Fix e-mail regex. Apostrophes are allowed in local parts but we use them to deliminate strings in the sieve script.

This directive is supposed to prevent mail delivery loops that would be caused by portforwarding to itself.
Behind this ip address, however, there is our general mail vm and not immediately the mailinglist setup.

flake-module.nix

@@ -88,7 +88,7 @@
                             ./patches/sieve-rs.patch
                           ];
                           # Replace the string with `lib.fakeHash` after version changes in order to get the new hash value.
-                          cargoHash = "sha256-gb2oFlVA/vE6DoWWW8SCFA3l7rtV2RuosPUY+6IcKNM=";
+                          cargoHash = "sha256-0U0Z13a2vRxMFnaaHeXBjvYDjKStgqmuDboUVssVMQw=";
                         }
                       );
                   };

flake.lock

@@ -9,11 +9,11 @@
         "rust-overlay": "rust-overlay"
       },
       "locked": {
-        "lastModified": 1740490964,
-        "narHash": "sha256-05mpcJZCX631rNCxJohUu+nhVOlAc3EfcNPBzOFSHMo=",
+        "lastModified": 1742814048,
+        "narHash": "sha256-8BK8oLQcpxTsQQiOrP80pPWirdOIk50ecCZjkUYMLVI=",
         "ref": "refs/heads/main",
-        "rev": "c37b6ec8654db4c6e3d79acaeeccb577a9fb66ce",
-        "revCount": 21,
+        "rev": "3570db39fda3627d60fbd4ef9c6326b3de074eb8",
+        "revCount": 23,
         "type": "git",
         "url": "https://gitea.mathebau.de/fachschaft/alias_to_sieve"
       },

nixos/machines/nyarlathotep/configuration.nix

@@ -15,10 +15,12 @@
     stalwartAdminHash = "$argon2i$v=19$m=4096,t=3,p=1$d0hYOTkzclpzSmFTZUplWnhVeWE$I7q9uB19RWL0oZKaPlMPSlGfFp6FQ/vrx80FFKCsalg";
     domains = [
       # lists.mathebau.de is forwarded to another VM and does not need to be listed here.
-      {
+      /*
+        {
         domain = "matheball.de";
         allowlistPass = config.sops.secrets."allowlistPass/matheball".path;
       }
+      */
       {
         domain = "mathebau.de";
         allowlistPass = config.sops.secrets."allowlistPass/mathebau".path;
@@ -73,6 +75,18 @@
       group = "stalwart-mail";
       mode = "0440";
     };
+    "dkim_rsa" = {
+      sopsFile = ./dkimKeys.secrets.yaml;
+      owner = "stalwart-mail";
+      group = "stalwart-mail";
+      mode = "0440";
+    };
+    "dkim_ed25519" = {
+      sopsFile = ./dkimKeys.secrets.yaml;
+      owner = "stalwart-mail";
+      group = "stalwart-mail";
+      mode = "0440";
+    };
     # password for https://stalw.art/docs/auth/authorization/administrator/#fallback-administrator encoded to be supplied in the basic auth header
     stalwartAdmin = {
       sopsFile = ./stalwartAdmin.secrets.yaml;

