modules/private/dns.nix

   1 { lib, pkgs, config, ... }:
   2 {
   3   options.myServices.dns.enable = lib.mkEnableOption "enable DNS resolver";
   4   config = let
   5     cfg = config.services.bind;
   6     keyIncludes = builtins.concatStringsSep "\n" (map (v: "include \"/var/secrets/bind/${v}.key\";") (builtins.attrNames config.myEnv.dns.keys));
   7     toKeyList = servers: keys: builtins.concatStringsSep "\n" (map (s: ''
   8       server ${s} {
   9         keys { ${builtins.concatStringsSep ";" keys}; };
  10       };
  11     '') servers);
  12     serverIncludes = builtins.concatStringsSep "\n" (map (v:
  13       lib.optionalString (builtins.length v.keys > 0) (toKeyList (lib.flatten (map (n: builtins.attrValues config.myEnv.dns.ns."${n}") v.masters)) v.keys)
  14     ) config.myEnv.dns.slaveZones);
  15     configFile = pkgs.writeText "named.conf" ''
  16       include "/etc/bind/rndc.key";
  17       controls {
  18         inet 127.0.0.1 allow {localhost;} keys {"rndc-key";};
  19       };
  20
  21       acl cachenetworks { ${lib.concatMapStrings (entry: " ${entry}; ") cfg.cacheNetworks} };
  22       acl badnetworks { ${lib.concatMapStrings (entry: " ${entry}; ") cfg.blockedNetworks} };
  23
  24       options {
  25         listen-on { ${lib.concatMapStrings (entry: " ${entry}; ") cfg.listenOn} };
  26         listen-on-v6 { ${lib.concatMapStrings (entry: " ${entry}; ") cfg.listenOnIpv6} };
  27         allow-query { cachenetworks; };
  28         blackhole { badnetworks; };
  29         forward first;
  30         forwarders { ${lib.concatMapStrings (entry: " ${entry}; ") cfg.forwarders} };
  31         directory "/var/run/named";
  32         pid-file "/var/run/named/named.pid";
  33         ${cfg.extraOptions}
  34       };
  35
  36       ${keyIncludes}
  37       ${serverIncludes}
  38
  39       ${cfg.extraConfig}
  40
  41       ${ lib.concatMapStrings
  42           ({ name, file, master ? true, extra ? "", slaves ? [], masters ? [] }:
  43             ''
  44               zone "${name}" {
  45                 type ${if master then "master" else "slave"};
  46                 file "${file}";
  47                 ${ if lib.lists.length slaves > 0 then
  48                   ''
  49                     allow-transfer {
  50                       ${lib.concatMapStrings (ip: "${ip};\n") slaves}
  51                     };
  52                   '' else ""}
  53                 ${ if lib.lists.length masters > 0 then
  54                   ''
  55                     masters {
  56                       ${lib.concatMapStrings (ip: "${ip};\n") masters}
  57                     };
  58                   '' else ""}
  59                 allow-query { any; };
  60                 ${extra}
  61               };
  62             '')
  63           cfg.zones }
  64     '';
  65     mxes = lib.attrsets.filterAttrs
  66       (n: v: v.mx.enable)
  67       config.myEnv.servers;
  68     ip4mxes = builtins.concatStringsSep "\n" (lib.mapAttrsToList
  69       (n: v: "${v.mx.subdomain} IN A     ${v.ips.main.ip4}")
  70       mxes);
  71     ip6mxes = builtins.concatStringsSep "\n" (lib.mapAttrsToList
  72       (n: v: builtins.concatStringsSep "\n" (map (i: "${v.mx.subdomain} IN AAAA  ${i}") v.ips.main.ip6))
  73       mxes);
  74     mxmxes = n: conf: builtins.concatStringsSep "\n" (lib.mapAttrsToList
  75       (_: v: "${n} IN MX ${v.mx.priority} ${v.mx.subdomain}.${conf.name}.")
