X-Git-Url: https://git.immae.eu/?p=perso%2FImmae%2FConfig%2FNix.git;a=blobdiff_plain;f=modules%2Fprivate%2Fmail%2Fpostfix.nix;h=70c3f466f7376b204e62f32319bd008c3d4a255c;hp=9fdc7bde8e05f0d3b99aff974cc5a164bac4d43a;hb=31d99b750fca57c660f98e23e12053eaf42d4929;hpb=8415083eb6acc343dfa404dbbc12fa0171a48a20

diff --git a/modules/private/mail/postfix.nix b/modules/private/mail/postfix.nix
index 9fdc7bd..70c3f46 100644
--- a/modules/private/mail/postfix.nix
+++ b/modules/private/mail/postfix.nix
@@ -1,7 +1,7 @@
-{ lib, pkgs, config, myconfig,  ... }:
+{ lib, pkgs, config, nodes, ... }:
 {
   config = lib.mkIf config.myServices.mail.enable {
-    services.backup.profiles.mail.excludeFile = ''
+    services.duplyBackup.profiles.mail.excludeFile = ''
       + /var/lib/postfix
       '';
     secrets.keys = [
@@ -13,12 +13,12 @@
         text = ''
           # We need to specify that option to trigger ssl connection
           tls_ciphers = TLSv1.2
-          user = ${myconfig.env.mail.postfix.mysql.user}
-          password = ${myconfig.env.mail.postfix.mysql.password}
-          hosts = unix:${myconfig.env.mail.postfix.mysql.socket}
-          dbname = ${myconfig.env.mail.postfix.mysql.database}
+          user = ${config.myEnv.mail.postfix.mysql.user}
+          password = ${config.myEnv.mail.postfix.mysql.password}
+          hosts = unix:${config.myEnv.mail.postfix.mysql.socket}
+          dbname = ${config.myEnv.mail.postfix.mysql.database}
           query = SELECT DISTINCT destination
-            FROM forwardings_merge
+            FROM forwardings
             WHERE
               ((regex = 1 AND '%s' REGEXP CONCAT('^',source,'$') ) OR (regex = 0 AND source = '%s'))
               AND active = 1
@@ -34,30 +34,19 @@
           '';
       }
       {
-        dest = "postfix/mysql_mailbox_maps";
+        dest = "postfix/ldap_mailboxes";
         user = config.services.postfix.user;
         group = config.services.postfix.group;
         permissions = "0440";
         text = ''
-          # We need to specify that option to trigger ssl connection
-          tls_ciphers = TLSv1.2
-          user = ${myconfig.env.mail.postfix.mysql.user}
-          password = ${myconfig.env.mail.postfix.mysql.password}
-          hosts = unix:${myconfig.env.mail.postfix.mysql.socket}
-          dbname = ${myconfig.env.mail.postfix.mysql.database}
-          result_format = /%d/%u
-          query = SELECT DISTINCT '%s'
-            FROM mailboxes
-            WHERE active = 1
-            AND (
-              (domain = '%d' AND user = '%u' AND regex = 0)
-              OR (
-                regex = 1
-                AND '%d' REGEXP CONCAT('^',domain,'$')
-                AND '%u' REGEXP CONCAT('^',user,'$')
-              )
-            )
-            LIMIT 1
+          server_host = ldaps://${config.myEnv.mail.dovecot.ldap.host}:636
+          search_base = ${config.myEnv.mail.dovecot.ldap.base}
+          query_filter = ${config.myEnv.mail.dovecot.ldap.postfix_mailbox_filter}
+          bind_dn = ${config.myEnv.mail.dovecot.ldap.dn}
+          bind_pw = ${config.myEnv.mail.dovecot.ldap.password}
+          result_attribute = immaePostfixAddress
+          result_format = dummy
+          version = 3
         '';
       }
       {
@@ -68,35 +57,178 @@
         text = ''
           # We need to specify that option to trigger ssl connection
           tls_ciphers = TLSv1.2
-          user = ${myconfig.env.mail.postfix.mysql.user}
-          password = ${myconfig.env.mail.postfix.mysql.password}
-          hosts = unix:${myconfig.env.mail.postfix.mysql.socket}
-          dbname = ${myconfig.env.mail.postfix.mysql.database}
+          user = ${config.myEnv.mail.postfix.mysql.user}
+          password = ${config.myEnv.mail.postfix.mysql.password}
+          hosts = unix:${config.myEnv.mail.postfix.mysql.socket}
+          dbname = ${config.myEnv.mail.postfix.mysql.database}
           query = SELECT DISTINCT destination
-            FROM forwardings_merge
+            FROM forwardings
             WHERE
-              ((regex = 1 AND '%s' REGEXP CONCAT('^',source,'$') ) OR (regex = 0 AND source = '%s'))