nixos/machines/nyarlathotep/dkimKeys.secrets.yaml

@@ -0,0 +1,40 @@
+dkim_rsa: ENC[AES256_GCM,data:cVzKHs/1H/8UL2aQ6fiXLFn0Y0yTGUUss/G9NiXtJMwWpa1SDuONs6CaplWF/c1z8Ph4b4GgQQHQqXGKnZIacpUlv1C0y1W5rr4DNqsWQ9F1Ncx7NIZDHJ3nQ2KKXy+I7NgxwdIuqBtg9ZticYZjf1ArcWUGnt+UEDmgXw4fSo05YS+scg0o5hyrkrduZntBBlUu8hH0qMrE8usptGAmR+iwJ33U5Xan0G0eURVCQJ9xV7tUkZERmZi1TtEmuKa7TCTzNWTHWjuDFRdQ0u6EWajCVa8/UcswTKuKLh0h9OU6DPt8lHYgshiSF1SRRiDq5ytjAFMMpA0hfrqpDx2LQtnyZIv/E8ZGtt5QeikUUTgLMmrqIkMddGufPp8lvFCLh1dlCf1QuiQQmNyMsNPAuu5UzUNCel4ideJFYm3hEoPUQ8uHNmujCOi89NpTwFyp9p0By/4fGWFPezn9VxOKhID0/zKUHp7jUAbZT66XbyDmv6TG0AYGNWhWsrjcCyGKCybOjV7+Wm5viVDFY5chojHciQMG/nEu47vBNJwUhAD/r0T3hisfixuh3rtDvj6w/UXB6xkQi8TDyfjWpZF2ay/DwNcK0HAyOfAYyXVWU7Ck2D8NY3+YQrxaYhY/GAjBM/R0n/dpHBh9EInlyEFhvZhB5KwEuaVHSxtcudFxt5IZ8wzEC8PZIuFHnPJDXfjth5SjzVaQ6tBkvof/eMQmc2XDMofZoQODPOYL5RUifWDx7fQlgsKgLmhR6PgWigqZxis4V7XAT3BiqaYyxxdnYK08mR7dmm04o+TPWx6gQ7xTpW0zoufetBglwuxdEuzWoaTEs+vH5YCJfEdZ3ddk7IT3R8pTC3YrAIrD+IWkxolVk4nUvYWkaO+7pVSGO/QFI0ZaHDV4qK8cCD2p315LecL2bSnymXPKuHCGQHauwvgyGgja5+fs7VtteYPNLc71TONAWAV4Gh+LIejKDe6gnovEkHSKU1/q9qkELMTbnjYLM42CRGfg9K7Rf0ywwdv654yQr6wC/+wzDLcfmcqjiw1a3woEecAsqQ+RmpiFq80eCi6ZZCnLCa+kseV1+j48B1lwgQZg+9LwrV8YHG0ciW8IxhZ9O0wUMv/o2Udwo+NfA5iha+EcIBSr7VoV/PVIKZSpb3JeNbfZ/AwOr1y8/LyyoX7VtvIK8jOdulpOtwHAZ0GX5dYrH/gWgjdyfVbd7irehO15y1L5jbNulzouv69aLYwwQxUcmRK+O/krNDDp6Jy0Clz6+di2Lvm8W7ykk7NwMgTqlyUIi7jWTC5xEzY22bANqMuyE2s1sFdfxqLY7Tbb5PBJ9uzy45mwbM0760aOca1fAawwfwgsL4FkgHHQxn2SIMxmOB3+5kgCrelLKzk3Eu3Hq58rW53oVX+hSUd9YGLuCN0Re7+kybkHfWF/4r+A682Z5Zp5GLla/kCntZDPYODtz0Wl62AC21MAGv/RKWaUGWPaktx9M3w28YHa+mffuiCUSMdlN5TB12TVhsF3BSQ9rNztEfSuEtZzS8HbarsGg25wuv6gUQ36whBvgjmJJ/5/7Zc9a+l/mhKIblek+U+J5oKkQkiV3UuUdGzR7iYMXE9skt1b3JNYer6BaJQ+uaiJQsu4KVWj4H3G47owbtO9q7JMVnQ9SwbjuGf8tge1VV/ppD0t3Ay8S0bX+fd3dkDRR9zEG0UfKuWvpsLjyBqs+b/tsntMMB89BRrle4mZFhKlXVorQ7n1KV8o+2KC4y1Nkbg10HcPPQmsL+YGQG3OkWixpslMeIv8Y89RjBVxY/5A4BiO9FIe0Zt+rpAFUoFLvujkQc7Qau+b3kRFDk7agiETblUQxYMSPu4IqMxS5OM5mlahcsfEaYFn2AT9EBCGVi+ZKu+rufcsVkMf3TmOpMvXX+u7db8EvC1iosY5UUP6RziFd0WqUHbpRSrXXusPm038ddM5iifw5dW4s62cWfrcGZInD2mWwVXDtg3lDgAZZAK3flIMFnaTi1XTHJ5YrkrUm/DpYORsCXm2sLYPhUGdYT5OXYSjR6/3D6VyTHoxODLQSbc7t53LePFNw8cXK26vw6hDl/34ZE8NzE9RKBGI94FlX26VupYdcMdVWs5Ko+Q0ooFpYKGazDW+lLXWX/ntRODDcm+c0MI5Bq9zSt6b1WKoCrMZpDYEjMdjBdAdiK6Ia7zlOdOZwn97Xp1Lav0G7+eO4xwSTS/busXsOBSAKhk/Q3njkgBtnDuI71U28XP1BjGaTEQuXM0yJ0DX,iv:QbZVXp5FQhmYZvXxXNxWKrNm5GqM+2P3a5pPk499mlc=,tag:F+KNoPRnoLLhOpEj6Czj6Q==,type:str]
