router: wireguard->openvpn via ssh

system/hosts/router/default.nix

@@ -49,7 +49,12 @@ let
   # vpn table, assign an id but don't actually add a rule for it, so it is the default
   vpn_table = 2;
 
-  vpn_mtu = config.networking.wireguard.interfaces.wg0.mtu;
+  vpn_iface =
+    if cfg.vpn.openvpn.enable && !cfg.vpn.wireguard.enable then "tun0"
+    else if cfg.vpn.wireguard.enable && !cfg.vpn.openvpn.enable then "wg0"
+    else throw "Exactly one of OpenVPN/Wireguard must be used";
+
+  vpn_mtu = config.networking.wireguard.interfaces.${vpn_iface}.mtu or 1320;
   vpn_ipv4_mss = vpn_mtu - 40;
   vpn_ipv6_mss = vpn_mtu - 60;
 
@@ -411,7 +416,8 @@ in {
   # ethernet wan
   router.interfaces.wan = {
     dependentServices = [
-      { service = "wireguard-wg0"; inNetns = false; }
+      (lib.mkIf cfg.vpn.wireguard.enable { service = "wireguard-${vpn_iface}"; inNetns = false; })
+      (lib.mkIf cfg.vpn.openvpn.enable { service = "openvpn-client"; inNetns = false; })
       { service = "wireguard-wg1"; inNetns = false; }
     ];
     systemdLink.linkConfig.MACAddressPolicy = "none";
@@ -503,12 +509,12 @@ in {
       selfIp4 = netAddresses.lan4;
       selfIp6 = netAddresses.lan6;
       lans = [ "br0" "wg1" ];
-      wans = [ "wg0" "veth-wan-a" ];
+      wans = [ vpn_iface "veth-wan-a" ];
       logPrefix = "lan ";
       netdevIngressWanRules = with notnft.dsl; with payload; [
         # check oif only from vpn
         # dont check it from veth-wan-a because of dnat fuckery and because we already check packets coming from wan there
-        [(is.eq meta.iifname (set [ "wg0" "wg1" ])) (is.eq (fib (f: with f; [ saddr mark iif ]) (f: f.oif)) missing) (log "lan oif missing ") drop]
+        [(is.eq meta.iifname (set [ vpn_iface "wg1" ])) (is.eq (fib (f: with f; [ saddr mark iif ]) (f: f.oif)) missing) (log "lan oif missing ") drop]
       ];
       inetDnatRules = 
         builtins.concatLists (map
@@ -517,10 +523,10 @@ in {
             rule4 = rule.target4; rule6 = rule.target6;
           in with notnft.dsl; with payload;
             lib.optional (rule4 != null)
-              [ (is.eq meta.iifname "wg0") (is.eq ip.protocol protocols) (is.eq th.dport rule.port)
+              [ (is.eq meta.iifname vpn_iface) (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.optional (rule6 != null)
-              [ (is.eq meta.iifname "wg0") (is.eq ip6.nexthdr protocols) (is.eq th.dport rule.port)
+              [ (is.eq meta.iifname vpn_iface) (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))
@@ -574,13 +580,14 @@ in {
           [(is.eq ip6.daddr "@block6") (log "block6 ") drop]
           [(is.eq ip.saddr "@block4") (log "block4/s ") drop]
           [(is.eq ip6.saddr "@block6") (log "block6/s ") drop]
+          [(mangle meta.mark wan_table)]
           # default to vpn...
-          [(mangle meta.mark vpn_table)]
+          # [(mangle meta.mark vpn_table)]
           # ...but unvpn traffic to/from force_unvpn4/force_unvpn6
-          [(is.eq ip.daddr "@force_unvpn4") (mangle meta.mark wan_table)]
+          # [(is.eq ip.daddr "@force_unvpn4") (mangle meta.mark wan_table)]
-          [(is.eq ip6.daddr "@force_unvpn6") (mangle meta.mark wan_table)]
+          # [(is.eq ip6.daddr "@force_unvpn6") (mangle meta.mark wan_table)]
-          [(is.eq ip.saddr "@force_unvpn4") (mangle meta.mark wan_table)]
+          # [(is.eq ip.saddr "@force_unvpn4") (mangle meta.mark wan_table)]
-          [(is.eq ip6.saddr "@force_unvpn6") (mangle meta.mark wan_table)]
+          # [(is.eq ip6.saddr "@force_unvpn6") (mangle meta.mark wan_table)]
           # ...force vpn to/from force_vpn4/force_vpn6
           # (disable this if it breaks some sites)
           [(is.eq ip.daddr "@force_vpn4") (mangle meta.mark vpn_table)]
@@ -619,12 +626,12 @@ in {
             lib.optionals (rule4 != null) [
               [ (is.eq meta.iifname lanSet) (is.eq ip.protocol protocols) (is.eq ip.saddr rule4.address)
                 (is.eq th.sport (if rule4.port != null then rule4.port else rule.port)) (mangle meta.mark vpn_table) ]
-              [ (is.eq meta.iifname "wg0") (is.eq ip.protocol protocols) (is.eq ip.daddr rule4.address)
+              [ (is.eq meta.iifname vpn_iface) (is.eq ip.protocol protocols) (is.eq ip.daddr rule4.address)
                 (is.eq th.dport (if rule4.port != null then rule4.port else rule.port)) (mangle meta.mark vpn_table) ]
             ] ++ lib.optionals (rule6 != null) [
               [ (is.eq meta.iifname lanSet) (is.eq ip6.nexthdr protocols) (is.eq ip6.saddr rule6.address)
                 (is.eq th.sport (if rule6.port != null then rule6.port else rule.port)) (mangle meta.mark vpn_table) ]
-              [ (is.eq meta.iifname "wg0") (is.eq ip6.nexthdr protocols) (is.eq ip6.daddr rule6.address)
+              [ (is.eq meta.iifname vpn_iface) (is.eq ip6.nexthdr protocols) (is.eq ip6.daddr rule6.address)
                 (is.eq th.dport (if rule6.port != null then rule6.port else rule.port)) (mangle meta.mark vpn_table) ]
             ])
           (builtins.filter (x: x.inVpn && (x.tcp || x.udp) && dnatRuleMode x == "mark") cfg.dnatRules))
@@ -756,9 +763,43 @@ in {
 
