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: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,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' }