  76       mxes);
  77   in lib.mkIf config.myServices.dns.enable {
  78     networking.firewall.allowedUDPPorts = [ 53 ];
  79     networking.firewall.allowedTCPPorts = [ 53 ];
  80     users.users.named.extraGroups = [ "keys" ];
  81     secrets.keys = lib.mapAttrsToList (k: v:
  82       {
  83         dest = "bind/${k}.key";
  84         permissions = "0400";
  85         user = "named";
  86         text = ''
  87           key "${k}"
  88             {
  89               algorithm ${v.algorithm};
  90               secret "${v.secret}";
  91             };
  92         '';
  93       }
  94     ) config.myEnv.dns.keys;
  95     services.bind = {
  96       enable = true;
  97       cacheNetworks = ["any"];
  98       configFile = configFile;
  99       extraOptions = ''
 100         allow-recursion { 127.0.0.1; };
 101         allow-transfer  { none; };
 102
 103         notify-source    ${config.myEnv.servers.eldiron.ips.main.ip4};
 104         notify-source-v6 ${lib.head config.myEnv.servers.eldiron.ips.main.ip6};
 105         version   none;
 106         hostname  none;
 107         server-id none;
 108         '';
 109       zones = with config.myEnv.dns;
 110         assert (builtins.substring ((builtins.stringLength soa.email)-1) 1 soa.email) != ".";
 111         assert (builtins.substring ((builtins.stringLength soa.primary)-1) 1 soa.primary) != ".";
 112         (map (conf: {
 113           name = conf.name;
 114           master = false;
 115           file = "/var/run/named/${conf.name}.zone";
 116           masters = if lib.attrsets.hasAttr "masters" conf
 117             then lib.lists.flatten (map (n: lib.attrsets.attrValues ns.${n}) conf.masters)
 118             else [];
 119         }) slaveZones)
 120         ++ (map (conf: {
 121           name = conf.name;
 122           master = true;
 123           extra = if lib.attrsets.hasAttr "extra" conf then conf.extra else "";
 124           slaves = if lib.attrsets.hasAttr "slaves" conf
 125             then lib.lists.flatten (map (n: lib.attrsets.attrValues ns.${n}) conf.slaves)
 126             else [];
 127           file = pkgs.writeText "${conf.name}.zone" ''
 128               $TTL 10800
 129               @ IN SOA ${soa.primary}. ${builtins.replaceStrings ["@"] ["."] soa.email}. ${soa.serial} ${soa.refresh} ${soa.retry} ${soa.expire} ${soa.ttl}
 130
 131               ${lib.concatStringsSep "\n" (map (x: "@ IN NS ${x}.") (lib.concatMap (n: lib.attrsets.mapAttrsToList (k: v: k) ns.${n}) conf.ns))}
 132               ${lib.optionalString (conf.withCAA != null) ''
 133                 ${conf.name}. IN CAA 0 issue "${conf.withCAA}"
 134               ''}
 135
 136               ${conf.entries}
 137
 138               ${if lib.attrsets.hasAttr "withEmail" conf && lib.lists.length conf.withEmail > 0 then ''
 139               ${ip4mxes}
 140               ${ip6mxes}
 141               ${lib.concatStringsSep "\n\n" (map (e:
 142               let
 143                 n = if e.domain == "" then "@" else "${e.domain}  ";
 144                 suffix = if e.domain == "" then "" else ".${e.domain}";
 145               in
 146               ''
 147               ; ------------------ mail: ${n} ---------------------------
 148               ${mxmxes n conf}
 149
 150               ; https://tools.ietf.org/html/rfc6186
 151               _submission._tcp${suffix}  SRV  0 1  587 smtp.immae.eu.
 152               _submissions._tcp${suffix} SRV  0 1  465 smtp.immae.eu.
 153               _imap._tcp${suffix}        SRV  0 1  143 imap.immae.eu.
 154               _imaps._tcp${suffix}       SRV  0 1  993 imap.immae.eu.
 155               _pop3._tcp${suffix}        SRV 10 1  110 pop3.immae.eu.
 156               _pop3s._tcp${suffix}       SRV 10 1  995 pop3.immae.eu.
 157               _sieve._tcp${suffix}       SRV  0 1 4190 imap.immae.eu.
 158
 159               ; MTA-STS
 160               ; https://blog.delouw.ch/2018/12/16/using-mta-sts-to-enhance-email-transport-security-and-privacy/
 161               ; https://support.google.com/a/answer/9261504
 162               _mta-sts${suffix}   IN TXT  "v=STSv1;id=20200109150200Z"
 163               _smtp._tls${suffix} IN TXT  "v=TLSRPTv1;rua=mailto:postmaster+mta-sts@immae.eu"
 164               mta-sts${suffix}    IN A    ${config.myEnv.servers.eldiron.ips.main.ip4}
 165               ${builtins.concatStringsSep "\n" (map (i: "mta-sts${suffix}    IN AAAA ${i}") config.myEnv.servers.eldiron.ips.main.ip6)}
 166
 167               ; Mail sender authentications
 168               ${n}                   IN TXT  "v=spf1 mx ~all"
 169               _dmarc${suffix}              IN TXT  "v=DMARC1; p=none; adkim=r; aspf=r; fo=1; rua=mailto:postmaster+rua@immae.eu; ruf=mailto:postmaster+ruf@immae.eu;"
 170               ${if e.send then ''
 171               immae_eu._domainkey${suffix} IN TXT  ( "v=DKIM1; k=rsa; s=email; "
 172                         "p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAzl3vLd8W5YAuumC5+ZT9OV7/14Pmh5JYtwyqKI3cfe9NnAqInt3xO4bZ7oqIxRKWN4SD39vm7O/QOvFdBt00ENOOzdP90s5gKw6eIP/4+vPTh0IWltAsmu9B2agzdtWUE7t2xFKIzEn8l9niRE2QYbVaqZv4sub98vY55fIgFoHtjkmNC7325S8fjDJGp6OPbyhAs6Xl5/adjF"
 173                         "0ko4Y2p6RaxLQfjlS0bxmK4Qg6C14pIXHtzVeqOuWrwApqt5+AULSn97iUtqV/IJlEEjC6DUR44t3C/G0G/k46iFclCqRRi0hdPrOHCtZDbtMubnTN9eaUiNpkXh1WnCflHwtjQwIDAQAB" )
 174               eldiron._domainkey${suffix}  IN TXT  ${config.myEnv.mail.dkim.eldiron.public}
 175               '' else ""}
 176               '') conf.withEmail)}
 177               '' + (if conf.name == "immae.eu" then ''
 178               ; ----------------- Accept DMARC reports -------------------
 179               ${lib.concatStringsSep "\n" (
 180                 lib.flatten (
 181                   map (z: map (e: "${e.domain}${if builtins.stringLength e.domain > 0 then "." else ""}${z.name}._report._dmarc IN TXT \"v=DMARC1;\"") (z.withEmail or [])) masterZones
 182                 )
 183               )}
 184               '' else "") else ""}
 185             '';
 186           }) masterZones);
 187     };
 188   };
 189 }