🔐 fix: Image Validation when Reusing OpenID Token (#9458)

* 🔧 fix: Enhance OpenID token handling with user ID for image path validation

* 🔧 fix: Change logger level to error for user info fetch failure and remove redundant info log in OpenID user lookup

* 🔧 refactor: Remove validateImageRequest from middleware exports and enhance validation logic in validateImageRequest.js

* Removed validateImageRequest from the middleware index.
* Improved error handling and validation checks in validateImageRequest.js, including handling of OpenID tokens, URL length, and malformed URLs.
* Updated tests in validateImages.spec.js to cover new validation scenarios and edge cases.

api/server/middleware/validateImageRequest.js

@@ -1,7 +1,7 @@
 const cookies = require('cookie');
 const jwt = require('jsonwebtoken');
+const { isEnabled } = require('@librechat/api');
 const { logger } = require('@librechat/data-schemas');
-const { getAppConfig } = require('~/server/services/Config/app');
 
 const OBJECT_ID_LENGTH = 24;
 const OBJECT_ID_PATTERN = /^[0-9a-f]{24}$/i;
@@ -22,50 +22,129 @@ function isValidObjectId(id) {
 }
 
 /**
- * Middleware to validate image request.
- * Must be set by `secureImageLinks` via custom config file.
+ * Validates a LibreChat refresh token
+ * @param {string} refreshToken - The refresh token to validate
+ * @returns {{valid: boolean, userId?: string, error?: string}} - Validation result
  */
-async function validateImageRequest(req, res, next) {
-  const appConfig = await getAppConfig({ role: req.user?.role });
-  if (!appConfig.secureImageLinks) {
-    return next();
-  }
-
-  const refreshToken = req.headers.cookie ? cookies.parse(req.headers.cookie).refreshToken : null;
-  if (!refreshToken) {
-    logger.warn('[validateImageRequest] Refresh token not provided');
-    return res.status(401).send('Unauthorized');
-  }
-
-  let payload;
+function validateToken(refreshToken) {
   try {
-    payload = jwt.verify(refreshToken, process.env.JWT_REFRESH_SECRET);
+    const payload = jwt.verify(refreshToken, process.env.JWT_REFRESH_SECRET);
+
+    if (!isValidObjectId(payload.id)) {
+      return { valid: false, error: 'Invalid User ID' };
+    }
+
+    const currentTimeInSeconds = Math.floor(Date.now() / 1000);
+    if (payload.exp < currentTimeInSeconds) {
+      return { valid: false, error: 'Refresh token expired' };
+    }
+
+    return { valid: true, userId: payload.id };
   } catch (err) {
-    logger.warn('[validateImageRequest]', err);
-    return res.status(403).send('Access Denied');
-  }
-
-  if (!isValidObjectId(payload.id)) {
-    logger.warn('[validateImageRequest] Invalid User ID');
-    return res.status(403).send('Access Denied');
-  }
-
-  const currentTimeInSeconds = Math.floor(Date.now() / 1000);
-  if (payload.exp < currentTimeInSeconds) {
-    logger.warn('[validateImageRequest] Refresh token expired');
-    return res.status(403).send('Access Denied');
-  }
-
-  const fullPath = decodeURIComponent(req.originalUrl);
-  const pathPattern = new RegExp(`^/images/${payload.id}/[^/]+$`);
-
-  if (pathPattern.test(fullPath)) {
-    logger.debug('[validateImageRequest] Image request validated');
-    next();
-  } else {
-    logger.warn('[validateImageRequest] Invalid image path');
-    res.status(403).send('Access Denied');
+    logger.warn('[validateToken]', err);
+    return { valid: false, error: 'Invalid token' };
   }
 }
 
-module.exports = validateImageRequest;
+/**
+ * Factory to create the `validateImageRequest` middleware with configured secureImageLinks
+ * @param {boolean} [secureImageLinks] - Whether secure image links are enabled
+ */
+function createValidateImageRequest(secureImageLinks) {
+  if (!secureImageLinks) {
+    return (_req, _res, next) => next();
+  }
+  /**
+   * Middleware to validate image request.
+   * Supports both LibreChat refresh tokens and OpenID JWT tokens.
+   * Must be set by `secureImageLinks` via custom config file.
+   */
+  return async function validateImageRequest(req, res, next) {
+    try {
+      const cookieHeader = req.headers.cookie;
+      if (!cookieHeader) {
+        logger.warn('[validateImageRequest] No cookies provided');
+        return res.status(401).send('Unauthorized');
+      }
+
+      const parsedCookies = cookies.parse(cookieHeader);
+      const refreshToken = parsedCookies.refreshToken;
+
+      if (!refreshToken) {
+        logger.warn('[validateImageRequest] Token not provided');
+        return res.status(401).send('Unauthorized');
+      }
+
+      const tokenProvider = parsedCookies.token_provider;
+      let userIdForPath;
+
+      if (tokenProvider === 'openid' && isEnabled(process.env.OPENID_REUSE_TOKENS)) {
+        const openidUserId = parsedCookies.openid_user_id;
+        if (!openidUserId) {
+          logger.warn('[validateImageRequest] No OpenID user ID cookie found');
+          return res.status(403).send('Access Denied');
+        }
+
+        const validationResult = validateToken(openidUserId);
+        if (!validationResult.valid) {
+          logger.warn(`[validateImageRequest] ${validationResult.error}`);
+          return res.status(403).send('Access Denied');
+        }
+        userIdForPath = validationResult.userId;
+      } else {
+        const validationResult = validateToken(refreshToken);
+        if (!validationResult.valid) {
+          logger.warn(`[validateImageRequest] ${validationResult.error}`);
+          return res.status(403).send('Access Denied');
+        }
+        userIdForPath = validationResult.userId;
+      }
+
+      if (!userIdForPath) {
+        logger.warn('[validateImageRequest] No user ID available for path validation');
+        return res.status(403).send('Access Denied');
+      }
+
+      const MAX_URL_LENGTH = 2048;
+      if (req.originalUrl.length > MAX_URL_LENGTH) {
+        logger.warn('[validateImageRequest] URL too long');
+        return res.status(403).send('Access Denied');
+      }
+
+      if (req.originalUrl.includes('\x00')) {
+        logger.warn('[validateImageRequest] URL contains null byte');
+        return res.status(403).send('Access Denied');
+      }
+
+      let fullPath;
+      try {
+        fullPath = decodeURIComponent(req.originalUrl);
+      } catch {
+        logger.warn('[validateImageRequest] Invalid URL encoding');
+        return res.status(403).send('Access Denied');
+      }
+
+      const agentAvatarPattern = /^\/images\/[a-f0-9]{24}\/agent-[^/]*$/;
+      if (agentAvatarPattern.test(fullPath)) {
+        logger.debug('[validateImageRequest] Image request validated');
+        return next();
+      }
+
+      const escapedUserId = userIdForPath.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+      const pathPattern = new RegExp(`^/images/${escapedUserId}/[^/]+$`);
+
+      if (pathPattern.test(fullPath)) {
+        logger.debug('[validateImageRequest] Image request validated');
+        next();
+      } else {
+        logger.warn('[validateImageRequest] Invalid image path');
+        res.status(403).send('Access Denied');
+      }
+    } catch (error) {
+      logger.error('[validateImageRequest] Error:', error);
+      res.status(500).send('Internal Server Error');
+    }
+  };
+}
+
+module.exports = createValidateImageRequest;