+dkim_ed25519: ENC[AES256_GCM,data:cZHm7bVpQ/VhYLt2CnNk9364k+J5ybgSLrR7Vm1GsCU6JcAvHl8Y5R7mqwgS+gTnHX7K02GuIGXa8909/aEotE0ZMY5irKJ25SGJqTaqQafbiMOz65CRQh5trtcMBF4s4wRYOkDGgz09KkELbkDHyQZFcrGqvgM=,iv:p9ROj/epqR3xtrimXF1onJJHH9JUqNG9z1MxKVu9uPg=,tag:m53rXkcu+ernS5JX+k8YcA==,type:str]
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1rasjnr2tlv9y70sj0z0hwpgpxdc974wzg5umtx2pnc6z0p05u3js6r8sln
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSB6VnhvWHdsZWNHemlueFo4
+            L0xCTGp4NlRuU3YwRWJiSHFBbmtURTNMQkVRCnlSbFc0Q2xINjRvU2tQeStQc1U5
+            VElxcTVuNm9MUm01RkpGYytrYWg0czgKLS0tIHZqUWhkMGRNNjJvUTQrOHBpZXVS
+            NlpjeDQxbVZIRHFCcmNtT1JSVHp1K2sKSNcC0fcOar/KKzs1twaozB8wfdFT9OdB
+            4quV/ycNpJpfs6+2r0RTLBxYFyusybu1swosAni+PJsRXS82+PTXHQ==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1epz92k2rkp43hkrg3u0jgkzhnkwx8y43kag7rvfzwl9wcddelvusyetxl7
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBsUTUzYzZuMkYvcTlrUmRK
+            aStnak5IWitFUSt0eVBQOHIzcTlrMFRFTjA4CmlYUTdobXFUK2tYMWtFekNqNnhp
+            R2RRRFdHc1p6bFVjYU9lbTRBeEM3Y2sKLS0tIHdsRW1wR25pVkZIYU1yMm9sQXpr
+            NFhiN0pyaHVWT1h5eVFXMWZDb0sxUGMKIVkYYheD8F9aaAyCA+m9ZGlV8vKbAW4r
+            H6FUe+ats30abxoYfHZfMJv17BxJtpodksSxWjnPYm0dfRf/EF/vSQ==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1ktwclxa640l89le6yecm8v2z6hmwr4lusd6x9gyzamhv57887szqtqp59a
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBvU3NzY0Uxc0NhY2xJZyti
+            TCtTS1crV3hzMXZNV3k4cm0zUFNuY2tBL0dNCnNpYytoaUI1eERhdG1PUlZ2eE5C
+            R2UrVlBwcXR2L1VNR3RJL1lEQmlTSDgKLS0tIFJyLzhZeG5zejFmL2VkYy8xVEM1
+            U3QwOXlRdU8yd3ozL2hUVzRXNGE0bDQKT7SLAqICsbFmRUF+3s2avpBt0dLUbHLX
+            AgQzx5v6GpMMNwCkCrOnpFX6al7zkRSYHe7hbn03BBORz9mPHek5ew==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2025-03-02T07:58:00Z"
+    mac: ENC[AES256_GCM,data:OvERjDFfHTJbTfwq9BmXBQy6pjeyIhao6zP4we0KeYL3skbw4+aaMixjUFzjauby0C7nJjEPBSk6pwK3lN+rScS5g7J8tTNtmhfEDQbfsS5zNDKzIQjYxbUbDr2cTPWwCA73gRGMwLbyNvdfuEp46jNV8OJ8km/y2nyG9lDcBb4=,iv:0RSU2MdZWiYEapwXGzevP9/vc/Sk1MS6a0MnCRQyIs8=,tag:vvngXS2IRzH999yzo4JyFQ==,type:str]
+    pgp: []
+    unencrypted_suffix: _unencrypted
+    version: 3.9.4