+              (
+                (regex = 1 AND CONCAT(SUBSTRING_INDEX('%u', '+', 1), '@%d') REGEXP CONCAT('^',source,'$') )
+              OR
+                (regex = 0 AND source = CONCAT(SUBSTRING_INDEX('%u', '+', 1), '@%d'))
+              )
+              AND active = 1
+            UNION SELECT CONCAT(SUBSTRING_INDEX('%u', '+', 1), '@%d') AS destination
+          '';
+      }
+      {
+        dest = "postfix/mysql_sender_relays_maps";
+        user = config.services.postfix.user;
+        group = config.services.postfix.group;
+        permissions = "0440";
+        text = ''
+          # We need to specify that option to trigger ssl connection
+          tls_ciphers = TLSv1.2
+          user = ${config.myEnv.mail.postfix.mysql.user}
+          password = ${config.myEnv.mail.postfix.mysql.password}
+          hosts = unix:${config.myEnv.mail.postfix.mysql.socket}
+          dbname = ${config.myEnv.mail.postfix.mysql.database}
+          # INSERT INTO sender_relays
+          #   (`from`, owner, relay, login, password, regex, active)
+          # VALUES
+          #   ( 'sender@otherhost.org'
+          #   , 'me@mail.immae.eu'
+          #   , '[otherhost.org]:587'
+          #   , 'otherhostlogin'
+          #   , AES_ENCRYPT('otherhostpassword', '${config.myEnv.mail.postfix.mysql.password_encrypt}')
+          #   , '0'
+          #   , '1');
+
+          query = SELECT DISTINCT `owner`
+            FROM sender_relays
+            WHERE
+              ((regex = 1 AND '%s' REGEXP CONCAT('^',`from`,'$') ) OR (regex = 0 AND `from` = '%s'))
+              AND active = 1
+          '';
+      }
+      {
+        dest = "postfix/mysql_sender_relays_hosts";
+        user = config.services.postfix.user;
+        group = config.services.postfix.group;
+        permissions = "0440";
+        text = ''
+          # We need to specify that option to trigger ssl connection
+          tls_ciphers = TLSv1.2
+          user = ${config.myEnv.mail.postfix.mysql.user}
+          password = ${config.myEnv.mail.postfix.mysql.password}
+          hosts = unix:${config.myEnv.mail.postfix.mysql.socket}
+          dbname = ${config.myEnv.mail.postfix.mysql.database}
+
+          query = SELECT DISTINCT relay
+            FROM sender_relays
+            WHERE
+              ((regex = 1 AND '%s' REGEXP CONCAT('^',`from`,'$') ) OR (regex = 0 AND `from` = '%s'))
+              AND active = 1
+          '';
+      }
+      {
+        dest = "postfix/mysql_sender_relays_creds";
+        user = config.services.postfix.user;
+        group = config.services.postfix.group;
+        permissions = "0440";
+        text = ''
+          # We need to specify that option to trigger ssl connection
+          tls_ciphers = TLSv1.2
+          user = ${config.myEnv.mail.postfix.mysql.user}
+          password = ${config.myEnv.mail.postfix.mysql.password}
+          hosts = unix:${config.myEnv.mail.postfix.mysql.socket}
+          dbname = ${config.myEnv.mail.postfix.mysql.database}
+
+          query = SELECT DISTINCT CONCAT(`login`, ':', AES_DECRYPT(`password`, '${config.myEnv.mail.postfix.mysql.password_encrypt}'))
+            FROM sender_relays
+            WHERE
+              ((regex = 1 AND '%s' REGEXP CONCAT('^',`from`,'$') ) OR (regex = 0 AND `from` = '%s'))
               AND active = 1
-            UNION SELECT '%s' AS destination
           '';
       }
-    ];
+      {
+        dest = "postfix/ldap_ejabberd_users_immae_fr";
+        user = config.services.postfix.user;
+        group = config.services.postfix.group;
+        permissions = "0440";
+        text = ''
+          server_host = ldaps://${config.myEnv.jabber.ldap.host}:636
+          search_base = ${config.myEnv.jabber.ldap.base}
+          query_filter = ${config.myEnv.jabber.postfix_user_filter}
+          domain = immae.fr
+          bind_dn = ${config.myEnv.jabber.ldap.dn}
+          bind_pw = ${config.myEnv.jabber.ldap.password}
+          result_attribute = immaeXmppUid
+          result_format = ejabberd@localhost
+          version = 3
