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router: hijack some dns requests

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chayleaf 2023-08-13 22:36:38 +07:00
parent ea1d12da4f
commit 5ce6702c31
2 changed files with 34 additions and 20 deletions
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47
system/hosts/router/default.nix
View file

@ -67,6 +67,10 @@ let
else if rule.udp then udp
else throw "Invalid rule: either tcp or udp must be set";
setIfNeeded = arr:
if builtins.length arr == 1 then builtins.head arr
else notnft.dsl.set arr;
# nftables rules generator
# selfIp4/selfIp6 = block packets from these addresses
# extraInetEntries = stuff to add to inet table
@ -163,7 +167,7 @@ let
[(is.eq ip6.nexthdr (f: f.ipv6-icmp)) (is.eq icmpv6.code (f: f.no-route))
(is.eq icmpv6.type (f: with f; set [ packet-too-big parameter-problem ])) accept]
[(is.eq ip6.nexthdr (f: f.ipv6-icmp)) (is.eq icmpv6.code (f: f.admin-prohibited))
(is.eq icmpv6.type (f: with f; set [ parameter-problem ])) accept]
(is.eq icmpv6.type (f: f.parameter-problem)) accept]
inetInboundWanRules;
# trust the lan
@ -183,22 +187,22 @@ let
[(vmap ct.state { established = accept; related = accept; invalid = drop; })]
[(is ct.status (f: f.dnat)) accept]
# accept lan->wan fw
[(is.eq meta.iifname (set lans)) (is.eq meta.oifname (set wans)) accept]
[(is.eq meta.iifname (setIfNeeded lans)) (is.eq meta.oifname (setIfNeeded wans)) accept]
# accept lan->lan fw
[(is.eq meta.iifname (set lans)) (is.eq meta.oifname (set lans)) accept]
[(is.eq meta.iifname (setIfNeeded lans)) (is.eq meta.oifname (setIfNeeded lans)) accept]
# accept wan->lan icmpv6 forward
[(is.eq meta.iifname (set wans)) (is.eq icmpv6.type (f: with f; set [ destination-unreachable time-exceeded echo-request echo-reply ])) accept]
[(is.eq meta.iifname (set wans)) (is.eq icmpv6.code (f: f.no-route)) (is.eq icmpv6.type (f: with f; set [ packet-too-big parameter-problem ])) accept]
[(is.eq meta.iifname (set wans)) (is.eq icmpv6.code (f: f.admin-prohibited)) (is.eq icmpv6.type (f: f.parameter-problem)) accept]
[(is.eq meta.iifname (setIfNeeded wans)) (is.eq icmpv6.type (f: with f; set [ destination-unreachable time-exceeded echo-request echo-reply ])) accept]
[(is.eq meta.iifname (setIfNeeded wans)) (is.eq icmpv6.code (f: f.no-route)) (is.eq icmpv6.type (f: with f; set [ packet-too-big parameter-problem ])) accept]
[(is.eq meta.iifname (setIfNeeded wans)) (is.eq icmpv6.code (f: f.admin-prohibited)) (is.eq icmpv6.type (f: f.parameter-problem)) accept]
inetForwardRules
[(log "${logPrefix}forward drop ")];
postrouting = add chain { type = f: f.nat; hook = f: f.postrouting; prio = f: f.srcnat; policy = f: f.accept; }
snat = add chain { type = f: f.nat; hook = f: f.postrouting; prio = f: f.srcnat; policy = f: f.accept; }
# masquerade ipv6 because my isp doesn't provide it and my vpn gives a single ipv6
[(is.eq meta.protocol (f: set [ f.ip f.ip6 ])) (is.eq meta.iifname (set lans)) (is.eq meta.oifname (set wans)) masquerade]
[(is.eq meta.protocol (f: set [ f.ip f.ip6 ])) (is.eq meta.iifname (setIfNeeded lans)) (is.eq meta.oifname (setIfNeeded wans)) masquerade]
inetSnatRules;
prerouting = add chain { type = f: f.nat; hook = f: f.prerouting; prio = f: f.dstnat; policy = f: f.accept; }
dnat = add chain { type = f: f.nat; hook = f: f.prerouting; prio = f: f.dstnat; policy = f: f.accept; }