nixos/modules/mail.nix

@@ -1,6 +1,7 @@
+
 /*
 * Building: We patch our version of stalwart and thus need to built it locally.
-*   Be aware that this needs some hours, about 12Gb RAM and a few Gb free space in /tmp.
+*   Be aware that this needs some hours, about 20Gb RAM and a few Gb free space in /tmp.
 *   If you only want to deploy configuration changes and no software updates, consider building on the target VM.
 *   It has stalwart in its nix store and does not need to rebuild it.
 * Forwarding mails: Update the Sops-secrets in the machine directory, rebuild on the VM and deploy.
@@ -65,7 +66,7 @@ in {
         openFirewall = true;
         settings = {
           server = {
-            lookup.default.hostname = "fb04184.mathematik.tu-darmstadt.de"; # Because the DNS PTR of 130.83.2.184 is this and this should be used in SMTP EHLO.
+            hostname = "fb04184.mathematik.tu-darmstadt.de"; # Because the DNS PTR of 130.83.2.184 is this and this should be used in SMTP EHLO.
             listener = {
               "smtp" = {
                 bind = ["[::]:25"];
@@ -82,7 +83,7 @@ in {
                 tls.implicit = true;
               };
               "management" = {
-                # Cthulhu forwards requests for http://fb04184.mathematik.tu-darmstadt.de/.well-known/acme-challenge/ http://imap.mathebau.de/.well-known/acme-challenge/ and http://smtp.mathebau.de/.well-known/acme-challenge/
+                # Cthulhu forwards requests for http://fb04184.mathematik.tu-darmstadt.de/.well-known/acme-challenge/ http://imap.mathebau.de/.well-known/acme-challenge/ and http://smtp.mathebau.de/.well-known/acme-challenge/ and http://mathebau.de/.well-known/acme-challenge/
                 # for TLS certificate challenge validation
                 # whereas the rest of the management interface is not available publically.
                 # It can be reached via SSH and portforwarding.
@@ -95,19 +96,28 @@ in {
             directory = "https://acme-v02.api.letsencrypt.org/directory"; # This setting is necessary for this block to be activated
             challenge = "http-01";
             contact = ["root@mathebau.de"];
-            domains = ["fb04184.mathematik.tu-darmstadt.de" "imap.mathebau.de" "smtp.mathebau.de"];
+            domains = ["fb04184.mathematik.tu-darmstadt.de" "imap.mathebau.de" "smtp.mathebau.de" "mathebau.de"];
             default = true;
           };
           # Reevaluate after DKIM and DMARC deployment
           spam.header.is-spam = "Dummyheader"; # disable moving to spam which would conflict with forwarding
           auth = {
-            # TODO check if HRZ conforms to these standards and we can validate them strictly
+            # TODO check if HRZ and our own VMs conform to these standards and we can validate them strictly
             dkim.verify = "relaxed";
             arc.verify = "relaxed";
             dmarc.verify = "relaxed";
             iprev.verify = "relaxed";
             spf.verify.ehlo = "relaxed";
             spf.verify.mail-from = "relaxed";
+
+            # Sign *our* outgoing mails with the configured signatures.
+            dkim.sign = [
+              {
+                "if" = "is_local_domain('', sender_domain) || sender_domain == 'lists.mathebau.de'";
+                "then" = "['rsa-' + sender_domain, 'ed25519-' + sender_domain]";
+              }
+              {"else" = false;}
+            ];
           };
 