+          '';
+      }
+    ] ++ (lib.mapAttrsToList (name: v: {
+      dest = "postfix/scripts/${name}-env";
+      user = "postfixscripts";
+      group = "root";
+      permissions = "0400";
+      text = builtins.toJSON v.env;
+    }) config.myEnv.mail.scripts);
 
     networking.firewall.allowedTCPPorts = [ 25 465 587 ];
 
-    nixpkgs.overlays = [ (self: super: {
-      postfix = super.postfix.override { withMySQL = true; };
-    }) ];
+    users.users.postfixscripts = {
+      group = "keys";
+      uid = config.ids.uids.postfixscripts;
+      description = "Postfix scripts user";
+    };
     users.users."${config.services.postfix.user}".extraGroups = [ "keys" ];
     services.filesWatcher.postfix = {
       restart = true;
       paths = [
         config.secrets.fullPaths."postfix/mysql_alias_maps"
-        config.secrets.fullPaths."postfix/mysql_mailbox_maps"
+        config.secrets.fullPaths."postfix/ldap_mailboxes"
         config.secrets.fullPaths."postfix/mysql_sender_login_maps"
+        config.secrets.fullPaths."postfix/ldap_ejabberd_users_immae_fr"
       ];
     };
     services.postfix = {
+      extraAliases = let
+        toScript = name: script: pkgs.writeScript name ''
+          #! ${pkgs.stdenv.shell}
+          mail=$(${pkgs.coreutils}/bin/cat -)
+          output=$(echo "$mail" | ${script} 2>&1)
+          ret=$?
+
+          if [ "$ret" != "0" ]; then
+            echo "$mail" \
+              | ${pkgs.procmail}/bin/formail -i "X-Return-Code: $ret" \
+              | /run/wrappers/bin/sendmail -i scripts_error+${name}@mail.immae.eu
+
+          messageId=$(echo "$mail" | ${pkgs.procmail}/bin/formail -x "Message-Id:")
+          repeat=$(echo "$mail" | ${pkgs.procmail}/bin/formail -X "From:" -X "Received:")
+
+          ${pkgs.coreutils}/bin/cat <<EOF | /run/wrappers/bin/sendmail -i scripts_error+${name}@mail.immae.eu
+          $repeat
+          To: scripts_error+${name}@mail.immae.eu
+          Subject: Log from script error
+          Content-Type: text/plain; charset="UTF-8"
+          Content-Transfer-Encoding: 8bit
+          References:$messageId
+          MIME-Version: 1.0
+          X-Return-Code: $ret
+
+          Error code: $ret
+          Output of message:
+          --------------
+          $output
+          --------------
+          EOF
+          fi
+          '';
+        scripts = lib.attrsets.mapAttrs (n: v:
+          toScript n (pkgs.callPackage (builtins.fetchGit { url = v.src.url; ref = "master"; rev = v.src.rev; }) { scriptEnv = "/var/secrets/postfix/scripts/${n}-env"; })
+        ) config.myEnv.mail.scripts // {
+          testmail = pkgs.writeScript "testmail" ''
+            #! ${pkgs.stdenv.shell}
+            ${pkgs.coreutils}/bin/touch \
+              "/var/lib/naemon/checks/email/$(${pkgs.procmail}/bin/formail -x To: | ${pkgs.coreutils}/bin/tr -d ' <>')"
+            '';
+        };
+      in builtins.concatStringsSep "\n" (lib.attrsets.mapAttrsToList (n: v: ''${n}: "|${v}"'') scripts);
       mapFiles = let
         recipient_maps = let
           name = n: i: "relay_${n}_${toString i}";
@@ -108,7 +240,7 @@
           pairs = n: v: lib.imap1 (i: m: pair n i m) v.recipient_maps;
         in lib.attrsets.filterAttrs (k: v: v != null) (
           lib.attrsets.listToAttrs (lib.flatten (
-            lib.attrsets.mapAttrsToList pairs myconfig.env.mail.postfix.backup_domains
+            lib.attrsets.mapAttrsToList pairs config.myEnv.mail.postfix.backup_domains
           ))
         );
         relay_restrictions = lib.attrsets.filterAttrs (k: v: v != null) (
@@ -118,10 +250,33 @@
               then pkgs.writeText "recipient_access_${n}" v.relay_restrictions
               else null
             )
-          ) myconfig.env.mail.postfix.backup_domains
+          ) config.myEnv.mail.postfix.backup_domains
         );
+        virtual_map = {
+          virtual = let
+            cfg = config.myEnv.monitoring.email_check.eldiron;
+            address = "${cfg.mail_address}@${cfg.mail_domain}";
+          in pkgs.writeText "postfix-virtual" (
+            builtins.concatStringsSep "\n" (
