1 files changed, 94 insertions, 0 deletions
diff --git a/src/js/contentscripts/clobberlocalstorage.js b/src/js/contentscripts/clobberlocalstorage.js
new file mode 100644
index 0000000..7ff3528
--- /dev/null
+++ b/src/js/contentscripts/clobberlocalstorage.js
@@ -0,0 +1,94 @@
+/*
+ * This file is part of Privacy Badger <https://www.eff.org/privacybadger>
+ * Copyright (C) 2014 Electronic Frontier Foundation
+ *
+ * Privacy Badger is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Privacy Badger is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Privacy Badger.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+(function () {
+
+// don't inject into non-HTML documents (such as XML documents)
+// but do inject into XHTML documents
+if (document instanceof HTMLDocument === false && (
+  document instanceof XMLDocument === false ||
+  document.createElement('div') instanceof HTMLDivElement === false
+)) {
+  return;
+}
+
+// don't bother asking to run when trivially in first-party context
+if (window.top == window) {
+  return;
+}
+
+// TODO race condition; fix waiting on https://crbug.com/478183
+chrome.runtime.sendMessage({
+  type: "checkLocation",
+  frameUrl: window.FRAME_URL
+}, function (blocked) {
+  if (blocked) {
+    // https://stackoverflow.com/questions/49092423/how-to-break-on-localstorage-changes
+    var code =
+      '('+ function() {
+
+        /*
+         * If localStorage is inaccessible, such as when "Block third-party cookies"
+         * in enabled in Chrome or when `dom.storage.enabled` is set to `false` in
+         * Firefox, do not go any further.
+         */
+        try {
+          // No localStorage raises an Exception in Chromium-based browsers, while
+          // it's equal to `null` in Firefox.
+          if (null === localStorage) {
+            throw false;
+          }
+        } catch (ex) {
+          return;
+        }
+
+        let lsProxy = new Proxy(localStorage, {
+          set: function (/*ls, prop, value*/) {
+            return true;
+          },
+          get: function (ls, prop) {
+            if (typeof ls[prop] == 'function') {
+              let fn = function () {};
+              if (prop == 'getItem' || prop == 'key') {
+                fn = function () { return null; };
+              }
+              return fn.bind(ls);
+            } else {
+              if (prop == 'length') {
+                return 0;
+              } else if (prop == '__proto__') {
+                return lsProxy;
+              }
+              return;
+            }
+          }
+        });
+
+        Object.defineProperty(window, 'localStorage', {
+          configurable: true,
+          enumerable: true,
+          value: lsProxy
+        });
+
+      } +')()';
+
+    window.injectScript(code);
+  }
+  return true;
+});
+
+}());