Fixing CSRF middleware for whitelisting

app.js

@@ -13,6 +13,11 @@ env.express(app);
 
 app.use(express.cookieParser());
 app.use(middleware.session());
+app.use(middleware.csrf({
+  whitelist: [
+    '/applications'
+  ]
+}));
 app.use(express.logger({stream:{
   write: function(msg, encoding) {
     logger.info(msg.trim());
@@ -20,7 +25,6 @@ app.use(express.logger({stream:{
 }}));
 app.use(express.compress());
 app.use(express.bodyParser());
-app.use(express.csrf());
 app.use(express.static(path.join(__dirname, 'static')));
 app.use(flash());
 

middleware.js

@@ -1,3 +1,4 @@
+var errors = require('./lib/errors');
 var express = require('express');
 var _ = require('underscore');
 
@@ -25,3 +26,57 @@ exports.session = function session (config) {
     })
   });
 };
+
+exports.csrf = function (options) {
+  options = options || {};
+  var value = options.value || defaultCsrfValue;
+  var list = options.whitelist;
+  return function (req, res, next) {
+    if (whitelisted(list, req.url))
+      return next();
+
+    var token = req.session._csrf || (req.session._csrf = uid(24));
+
+    if ('GET' === req.method || 'HEAD' === req.method)
+      return next();
+
+    var val = value(req);
+    if (val != token) {
+      // logger.debug("CSRF token failure");
+      return next(errors.Forbidden());
+    }
+    next();
+  };
+};
+
+function defaultCsrfValue (req) {
+  return (req.body && req.body._csrf)
+    || (req.query && req.query._csrf)
+    || (req.headers['x-csrf-token']);
+}
+
+function whitelisted (list, input) {
+  var pattern;
+
+  for (var i = list.length; i--;) {
+    pattern = list[i];
+    if (RegExp('^' + list[i] + '$').test(input))
+      return true;
+  }
+
+  return false;
+}
+
+function uid (len) {
+  var buf = [];
+  var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+  var charlen = chars.length;
+  for (var i = 0; i < len; ++i) {
+    buf.push(chars[getRandomInt(0, charlen - 1)]);
+  }
+  return buf.join('');
+};
+
+function getRandomInt (min, max) {
+  return Math.floor(Math.random() * (max - min + 1)) + min;
+}