Title: [244002] releases/WebKitGTK/webkit-2.24
Revision
244002
Author
carlo...@webkit.org
Date
2019-04-08 05:38:43 -0700 (Mon, 08 Apr 2019)

Log Message

Merge r242917 - Fix an edge case where HTMLFormElement::removeFormElement is invoked twice with the same element
https://bugs.webkit.org/show_bug.cgi?id=195663
<rdar://problem/48576391>

Reviewed by Ryosuke Niwa.

Source/WebCore:

Currently, it's possible for HTMLFormControlElement's destructor to be reentrant. This may happen if the form
control element is ref'd while carrying out its destructor's logic. This may happen in two places in
HTMLFormControlElement (didChangeForm and resetDefaultButton), both of which actually don't require ensuring a
protected reference to the form control element since they should never result in any script execution.

To fix the bug, convert these strong references into raw pointers, and add ScriptDisallowedScope to ensure that
we don't change these codepaths in the future, such that they trigger arbitrary script execution.

Test: fast/forms/remove-associated-element-after-gc.html

* html/HTMLFormControlElement.cpp:
(WebCore::HTMLFormControlElement::didChangeForm):
* html/HTMLFormElement.cpp:
(WebCore::HTMLFormElement::resetDefaultButton):

LayoutTests:

Add a layout test to exercise the scenario described in the WebCore ChangeLog.

* fast/forms/remove-associated-element-after-gc-expected.txt: Added.
* fast/forms/remove-associated-element-after-gc.html: Added.

Modified Paths

Added Paths

Diff

Modified: releases/WebKitGTK/webkit-2.24/LayoutTests/ChangeLog (244001 => 244002)


--- releases/WebKitGTK/webkit-2.24/LayoutTests/ChangeLog	2019-04-08 12:38:37 UTC (rev 244001)
+++ releases/WebKitGTK/webkit-2.24/LayoutTests/ChangeLog	2019-04-08 12:38:43 UTC (rev 244002)
@@ -1,3 +1,16 @@
+2019-03-13  Wenson Hsieh  <wenson_hs...@apple.com>
+
+        Fix an edge case where HTMLFormElement::removeFormElement is invoked twice with the same element
+        https://bugs.webkit.org/show_bug.cgi?id=195663
+        <rdar://problem/48576391>
+
+        Reviewed by Ryosuke Niwa.
+
+        Add a layout test to exercise the scenario described in the WebCore ChangeLog.
+
+        * fast/forms/remove-associated-element-after-gc-expected.txt: Added.
+        * fast/forms/remove-associated-element-after-gc.html: Added.
+
 2019-04-03  Michael Catanzaro  <mcatanz...@igalia.com>
 
         Get rid of HTMLInputElement::setEditingValue

Added: releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc-expected.txt (0 => 244002)


--- releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc-expected.txt	                        (rev 0)
+++ releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc-expected.txt	2019-04-08 12:38:43 UTC (rev 244002)
@@ -0,0 +1 @@
+PASS

Added: releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc.html (0 => 244002)


--- releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc.html	                        (rev 0)
+++ releases/WebKitGTK/webkit-2.24/LayoutTests/fast/forms/remove-associated-element-after-gc.html	2019-04-08 12:38:43 UTC (rev 244002)
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+input:default {
+    color: red;
+}
+</style>
+</head>
+<body>
+<table>
+<form><input type="submit"></form>
+</table>
+<p>This test passes if we avoid crashing, and if the green text "PASS" appears. This test requires DumpRenderTree or WebKitTestRunner.</p>
+</body>
+<script>
+if (window.testRunner) {
+    testRunner.waitUntilDone();
+    testRunner.dumpAsText();
+}
+
+document.addEventListener("DOMContentLoaded", () => {
+    let currentIteration = 1;
+    const href = ""
+    const index = href.lastIndexOf("#");
+    if (index !== -1)
+        currentIteration = parseInt(href.substring(index + 1));
+
+    if (currentIteration === 5) {
+        document.writeln("<pre style='color: green'>PASS</pre>");
+        if (window.testRunner)
+            testRunner.notifyDone();
+        return;
+    }
+
+    if (window.GCController)
+        GCController.collect();
+
+    location.href = "" index)}#${currentIteration + 1}`;
+    location.reload();
+}, false);
+</script>
+</html>

