Правила Nftables для усиления защиты установки Discourse

Поддержка Самостоятельное хостинг
5

Спасибо @OrkoGrayskull!

Есть ли какие-либо обновления по этой теме теперь, когда в /etc/docker/daemon.json можно установить firewall-backend в значение nftables, и я полагаю, вы теперь используете Debian Trixie или Bookworm? Я экспериментирую с этим…

Я обнаружил, что в файле /etc/sysctl.conf необходимо установить net.ipv4.ip_forward=1.

В документации Docker с nftables указано:

Не изменяйте таблицы Docker напрямую, так как изменения, скорее всего, будут потеряны. Docker ожидает полного контроля над своими таблицами.

Поэтому я надеюсь не трогать правила Docker…

Вот что у меня сейчас есть, некоторые правила я добавил через Ansible (этот сервер пересылает SMTP через Postfix в Discourse, поэтому нужен порт 25):

table inet ansible_firewall {
        chain inbound_ipv4 {
                icmp type echo-request limit rate 5/second accept comment "Accept IPv4 rate limited ICMP pings"
        }

        chain inbound_ipv6 {
                icmpv6 type { nd-router-advert, nd-neighbor-solicit, nd-neighbor-advert } accept comment "Accept IPv6 neighbour discovery"
                icmpv6 type echo-request limit rate 5/second accept comment "Accept IPv6 rate limited ICMP pings"
        }

        chain inbound {
                type filter hook input priority filter; policy drop;
                ct state vmap { invalid : drop, established : accept, related : accept } comment "Allow traffic from established and related packets, drop invalid"
                iifname "lo" accept comment "Allow loopback traffic"
                meta protocol vmap { ip : jump inbound_ipv4, ip6 : jump inbound_ipv6 } comment "Jump to chain according to layer 3 protocol using a verdict map"
                tcp dport 22 accept comment "Allow SSH on port TCP/22"
                tcp dport { 80, 443 } accept comment "Allow HTTP on port TCP/80 and HTTPS on port TCP/443"
        }

        chain forward {
                type filter hook forward priority filter; policy drop;
        }

        chain output {
                type filter hook output priority filter; policy accept;
                oifname "lo" accept comment "Allow outgoing from loopback interface"
        }
}

А вот правила от Docker / Discourse (обратите внимание, что на этом сервере нет IPv6-адреса):

table ip docker-bridges {
        map filter-forward-in-jumps {
                type ifname : verdict
                elements = { "docker0" : jump filter-forward-in__docker0 }
        }

        map filter-forward-out-jumps {
                type ifname : verdict
                elements = { "docker0" : jump filter-forward-out__docker0 }
        }

        map nat-postrouting-in-jumps {
                type ifname : verdict
                elements = { "docker0" : jump nat-postrouting-in__docker0 }
        }

        map nat-postrouting-out-jumps {
                type ifname : verdict
                elements = { "docker0" : jump nat-postrouting-out__docker0 }
        }

        chain filter-FORWARD {
                type filter hook forward priority filter; policy accept;
                oifname vmap @filter-forward-in-jumps
                iifname vmap @filter-forward-out-jumps
        }

        chain nat-OUTPUT {
                type nat hook output priority -100; policy accept;
                ip daddr != 127.0.0.0/8 fib daddr type local counter jump nat-prerouting-and-output
        }

        chain nat-POSTROUTING {
                type nat hook postrouting priority srcnat; policy accept;
                iifname vmap @nat-postrouting-out-jumps
                oifname vmap @nat-postrouting-in-jumps
        }

        chain nat-PREROUTING {
                type nat hook prerouting priority dstnat; policy accept;
                fib daddr type local counter jump nat-prerouting-and-output
        }

        chain nat-prerouting-and-output {
                iifname != "docker0" tcp dport 80 counter dnat to 172.17.0.2:80 comment "DNAT"
                iifname != "docker0" tcp dport 443 counter dnat to 172.17.0.2:443 comment "DNAT"
        }

        chain raw-PREROUTING {
                type filter hook prerouting priority raw; policy accept;
                ip daddr 172.17.0.2 iifname != "docker0" counter drop comment "DROP DIRECT ACCESS"
        }

        chain filter-forward-in__docker0 {
                ct state established,related counter accept
                iifname "docker0" counter accept comment "ICC"
                ip daddr 172.17.0.2 tcp dport 80 counter accept
                ip daddr 172.17.0.2 tcp dport 443 counter accept
                counter drop comment "UNPUBLISHED PORT DROP"
        }

        chain filter-forward-out__docker0 {
                ct state established,related counter accept
                counter accept comment "OUTGOING"
        }

        chain nat-postrouting-in__docker0 {
        }

        chain nat-postrouting-out__docker0 {
                oifname != "docker0" ip saddr 172.17.0.0/16 counter masquerade comment "MASQUERADE"
        }
}
table ip6 docker-bridges {
        map filter-forward-in-jumps {
                type ifname : verdict
        }

        map filter-forward-out-jumps {
                type ifname : verdict
        }

        map nat-postrouting-in-jumps {
                type ifname : verdict
        }

        map nat-postrouting-out-jumps {
                type ifname : verdict
        }

        chain filter-FORWARD {
                type filter hook forward priority filter; policy accept;
                oifname vmap @filter-forward-in-jumps
                iifname vmap @filter-forward-out-jumps
        }

        chain nat-OUTPUT {
                type nat hook output priority -100; policy accept;
                ip6 daddr != ::1 fib daddr type local counter jump nat-prerouting-and-output
        }

        chain nat-POSTROUTING {
                type nat hook postrouting priority srcnat; policy accept;
                iifname vmap @nat-postrouting-out-jumps
                oifname vmap @nat-postrouting-in-jumps
        }

        chain nat-PREROUTING {
                type nat hook prerouting priority dstnat; policy accept;
                fib daddr type local counter jump nat-prerouting-and-output
        }

        chain nat-prerouting-and-output {
        }

        chain raw-PREROUTING {
                type filter hook prerouting priority raw; policy accept;
        }
}

И всё, кроме портов 80 и 443, работает нормально… :roll_eyes: