null ptr deref in WebCore::Frame::setPrinting

https://bugs.webkit.org/show_bug.cgi?id=240173

Reviewed by Wenson Hsieh.

Check m_doc in Frame::setPrinting before access, as it is a RefPtr that can become null.

* page/Frame.cpp:
(WebCore::Frame::setPrinting):

Canonical link: https://commits.webkit.org/250369@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@293922 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,15 @@
+2022-05-06  Gabriel Nava Marino  <gnavamarino@apple.com>
+
+        null ptr deref in WebCore::Frame::setPrinting
+        https://bugs.webkit.org/show_bug.cgi?id=240173
+
+        Reviewed by Wenson Hsieh.
+
+        Check m_doc in Frame::setPrinting before access, as it is a RefPtr that can become null.
+
+        * page/Frame.cpp:
+        (WebCore::Frame::setPrinting):
+
 2022-05-05  Ben Nham  <nham@apple.com>
 
         Add support for Notification objects with custom data

Source/WebCore/page/Frame.cpp

@@ -602,7 +602,7 @@ bool Frame::requestDOMPasteAccess(DOMPasteAccessCategory pasteAccessCategory)
 
 void Frame::setPrinting(bool printing, const FloatSize& pageSize, const FloatSize& originalPageSize, float maximumShrinkRatio, AdjustViewSizeOrNot shouldAdjustViewSize)
 {
-    if (!view())
+    if (!view() || !document())
         return;
     // In setting printing, we should not validate resources already cached for the document.
     // See https://bugs.webkit.org/show_bug.cgi?id=43704