fix(backup): resolve symlinks and add the all-in-one frontend dir to the destination guard

Codex round 3 found two more bypasses of the public-root guard,
both specific to the all-in-one image (Dockerfile.aio):

- /app/frontend/dist (FRONTEND_DIR) ships nodejs-owned and is
  served unauthenticated as the built SPA -- missing from the
  protected-roots list.
- /app/storage is a symlink to /data/storage (the actual
  STORAGE_PATH). A destination given as /app/storage/uploads/logos
  passed the guard's lexical path.resolve() comparison while
  resolving, on disk, to the exact same directory as the protected
  STORAGE_PATH/uploads/logos. isUnderPubliclyServableRoot now
  resolves symlinks in whatever prefix of each path already
  exists (resolveRealish) before comparing, rather than relying on
  path.resolve() alone.

Also restores three fs.mkdir spies in the test file that were
never un-spied, which silently leaked a rejected mock into any
later test doing a real fs.mkdir -- exactly what the new symlink
test needed to set up its fixture.

Found by codex review, round 3.

backend/__tests__/routes/databaseBackupConfigDestination.test.js

@@ -0,0 +1,122 @@
+/**
+ * PUT /api/admin/database-backup/config must reject a
+ * database_backup_destination_path that resolves inside a publicly served
+ * directory (GHSA-jw8m-43r2-jqrm class, #1365).
+ *
+ * Before #1365, database_backup_destination_path was silently ignored by
+ * databaseBackupService.backup() (a destructuring bug always fell back to
+ * the hardcoded /backup/database), so this setting being freely writable by
+ * any backup.create holder — the built-in `admin` role has it without
+ * settings.edit or backup.restore — was harmless. Making the setting
+ * actually take effect reopens the exact exfiltration path GHSA-jw8m fixed
+ * for the per-request override, through the persisted setting instead.
+ */
+
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(
+  fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-dbbackup-config-')), 'db.sqlite',
+);
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'dbbackup-config-test-secret';
+process.env.STORAGE_PATH = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-dbbackup-storage-'));
+
+const request = require('supertest');
+const express = require('express');
+const bcrypt = require('bcrypt');
+const jwt = require('jsonwebtoken');
+
+const { bootCrmDb, seedMinimal } = require('../integration/helpers/crmDb');
+
+describe('database backup destination-path config guard (GHSA-jw8m class, #1365)', () => {
+  let db; let cleanup; let app; let adminToken;
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    await seedMinimal(db);
+
+    const role = await db('roles').where({ name: 'admin' }).first();
+    const r = await db('admin_users').insert({
+      username: 'limited-admin',
+      email: 'limited-admin-config@example.com',
+      password_hash: await bcrypt.hash('Passw0rd!', 4),
+      role_id: role.id,
+      is_active: 1,
+      created_at: new Date(),
+      updated_at: new Date(),
+    }).returning('id');
+    const id = r[0]?.id ?? r[0];
+    adminToken = jwt.sign(
+      { id, username: 'limited-admin', type: 'admin', role: 'admin', loginTime: Date.now() },
+      process.env.JWT_SECRET,
+      { expiresIn: '1h', issuer: 'picpeak-auth' },
+    );
+
+    app = express();
+    app.use(express.json());
+    app.use('/api/admin/database-backup', require('../../src/routes/adminDatabaseBackup'));
+  }, 120000);
+
+  afterAll(async () => { if (cleanup) await cleanup(); });
+
+  it('rejects a destination inside the public uploads/logos mount', async () => {
+    const res = await request(app)
+      .put('/api/admin/database-backup/config')
+      .set('Authorization', `Bearer ${adminToken}`)
+      .send({ database_backup_destination_path: path.join(process.env.STORAGE_PATH, 'uploads', 'logos') });
+
+    expect(res.status).toBe(400);
+
+    // The seeded default must survive untouched — the rejected value never lands.
+    const row = await db('app_settings').where({ setting_key: 'database_backup_destination_path' }).first();
+    expect(JSON.parse(row.setting_value)).toBe('/backup/database');
+  });
+
+  it('rejects a destination inside the public fonts mount', async () => {
+    const res = await request(app)
+      .put('/api/admin/database-backup/config')
+      .set('Authorization', `Bearer ${adminToken}`)
+      .send({ database_backup_destination_path: path.join(process.env.STORAGE_PATH, 'fonts') });
+
+    expect(res.status).toBe(400);
+  });
+
+  it('accepts a destination outside any public mount', async () => {
+    const safePath = path.join(process.env.STORAGE_PATH, 'db-backups');
+    const res = await request(app)
+      .put('/api/admin/database-backup/config')
+      .set('Authorization', `Bearer ${adminToken}`)
+      .send({ database_backup_destination_path: safePath });
+
+    expect(res.status).toBe(200);
+
+    const row = await db('app_settings').where({ setting_key: 'database_backup_destination_path' }).first();
+    expect(JSON.parse(row.setting_value)).toBe(safePath);
+  });
+
+  // A retention of 0 or less pushes cleanupOldBackups' cutoff to today or
+  // the future, deleting every completed backup on the next scheduled run
+  // — a backup.create holder achieving what backup.delete gates on /cleanup.
+  it.each([-1, 0])('rejects database_backup_retention_days=%s', async (bad) => {
+    const res = await request(app)
+      .put('/api/admin/database-backup/config')
+      .set('Authorization', `Bearer ${adminToken}`)
+      .send({ database_backup_retention_days: bad });
+
+    expect(res.status).toBe(400);
+  });
+
+  it('accepts a positive database_backup_retention_days', async () => {
+    const res = await request(app)
+      .put('/api/admin/database-backup/config')
+      .set('Authorization', `Bearer ${adminToken}`)
+      .send({ database_backup_retention_days: 90 });
+
+    expect(res.status).toBe(200);
+
+    const row = await db('app_settings').where({ setting_key: 'database_backup_retention_days' }).first();
+    expect(JSON.parse(row.setting_value)).toBe(90);
+  });
+});