   # vpn socket is in wan namespace, meaning traffic gets sent through the wan namespace
   # vpn interface is in default namespace, meaning it can be used in the default namespace
-  networking.wireguard.interfaces.wg0 = cfg.wireguard // {
+  # networking.wireguard.interfaces.${vpn_iface} = cfg.vpn.wireguard.config // {
-    socketNamespace = "wan";
+  #   socketNamespace = "wan";
-    interfaceNamespace = "init";
+  #   interfaceNamespace = "init";
+  # };
+
+  systemd.services.vpn-tunnel = {
+    description = "VPN Tunnel";
+    wantedBy = [
+      "multi-user.target"
+      (lib.mkIf cfg.vpn.openvpn.enable "openvpn-client.service")
+      (lib.mkIf cfg.vpn.wireguard.enable "wireguard-${vpn_iface}.service")
+    ];
+    after = [ "network.target" "netns-wan.service" ]; 
+    bindsTo = [ "netns-wan.service" ]; 
+    stopIfChanged = false;
+    path = [ config.programs.ssh.package ];
+    script = ''
+      while true; do
+        ${config.programs.ssh.package}/bin/ssh \
+          -i /secrets/vpn/sshtunnel.key \
+          -L ${netAddresses.netnsWan4}:${toString cfg.vpn.tunnel.localPort}:127.0.0.1:${toString cfg.vpn.tunnel.remotePort} \
+          -p ${toString cfg.vpn.tunnel.port} \
+          -N -T -v \
+          sshtunnel@${cfg.vpn.tunnel.ip}
+        echo "Restarting..."
+        sleep 10
+      done
+    '';
+    serviceConfig = {
+      Restart = "always";
+      Type = "simple";
+      NetworkNamespacePath = "/var/run/netns/wan";
+    };
+  };
+
+  services.openvpn.servers = lib.mkIf cfg.vpn.openvpn.enable {
+    client.config = cfg.vpn.openvpn.config;
   };
 