           # Forward outgoing mail to HRZ or mail VMs.
@@ -131,39 +141,62 @@ in {
               starttls = "optional"; # e.g. Lobon does not offer starttls
             };
           };
-          remote."hrz" = {
-            address = "mailout.hrz.tu-darmstadt.de";
-            port = 25;
-            protocol = "smtp";
-            tls.implicit = false; # Don't assume TLS on this port but use STARTTLS
-          };
-          remote."mailman" = {
-            address = "lobon.mathebau.de"; # must be created in DNS as a MX record because this field does not accept ip addresses.
-            port = 25;
-            protocol = "smtp";
-            tls.implicit = false; # Don't assume TLS on this port but use STARTTLS
+          remote = {
+            "hrz" = {
+              address = "mailout.hrz.tu-darmstadt.de";
+              port = 25;
+              protocol = "smtp";
+              tls.implicit = false; # Don't assume TLS on this port but use STARTTLS
+            };
+            "mailman" = {
+              address = "lobon.mathebau.de"; # must be created in DNS as a MX record because this field does not accept ip addresses.
+              port = 25;
+              protocol = "smtp";
+              tls.implicit = false; # Don't assume TLS on this port but use STARTTLS
+            };
           };
 
-          session.rcpt = {
-            # In order to accept mail that we only forward
-            # without having to generate an account.
-            # Invalid addresses are filtered by DFN beforehand.
-            catch-all = true;
-            relay = [
+          session = {
+            ehlo.require = [
               {
-                "if" = "!is_empty(authenticated_as) || rcpt_domain == 'lists.mathebau.de' || starts_with(remote_ip, '192.168.0.')"; #TODO restrict trust by IP
-                "then" = true;
+                "if" = "starts_with(remote_ip, '192.168.0.')"; #TODO setup vms properly
+                "then" = false;
               }
-              {"else" = false;}
+              {"else" = true;}
             ];
+            ehlo.reject-non-fqdn = [
+              {
+                "if" = "starts_with(remote_ip, '192.168.0.')"; #TODO setup vms properly
+                "then" = false;
+              }
+              {"else" = true;}
+            ];
+
+            rcpt = {
+              # In order to accept mail that we only forward
+              # without having to generate an account.
+              # Invalid addresses are filtered by DFN beforehand.
+              # See also https://stalw.art/docs/smtp/inbound/rcpt/#catch-all-addresses
+              catch-all = true;
+              relay = [
+                {
+                  "if" = "!is_empty(authenticated_as) || rcpt_domain == 'lists.mathebau.de' || starts_with(remote_ip, '192.168.0.')"; #TODO restrict trust by IP
+                  "then" = true;
+                }
+                {"else" = false;}
+              ];
+            };
+            data.script = "'redirects'";
           };
 