backend/src/routes/adminDatabaseBackup.js

@@ -2,7 +2,7 @@ const express = require('express');
 const router = express.Router();
 const { adminAuth } = require('../middleware/auth');
 const { requirePermission } = require('../middleware/permissions');
-const { databaseBackupService } = require('../services/databaseBackup');
+const { databaseBackupService, isUnderPubliclyServableRoot } = require('../services/databaseBackup');
 const { db } = require('../database/db');
 const logger = require('../utils/logger');
 const { getPagination } = require('../utils/routeHelpers');
@@ -60,7 +60,28 @@ router.put('/config', requirePermission('backup.create'), async (req, res) => {
       'database_backup_email_on_failure',
       'database_backup_email_on_success'
     ];
-    
+
+    // A backup.create holder (the built-in `admin` role has it without
+    // settings.edit or backup.restore) could otherwise point backups at a
+    // public static mount and fetch the dump unauthenticated — see
+    // isUnderPubliclyServableRoot's comment (GHSA-jw8m-43r2-jqrm class).
+    if (
+      typeof req.body.database_backup_destination_path === 'string'
+      && isUnderPubliclyServableRoot(req.body.database_backup_destination_path)
+    ) {
+      return res.status(400).json({ error: 'Destination path must not be inside a publicly served directory' });
+    }
+
+    // A retention of 0 or less pushes cleanupOldBackups' cutoff to today or
+    // the future, deleting every completed backup on the next scheduled run
+    // — a backup.create holder achieving what backup.delete gates on /cleanup.
+    if (
+      req.body.database_backup_retention_days !== undefined
+      && (!Number.isFinite(req.body.database_backup_retention_days) || req.body.database_backup_retention_days < 1)
+    ) {
+      return res.status(400).json({ error: 'database_backup_retention_days must be a positive number' });
+    }
+
     const updates = [];
     
     for (const [key, value] of Object.entries(req.body)) {

backend/src/services/__tests__/databaseBackup.test.js

@@ -1,6 +1,6 @@
-const { DatabaseBackupService } = require('../databaseBackup');
 const { db } = require('../../database/db');
 const fs = require('fs').promises;
+const path = require('path');
 const crypto = require('crypto');
 
 // Mock dependencies
@@ -8,6 +8,10 @@ jest.mock('../../database/db');
 jest.mock('../../utils/logger');
 jest.mock('../emailProcessor');
 jest.mock('child_process');
+jest.mock('node-cron', () => ({ schedule: jest.fn(() => ({ stop: jest.fn() })) }));
+
+const { DatabaseBackupService, startScheduledBackups, databaseBackupService, isUnderPubliclyServableRoot } = require('../databaseBackup');
+const cron = require('node-cron');
 
 describe('DatabaseBackupService', () => {
   let service;
@@ -191,6 +195,213 @@ describe('DatabaseBackupService', () => {
     });
   });
 
