netns: configure the device in a way that should allow named endpoints to be resolved outside the netns
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@@ -163,22 +163,40 @@ let
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systemd.services."netns-${name}-wg" = {
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description = "configure the wireguard device which provides ${name} with an IP";
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wantedBy = [ "netns-${name}.target" ];
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before = [ "netns-${name}.target" ];
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after = [ "netns-${name}.service" ];
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partOf = [ "netns-${name}.service" ];
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before = [ "netns-${name}.target" ];
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after = [
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"netns-${name}.service"
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# in case the endpoint is a domain or host name, wait for the DNS resolver to be available
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# before even trying configure the device. not strictly necessary, just avoids wasting resources/retries.
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"nss-lookup.target"
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];
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serviceConfig.Type = "oneshot";
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serviceConfig.RemainAfterExit = true;
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serviceConfig.Restart = "on-failure";
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serviceConfig.RestartSec = "10s";
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serviceConfig.RestartMaxDelaySec = "180s";
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serviceConfig.RestartSteps = 9; # roughly: 10s, 30s, 50s, ... 180s, then keep the 180s retry
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script = ''
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${ip} link add wg-${name} type wireguard
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${ip} link set wg-${name} netns ${name}
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${in-ns} ${ip} address add ${netnsPubIpv4} dev wg-${name}
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${in-ns} ${wg'} set wg-${name} private-key ${wg.privateKeyFile}
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${in-ns} ${ip} link set up dev wg-${name}
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# TODO: endpoint configuration should be split out into a retryable thing, capable of DNS lookups
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${in-ns} ${wg'} set wg-${name} peer ${wg.peer.publicKey} endpoint ${wg.peer.endpoint} \
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# resolve the endpoint *now*, from a namespace which can do DNS lookups, before moving it into its destination netns
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# at this point, our wg device can neither send nor receive traffic, because we haven't given it a private key.
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# hence, it's 100% safe to configure peers even inside the root ns at this point.
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#
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# N.B.: `wg` resolves the endpoint _immediately_; it doesn't save DNS info into the device at all,
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# so the possibility of any code not visible here trying to re-resolve the endpoint at a later time
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# (i.e. from within the namespace) is 0.
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${wg'} set wg-${name} peer ${wg.peer.publicKey} endpoint ${wg.peer.endpoint} \
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persistent-keepalive 25 \
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allowed-ips 0.0.0.0/0
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${ip} link set wg-${name} netns ${name}
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${in-ns} ${wg'} set wg-${name} private-key ${wg.privateKeyFile}
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${in-ns} ${ip} address add ${netnsPubIpv4} dev wg-${name}
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${in-ns} ${ip} link set up dev wg-${name}
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# in the namespace, make this device the default route
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${in-ns} ${ip} route replace 0.0.0.0/0 dev wg-${name} table main
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'';
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serviceConfig.ExecStopPost = [
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@@ -188,49 +188,51 @@ let
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# but i couldn't get that to work for netns with SNAT, so set rpfilter to "loose".
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networking.firewall.checkReversePath = "loose";
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systemd.services."${name}-refresh" = {
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# periodically re-apply peers, to ensure DNS mappings stay fresh
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# borrowed from <repo:nixos/nixpkgs:nixos/modules/services/networking/wireguard.nix>
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wantedBy = [ "network.target" ];
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path = [ config.sane.programs.wireguard-tools.package ];
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serviceConfig.Restart = "always";
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serviceConfig.RestartSec = "60"; #< retry delay when we fail (because e.g. there's no network)
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serviceConfig.Type = "simple";
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unitConfig.StartLimitIntervalSec = 0;
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script = ''
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while wg set ${name} peer ${publicKey} endpoint ${endpoint}; do
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echo "${name} set to:" "$(wg show ${name} endpoints)"
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# in the normal case that DNS resolves, and whatnot, sleep before the next attempt
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sleep 180
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done
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'';
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# systemd hardening (systemd-analyze security wg-home-refresh.service)
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serviceConfig.AmbientCapabilities = "CAP_NET_ADMIN";
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serviceConfig.CapabilityBoundingSet = "CAP_NET_ADMIN";
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serviceConfig.LockPersonality = true;
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serviceConfig.MemoryDenyWriteExecute = true;
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serviceConfig.NoNewPrivileges = true;
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serviceConfig.ProtectClock = true;
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serviceConfig.ProtectHostname = true;
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serviceConfig.RemoveIPC = true;
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serviceConfig.RestrictAddressFamilies = "AF_INET AF_INET6 AF_NETLINK";
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#VVV this includes anything it reads from, e.g. /bin/sh; /nix/store/...