   # use main netns's address instead of 127.0.0.1
@@ -847,6 +888,7 @@ in {
     wants = [ "nftables-default.service" "avahi-daemon.service" ];
     # allow it to call nft
     serviceConfig.AmbientCapabilities = [ "CAP_NET_ADMIN" ];
+    serviceConfig.CapabilityBoundingSet = [ "CAP_NET_ADMIN" ];
   };
   systemd.services.update-rkn-blacklist = {
     # fetch vpn_ips.json and vpn_domains.json for unbound
@@ -864,7 +906,6 @@ in {
   systemd.timers.update-rkn-blacklist = {
     wantedBy = [ "timers.target" ];
     partOf = [ "update-rkn-blacklist.service" ];
-    # slightly unusual time to reduce server load
     timerConfig.OnCalendar = [ "*-*-* 00:00:00" ]; # every day
     timerConfig.RandomizedDelaySec = 43200; # execute at random time in the first 12 hours
   };

system/hosts/router/options.nix

@@ -5,6 +5,38 @@
 
 {
   options.router-settings = {
+    vpn = {
+      tunnel = {
+        enable = lib.mkEnableOption "VPN tunnel";
+        localPort = lib.mkOption {
+          description = "local port";
+          type = lib.types.port;
+        };
+        remotePort = lib.mkOption {
+          description = "remote port";
+          type = lib.types.port;
+        };
+        ip = lib.mkOption {
+          description = "remote ip";
+          type = router-lib.types.ipv4;
+        };
+        port = lib.mkOption {
+          description = "SSH port";
+          type = lib.types.port;
+          default = 22;
+        };
+      };
+      openvpn.enable = lib.mkEnableOption "OpenVPN";
+      openvpn.config = lib.mkOption {
+        description = "OpenVPN config";
+        type = lib.types.lines;
+      };
+      wireguard.enable = lib.mkEnableOption "Wireguard";
+      wireguard.config = lib.mkOption {
+        description = "wireguard config";
+        type = lib.types.attrs;
+      };
+    };
     routerMac = lib.mkOption {
       description = "router's mac address";
       type = lib.types.str;
@@ -82,10 +114,6 @@
       description = "wlan passphrase";
       type = lib.types.str;
     };
-    wireguard = lib.mkOption {
-      description = "wireguard config";
-      type = lib.types.attrs;
-    };
     dhcpReservations = lib.mkOption {
       description = "dhcp reservations (ipv4)";
       default = [ ];

