Add a custom sanitization function for the "Tag" property (#546)

* Add a custom sanitization function for the tag property in create call body

* remove tag.* property from schema

* do not escape URLs but validate them

* apply suggestions from PR review

---------

Co-authored-by: Markus Frindt <m.frindt@cognigy.com>

lib/http-routes/api/create-call.js

@@ -5,7 +5,7 @@ const CallInfo = require('../../session/call-info');
 const {CallDirection, CallStatus} = require('../../utils/constants');
 const uuidv4 = require('uuid-random');
 const SipError = require('drachtio-srf').SipError;
-const { validationResult } = require('express-validator');
+const { validationResult, body } = require('express-validator');
 const { validate } = require('@jambonz/verb-specifications');
 const sysError = require('./error');
 const HttpRequestor = require('../../utils/http-requestor');
@@ -13,7 +13,7 @@ const WsRequestor = require('../../utils/ws-requestor');
 const RootSpan = require('../../utils/call-tracer');
 const dbUtils = require('../../utils/db-utils');
 const { mergeSdpMedia, extractSdpMedia } = require('../../utils/sdp-utils');
-const { createCallSchema } = require('../schemas/create-call');
+const { createCallSchema, customSanitizeFunction } = require('../schemas/create-call');
 
 const removeNullProperties = (obj) => (Object.keys(obj).forEach((key) => obj[key] === null && delete obj[key]), obj);
 const removeNulls = (req, res, next) => {
@@ -24,6 +24,12 @@ const removeNulls = (req, res, next) => {
 router.post('/',
   removeNulls,
   createCallSchema,
+  body('tag').custom((value) => {
+    if (value) {
+      customSanitizeFunction(value);
+    }
+    return true;
+  }),
   async(req, res) => {
     const {logger} = req.app.locals;
     const errors = validationResult(req);

lib/http-routes/schemas/create-call.js

@@ -46,11 +46,6 @@ const createCallSchema = checkSchema({
     optional: true,
     errorMessage: 'Invalid tag',
   },
-  'tag.*': {
-    trim: true,
-    escape: true,
-    stripLow: true,
-  },
   app_json: {
     isString: true,
     optional: true,
@@ -109,6 +104,34 @@ const createCallSchema = checkSchema({
   }
 }, ['body']);
 
-module.exports = {
-  createCallSchema
+const customSanitizeFunction = (value) => {
+  try {
+    if (Array.isArray(value)) {
+      value = value.map((item) => customSanitizeFunction(item));
+    } else if (typeof value === 'object') {
+      Object.keys(value).forEach((key) => {
+        value[key] = customSanitizeFunction(value[key]);
+      });
+    } else if (typeof value === 'string') {
+      /* trims characters at the beginning and at the end of a string */
+      value = value.trim();
+
+      /* We don't escape URLs but verify them via new URL */
+      if (value.includes('http')) {
+        value = new URL(value).toString();
+      } else {
+        /* replaces <, >, &, ', " and / with their corresponding HTML entities */
+        value = escape(value);
+      }
+    }
+  } catch (error) {
+    value = `Error: ${error.message}`;
+  }
+
+  return value;
+};
+
+module.exports = {
+  createCallSchema,
+  customSanitizeFunction
 };