+  describe('backup() destination path resolution (#1365)', () => {
+    // getBackupConfig() returns database_backup_*-prefixed keys.
+    // Regression: backup() used to destructure the unprefixed names
+    // (`destinationPath`, ...) straight off that object, which never
+    // matched, so the configured path was silently ignored and every
+    // run tried to create the hardcoded /backup/database default.
+    it('creates the directory from database_backup_destination_path when configured', async () => {
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_destination_path', setting_value: JSON.stringify('/data/db-backups') }
+        ])
+      });
+
+      const stop = new Error('stop after mkdir — nothing past it matters for this test');
+      const mkdirSpy = jest.spyOn(fs, 'mkdir').mockRejectedValue(stop);
+
+      await expect(service.backup({})).rejects.toThrow(stop.message);
+
+      expect(mkdirSpy).toHaveBeenCalledWith('/data/db-backups', { recursive: true });
+      mkdirSpy.mockRestore();
+    });
+
+    it('falls back to /backup/database only when nothing is configured', async () => {
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([])
+      });
+
+      const stop = new Error('stop after mkdir');
+      const mkdirSpy = jest.spyOn(fs, 'mkdir').mockRejectedValue(stop);
+
+      await expect(service.backup({})).rejects.toThrow(stop.message);
+
+      expect(mkdirSpy).toHaveBeenCalledWith('/backup/database', { recursive: true });
+      mkdirSpy.mockRestore();
+    });
+  });
+
+  describe('isUnderPubliclyServableRoot (GHSA-jw8m class, #1365)', () => {
+    const originalStoragePath = process.env.STORAGE_PATH;
+    const storage = '/tmp/picpeak-test-storage';
+
+    beforeEach(() => {
+      process.env.STORAGE_PATH = storage;
+    });
+
+    afterAll(() => {
+      if (originalStoragePath === undefined) {
+        delete process.env.STORAGE_PATH;
+      } else {
+        process.env.STORAGE_PATH = originalStoragePath;
+      }
+    });
+
+    it.each([
+      path.join(storage, 'uploads', 'logos'),
+      path.join(storage, 'uploads', 'logos', 'sub'),
+      path.join(storage, 'uploads', 'favicons'),
+      path.join(storage, 'fonts'),
+      path.join(storage, 'fonts', 'inter'),
+      // Bundled fallback fonts — nodejs-owned per the Dockerfile's
+      // COPY --chown, and served at the same public /fonts route.
+      path.resolve(__dirname, '../../../assets/fonts'),
+      // Case-insensitive-but-preserving filesystems (APFS, NTFS, Docker
+      // Desktop bind mounts of either) resolve this to the same directory
+      // as uploads/logos even though path.resolve() never folds case.
+      path.join(storage, 'UPLOADS', 'Logos')
+    ])('flags %s as publicly servable', (candidate) => {
+      expect(isUnderPubliclyServableRoot(candidate)).toBe(true);
+    });
+
+    it.each([
+      path.join(storage, 'backups'),
+      path.join(storage, 'uploads', 'contracts', 'signed'),
+      path.join(storage, 'uploads', 'transfers', '123'),
+      '/data/db-backups'
+    ])('does not flag %s', (candidate) => {
+      expect(isUnderPubliclyServableRoot(candidate)).toBe(false);
+    });
+
+    it('backup() refuses a destination inside a publicly servable root without ever calling mkdir', async () => {
+      const publicPath = path.join(storage, 'uploads', 'logos');
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_destination_path', setting_value: JSON.stringify(publicPath) }
+        ])
+      });
+
+      const mkdirSpy = jest.spyOn(fs, 'mkdir');
+
+      await expect(service.backup({})).rejects.toThrow('publicly served directory');
+
+      expect(mkdirSpy).not.toHaveBeenCalled();
+      mkdirSpy.mockRestore();
+    });
+
+    it('flags FRONTEND_DIR — the all-in-one image serves its built SPA unauthenticated', () => {
+      const originalFrontendDir = process.env.FRONTEND_DIR;
+      process.env.FRONTEND_DIR = '/app/frontend/dist';
+      try {
+        expect(isUnderPubliclyServableRoot('/app/frontend/dist')).toBe(true);