+              ["${address} testmail@localhost"] ++
+              lib.attrsets.mapAttrsToList (
+                n: v: lib.optionalString v.external ''
+                  script_${n}@mail.immae.eu ${n}@localhost, scripts@mail.immae.eu
+                ''
+              ) config.myEnv.mail.scripts
+            )
+          );
+        };
+        sasl_access = {
+          host_sender_login = with lib.attrsets; let
+            addresses = zipAttrs (lib.flatten (mapAttrsToList
+              (n: v: (map (e: { "${e}" = "${n}@immae.eu"; }) v.emails)) config.myEnv.servers));
+            joined = builtins.concatStringsSep ",";
+          in pkgs.writeText "host-sender-login"
+            (builtins.concatStringsSep "\n" (mapAttrsToList (n: v: "${n} ${joined v}") addresses));
+        };
       in
-        recipient_maps // relay_restrictions;
+        recipient_maps // relay_restrictions // virtual_map // sasl_access;
       config = {
         ### postfix module overrides
         readme_directory = "${pkgs.postfix}/share/postfix/doc";
@@ -130,12 +285,20 @@
         smtp_tls_key_file = lib.mkForce "";
 
         message_size_limit = "1073741824"; # Don't put 0 here, it's not equivalent to "unlimited"
+        mailbox_size_limit = "1073741825"; # Workaround, local delivered mails should all go through scripts
         alias_database = "\$alias_maps";
 
+        ### Aliases scripts user
+        default_privs = "postfixscripts";
+
         ### Virtual mailboxes config
-        virtual_alias_maps = "mysql:${config.secrets.fullPaths."postfix/mysql_alias_maps"}";
-        virtual_mailbox_domains = myconfig.env.mail.postfix.additional_mailbox_domains
-        ++ lib.remove "localhost.immae.eu" (lib.remove null (lib.flatten (map
+        virtual_alias_maps = [
+          "hash:/etc/postfix/virtual"
+          "mysql:${config.secrets.fullPaths."postfix/mysql_alias_maps"}"
+          "ldap:${config.secrets.fullPaths."postfix/ldap_ejabberd_users_immae_fr"}"
+        ];
+        virtual_mailbox_domains = config.myEnv.mail.postfix.additional_mailbox_domains
+        ++ lib.remove null (lib.flatten (map
             (zone: map
               (e: if e.receive
               then "${e.domain}${lib.optionalString (e.domain != "") "."}${zone.name}"
@@ -143,26 +306,26 @@
               )
               (zone.withEmail or [])
             )
-            myconfig.env.dns.masterZones
-          )));
-        virtual_mailbox_maps = "mysql:${config.secrets.fullPaths."postfix/mysql_mailbox_maps"}";
+            config.myEnv.dns.masterZones
+          ));
+        virtual_mailbox_maps = [
+          "ldap:${config.secrets.fullPaths."postfix/ldap_mailboxes"}"
+        ];
         dovecot_destination_recipient_limit = "1";
         virtual_transport = "dovecot";
 
         ### Relay domains
-        relay_domains = lib.flatten (lib.attrsets.mapAttrsToList (n: v: v.domains or []) myconfig.env.mail.postfix.backup_domains);
+        relay_domains = lib.flatten (lib.attrsets.mapAttrsToList (n: v: v.domains or []) config.myEnv.mail.postfix.backup_domains);
         relay_recipient_maps = lib.flatten (lib.attrsets.mapAttrsToList (n: v:
           lib.imap1 (i: m: "${m.type}:/etc/postfix/relay_${n}_${toString i}") v.recipient_maps
-        ) myconfig.env.mail.postfix.backup_domains);
+        ) config.myEnv.mail.postfix.backup_domains);
         smtpd_relay_restrictions = [
-          "permit_mynetworks"
-          "permit_sasl_authenticated"
           "defer_unauth_destination"
         ] ++ lib.flatten (lib.attrsets.mapAttrsToList (n: v:
           if lib.attrsets.hasAttr "relay_restrictions" v
           then [ "check_recipient_access hash:/etc/postfix/recipient_access_${n}" ]
           else []
-        ) myconfig.env.mail.postfix.backup_domains);
+        ) config.myEnv.mail.postfix.backup_domains);
 
         ### Additional smtpd configuration
         smtpd_tls_received_header = "yes";
@@ -173,32 +336,43 @@
         smtp_tls_loglevel = "1";
 
         ### Force ip bind for smtp
-        smtp_bind_address  = myconfig.env.servers.eldiron.ips.main.ip4;
