missing counter drop
iif lo notrack accept
# drop packets to address not configured on incoming interface (strong host model)
fib daddr . iif type != { local, broadcast, multicast } counter drop
tcp dport 443 notrack accept
tcp dport { 22, 80 } tcp flags syn notrack accept
meta l4proto { icmp, ipv6-icmp } notrack accept
}
chain input {
type filter hook input priority filter
policy drop
iif lo goto input-loopback
tcp dport 443 accept
meta l4proto { icmp, ipv6-icmp } accept
ct state vmap { established : accept, related : accept, new : goto graceful-reject }
tcp dport 22 ip saddr @ip-connlimit-ssh counter reject with tcp reset
tcp dport 22 ip6 saddr and ffff:ffff:ffff:ffff:ffff:: @ip6-connlimit-ssh counter reject with tcp reset
tcp dport 80 ip saddr @ip-connlimit-http counter reject with tcp reset
tcp dport 80 ip6 saddr and ffff:ffff:ffff:ffff:: @ip6-connlimit-http counter reject with tcp reset
tcp dport { 22, 80 } synproxy mss 1460 wscale 7 timestamp sack-perm
}
chain input-loopback {
tcp flags != syn accept
tcp dport 22 ip saddr != $ip-allowlist-ssh add @ip-connlimit-ssh { ip saddr ct count over 1 } counter reject with tcp reset
tcp dport 22 ip6 saddr != $ip6-allowlist-ssh add @ip6-connlimit-ssh { ip6 saddr and ffff:ffff:ffff:ffff:ffff:: ct count over 1 } counter reject with tcp reset
tcp dport 80 add @ip-connlimit-http { ip saddr ct count over 32 } counter reject with tcp reset
tcp dport 80 add @ip6-connlimit-http { ip6 saddr and ffff:ffff:ffff:ffff:: ct count over 32 } counter reject with tcp reset
accept
}
chain forward {
type filter hook forward priority filter
policy drop
}
chain output-raw {
type filter hook output priority raw
oif lo notrack accept
tcp sport 443 notrack accept
meta l4proto { icmp, ipv6-icmp } notrack accept
}
chain output {
type filter hook output priority filter
oif lo goto output-loopback
skuid != { root, systemd-network, unbound, chrony, http, attestation } counter goto graceful-reject
}
chain output-loopback {
skuid unbound meta l4proto { tcp, udp } th sport 53 th dport >= 1024 th dport != 8080 accept
skuid { chrony, attestation } meta l4proto { tcp, udp } th sport >= 1024 th sport != 8080 th dport 53 accept
skuid attestation tcp sport 8080 tcp dport >= 1024 tcp dport != 8080 accept
skuid http tcp sport >= 1024 tcp sport != 8080 tcp dport 8080 accept
skuid != root counter goto graceful-reject
accept
}
chain graceful-reject {
meta l4proto udp reject
meta l4proto tcp reject with tcp reset
reject
}
}