+        expect(isUnderPubliclyServableRoot(path.join('/app/frontend/dist', 'assets'))).toBe(true);
+      } finally {
+        if (originalFrontendDir === undefined) delete process.env.FRONTEND_DIR;
+        else process.env.FRONTEND_DIR = originalFrontendDir;
+      }
+    });
+
+    it('resolves a symlinked alias of a public root to the same real directory (all-in-one /app/storage -> /data/storage)', async () => {
+      const os = require('os');
+      const realRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'picpeak-real-'));
+      const linkRoot = path.join(os.tmpdir(), `picpeak-link-${process.pid}-${Date.now()}`);
+      await fs.mkdir(path.join(realRoot, 'uploads', 'logos'), { recursive: true });
+      await fs.symlink(realRoot, linkRoot, 'dir');
+
+      try {
+        // STORAGE_PATH (what the guard's roots are built from) is the real
+        // path; the attacker-supplied destination goes through the symlink
+        // — exactly the all-in-one image's /app/storage -> /data/storage.
+        process.env.STORAGE_PATH = realRoot;
+        const aliased = path.join(linkRoot, 'uploads', 'logos');
+
+        expect(isUnderPubliclyServableRoot(aliased)).toBe(true);
+      } finally {
+        await fs.unlink(linkRoot);
+        await fs.rm(realRoot, { recursive: true, force: true });
+      }
+    });
+  });
+
+  describe('startScheduledBackups (#1365)', () => {
+    // Same key-mismatch bug as backup(): getBackupConfig() returns
+    // database_backup_*-prefixed keys, but this read `config.enabled` /
+    // `config.schedule` / `config.retentionDays` — always undefined, so
+    // the scheduler silently treated every install as disabled.
+    it('does not start the schedule while database_backup_enabled is false', async () => {
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_enabled', setting_value: 'false' }
+        ])
+      });
+
+      await startScheduledBackups();
+
+      expect(cron.schedule).not.toHaveBeenCalled();
+    });
+
+    it('starts the schedule with the configured cron when database_backup_enabled is true', async () => {
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_enabled', setting_value: 'true' },
+          { setting_key: 'database_backup_schedule', setting_value: JSON.stringify('0 4 * * *') }
+        ])
+      });
+
+      await startScheduledBackups();
+
+      expect(cron.schedule).toHaveBeenCalledWith('0 4 * * *', expect.any(Function));
+    });
+
+    it('re-reads retention on every tick instead of the value captured at schedule start (#1365)', async () => {
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_enabled', setting_value: 'true' },
+          { setting_key: 'database_backup_retention_days', setting_value: JSON.stringify(30) }
+        ])
+      });
+
+      await startScheduledBackups();
+      const tick = cron.schedule.mock.calls[0][1];
+
+      // A /config update between schedule-start and this tick raised
+      // retention to 365 — the closed-over 30 must not be what runs.
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue([
+          { setting_key: 'database_backup_enabled', setting_value: 'true' },
+          { setting_key: 'database_backup_retention_days', setting_value: JSON.stringify(365) }
+        ])
+      });
+      jest.spyOn(databaseBackupService, 'backup').mockResolvedValue({ success: true });
+      const cleanupSpy = jest.spyOn(databaseBackupService, 'cleanupOldBackups').mockResolvedValue(undefined);
+
+      await tick();
+
+      expect(cleanupSpy).toHaveBeenCalledWith(365);
+
+      jest.restoreAllMocks();
+    });
+  });
+
+  describe('cleanupOldBackups destructive-retention guard (#1365)', () => {
+    it.each([-1, 0, NaN, Infinity])('refuses retentionDays=%s without touching the database', async (bad) => {
+      const dbSpy = jest.fn();
+      db.mockImplementation(dbSpy);
+
+      await service.cleanupOldBackups(bad);
+
+      expect(dbSpy).not.toHaveBeenCalled();
+    });
+  });
+
   describe('cleanupOldBackups', () => {
     it('should delete old backup files and records', async () => {
       const oldBackups = [

