shopify-ai-backup/review/FIXES_APPLIED.md

# Security & Functionality Fixes Applied

**Date:** February 21, 2026

## Summary of Fixes Applied

### Critical Fixes (Fixed)

#### 1. Webhook Signature Verification Buffer Length Check
**File:** `server.js:15162-15170`
**Issue:** `timingSafeEqual()` throws error if buffer lengths differ, potentially bypassing verification.
**Fix:** Added buffer length comparison before calling `timingSafeEqual()`.

```javascript
const sigBuffer = Buffer.from(signature);
const expectedBuffer = Buffer.from(expectedSignature);
if (sigBuffer.length !== expectedBuffer.length || !require('crypto').timingSafeEqual(sigBuffer, expectedBuffer)) {
  // reject
}
```

#### 2. Duplicate Variable Declaration in Webhook Handler
**File:** `server.js:15253`
**Issue:** `eventId` was declared twice in the same function scope, causing SyntaxError.
**Fix:** Removed the duplicate declaration at line 15253.

#### 3. Session Secret Auto-Generation with Persistence
**File:** `server.js:390-420`
**Issue:** Session secret was regenerated on each restart, invalidating all sessions.
**Fix:** Session secret is now persisted to `generated-secrets.json` and reused on restart.

```javascript
const secretsFile = path.join(STATE_DIR, 'generated-secrets.json');
// Load existing secret or generate and persist new one
```

#### 4. SQLCipher Key Validation
**File:** `src/database/connection.js:18-29`
**Issue:** SQLCipher key was only escaping quotes, not fully validating format.
**Fix:** Added comprehensive key validation:
- Minimum 32 characters
- Must be hexadecimal only (0-9, a-f, A-F)

```javascript
function validateSqlcipherKey(key) {
  if (!key || typeof key !== 'string') throw new Error('...');
  if (key.length < 32) throw new Error('...');
  if (!/^[a-fA-F0-9]+$/.test(key)) throw new Error('...');
  return true;
}
```

#### 5. JSON Body Size Limit in External API
**File:** `src/external-admin-api/handlers.js:108-131`
**Issue:** No size limit on JSON body parsing, potential memory exhaustion.
**Fix:** Added `maxBodySize` parameter (default 6MB) with streaming size check.

```javascript
async function parseJsonBody(req, maxBodySize = 6 * 1024 * 1024) {
  // ... size tracking and rejection if exceeded
}
```

### High Priority Fixes (Fixed)

#### 6. CORS Headers
**File:** `server.js:8940-8950`
**Issue:** No explicit CORS configuration.
**Fix:** Added comprehensive CORS headers to `sendJson()`:
- `Access-Control-Allow-Origin`
- `Access-Control-Allow-Methods`
- `Access-Control-Allow-Headers`
- `Access-Control-Allow-Credentials`

#### 7. Pending Payment Session Cleanup
**File:** `server.js:1130-1190`
**Issue:** Pending payment sessions accumulate without cleanup.
**Fix:** Added `cleanupStalePendingPayments()` function that:
- Removes pending records older than 48 hours
- Runs during periodic memory cleanup
- Persists changes after cleanup

#### 8. Builder State Debouncing
**File:** `public/builder.js:19-46`
**Issue:** Every property change triggered localStorage write (performance impact).
**Fix:** Implemented debounced save with 500ms delay.

```javascript
let builderStateSaveTimer = null;
function saveBuilderState(state) {
  pendingBuilderState = state;
  if (builderStateSaveTimer) clearTimeout(builderStateSaveTimer);
  builderStateSaveTimer = setTimeout(() => {
    localStorage.setItem(BUILDER_STATE_KEY, JSON.stringify(pendingBuilderState));
  }, 500);
}
```

#### 9. Zip Extraction Symlink Protection
**File:** `server.js:8950-8975`
**Issue:** Extracted archives could contain symlinks pointing outside workspace.
**Fix:** Added `scanForSymlinks()` function that removes symlinks after extraction.

#### 10. Enhanced Environment Validation
**File:** `server.js:20672-20720`
**Issue:** Limited production environment checks.
**Fix:** Enhanced validation with:
- Critical variables check (DATABASE_ENCRYPTION_KEY added)
- Recommended variables warnings
- Better console output formatting

### Medium Priority Fixes (Fixed)

#### 11. Dangerous File Type Blocking in Zip Extraction
**File:** `server.js:8922-8927`
**Fix:** Added blocking of potentially dangerous file types:
- `.exe`, `.bat`, `.cmd`, `.sh`, `.ps1`, `.vbs`

## Files Modified

1. `chat/server.js` - Main server file (multiple fixes)
2. `chat/src/database/connection.js` - Database connection with SQLCipher validation
3. `chat/src/external-admin-api/handlers.js` - JSON body size limit
4. `chat/public/builder.js` - State persistence debouncing

## Remaining Recommendations (Non-Critical)

These are recommended but not critical for launch:

### Post-Launch Items

1. **OAuth State in Database** - Currently stored in memory, will be lost on restart/multi-instance
2. **Atomic Token Operations** - Consider using database transactions for high-concurrency scenarios
3. **2FA for Admin** - Add two-factor authentication requirement for admin accounts
4. **IP-Based Admin Restrictions** - Consider limiting admin panel access by IP

## Testing Performed

- Webhook signature verification with various buffer lengths
- Session persistence across simulated restarts
- SQLCipher key validation with various formats
- JSON body parsing with oversized payloads
- Builder state persistence under rapid changes
- Zip extraction with path traversal attempts

## Verification Steps

1. **Webhook Test:**
```bash
curl -X POST http://localhost:4000/webhooks/dodo \
  -H "dodo-signature: sha256_invalid" \
  -d '{"test": true}'
# Should return 401, not crash
```

2. **Session Persistence Test:**
- Start server
- Login as user
- Restart server
- Verify session still valid

3. **SQLCipher Test:**
```bash
# Valid key
DATABASE_ENCRYPTION_KEY=0123456789abcdef0123456789abcdef node server.js
# Invalid key should fail with clear error
DATABASE_ENCRYPTION_KEY="invalid!key" node server.js
```

## Conclusion

All critical and high-priority security and functionality issues have been addressed. The application is now ready for launch with the following improvements:

- Robust webhook handling
- Persistent session secrets
- Validated SQLCipher keys
- Protected JSON parsing
- CORS support
- Automatic cleanup of stale data
- Better error handling and user feedback