-        smtp_bind_address6 = builtins.head myconfig.env.servers.eldiron.ips.main.ip6;
+        smtp_bind_address  = config.hostEnv.ips.main.ip4;
+        smtp_bind_address6 = builtins.head config.hostEnv.ips.main.ip6;
 
-        # #Unneeded if postfix can only send e-mail from "self" domains
-        # #smtp_sasl_auth_enable = "yes";
-        # #smtp_sasl_password_maps = "hash:/etc/postfix/relay_creds";
-        # #smtp_sasl_security_options = "noanonymous";
-        # #smtp_sender_dependent_authentication = "yes";
-        # #sender_dependent_relayhost_maps = "hash:/etc/postfix/sender_relay";
+        # Use some relays when authorized senders are not myself
+        smtp_sasl_mechanism_filter = "plain,login"; # GSSAPI Not correctly supported by postfix
+        smtp_sasl_auth_enable = "yes";
+        smtp_sasl_password_maps =
+          "mysql:${config.secrets.fullPaths."postfix/mysql_sender_relays_creds"}";
+        smtp_sasl_security_options = "noanonymous";
+        smtp_sender_dependent_authentication = "yes";
+        sender_dependent_relayhost_maps =
+          "mysql:${config.secrets.fullPaths."postfix/mysql_sender_relays_hosts"}";
 
         ### opendkim, opendmarc, openarc milters
         non_smtpd_milters = [
           "unix:${config.myServices.mail.milters.sockets.opendkim}"
-          "unix:${config.myServices.mail.milters.sockets.opendmarc}"
-          "unix:${config.myServices.mail.milters.sockets.openarc}"
         ];
         smtpd_milters = [
           "unix:${config.myServices.mail.milters.sockets.opendkim}"
-          "unix:${config.myServices.mail.milters.sockets.opendmarc}"
           "unix:${config.myServices.mail.milters.sockets.openarc}"
+          "unix:${config.myServices.mail.milters.sockets.opendmarc}"
         ];
+
+        smtp_use_tls = true;
+        smtpd_use_tls = true;
+        smtpd_tls_chain_files = builtins.concatStringsSep "," [ "/var/lib/acme/mail/full.pem" "/var/lib/acme/mail-rsa/full.pem" ];
+
+        maximal_queue_lifetime = "6w";
+        bounce_queue_lifetime = "6w";
       };
       enable = true;
       enableSmtp = true;
       enableSubmission = true;
       submissionOptions = {
+        # Don’t use "long form", only commas (cf
+        # http://www.postfix.org/master.5.html long form is not handled
+        # well by the submission function)
         smtpd_tls_security_level = "encrypt";
         smtpd_sasl_auth_enable = "yes";
         smtpd_tls_auth_only = "yes";
@@ -207,27 +381,28 @@
         smtpd_sasl_path = "private/auth";
         smtpd_reject_unlisted_recipient = "no";
         smtpd_client_restrictions = "permit_sasl_authenticated,reject";
+        smtpd_relay_restrictions = "permit_sasl_authenticated,reject";
         # Refuse to send e-mails with a From that is not handled
         smtpd_sender_restrictions =
           "reject_sender_login_mismatch,reject_unlisted_sender,permit_sasl_authenticated,reject";
-        smtpd_sender_login_maps = "mysql:${config.secrets.fullPaths."postfix/mysql_sender_login_maps"}";
+        smtpd_sender_login_maps = builtins.concatStringsSep "," [
+          "hash:/etc/postfix/host_sender_login"
+          "mysql:${config.secrets.fullPaths."postfix/mysql_sender_relays_maps"}"
+          "mysql:${config.secrets.fullPaths."postfix/mysql_sender_login_maps"}"
+        ];
         smtpd_recipient_restrictions = "permit_sasl_authenticated,reject";
         milter_macro_daemon_name = "ORIGINATING";
-        smtpd_milters = "unix:${config.myServices.mail.milters.sockets.opendkim}";
+        smtpd_milters = builtins.concatStringsSep "," [
+          # FIXME: put it back when opensmtpd is upgraded and able to
+          # rewrite the from header
+          #"unix:/run/milter_verify_from/verify_from.sock"
+          "unix:${config.myServices.mail.milters.sockets.opendkim}"
+        ];
       };
-      # FIXME: Mail adressed to localhost.immae.eu will still have mx-1 as
-      # prioritized MX, which provokes "mail for localhost.immae.eu loops
-      # back to myself" errors. This transport entry forces to push
-      # e-mails to its right destination.