backend/src/services/backupService.js

@@ -1041,7 +1041,7 @@ function buildManifestFiles(backedUpFiles, allFiles) {
 
 async function saveManifestToLocal(manifest, manifestFileName, config) {
   const manifestDir = config.backup_manifest_path
-    || path.join(config.backup_destination_path || '/backup', 'manifests');
+    || path.join(config.backup_destination_path || path.join(getStoragePath(), 'backups'), 'manifests');
   await fs.mkdir(manifestDir, { recursive: true });
   const manifestPath = path.join(manifestDir, manifestFileName);
   await backupManifest.saveManifest(manifest, manifestPath, config.backup_manifest_format || 'json');

backend/src/services/databaseBackup.js

@@ -4,7 +4,7 @@ const crypto = require('crypto');
 const { spawnAsync, spawnToFile } = require('../utils/safeExec');
 const zlib = require('zlib');
 const { pipeline } = require('stream/promises');
-const { createReadStream, createWriteStream } = require('fs');
+const { createReadStream, createWriteStream, realpathSync } = require('fs');
 const { db } = require('../database/db');
 const knexConfig = require('../../knexfile');
 const logger = require('../utils/logger');
@@ -28,6 +28,76 @@ const packageJson = require('../../package.json');
 // createSQLiteBackup below.
 const FACE_TABLES = ['photo_faces', 'event_people', 'event_people_merge_dismissals'];
 
+function getStoragePath() {
+  return process.env.STORAGE_PATH || path.join(__dirname, '../../../storage');
+}
+
+// Public, unauthenticated static mounts (server.js) that must never become a
+// backup destination — a dump landing there is downloadable by anyone who
+// learns or guesses the filename, GHSA-jw8m-43r2-jqrm's exact class. Before
+// #1365, `database_backup_destination_path` was silently ignored (a
+// destructuring bug always fell back to the hardcoded /backup/database), so
+// this setting being freely writable by any backup.create holder — the
+// built-in `admin` role has it without settings.edit or backup.restore — was
+// harmless. Making the setting actually take effect reopens that exact
+// exfiltration path unless it's rejected here too.
+function getPubliclyServableRoots() {
+  const storage = getStoragePath();
+  return [
+    path.join(storage, 'uploads', 'logos'),
+    path.join(storage, 'uploads', 'favicons'),
+    path.join(storage, 'fonts'),
+    // Bundled fallback fonts (server.js mounts both at /fonts, storage wins
+    // on overlap but express.static falls through to this one on a miss).
+    // COPY --chown=nodejs:nodejs in the Dockerfile makes this nodejs-owned
+    // and therefore writable at runtime, not just a read-only image layer.
+    path.resolve(__dirname, '../../assets/fonts'),
+    // The all-in-one image's built frontend bundle (Dockerfile.aio ships it
+    // nodejs-owned) — server.js serves it unauthenticated as the SPA itself.
+    process.env.FRONTEND_DIR || path.resolve(__dirname, '../../../frontend/dist')
+  ];
+}
+
+// Resolves symlinks in whatever prefix of candidatePath currently exists,
+// then re-appends any not-yet-created remainder literally. A plain
+// fs.realpathSync would throw ENOENT for the common case where the backup
+// destination doesn't exist yet; a plain path.resolve() would miss the
+// all-in-one image's `/app/storage -> /data/storage` symlink (Dockerfile.aio),
+// which lets `/app/storage/uploads/logos` alias the real public logos
+// directory under a name that never lexically matches it.
+function resolveRealish(candidatePath) {
+  let current = path.resolve(candidatePath);
+  const remainder = [];
+  for (;;) {
+    try {
+      const real = realpathSync(current);
+      return remainder.length ? path.join(real, ...remainder) : real;
+    } catch (error) {
+      if (error.code !== 'ENOENT') {
+        return path.resolve(candidatePath);
+      }
+      const parent = path.dirname(current);
+      if (parent === current) {
+        return path.resolve(candidatePath);
+      }
+      remainder.unshift(path.basename(current));
+      current = parent;
+    }
+  }
+}
+
+function isUnderPubliclyServableRoot(candidatePath) {
+  // Lowercased comparison: on a case-insensitive-but-preserving filesystem
+  // (default macOS APFS, NTFS, and Docker Desktop's bind-mount passthrough
+  // of either) `STORAGE_PATH/UPLOADS/logos` and `.../uploads/logos` name the
+  // same directory on disk even though path.resolve() never folds case.
+  const resolved = resolveRealish(candidatePath).toLowerCase();
+  return getPubliclyServableRoots().some((root) => {
+    const resolvedRoot = resolveRealish(root).toLowerCase();
+    return resolved === resolvedRoot || resolved.startsWith(resolvedRoot + path.sep);
+  });
+}
+
 /**
  * Database Backup Service
  * Supports both SQLite and PostgreSQL with proper escaping,
@@ -375,15 +445,33 @@ class DatabaseBackupService {
     let backupRun = null;
     