system/hosts/server/certspotter.nix

@@ -5,33 +5,19 @@
 
 let
   cfg = config.server;
-in {
+  python = pkgs.python3.withPackages (p: with p; [ cryptography pyasn1 pyasn1-modules requests ]);
-  security.acme.certs = lib.flip builtins.mapAttrs (lib.filterAttrs (k: v: v.enableACME) config.services.nginx.virtualHosts) (k: v: {
+  tool = pkgs.writeScript "certspotter.py" ''
-    postRun = let
-      python = pkgs.python3.withPackages (p: with p; [ cryptography pyasn1 pyasn1-modules ]);
-      tbs-hash = pkgs.writeScript "tbs-hash.py" ''
     #!${python}/bin/python3
-        import hashlib
+    ${builtins.readFile ./certspotter.py}
-        from pyasn1.codec.der.decoder import decode
-        from pyasn1.codec.der.encoder import encode
-        from pyasn1_modules import rfc5280
-        from cryptography import x509
-
-        with open('full.pem', 'rb') as f: 
-          cert = x509.load_pem_x509_certificate(f.read())
-        tbs, _leftover = decode(cert.tbs_certificate_bytes, asn1Spec=rfc5280.TBSCertificate())
-        precert_exts = [v.dotted_string for k, v in x509.ExtensionOID.__dict__.items() if k.startswith('PRECERT_')]
-        exts = [ext for ext in tbs["extensions"] if str(ext["extnID"]) not in precert_exts]
-        tbs["extensions"].clear()
-        tbs["extensions"].extend(exts)
-        print(hashlib.sha256(encode(tbs)).hexdigest())
   '';
-    in ''
+in {
-      ${tbs-hash} > "/var/lib/certspotter/tbs-hashes/${k}"
+  security.acme.certs = lib.mkIf config.services.certspotter.enable (lib.flip builtins.mapAttrs (lib.filterAttrs (k: v: v.enableACME) config.services.nginx.virtualHosts) (k: v: {
+    postRun = ''
+      ${tool} tbs full.pem > "/var/lib/certspotter/tbs-hashes/${k}"
     '';
-  });
+  }));
   services.certspotter = {
-    enable = true;
+    enable = false;
     extraFlags = [ ];
     watchlist = [ ".${cfg.domainName}" ];
     hooks = lib.toList (pkgs.writeShellScript "certspotter-hook" ''
@@ -41,4 +27,25 @@ in {
       (echo "Subject: $SUMMARY" && echo && cat "$TEXT_FILENAME") | /run/wrappers/bin/sendmail -i webmaster-certspotter@${cfg.domainName}
     '');
   };
+  systemd.services.certspotter-lite = {
+    script = ''
+      exec ${tool} spot \
+        -c /var/lib/acme/certspotter-lite.txt \
+        -d ${cfg.domainName} \
+        -t webmaster-certspotter@${cfg.domainName} \
+        -s /run/wrappers/bin/sendmail \
+        /var/lib/acme/*/full.pem
+    '';
+    serviceConfig = {
+      User = "acme";
+      Group = "acme";
+      Type = "oneshot";
+    };
+  };
+  systemd.timers.certspotter-lite = {
+    wantedBy = [ "timers.target" ];
+    partOf = [ "certspotter-lite.service" ];
+    timerConfig.OnCalendar = [ "*-*-* 00:00:00" ]; # every day
+    timerConfig.RandomizedDelaySec = 43200; # execute at random time in the first 12 hours
+  };
 }