-      transport = ''
-        localhost.immae.eu   smtp:[immae.eu]:25
-        '';
       destination = ["localhost"];
       # This needs to reverse DNS
-      hostname = "eldiron.immae.eu";
+      hostname = config.hostEnv.fqdn;
       setSendmail = true;
-      sslCert = "/var/lib/acme/mail/fullchain.pem";
-      sslKey = "/var/lib/acme/mail/key.pem";
       recipientDelimiter = "+";
       masterConfig = {
         submissions = {
@@ -249,10 +424,19 @@
             # its checks "per user" (milter is not yet dispatched to
             # users), so we wrap dovecot-lda inside rspamc per recipient
             # here.
-            dovecot_exe = "${pkgs.dovecot}/libexec/dovecot/dovecot-lda -f \${sender} -a \${original_recipient} -d \${user}@\${nexthop}";
+            rspamc_dovecot = pkgs.writeScriptBin "rspamc_dovecot" ''
+              #! ${pkgs.stdenv.shell}
+              sender="$1"
+              original_recipient="$2"
+              user="$3"
+
+              ${pkgs.coreutils}/bin/cat - | \
+                (${pkgs.rspamd}/bin/rspamc -h ${config.myServices.mail.rspamd.sockets.worker-controller} -c bayes -d "$user" --mime || true) | \
+                ${pkgs.dovecot}/libexec/dovecot/dovecot-lda -f "$sender" -a "$original_recipient" -d "$user"
+              '';
           in [
-            "flags=DRhu" "user=vhost:vhost"
-            "argv=${pkgs.rspamd}/bin/rspamc -h ${config.myServices.mail.rspamd.sockets.worker-controller} -c bayes -d \${user}@\${nexthop} --mime --exec {${dovecot_exe}}"
+            "flags=ODRhu" "user=vhost:vhost"
+            "argv=${rspamc_dovecot}/bin/rspamc_dovecot \${sender} \${original_recipient} \${user}@\${nexthop}"
           ];
         };
       };
@@ -265,5 +449,34 @@
         "smtp.immae.eu" = null;
       };
     };
+    security.acme.certs."mail-rsa" = {
+      postRun = ''
+        systemctl restart postfix.service
+        '';
+      extraDomains = {
+        "smtp.immae.eu" = null;
+      };
+    };
+    system.activationScripts.testmail = {
+      deps = [ "users" ];
+      text = let
+        allCfg = config.myEnv.monitoring.email_check;
+        cfg = allCfg.eldiron;
+        reverseTargets = builtins.attrNames (lib.attrsets.filterAttrs (k: v: builtins.elem "eldiron" v.targets) allCfg);
+        to_email = cfg': host':
+          let sep = if lib.strings.hasInfix "+" cfg'.mail_address then "_" else "+";
+          in "${cfg'.mail_address}${sep}${host'}@${cfg'.mail_domain}";
+        mails_to_receive = builtins.concatStringsSep " " (map (to_email cfg) reverseTargets);
+      in ''
+        install -m 0555 -o postfixscripts -g keys -d /var/lib/naemon/checks/email
+        for f in ${mails_to_receive}; do
+          if [ ! -f /var/lib/naemon/checks/email/$f ]; then
+            install -m 0644 -o postfixscripts -g keys /dev/null -T /var/lib/naemon/checks/email/$f
+            touch -m -d @0 /var/lib/naemon/checks/email/$f
+          fi
+        done
+        '';
+    };
+    systemd.services.postfix.serviceConfig.Slice = "mail.slice";
   };
 }