     try {
-      // Get configuration
+      // Get configuration. getBackupConfig() returns the raw
+      // database_backup_*-prefixed setting keys, not the unprefixed
+      // names used internally below — map them explicitly rather than
+      // spreading `config` straight into the destructure, which silently
+      // matched nothing and always fell through to the hardcoded
+      // defaults (notably `/backup/database`, regardless of what was
+      // configured).
       const config = await this.getBackupConfig();
       const {
         destinationPath = '/backup/database',
         compress = true,
         validateIntegrity = true,
         includeChecksums = true
-      } = { ...config, ...options };
+      } = {
+        destinationPath: config.database_backup_destination_path,
+        compress: config.database_backup_compress,
+        validateIntegrity: config.database_backup_validate_integrity,
+        includeChecksums: config.database_backup_include_checksums,
+        ...options
+      };
       
+      if (isUnderPubliclyServableRoot(destinationPath)) {
+        throw new Error(
+          `Refusing to write a database backup to a publicly served directory: ${destinationPath}`
+        );
+      }
+
       // Create backup directory
       await fs.mkdir(destinationPath, { recursive: true });
       
@@ -502,7 +590,7 @@ class DatabaseBackupService {
       logger.info(`Database backup completed: ${finalFile} (${(finalStats.size / 1024 / 1024).toFixed(2)} MB) in ${durationSeconds}s`);
       
       // Send success notification if configured
-      if (config.emailOnSuccess) {
+      if (config.database_backup_email_on_success) {
         await this.sendBackupNotification('success', {
           duration: durationSeconds,
           size: finalStats.size,
@@ -536,7 +624,7 @@ class DatabaseBackupService {
       
       // Send failure notification
       const config = await this.getBackupConfig();
-      if (config.emailOnFailure) {
+      if (config.database_backup_email_on_failure) {
         await this.sendBackupNotification('failure', {
           error: error.message
         });
@@ -617,10 +705,19 @@ class DatabaseBackupService {
    * Clean up old backups
    */
   async cleanupOldBackups(retentionDays = 30) {
+    // A zero/negative/non-finite value pushes the cutoff to today or the
+    // future, matching (and deleting) every completed backup — including
+    // the one a scheduled run just created. Defense in depth: PUT /config
+    // already rejects such values, but this is also reachable with
+    // whatever database_backup_retention_days happens to be persisted.
+    if (!Number.isFinite(retentionDays) || retentionDays < 1) {
+      logger.error(`Refusing to clean up backups with invalid retentionDays: ${retentionDays}`);
+      return;
+    }
     try {
       const cutoffDate = new Date();
       cutoffDate.setDate(cutoffDate.getDate() - retentionDays);
-      
+
       // Get old backup records
       const oldBackups = await db('database_backup_runs')
         .where('completed_at', '<', cutoffDate)
@@ -765,25 +862,30 @@ async function startScheduledBackups() {
   
   try {
     const config = await databaseBackupService.getBackupConfig();
-    
-    if (!config.enabled) {
+
+    if (!config.database_backup_enabled) {
       logger.info('Database backup service is disabled');
       return;
     }
-    
+
     // Stop existing schedule
     if (backupSchedule) {
       backupSchedule.stop();
     }
-    
+
     // Default schedule: 3 AM daily (offset from file backups at 2 AM)
-    const schedule = config.schedule || '0 3 * * *';
-    
+    const schedule = config.database_backup_schedule || '0 3 * * *';
+
     backupSchedule = cron.schedule(schedule, async () => {
       logger.info('Starting scheduled database backup');
       try {
         await databaseBackupService.backup();
-        await databaseBackupService.cleanupOldBackups(config.retentionDays || 30);
+        // Re-read retention on every tick rather than closing over the value
+        // from schedule start — a retention-only /config update doesn't
+        // restart the schedule (only enabled/schedule changes do), so the
+        // closed-over value would otherwise run stale until next restart.
+        const latestConfig = await databaseBackupService.getBackupConfig();
+        await databaseBackupService.cleanupOldBackups(latestConfig.database_backup_retention_days || 30);
       } catch (error) {
         logger.error('Scheduled database backup failed:', error);
       }
@@ -810,5 +912,6 @@ module.exports = {
   databaseBackupService,
   startScheduledBackups,
   stopScheduledBackups,
+  isUnderPubliclyServableRoot,
   DatabaseBackupService // Export class for testing
 };