[Webkit-unassigned] [Bug 52147] New: WebCore::ImageDocumentParser::appendBytes ReadAV at NULL (d3eaf04ec8c67346dfeface66b7dc103)

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=52147

           Summary: WebCore::ImageDocumentParser::appendBytes ReadAV at NULL
                    (d3eaf04ec8c67346dfeface66b7dc103)
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: PC
        OS/Version: Windows Vista
            Status: NEW
          Severity: Normal
          Priority: P1
         Component: HTML DOM
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: skylined at chromium.org
                CC: eric at webkit.org


Created an attachment (id=78398)
 --> (https://bugs.webkit.org/attachment.cgi?id=78398&action=review)
Repro

Repro:
<script>
oWin = window.open('repro.gif');
setTimeout(function() {
  var oBody = oWin.document.body;
  oWin.document.open();
  oWin.document.createRange().surroundContents(oBody);
  oWin.document.close();
}, 1000);
</script>
Repro.gif must be a file served with an image mime type, eg. "image/gif", but which is not a valid image. That way Chromium creates an ImageDocument in the same domain as the main document, but the image element can become NULL.

id:             chrome.dll!WebCore::ImageDocumentParser::appendBytes ReadAV at NULL (d3eaf04ec8c67346dfeface66b7dc103)
description:    Attempt to read from unallocated NULL pointer+0x44 in chrome.dll!WebCore::ImageDocumentParser::appendBytes
stack:          chrome.dll!WebCore::ImageDocumentParser::appendBytes
                chrome.dll!WebCore::DocumentWriter::endIfNotLoadingMainResource
                chrome.dll!WebCore::Document::close
                chrome.dll!WebCore::HTMLDocumentInternal::closeCallback
                chrome.dll!v8::internal::HandleApiCallHelper<...>
                chrome.dll!v8::internal::Builtin_HandleApiCall
                chrome.dll!v8::internal::Invoke
                chrome.dll!v8::internal::Execution::Call
                ...

Here's the problem:
CachedImage* ImageDocument::cachedImage()
{ 
    if (!m_imageElement)
        createDocumentStructure();

    return m_imageElement->cachedImage();
}

This code assumes that if m_imageElement is NULL, createDocumentStructure() will set m_imageElement to something non-NULL. However, it appears this is not the case if the image is invalid, which can lead to NULL ptrs.

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