From 1e45f2d4e134d3ff5ced2b48f10dd2b4d7d76afa Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Fri, 15 Jan 2016 15:05:46 -0600
Subject: [PATCH] Wraps worker script if its cross-origin location is detected.

---
 src/display/api.js | 17 +++++++++++++++++
 src/shared/util.js | 16 ++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/display/api.js b/src/display/api.js
index 864a80ebe..74f0f87ed 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -48,6 +48,7 @@ var error = sharedUtil.error;
 var deprecated = sharedUtil.deprecated;
 var info = sharedUtil.info;
 var isArrayBuffer = sharedUtil.isArrayBuffer;
+var isSameOrigin = sharedUtil.isSameOrigin;
 var loadJpegStream = sharedUtil.loadJpegStream;
 var stringToBytes = sharedUtil.stringToBytes;
 var warn = sharedUtil.warn;
@@ -1226,6 +1227,14 @@ var PDFWorker = (function PDFWorkerClosure() {
     return PDFJS.fakeWorkerFilesLoadedCapability.promise;
   }
 
+  function createCDNWrapper(url) {
+    // We will rely on blob URL's property to specify origin.
+    // We want this function to fail in case if createObjectURL or Blob do not
+    // exist or fail for some reason -- our Worker creation will fail anyway.
+    var wrapper = 'importScripts(\'' + url + '\');';
+    return URL.createObjectURL(new Blob([wrapper]));
+  }
+
   function PDFWorker(name) {
     this.name = name;
     this.destroyed = false;
@@ -1261,6 +1270,14 @@ var PDFWorker = (function PDFWorkerClosure() {
         var workerSrc = getWorkerSrc();
 
         try {
+//#if GENERIC
+//        // Wraps workerSrc path into blob URL, if the former does not belong
+//        // to the same origin.
+//        if (!isSameOrigin(window.location.href, workerSrc)) {
+//          workerSrc = createCDNWrapper(
+//            combineUrl(window.location.href, workerSrc));
+//        }
+//#endif
           // Some versions of FF can't create a worker on localhost, see:
           // https://bugzilla.mozilla.org/show_bug.cgi?id=683280
           var worker = new Worker(workerSrc);
diff --git a/src/shared/util.js b/src/shared/util.js
index 286968881..ce7e79598 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -293,6 +293,21 @@ function combineUrl(baseUrl, url) {
   return new URL(url, baseUrl).href;
 }
 
+// Checks if URLs have the same origin. For non-HTTP based URLs, returns false.
+function isSameOrigin(baseUrl, otherUrl) {
+  try {
+    var base = new URL(baseUrl);
+    if (!base.origin || base.origin === 'null') {
+      return false; // non-HTTP url
+    }
+  } catch (e) {
+    return false;
+  }
+
+  var other = new URL(otherUrl, base);
+  return base.origin === other.origin;
+}
+
 // Validates if URL is safe and allowed, e.g. to avoid XSS.
 function isValidUrl(url, allowRelative) {
   if (!url) {
@@ -2291,6 +2306,7 @@ exports.isExternalLinkTargetSet = isExternalLinkTargetSet;
 exports.isInt = isInt;
 exports.isNum = isNum;
 exports.isString = isString;
+exports.isSameOrigin = isSameOrigin;
 exports.isValidUrl = isValidUrl;
 exports.loadJpegStream = loadJpegStream;
 exports.log2 = log2;