Bug 1322862 - Make __webDriverArguments et al. content safe. r=automatedtester, a=test-only
authorAndreas Tolfsen <ato@mozilla.com>
Sat, 10 Dec 2016 16:15:53 -1000
changeset 480398 4786fd72894dc9c5f0f862eb240ce6c893d9a7be
parent 480397 9ee72b7bb80424b810d55de40a749338b6731a2b
child 480399 55fa23c4fe239af7f1d94155ce4457cd56951622
push id44524
push usermartin.thomson@gmail.com
push dateWed, 08 Feb 2017 05:10:11 +0000
reviewersautomatedtester, test-only
bugs1322862
milestone52.0
Bug 1322862 - Make __webDriverArguments et al. content safe. r=automatedtester, a=test-only Properties created in a more privileged scope than content cause permission denied errors when they are accessed from a less privileged scope. This is the case when we assign a document unload handler from chrome to a sandbox with content privileges. A permission denied error will be thrown if this handler is inspected from the code evaluated inside the sandbox. By cloning the properties along with their functions and wrapping their reflectors, we can ensure they can be safely inspected from content. MozReview-Commit-ID: Hy5MYvdTsv8
testing/marionette/evaluate.js
testing/marionette/harness/marionette_harness/tests/unit/test_execute_script.py
--- a/testing/marionette/evaluate.js
+++ b/testing/marionette/evaluate.js
@@ -108,17 +108,17 @@ evaluate.sandbox = function (sb, script,
     unloadHandler = () => reject(
         new JavaScriptError("Document was unloaded during execution"));
 
     // wrap in function
     if (!opts.directInject) {
       if (opts.async) {
         sb[CALLBACK] = sb[COMPLETE];
       }
-      sb[ARGUMENTS] = Cu.cloneInto(args, sb, {wrapReflectors: true});
+      sb[ARGUMENTS] = sandbox.cloneInto(args, sb);
 
       // callback function made private
       // so that introspection is possible
       // on the arguments object
       if (opts.async) {
         sb[CALLBACK] = sb[COMPLETE];
         src += `${ARGUMENTS}.push(rv => ${CALLBACK}(rv));`;
       }
@@ -133,30 +133,28 @@ evaluate.sandbox = function (sb, script,
     }
 
     // onerror is not hooked on by default because of the inability to
     // differentiate content errors from chrome errors.
     //
     // see bug 1128760 for more details
     if (opts.debug) {
       sb.window.onerror = (msg, url, line) => {
-        let err = new JavaScriptError(`${msg} at: ${url} line: ${line}`);
+        let err = new JavaScriptError(`${msg} at ${url}:${line}`);
         reject(err);
       };
     }
 
     // timeout and unload handlers
-    scriptTimeoutID = setTimeout(
-        timeoutHandler, opts.timeout || DEFAULT_TIMEOUT);
-    sb.window.addEventListener("unload", unloadHandler);
+    scriptTimeoutID = setTimeout(timeoutHandler, opts.timeout || DEFAULT_TIMEOUT);
+    sb.window.onunload = sandbox.cloneInto(unloadHandler, sb);
 
     let res;
     try {
-      res = Cu.evalInSandbox(
-          src, sb, "1.8", opts.filename || "dummy file", 0);
+      res = Cu.evalInSandbox(src, sb, "1.8", opts.filename || "dummy file", 0);
     } catch (e) {
       let err = new JavaScriptError(
           e,
           "execute_script",
           opts.filename,
           opts.line,
           script);
       reject(err);
@@ -172,16 +170,28 @@ evaluate.sandbox = function (sb, script,
     sb.window.removeEventListener("unload", unloadHandler);
     return res;
   });
 };
 
 this.sandbox = {};
 
 /**
+ * Provides a safe way to take an object defined in a privileged scope and
+ * create a structured clone of it in a less-privileged scope.  It returns
+ * a reference to the clone.
+ *
+ * Unlike for |Components.utils.cloneInto|, |obj| may contain functions
+ * and DOM elemnets.
+ */
+sandbox.cloneInto = function (obj, sb) {
+  return Cu.cloneInto(obj, sb, {cloneFunctions: true, wrapReflectors: true});
+};
+
+/**
  * Augment given sandbox by an adapter that has an {@code exports}
  * map property, or a normal map, of function names and function
  * references.
  *
  * @param {Sandbox} sb
  *     The sandbox to augment.
  * @param {Object} adapter
  *     Object that holds an {@code exports} property, or a map, of
--- a/testing/marionette/harness/marionette_harness/tests/unit/test_execute_script.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_execute_script.py
@@ -257,16 +257,27 @@ class TestExecuteContent(MarionetteTestC
             "return window.n", sandbox=None),
             "setTimeout already fired")
 
         # if event was cancelled, this will time out
         Wait(self.marionette, timeout=8).until(
             content_timeout_triggered,
             message="Scheduled setTimeout event was cancelled by call to execute_script")
 
+    def test_privileged_code_inspection(self):
+        # test permission denied on toString of unload event handler
+        self.marionette.navigate(inline("""
+            <script>
+            window.addEventListener = (type, handler) => handler.toString();
+            </script>"""))
+        self.marionette.execute_script("", sandbox=None)
+
+        # test inspection of arguments
+        self.marionette.execute_script("__webDriverArguments.toString()")
+
 
 class TestExecuteChrome(WindowManagerMixin, TestExecuteContent):
 
     def setUp(self):
         super(TestExecuteChrome, self).setUp()
 
         self.marionette.set_context("chrome")
 
@@ -332,16 +343,19 @@ class TestExecuteChrome(WindowManagerMix
         pass
 
     def test_return_web_element_nodelist(self):
         pass
 
     def test_window_set_timeout_is_not_cancelled(self):
         pass
 
+    def test_privileged_code_inspection(self):
+        pass
+
 
 class TestElementCollections(MarionetteTestCase):
 
     def assertSequenceIsInstance(self, seq, typ):
         for item in seq:
             self.assertIsInstance(item, typ)
 
     def test_array(self):