system/hosts/server/certspotter.py

@@ -0,0 +1,158 @@
+import argparse
+import hashlib
+import requests
+import subprocess
+import traceback
+from datetime import date
+from pyasn1.codec.der.decoder import decode
+from pyasn1.codec.der.encoder import encode
+from pyasn1_modules import rfc5280
+from cryptography import x509
+
+
+def calc_tbs(pem: bytes) -> str:
+    cert = x509.load_pem_x509_certificate(pem)
+    tbs, _leftover = decode(
+        cert.tbs_certificate_bytes, asn1Spec=rfc5280.TBSCertificate()
+    )
+    precert_exts = [
+        v.dotted_string
+        for k, v in x509.ExtensionOID.__dict__.items()
+        if k.startswith("PRECERT_")
+    ]
+    exts = [ext for ext in tbs["extensions"] if str(ext["extnID"]) not in precert_exts]
+    tbs["extensions"].clear()
+    tbs["extensions"].extend(exts)
+    return hashlib.sha256(encode(tbs)).hexdigest()
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers(required=True)
+    spot = subparsers.add_parser("spot")
+    spot.set_defaults(func=spotter)
+    spot.add_argument("--sendmail", "-s", type=str, required=True)
+    spot.add_argument("--from", "-f", type=str, required=False, default="Certificate Monitoring")
+    spot.add_argument("--to", "-t", type=str, required=False)
+    spot.add_argument("--domain", "-d", type=str, required=True)
+    spot.add_argument("--cache_file", "-c", type=str, required=True)
+    spot.add_argument("certs", type=str, nargs="*")
+    tbs = subparsers.add_parser("tbs")
+    tbs.set_defaults(func=print_tbs)
+    tbs.add_argument("path", type=str)
+    args = parser.parse_args()
+    args.func(args)
+
+
+def print_tbs(args) -> None:
+    with open(args.path, "rb") as f:
+        print(calc_tbs(f.read()))
+
+
+def send_mail(
+    sendmail: str, from_: str | None, to: str | None, subject: str, text: str
+):
+    proc = subprocess.Popen(
+        [sendmail, "-i"] + (["-F", from_] if from_ else []) + (['--', to] if to else []),
+        stdin=subprocess.PIPE,
+    )
+    assert proc.stdin is not None
+    proc.stdin.write(f"Subject: {subject}\n\n".encode("utf-8"))
+    proc.stdin.write((text + "\n").encode("utf-8"))
+    proc.stdin.close()
+    proc.wait()
+    assert proc.returncode == 0
+
+
+def spotter(args) -> None:
+    try:
+        spotter1(args)
+    except Exception:
+        subject = "Certificate monitoring failure"
+        text = traceback.format_exc()
+        send_mail(args.sendmail, args.__dict__["from"], args.to, subject, text)
+
+
+def spotter1(args) -> None:
+    url = f"https://crt.sh/?CN={args.domain}&dir=^&sort=1&group=none"
+
+    try:
+        with open(args.cache_file, "rt") as f:
+            lastid = int(f.read())
+    except FileNotFoundError:
+        lastid = 0
+
+    body = requests.get(url).text
+
+    def parse_row(row: str, tag: str) -> list[str]:
+        ret = []
+        for col in row.split(f"</{tag}>")[:-1]:
+            if "</A>" in col:
+                col = col.split("</A>")[-2].split(">")[-1]
+            else:
+                col = col.split(">")[-1]
+            ret.append(col)
+        return ret
+
+    cols: list[str] = []
+    rows: list[dict[str, str]] = []
+    for s_row in body.split("<TR>")[2:]:
+        s_row = s_row.split("</TR>")[0]
+        if "<TH" in s_row:
+            cols = parse_row(s_row, "TH")
+        elif cols:
+            rows.append({k: v for k, v in zip(cols, parse_row(s_row, "TD"))})
+
+    today = date.today()
+    pem_urls = {}
+    issuers = {}
+    cns = {}
+
+    if not rows:
+        raise Exception("No rows found!")
+
+    for row in rows:
+        crtid = int(row["crt.sh ID"])
+        if crtid <= lastid:
+            continue
+        d = date.fromisoformat(row["Logged At"])
+        if (today - d).days > 30:
+            continue
+        pem_urls[crtid] = f"https://crt.sh/?d={crtid}"
+        issuers[crtid] = row.get("Issuer Name", "")
+        cns[crtid] = row.get("Matching Identities", "")
+
+    if not pem_urls:
+        return
+
+    valid_hashes: set[str] = set()
+    for path in args.certs:
+        with open(path, "rb") as f1:
+            valid_hashes.add(calc_tbs(f1.read()))
+
+    pems: dict[int, bytes] = {}
+
+    for id, pem_url in pem_urls.items():
+        lastid = max(id, lastid)
+        pems[id] = requests.get(pem_url).content
+
+    invalid_ids: set[int] = set()
+
+    for id, pem in pems.items():
+        if calc_tbs(pem) not in valid_hashes:
+            invalid_ids.add(id)
+
+    if invalid_ids:
+        subject = f"{len(invalid_ids)} invalid certs discovered!"
+        text = "\n".join(
+            f"https://crt.sh/?id={id} ({cns[id]}, {issuers[id]})"
+            for id in sorted(invalid_ids)
+        )
+        send_mail(args.sendmail, args.__dict__["from"], args.to, subject, text)
+
+    with open(args.cache_file, "wt") as f:
+        f.write(str(lastid))
+
+
+if __name__ == "__main__":
+    main()