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# see `systemd-analyze filesystems` for a full list
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serviceConfig.RestrictFileSystems = "@common-block @basic-api";
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serviceConfig.RestrictRealtime = true;
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serviceConfig.RestrictSUIDSGID = true;
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serviceConfig.SystemCallArchitectures = "native";
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serviceConfig.SystemCallFilter = [
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"@system-service"
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"@sandbox"
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"~@chown"
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"~@cpu-emulation"
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"~@keyring"
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];
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serviceConfig.DevicePolicy = "closed"; # only allow /dev/{null,zero,full,random,urandom}
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# serviceConfig.DeviceAllow = "/dev/...";
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serviceConfig.RestrictNamespaces = true;
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};
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# XXX: all my wireguard DNS endpoints are static at the moment, so refresh logic isn't needed.
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# re-enable this should that ever change.
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# systemd.services."${name}-refresh" = {
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# # periodically re-apply peers, to ensure DNS mappings stay fresh
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# # borrowed from <repo:nixos/nixpkgs:nixos/modules/services/networking/wireguard.nix>
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# wantedBy = [ "network.target" ];
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# path = [ config.sane.programs.wireguard-tools.package ];
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# serviceConfig.Restart = "always";
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# serviceConfig.RestartSec = "60"; #< retry delay when we fail (because e.g. there's no network)
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# serviceConfig.Type = "simple";
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# unitConfig.StartLimitIntervalSec = 0;
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# script = ''
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# while wg set ${name} peer ${publicKey} endpoint ${endpoint}; do
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# echo "${name} set to:" "$(wg show ${name} endpoints)"
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# # in the normal case that DNS resolves, and whatnot, sleep before the next attempt
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# sleep 180
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# done
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# '';
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# # systemd hardening (systemd-analyze security wg-home-refresh.service)
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# serviceConfig.AmbientCapabilities = "CAP_NET_ADMIN";
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# serviceConfig.CapabilityBoundingSet = "CAP_NET_ADMIN";
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# serviceConfig.LockPersonality = true;
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# serviceConfig.MemoryDenyWriteExecute = true;
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# serviceConfig.NoNewPrivileges = true;
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# serviceConfig.ProtectClock = true;
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# serviceConfig.ProtectHostname = true;
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# serviceConfig.RemoveIPC = true;
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# serviceConfig.RestrictAddressFamilies = "AF_INET AF_INET6 AF_NETLINK";
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# #VVV this includes anything it reads from, e.g. /bin/sh; /nix/store/...
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# # see `systemd-analyze filesystems` for a full list
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# serviceConfig.RestrictFileSystems = "@common-block @basic-api";
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# serviceConfig.RestrictRealtime = true;
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# serviceConfig.RestrictSUIDSGID = true;
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# serviceConfig.SystemCallArchitectures = "native";
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# serviceConfig.SystemCallFilter = [
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# "@system-service"
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# "@sandbox"
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# "~@chown"
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# "~@cpu-emulation"
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# "~@keyring"
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# ];
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# serviceConfig.DevicePolicy = "closed"; # only allow /dev/{null,zero,full,random,urandom}
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# # serviceConfig.DeviceAllow = "/dev/...";
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# serviceConfig.RestrictNamespaces = true;
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# };
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# networking.firewall.extraCommands = with pkgs; ''
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# # wireguard packet marking. without this, rpfilter drops responses from a wireguard VPN
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