Modified: releases/WebKitGTK/webkit-2.24/Source/WebCore/ChangeLog (244001 => 244002)


--- releases/WebKitGTK/webkit-2.24/Source/WebCore/ChangeLog	2019-04-08 12:38:37 UTC (rev 244001)
+++ releases/WebKitGTK/webkit-2.24/Source/WebCore/ChangeLog	2019-04-08 12:38:43 UTC (rev 244002)
@@ -1,3 +1,26 @@
+2019-03-13  Wenson Hsieh  <wenson_hs...@apple.com>
+
+        Fix an edge case where HTMLFormElement::removeFormElement is invoked twice with the same element
+        https://bugs.webkit.org/show_bug.cgi?id=195663
+        <rdar://problem/48576391>
+
+        Reviewed by Ryosuke Niwa.
+
+        Currently, it's possible for HTMLFormControlElement's destructor to be reentrant. This may happen if the form
+        control element is ref'd while carrying out its destructor's logic. This may happen in two places in
+        HTMLFormControlElement (didChangeForm and resetDefaultButton), both of which actually don't require ensuring a
+        protected reference to the form control element since they should never result in any script execution.
+
+        To fix the bug, convert these strong references into raw pointers, and add ScriptDisallowedScope to ensure that
+        we don't change these codepaths in the future, such that they trigger arbitrary script execution.
+
+        Test: fast/forms/remove-associated-element-after-gc.html
+
+        * html/HTMLFormControlElement.cpp:
+        (WebCore::HTMLFormControlElement::didChangeForm):
+        * html/HTMLFormElement.cpp:
+        (WebCore::HTMLFormElement::resetDefaultButton):
+
 2019-04-04  Miguel Gomez  <mago...@igalia.com>
 
         [GTK][WPE] Use a timer to request the creation of pending tiles

Modified: releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormControlElement.cpp (244001 => 244002)


--- releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormControlElement.cpp	2019-04-08 12:38:37 UTC (rev 244001)
+++ releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormControlElement.cpp	2019-04-08 12:38:43 UTC (rev 244002)
@@ -40,6 +40,7 @@
 #include "HTMLTextAreaElement.h"
 #include "RenderBox.h"
 #include "RenderTheme.h"
+#include "ScriptDisallowedScope.h"
 #include "Settings.h"
 #include "StyleTreeResolver.h"
 #include "ValidationMessage.h"
@@ -556,8 +557,10 @@
 
 void HTMLFormControlElement::didChangeForm()
 {
+    ScriptDisallowedScope::InMainThread scriptDisallowedScope;
+
     FormAssociatedElement::didChangeForm();
-    if (RefPtr<HTMLFormElement> form = this->form()) {
+    if (auto* form = this->form()) {
         if (m_willValidateInitialized && m_willValidate && !isValidFormControlElement())
             form->registerInvalidAssociatedFormControl(*this);
     }

Modified: releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormElement.cpp (244001 => 244002)


--- releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormElement.cpp	2019-04-08 12:38:37 UTC (rev 244001)
+++ releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormElement.cpp	2019-04-08 12:38:43 UTC (rev 244002)
@@ -704,7 +704,9 @@
         return;
     }
 
-    RefPtr<HTMLFormControlElement> oldDefault = m_defaultButton;
+    ScriptDisallowedScope::InMainThread scriptDisallowedScope;
+
+    auto* oldDefault = m_defaultButton;
     m_defaultButton = nullptr;
     defaultButton();
     if (m_defaultButton != oldDefault) {
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