           # Stalwart gets its configuration from two places: A TOML configuration file that we control in this module
           # and from a database that can be configured from web management interface or via Rest API.
-          # We here define what comes from the TOML-file and especially add "sieve.trusted.scripts.*" to the default ones
+          # We here define what comes from the TOML-file and especially add "sieve.trusted.*" to the default ones
           # because only TOML-based keys may use macros to load files from disk.
           # We want this to be able to load our sieve-script for mail forwarding.
           # See https://stalw.art/docs/configuration/overview/#local-and-database-settings for more details.
+          #
+          # Unfortunately, the set of served domains as well as the catch-all accounts are still not configured via this nix module.
           config.local-keys =
             [
               "store.*"
@@ -181,9 +214,47 @@ in {
               "lookup.default.hostname"
               "certificate.*"
             ] # the default ones
-            ++ ["sieve.trusted.scripts.*"]; #for macros to be able to include our redirection script
-          sieve.trusted.scripts.redirects.contents = "%{file:/tmp/virt_aliases}%"; # generated redirect script
-          session.data.script = "'redirects'";
+            ++ ["sieve.trusted.*"]; #for macros to be able to include our redirection script
+          sieve.trusted = {
+            scripts.redirects.contents = "%{file:/tmp/virt_aliases}%"; # generated redirect script
+            return-path = "sender"; # set the outgoing MAIL FROM to the original sender as specified in the incoming MAIL FROM.
+
+            # If we are the sender, we sign the message with DKIM. Else we leave it alone.
+            sign = [
+              {
+                "if" = "is_local_domain('', sender_domain) || sender_domain == 'lists.mathebau.de'";
+                "then" = "['rsa-' + sender_domain, 'ed25519-' + sender_domain]";
+              }
+              {"else" = false;}
+            ];
+            limits = {
+              redirects = 500;
+              out-messages = 500;
+            };
+          };
+          # See https://stalw.art/docs/smtp/authentication/dkim/sign
+          # We need two blocks per domain because the domain setting in the blocks does not accept variables like `sender_domain`.
+          signature = let
+            signatureTemplate = domain: {
+              "rsa-${domain}" = {
+                private-key = "%{file:/run/secrets/dkim_rsa}%";
+                domain = "${domain}";
+                selector = "rsa-default";
+                headers = ["From" "To" "Cc" "Date" "Subject" "Message-ID" "Organization" "MIME-Version" "Content-Type" "In-Reply-To" "References" "List-Id" "User-Agent" "Thread-Topic" "Thread-Index"]; # default from https://stalw.art/docs/smtp/authentication/dkim/sign#signatures
+                algorithm = "rsa-sha256";
+                canonicalization = "relaxed/relaxed";
+              };
+              "ed25519-${domain}" = {
+                private-key = "%{file:/run/secrets/dkim_ed25519}%";
+                domain = "${domain}";
+                selector = "ed-default";
+                headers = ["From" "To" "Cc" "Date" "Subject" "Message-ID" "Organization" "MIME-Version" "Content-Type" "In-Reply-To" "References" "List-Id" "User-Agent" "Thread-Topic" "Thread-Index"];
+                algorithm = "ed25519-sha256";
+                canonicalization = "relaxed/relaxed";
+              };
+            };
+          in
+            map signatureTemplate (["lists.mathebau.de"] ++ (map ({domain, ...}: domain) cfg.domains));
 
