[webkit-changes] [WebKit/WebKit] 633fbf: Use-after-free in FullscreenManager::requestFullsc...

[aestes]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 633fbf1eab41bddec1989aadbb319a65200f6633
      https://github.com/WebKit/WebKit/commit/633fbf1eab41bddec1989aadbb319a65200f6633
  Author: Andy Estes <aestes at apple.com>
  Date:   2023-12-19 (Tue, 19 Dec 2023)

  Changed paths:
    A LayoutTests/fullscreen/fullscreen-cancel-after-request-crash-expected.txt
    A LayoutTests/fullscreen/fullscreen-cancel-after-request-crash.html
    M Source/WebCore/dom/FullscreenManager.cpp

  Log Message:
  -----------
  Use-after-free in FullscreenManager::requestFullscreenForElement
https://bugs.webkit.org/show_bug.cgi?id=263140
rdar://116736343

Reviewed by Chris Dumez.

Calling DeferredPromise::reject from the failedPreflights lambda in
FullscreenManager::requestFullscreenForElement may cause the Document that owns the
FullscreenManager to be deallocated, resulting in a use-after-free when the document is accessed
again after rejecting the promise. Resolved this by keeping a Ref to m_document for the lifetime of
the failedPreflights lambda.

Added a layout test.

* LayoutTests/fullscreen/fullscreen-cancel-after-request-crash-expected.txt: Added.
* LayoutTests/fullscreen/fullscreen-cancel-after-request-crash.html: Added.
* Source/WebCore/dom/FullscreenManager.cpp:
(WebCore::FullscreenManager::requestFullscreenForElement):

Originally-landed-as: 267815.332 at safari-7617-branch (dc44d44d42fd). rdar://119594954
Canonical link: https://commits.webkit.org/272320@main