Node Express and csurf - 403 (Forbidden) invalid csrf token

Question

Looked through and tried everything I could find on here, and elsewhere by Googling...and I'm just not able to get past this. I'm using Node, Express, EJS, and attempting to use csurf on a form, that is posted w/ jQuery ajax. No matter how I configure csurf, I get "403 (Forbidden) invalid csrf token"

I've tried configuring both globally in app.js and in the controller. Here's what I tried in app.js:

var express = require('express');
var session  = require('express-session');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var mysql = require('mysql');
var flash = require("connect-flash");
var csrf = require("csurf");

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

app.use(logger('dev'));
app.use(cookieParser());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: false}));
app.use(session({
    secret: 'somethingsecret',
    resave: true,
    saveUninitialized: true,
    httpOnly: true,
    secure: false
}));
app.use(csrf());
app.use(function (req, res, next) {
    var token = req.csrfToken();
    res.cookie('XSRF-TOKEN', token);
    res.locals.csrfToken = token;
    console.log("csrf token = " + token);
    next();
});
app.use(flash());
app.use(express.static(path.join(__dirname, 'public')));

app.use(function (err, req, res, next) {
    if (err.code !== 'EBADCSRFTOKEN') return next(err);

    // handle CSRF token errors here
    res.status(403);
    res.send('form tampered with');
})

//routing
var routes = require('./routes/index');
var users = require('./routes/users');
var register = require('./routes/register');

app.use('/', routes);
app.use('/users', users);
app.use('/register', register);

...with this controller:

var express = require("express");
var router = express.Router();
var bodyParser = require("body-parser");
var userSvc = require("../service/userservice");

var jsonParser = bodyParser.json();

router.get("/", function(req, res, next) {
    console.log("token = " + token);
    userSvc.getAllPublicRoles(function(data) {
        res.render("register", {
            title: "Register a new account",
            roles: data
        });
    });
});

router.post("/new", jsonParser, function(req, res, next) {
    userSvc.addUser(req.body, function(result) {
        console.log("New user id = " + result.insertId);
        res.send('{"success" : "Updated Successfully", "status" : 200}');
    });
});

...and this view:

form:

<form id="registerForm" class="form-horizontal" method="post">
    <input type="hidden" name="_csrf" value="<%= csrfToken %>" />

ajax call:

        $.ajax({
            url: "/register/new",
            type: "POST",
            dataType: "json",
            data: user
        }).done(function(data) {
            if (data) {
                console.log("Success! = " + data);
            }
        }).fail(function(data) {
            console.log("Something went wrong: " + data.responseText);
        });

Then I just tried just doing everything in the controller, removing all references, calls, etc. from app.js, and using the same form and ajax call as above:

var express = require("express");
var router = express.Router();
var bodyParser = require("body-parser");
var csrf = require("csurf");
var userSvc = require("../service/userservice");

var csrfProtection = csrf();
var jsonParser = bodyParser.json();

router.get("/", csrfProtection, function(req, res, next) {
    var token = req.csrfToken();
    console.log("token = " + token);
    userSvc.getAllPublicRoles(function(data) {
        res.render("register", {
            title: "Register a new account",
            csrfToken: token,
            roles: data
        });
    });
});

router.post("/new", jsonParser, csrfProtection, function(req, res, next) {
    userSvc.addUser(req.body, function(result) {
        console.log("New user id = " + result.insertId);
        res.send('{"success" : "Updated Successfully", "status" : 200}');
    });
});

Not sure where to go from here. I've been using node for about two weeks, in my spare time, so pardon my ignorance here.

Answer 1

If you want to store the token in a cookie instead of the session, let csurf create the cookie for you e.g.

// Store the token in a cookie called '_csrf'
app.use(csrf({cookie: true));

// Make the token available to all views
app.use(function (req, res, next){
    res.locals._csrf = req.csrfToken();
    next();
});

Then you need to make sure the token is available when you're making the call using AJAX either via the POST'ed data, or as a custom request header such as 'xsrf-token'.

At the minute, you're providing the token to the form, but not the actual request (sent using AJAX).

For example, you could render the token in the AJAX setup:

$.ajaxSetup({
   headers: {"X-CSRF-Token": "{{csrfToken}}" }
}); 

Answer 2

After several more hours of troubleshooting and searching, I found a post that helped answer it. All I needed was to pass the header value in the ajax post. Makes sense, I just overlooked it. Like so:

<input type="hidden" id="_csrf" name="_csrf" value="<%= csrfToken %>" />

...and then in jQuery:

    $.ajaxSetup({
        headers: {"X-CSRF-Token": $("#_csrf").val()}
    });

Answer 3

An another approach over my personal project is to resend a new token when I sucessfully submit my form:

For example over my form (that does file upload) I have the follwing html:

<form id="upload_form" type="multipart/form-data" data-csrf="{{csrfToken}}" method="post" action="/data_assets">
  <input id="excell_upload" type="file" style="visible:hidden" name="data_assets"/>
</form>

And on file change I trigger the upload like that:

 $('#excell_upload').on('change',function(event){

      event.preventDefault();
      var formData = new FormData($("#upload_form")[0]);

      $.ajax({
        'type':$("#upload_form").attr('method'),
        'data': formData,
        'url': $("#upload_form").attr('action'),
        'processData': false,
        'contentType': false,
        'mimeType': 'multipart/form-data',
        'headers': {"X-CSRF-Token": $("#upload_form").attr('data-csrf') },
        'beforeSend': function (x) {
           if (x && x.overrideMimeType) {
               x.overrideMimeType("multipart/form-data");
          }
          $('#trigger_upload').addClass('disabled');
        },
        'success':function(data){
          $('#upload_form').attr('data-csrf',data.csrfToken)
        },
        'fail':function(){

        },
        'complete':function(){
          $('#trigger_upload').removeClass('disabled');
        }
      });
    });

As you notice I receive a new csrf token in order to be able to reuse my form for new submits. I regenerate the CSRF token like that:

app.post('/data_assets',function(req,res,next){
  res.json({'csrfToken':req.csrfToken()});
});