Fix cron jobs always 403ing: wire cronjob_pw through to the curl requests

CronjobsController requires a `cronpw` query param matching
AppModel.cronjob_pw, but cronjob_pw is generated at install time and
INSERTed straight into the DB -- nothing ever surfaced it to the cron
units' curl invocations, so every cron request has 403'd since this
service existed. Cache the value to a cfg.user-only-readable file at
generation time (backfilling it from the DB for already-installed
deployments), and have each cron unit read it back and append it as
`?cronpw=`.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

nixos-module/default.nix

@@ -23,6 +23,13 @@ let
   runDir = "/run/hortusfox/www";     # ephemeral symlink tree (tmpfs)
   stateDir = "/var/lib/hortusfox";   # persistent writable data
 
+  # The app's CronjobsController requires a `?cronpw=` query param matching
+  # AppModel.cronjob_pw (see hortusfox-setup's step 5 below) -- cache that
+  # value here, readable only by cfg.user, so the cron units below can read
+  # it back at request time without ever going through Nix (cronjob_pw is
+  # DB-generated at install time, not a Nix-level secret).
+  cronPwFile = "${stateDir}/.cronjob-pw";
+
   # Writable subdirs that must survive reboots.
   writableDirs = [
     "cache" "app/logs"
@@ -152,6 +159,20 @@ let
   cronPort = if cfg.proxy.ssl then 443 else 80;
   cronUrl = path: "${scheme}://${cfg.domain}:${toString cronPort}${path}";
 
+  # The actual ExecStart for each cron unit: read the cached cronjob_pw
+  # (written by hortusfox-setup) and append it as the `?cronpw=` query param
+  # CronjobsController requires, or every cron request gets a bare 403.
+  # A wrapper script rather than a plain curl invocation because systemd's
+  # ExecStart doesn't run through a shell, so it can't itself do the
+  # `$(cat ...)` substitution.
+  cronScript = name: job: pkgs.writeShellScript "hortusfox-cron-${name}" ''
+    set -euo pipefail
+    cronpw="$(${pkgs.coreutils}/bin/cat "${cronPwFile}")"
+    exec ${pkgs.curl}/bin/curl -fsS --max-time 300 \
+      --resolve ${cfg.domain}:${toString cronPort}:127.0.0.1 \
+      "${cronUrl job.path}?cronpw=$cronpw"
+  '';
+
   # Baseline systemd sandboxing shared by this module's own units
   # (hortusfox-setup and the cron jobs; phpfpm-hortusfox gets its own,
   # layered on top of what services.phpfpm already sets). Deliberately
@@ -538,6 +559,11 @@ in {
             #    migration's own column default, same as upstream's
             #    installer does.
             cronjob_pw="$(php -r 'echo md5(random_bytes(55) . date("Y-m-d H:i:s"));')"
+            # Cache it for the cron units (see cronScript above) -- this is
+            # the only place that ever learns the value in plaintext outside
+            # the DB itself.
+            printf '%s' "$cronjob_pw" > "${cronPwFile}"
+            chmod 600 "${cronPwFile}"
             mariadb "${cfg.database.name}" -e "INSERT INTO AppModel (id, workspace, language, timezone, scroller, chat_enable, chat_timelimit, chat_showusers, chat_indicator, chat_system, history_enable, history_name, enable_media_share, cronjob_pw, overlay_alpha, smtp_enable_auth, smtp_fromname, smtp_fromaddress, smtp_host, smtp_port, smtp_username, smtp_password, smtp_encryption, pwa_enable, owm_enable, owm_api_key, owm_latitude, owm_longitude, owm_unittype, owm_cache) VALUES (NULL, '${sqlEscape envVars.APP_WORKSPACE}', '${sqlEscape cfg.language}', '${sqlEscape cfg.timezone}', 1, 1, 5, 1, 1, 1, 1, 'History', 0, '$cronjob_pw', NULL, 1, '${sqlEscape cfg.smtp.fromName}', '${sqlEscape cfg.smtp.fromAddress}', '${sqlEscape cfg.smtp.host}', ${toString cfg.smtp.port}, '${sqlEscape cfg.smtp.username}', NULL, '${sqlEscape cfg.smtp.encryption}', 0, 0, NULL, NULL, NULL, 'default', 300);"
 
             # 6. Seed the initial admin account. migrate:fresh creates no
@@ -557,6 +583,15 @@ in {
           else
             php asatru migrate:upgrade || true
           fi
+
+          # Backfill for deployments that installed before cronjob_pw was
+          # cached to disk (it's always been DB-only until now): pull the
+          # value AppModel already has back out, rather than regenerating
+          # one that wouldn't match it.
+          if [ ! -s "${cronPwFile}" ]; then
+            mariadb -N "${cfg.database.name}" -e "SELECT cronjob_pw FROM AppModel LIMIT 1" > "${cronPwFile}"
+            chmod 600 "${cronPwFile}"
+          fi
         '';
       };
 
@@ -582,11 +617,10 @@ in {
         serviceConfig = commonHardening // {
           Type = "oneshot";
           User = cfg.user;
-          ExecStart = "${pkgs.curl}/bin/curl -fsS --max-time 300 "
+          ExecStart = "${cronScript name job}";
-            + "--resolve ${cfg.domain}:${toString cronPort}:127.0.0.1 "
+          # Only touches the filesystem to read cronPwFile back -- stateDir
-            + "${cronUrl job.path}";
+          # stays visible (read-only) under ProtectSystem=strict since it
-          # A single outbound curl to the app's own loopback address --
+          # isn't under /home, so no ReadWritePaths/ReadOnlyPaths needed.
-          # doesn't touch the filesystem at all, so lock it down fully.
           ProtectSystem = "strict";
           ProtectHome = "tmpfs";
         };

tests/vm-test.nix

@@ -92,5 +92,12 @@ pkgs.testers.nixosTest {
     assert "/auth" not in final_url, (
         f"login didn't redirect away from /auth -- login failed (landed on {final_url}):\n{login_response}"
     )
+
+    # The cron units curl the app's own cronjob endpoints with a `?cronpw=`
+    # query param matching AppModel.cronjob_pw -- exercise one directly
+    # rather than just trusting it, since this exact wiring broke silently
+    # in production (every cron request 403'd, forever, with nothing short
+    # of reading the journal ever surfacing it) before this assertion existed.
+    machine.succeed("systemctl start hortusfox-cron-tasks-recurring.service")
   '';
 }