           authentication.fallback-admin = {
             user = "admin";
@@ -229,9 +300,10 @@ in {
               echo "process ${domain}"
               # This line gets the available mailboxes from stalwart's Rest API, searches for their addresses and collects them to a file for submission.
               # The regex searches for alphanumerics combined with some special characters as local paths and the right domain.
-              ${pkgs.curl}/bin/curl -s --header "authorization: Basic $(<${cfg.stalwartAdmin})" http://localhost/api/principal | ${pkgs.gnugrep}/bin/grep -o -e "[A-Za-z0-9.!#\$%&'*+-/=?^_{|}~]*@${domain}" | tee /tmp/addresses
+              # Exclude @domain.tld which is not a valid mail address but used for catch-all accounts.
+              ${pkgs.curl}/bin/curl -s --header "authorization: Basic $(<${cfg.stalwartAdmin})" http://localhost/api/principal | ${pkgs.gnugrep}/bin/grep -o -e "[A-Za-z0-9.!#\$%&*+-/=?^_{|}~]*@${domain}" | grep -v "@${domain}" | tee /tmp/addresses
               # This line searches for available redirects and adds them to the submission file.
-              ${pkgs.gnugrep}/bin/grep -o -e "[A-Za-z0-9.!#\$%&'*+-/=?^_{|}~]*@${domain}" /tmp/virt_aliases >> /tmp/addresses # This doesn't catch all RFC conform local parts. Improve if you need.
+              ${pkgs.gnugrep}/bin/grep -o -e "[A-Za-z0-9.!#\$%&*+-/=?^_{|}~]*@${domain}" /tmp/virt_aliases >> /tmp/addresses # This doesn't catch all RFC conform local parts. Improve if you need.
               # Post local-parts to HRZ, see https://www-cgi.hrz.tu-darmstadt.de/mail/index.php?bereich=whitelist_upload
               ${pkgs.curl}/bin/curl -s https://www-cgi.hrz.tu-darmstadt.de/mail/whitelist-update.php -F emaildomain=${domain} -F password=$(cat ${allowlistPass}) -F emailliste=@/tmp/addresses -F meldungen=voll
               # Cleanup submission file
@@ -239,12 +311,15 @@ in {
             '';
           in
             lib.strings.concatStringsSep "" (map scriptTemplate cfg.domains);
+
+          unitConfig.JoinsNamespaceOf = "stalwart-mail.service"; # allow access to sieve script
+
           serviceConfig = {
             Type = "oneshot";
             User = "stalwart-mail";
             NoNewPrivileges = true;
             # See https://www.man7.org/linux/man-pages/man5/systemd.exec.5.html
-            PrivateTmp = false; # allow access to sieve script
+            PrivateTmp = true;
             ProtectHome = true;
             ReadOnlyPaths = "/";
             ReadWritePaths = "/tmp";
@@ -266,35 +341,8 @@ in {
         # This service is defined by the nixpkgs stalwart module and we only modify it.
         "stalwart-mail" = {
           restartTriggers = lib.attrsets.mapAttrsToList (_: aliaslist: aliaslist.sopsFile) config.sops.secrets; # restart if secrets, especially alias files, have changed.
-          serviceConfig.PrivateTmp = lib.mkForce false; # enable access to generated Sieve script
-        };
-        "virt-aliases-generator" = {
-          description = "Virtual Aliases Generator: Generate a sieve script from the virtual alias file";
-          script = lib.strings.concatStringsSep "" (["${pkgs.alias-to-sieve}/bin/alias_to_sieve "] ++ map (x: "${x.virt_aliases} ${x.domain} ") cfg.domains ++ ["> /tmp/virt_aliases"]);
-          wantedBy = ["stalwart-mail.service"]; # Rerun on stalwart restart because forwardings may have changed.
-          serviceConfig = {
-            Type = "oneshot";
-            User = "stalwart-mail";
-            NoNewPrivileges = true;
-            # See https://www.man7.org/linux/man-pages/man5/systemd.exec.5.html
-            PrivateTmp = false;
-            ProtectHome = true;
-            ReadOnlyPaths = "/";
-            ReadWritePaths = "/tmp";
-            InaccessiblePaths = "-/lost+found";
-            PrivateDevices = true;
-            PrivateUsers = true;
-            ProtectHostname = true;
-            ProtectClock = true;
-            ProtectKernelTunables = true;
-            ProtectKernelModules = true;
-            ProtectKernelLogs = true;
-            ProtectControlGroups = true;
-            LockPersonality = true;
-            MemoryDenyWriteExecute = true;
-            RestrictRealtime = true;
-            RestrictSUIDSGID = true;
-          };
+          #Generate a sieve script from the virtual alias file
+          preStart = lib.strings.concatStringsSep "" (["${pkgs.alias-to-sieve}/bin/alias_to_sieve "] ++ map (x: "${x.virt_aliases} ${x.domain} ") cfg.domains ++ ["> /tmp/virt_aliases"]);
         };
       };
     };

nixos/modules/mailman.nix

@@ -32,8 +32,6 @@ in {
         config = {
           transport_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
           local_recipient_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
-          proxy_interfaces = "130.83.2.184";
-          smtputf8_enable = "no"; # HRZ does not know SMTPUTF8
         };
         relayHost = "mathebau.de"; # Relay to mail vm which relays to HRZ (see https://www.hrz.tu-darmstadt.de/services/it_services/email_infrastruktur/index.de.jsp)
       };

patches/sieve-rs.patch

@@ -8,7 +8,7 @@ index be36759b..b4316639 100644
  version = "0.6.0"
 -source = "registry+https://github.com/rust-lang/crates.io-index"
 -checksum = "15ac54053752c25a0e545dd1953de716abcc80b12cfe0b6c2f2c1c73759d4f45"
-+source = "git+https://gitea.mathebau.de/fachschaft/sieve-rs.git#71324550504c0f84fe3e814d05cbe22f90a3b228"
++source = "git+https://github.com/stalwartlabs/sieve.git#56450c6ccdf76f1de95931db24896599159efc53"
  dependencies = [
   "ahash 0.8.11",
   "bincode",
@@ -23,5 +23,5 @@ index f055474f..2b64c9ac 100644
 +
 +
 +[patch.crates-io]
-+sieve-rs = { git = 'https://gitea.mathebau.de/fachschaft/sieve-rs.git' }
++sieve-rs = { git = 'https://github.com/stalwartlabs/sieve.git' }