Changeset 243684 in webkit

Timestamp:

Mar 31, 2019, 1:01:44 PM (7 years ago)

Author:

Wenson Hsieh

Message:

[iOS] Crash when changing inputmode for certain types of focusable elements
​https://bugs.webkit.org/show_bug.cgi?id=196431
<rdar://problem/49454962>

Reviewed by Tim Horton.

Source/WebKit:

The crash is happening because WebPage::focusedElementDidChangeInputMode assumes that the document's focused
element must be the same as m_focusedElement in WebPage. However, this is not the case, since m_focusedElement
is only set for certain types of elements that require user input (e.g. text fields, editable content, select
menus, etc.). The function then attempts to dereference m_focusedElement, which may be null if the document's
focused element doesn't fall into one of the aforementioned categories.

To fix this, bail if the element that is changing inputmode is not equal to the WebPage's current focused
element. See below for more details.

Test: fast/forms/change-inputmode-crash.html

• WebProcess/WebPage/WebPage.cpp:

(WebKit::isTextFormControlOrEditableContent):

Clean up some existing logic by introducing a helper method for determining whether an element should
propagate inputmode attribute changes to the UI process. Also, check the element type using type traits instead
of checking against the tag name.

(WebKit::WebPage::elementDidFocus):
(WebKit::WebPage::focusedElementDidChangeInputMode):

LayoutTests:

Add a layout test that exercises the edge case; see WebKit ChangeLogs for more details.

• fast/forms/change-inputmode-crash-expected.txt: Added.
• fast/forms/change-inputmode-crash.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/forms/change-inputmode-crash-expected.txt (added)
• LayoutTests/fast/forms/change-inputmode-crash.html (added)
• Source/WebKit/ChangeLog (modified) (1 diff)
• Source/WebKit/WebProcess/WebPage/WebPage.cpp (modified) (4 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2019-03-31  Wenson Hsieh  <wenson_hsieh@apple.com>
+
+        [iOS] Crash when changing inputmode for certain types of focusable elements
+        https://bugs.webkit.org/show_bug.cgi?id=196431
+        <rdar://problem/49454962>
+
+        Reviewed by Tim Horton.
+
+        Add a layout test that exercises the edge case; see WebKit ChangeLogs for more details.
+
+        * fast/forms/change-inputmode-crash-expected.txt: Added.
+        * fast/forms/change-inputmode-crash.html: Added.
+
 2019-03-29  Dean Jackson  <dino@apple.com>
 

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2019-03-31  Wenson Hsieh  <wenson_hsieh@apple.com>
+
+        [iOS] Crash when changing inputmode for certain types of focusable elements
+        https://bugs.webkit.org/show_bug.cgi?id=196431
+        <rdar://problem/49454962>
+
+        Reviewed by Tim Horton.
+
+        The crash is happening because WebPage::focusedElementDidChangeInputMode assumes that the document's focused
+        element must be the same as m_focusedElement in WebPage. However, this is not the case, since m_focusedElement
+        is only set for certain types of elements that require user input (e.g. text fields, editable content, select
+        menus, etc.). The function then attempts to dereference m_focusedElement, which may be null if the document's
+        focused element doesn't fall into one of the aforementioned categories.
+
+        To fix this, bail if the element that is changing inputmode is not equal to the WebPage's current focused
+        element. See below for more details.
+
+        Test: fast/forms/change-inputmode-crash.html
+
+        * WebProcess/WebPage/WebPage.cpp:
+        (WebKit::isTextFormControlOrEditableContent):
+
+        Clean up some existing logic by introducing a helper method for determining whether an element should
+        propagate inputmode attribute changes to the UI process. Also, check the element type using type traits instead
+        of checking against the tag name.
+
+        (WebKit::WebPage::elementDidFocus):
+        (WebKit::WebPage::focusedElementDidChangeInputMode):
+
 2019-03-31  Sam Weinig  <weinig@apple.com>
 

trunk/Source/WebKit/WebProcess/WebPage/WebPage.cpp

@@ -174 +174 @@
 #include <WebCore/HTMLPlugInElement.h>
 #include <WebCore/HTMLPlugInImageElement.h>
+#include <WebCore/HTMLSelectElement.h>
 #include <WebCore/HTMLTextAreaElement.h>
+#include <WebCore/HTMLTextFormControlElement.h>
 #include <WebCore/HTMLUListElement.h>
 #include <WebCore/HistoryController.h>
@@ -5346 +5348 @@
 }
 
+static bool isTextFormControlOrEditableContent(const WebCore::Element& element)
+{
+    return is<HTMLTextFormControlElement>(element) || element.hasEditableStyle();
+}
+
 void WebPage::elementDidFocus(WebCore::Element& element)
 {
@@ -5354 +5361 @@
     }
 
-    if (element.hasTagName(WebCore::HTMLNames::selectTag) || element.hasTagName(WebCore::HTMLNames::inputTag) || element.hasTagName(WebCore::HTMLNames::textareaTag) || element.hasEditableStyle()) {
+    if (is<HTMLSelectElement>(element) || isTextFormControlOrEditableContent(element)) {
         m_focusedElement = &element;
 
@@ -5400 +5407 @@
 void WebPage::focusedElementDidChangeInputMode(WebCore::Element& element, WebCore::InputMode mode)
 {
+    if (m_focusedElement != &element)
+        return;
+
 #if PLATFORM(IOS_FAMILY)
-    ASSERT(m_focusedElement == &element);
     ASSERT(is<HTMLElement>(element));
     ASSERT(downcast<HTMLElement>(element).canonicalInputMode() == mode);
 
-    if (!is<HTMLTextAreaElement>(*m_focusedElement) && !is<HTMLInputElement>(*m_focusedElement) && !m_focusedElement->hasEditableStyle())
+    if (!isTextFormControlOrEditableContent(element))
         return;
 
     send(Messages::WebPageProxy::FocusedElementDidChangeInputMode(mode));
 #else
-    UNUSED_PARAM(element);
     UNUSED_PARAM(mode);
 #endif