Changeset 244002 in webkit

Timestamp:

Apr 8, 2019, 5:38:43 AM (7 years ago)

Author:

Carlos Garcia Campos

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.

Location:

releases/WebKitGTK/webkit-2.24

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/forms/remove-associated-element-after-gc-expected.txt (added)
• LayoutTests/fast/forms/remove-associated-element-after-gc.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/html/HTMLFormControlElement.cpp (modified) (2 diffs)
• Source/WebCore/html/HTMLFormElement.cpp (modified) (1 diff)

releases/WebKitGTK/webkit-2.24/LayoutTests/ChangeLog

@@ +1 @@
+2019-03-13  Wenson Hsieh  <wenson_hsieh@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  <mcatanzaro@igalia.com>
 

releases/WebKitGTK/webkit-2.24/Source/WebCore/ChangeLog

@@ +1 @@
+2019-03-13  Wenson Hsieh  <wenson_hsieh@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  <magomez@igalia.com>
 

releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormControlElement.cpp

@@ -41 +41 @@
 #include "RenderBox.h"
 #include "RenderTheme.h"
+#include "ScriptDisallowedScope.h"
 #include "Settings.h"
 #include "StyleTreeResolver.h"
@@ -557 +558 @@
 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);

releases/WebKitGTK/webkit-2.24/Source/WebCore/html/HTMLFormElement.cpp

@@ -705 +705 @@
     }
 
-    RefPtr<HTMLFormControlElement> oldDefault = m_defaultButton;
+    ScriptDisallowedScope::InMainThread scriptDisallowedScope;
+
+    auto* oldDefault = m_defaultButton;
     m_defaultButton = nullptr;
     defaultButton();