inetDnatRules;
} // extraInetEntries);
};
@ -288,13 +292,13 @@ in {
rangesTcpOnly = builtins.filter (x: !builtins.elem x allowedUDPPortRanges) allowedTCPPortRanges;
rangesUdpOnly = builtins.filter (x: !builtins.elem x allowedTCPPortRanges) allowedUDPPortRanges;
in lib.optional (tcpAndUdp != [ ]) {
port = notnft.dsl.set tcpAndUdp; tcp = true; udp = true;
port = setIfNeeded tcpAndUdp; tcp = true; udp = true;
target4.address = serverAddress4; target6.address = serverAddress6;
} ++ lib.optional (tcpOnly != [ ]) {
port = notnft.dsl.set tcpOnly; tcp = true; udp = false;
port = setIfNeeded tcpOnly; tcp = true; udp = false;
target4.address = serverAddress4; target6.address = serverAddress6;
} ++ lib.optional (udpOnly != [ ]) {
port = notnft.dsl.set udpOnly; tcp = false; udp = true;
port = setIfNeeded udpOnly; tcp = false; udp = true;
target4.address = serverAddress4; target6.address = serverAddress6;
} ++ lib.flip map rangesTcpAndUdp (range: {
port = notnft.dsl.range range.from range.to; tcp = true; udp = true;
@ -475,14 +479,23 @@ in {
protocols = dnatRuleProtos rule;
rule4 = rule.target4; rule6 = rule.target6;
in with notnft.dsl; with payload;
lib.optionals (rule4 != null) [
lib.optional (rule4 != null)
[ (is.eq meta.iifname "wg0") (is.eq ip.protocol protocols) (is.eq th.dport rule.port)
(if rule4.port == null then dnat.ip rule4.address else dnat.ip rule4.address rule4.port) ]
] ++ lib.optionals (rule6 != null) [
++ lib.optional (rule6 != null)
[ (is.eq meta.iifname "wg0") (is.eq ip6.nexthdr protocols) (is.eq th.dport rule.port)
(if rule6.port == null then dnat.ip6 rule6.address else dnat.ip6 rule6.address rule6.port) ]
])
(builtins.filter (x: x.inVpn && (x.tcp || x.udp)) cfg.dnatRules));
)
(builtins.filter (x: x.inVpn && (x.tcp || x.udp)) cfg.dnatRules))
++ (with notnft.dsl; with payload; [
# hijack Microsoft DNS server hosted on Cloudflare
[(is.eq meta.iifname "br0") (is.eq ip.daddr "162.159.36.2") (is.eq ip.protocol (f: set [ f.tcp f.udp ])) (dnat.ip netAddresses.lan4)]
] ++ lib.optionals (cfg.naughtyMacs != []) [
[(is.eq meta.iifname "br0") (is.eq ether.saddr (setIfNeeded cfg.naughtyMacs)) (is.eq ip.protocol (f: set [ f.tcp f.udp ]))
(is.eq th.dport (set [ 53 853 ])) (dnat.ip netAddresses.lan4)]
[(is.eq meta.iifname "br0") (is.eq ether.saddr (setIfNeeded cfg.naughtyMacs)) (is.eq ip6.nexthdr (f: set [ f.tcp f.udp ]))
(is.eq th.dport (set [ 53 853 ])) (dnat.ip6 netAddresses.lan6)]
]);
inetForwardRules = with notnft.dsl; with payload; [
# allow access to lan from the wan namespace
[(is.eq meta.iifname "veth-wan-a") (is.eq meta.oifname "br0") accept]
@ -758,6 +771,8 @@ in {
environment.etc."unbound/iot_ips.json".text = builtins.toJSON [
# local multicast
"224.0.0.0/24"
# local broadcast
"255.255.255.255"
];
environment.etc."unbound/iot_domains.json".text = builtins.toJSON [
# ntp time sync

7
system/hosts/router/options.nix
View file

@ -13,10 +13,9 @@
description = "server's mac address";
type = lib.types.str;
};
# TODO: take this from server config
domainName = lib.mkOption {
description = "server's domain name";
type = lib.types.str;
naughtyMacs = lib.mkOption {
description = "misbehaving (using wrong DNS server) clients' macs";
type = with lib.types; listOf str;
};
vacuumMac = lib.mkOption {
description = "robot vacuum's mac address";