Merge pull request #1327 from vinodkiran/BUGFIX/XSS

Bugfix/xss

packages/server/src/index.ts

@@ -58,6 +58,7 @@ import { CachePool } from './CachePool'
 import { ICommonObject, IMessage, INodeOptionsValue } from 'flowise-components'
 import { createRateLimiter, getRateLimiter, initializeRateLimiter } from './utils/rateLimit'
 import { addAPIKey, compareKeys, deleteAPIKey, getApiKey, getAPIKeys, updateAPIKey } from './utils/apiKey'
+import { sanitizeMiddleware } from './utils/XSS'
 import axios from 'axios'
 import { Client } from 'langchainhub'
 import { parsePrompt } from './utils/hub'
@@ -118,9 +119,15 @@ export class App {
         // Allow access from *
         this.app.use(cors())
 
+        // Switch off the default 'X-Powered-By: Express' header
+        this.app.disable('x-powered-by')
+
         // Add the expressRequestLogger middleware to log all requests
         this.app.use(expressRequestLogger)
 
+        // Add the sanitizeMiddleware to guard against XSS
+        this.app.use(sanitizeMiddleware)
+
         if (process.env.FLOWISE_USERNAME && process.env.FLOWISE_PASSWORD) {
             const username = process.env.FLOWISE_USERNAME
             const password = process.env.FLOWISE_PASSWORD
@@ -967,6 +974,12 @@ export class App {
         // Download file from assistant
         this.app.post('/api/v1/openai-assistants-file', async (req: Request, res: Response) => {
             const filePath = path.join(getUserHome(), '.flowise', 'openai-assistant', req.body.fileName)
+            //raise error if file path is not absolute
+            if (!path.isAbsolute(filePath)) return res.status(500).send(`Invalid file path`)
+            //raise error if file path contains '..'
+            if (filePath.includes('..')) return res.status(500).send(`Invalid file path`)
+            //only return from the .flowise openai-assistant folder
+            if (!(filePath.includes('.flowise') && filePath.includes('openai-assistant'))) return res.status(500).send(`Invalid file path`)
             res.setHeader('Content-Disposition', 'attachment; filename=' + path.basename(filePath))
             const fileStream = fs.createReadStream(filePath)
             fileStream.pipe(res)

packages/server/src/utils/XSS.ts

@@ -0,0 +1,13 @@
+import { Request, Response, NextFunction } from 'express'
+import sanitizeHtml from 'sanitize-html'
+
+export function sanitizeMiddleware(req: Request, res: Response, next: NextFunction): void {
+    // decoding is necessary as the url is encoded by the browser
+    const decodedURI = decodeURI(req.url)
+    req.url = sanitizeHtml(decodedURI)
+    for (let p in req.query) {
+        req.query[p] = sanitizeHtml(req.query[p] as string)
+    }
+
+    next()
+}