109487 - [W] UMR: Uninitialized memory read in nsHTMLInputElement::HandleDOMEvent

Status: VERIFIED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[[e-mail] (gone - use [e-mail] instead)]

Just saw this on my Win2K box, (latest tip) when reading 2 IMAP messages with 
pictures attached.

    [W] UMR: Uninitialized memory read in nsHTMLInputElement::HandleDOMEvent
(nsIPresContext *,nsEvent *,nsIDOMEvent * *,UINT,nsEventStatus *) {1 occurrence}
        Reading 4 bytes from 0x0013f050 (4 bytes at 0x0013f050 uninitialized)
        Address 0x0013f050 points into a thread's stack 
        Address 0x0013f050 is 28 bytes past the start of local 
variable 'blurevent' in nsEventStateManager::PreHandleEvent(nsIPresContext 
*,nsEvent *,nsIFrame *,nsEventStatus *,nsIView *)
        Thread ID: 0x38c
        Error location
        nsHTMLInputElement::HandleDOMEvent(nsIPresContext *,nsEvent 
*,nsIDOMEvent * *,UINT,nsEventStatus *) [nsHTMLInputElement.cpp:1134]
          // If NS_EVENT_FLAG_NO_CONTENT_DISPATCH is set we will not allow 
content to handle
          // this event.  But to allow middle mouse button paste to work we 
must allow
          // middle clicks to go to text fields anyway.
     =>   PRBool noContentDispatch = aEvent->flags & 
NS_EVENT_FLAG_NO_CONTENT_DISPATCH;
          if (type == NS_FORM_INPUT_TEXT && aEvent->message == 
NS_MOUSE_MIDDLE_CLICK) {
            aEvent->flags &= ~NS_EVENT_FLAG_NO_CONTENT_DISPATCH;
          }
        nsEventStateManager::PreHandleEvent(nsIPresContext *,nsEvent *,nsIFrame 
*,nsEventStatus *,nsIView *) [nsEventStateManager.cpp:674]
                    oldPresContext->GetEventStateManager(getter_AddRefs(esm));
                    esm->SetFocusedContent(gLastFocusedContent);
                    if(focusedContent)
     =>               focusedContent->HandleDOMEvent(oldPresContext, &event, 
nsnull, NS_EVENT_FLAG_INIT, &status);
                    esm->SetFocusedContent(nsnull);
                    NS_IF_RELEASE(gLastFocusedContent);
                  }
        PresShell::HandleEventInternal(nsEvent *,nsIView *,UINT,nsEventStatus 
*) [nsPresShell.cpp:5809]
          nsIEventStateManager *manager;
          if (NS_OK == mPresContext->GetEventStateManager(&manager) && 
GetCurrentEventFrame()) {
            //1. Give event to event manager for pre event state changes and 
generation of synthetic events.
     =>     rv = manager->PreHandleEvent(mPresContext, aEvent, 
mCurrentEventFrame, aStatus, aView);
        
            //2. Give event to the DOM for third party and JS use.
            if ((GetCurrentEventFrame()) && NS_OK == rv) {
        PresShell::HandleEvent(nsIView *,nsGUIEvent *,nsEventStatus *,int,int&) 
[nsPresShell.cpp:5740]
                }
              }
              if (GetCurrentEventFrame()) {
     =>         rv = HandleEventInternal(aEvent, aView, NS_EVENT_FLAG_INIT, 
aEventStatus);
              }
              NS_RELEASE(manager);
            }
        nsView::HandleEvent(nsGUIEvent *,UINT,nsEventStatus *,int,int&) 
[nsView.cpp:362]
            //if no child's bounds matched the event or we consumed but still 
want
            //default behavior check the view itself. -EDV
            if (nsnull != mClientData && nsnull != obs) {
     =>       obs->HandleEvent((nsIView *)this, event, aStatus, aForceHandle, 
aHandled);
            }
          }
          /* XXX Just some debug code to see what event are being thrown away 
because
    nsViewManager::DispatchEvent(nsGUIEvent *,nsEventStatus *) 
[nsViewManager.cpp:1872]
                                    NS_VIEW_FLAG_CHECK_SIBLINGS,
                                    aStatus,
                                    PR_TRUE,
     =>                             handled);
        
                  aEvent->point.x -= offset.x;
                  aEvent->point.y -= offset.y;
    HandleEvent    [nsView.cpp:81]
          {
            nsViewManager *vm = view->GetViewManager();
        
     =>     vm->DispatchEvent(aEvent, &result);
          }
        
          return result;
    nsWindow::DispatchEvent(nsGUIEvent *,nsEventStatus&) [nsWindow.obj:744]
    nsWindow::DispatchFocus(UINT,int) [nsWindow.cpp:4506]
        
            event.nativeMsg = (void *)&pluginEvent;
        
     =>     PRBool result = DispatchWindowEvent(&event);
            NS_RELEASE(event.widget);
            return result;
          }
    nsWindow::ProcessMessage(UINT,UINT,long,long *) [nsWindow.cpp:3409]
                  isMozWindowTakingFocus = PR_FALSE;
                if(gJustGotDeactivate) {
                  gJustGotDeactivate = PR_FALSE;
     =>           result = DispatchFocus(NS_DEACTIVATE, isMozWindowTakingFocus);
                }
                result = DispatchFocus(NS_LOSTFOCUS, isMozWindowTakingFocus);
                break;

Comment 1

[Johnny Stenback (:jst)]

I bet there's a ton of these in our code, it's all because our nsEvent structs
don't have constructors that would take care of initializing everything properly.

This patch fixes this particular UMR:

Index: content/events/src/nsEventStateManager.cpp
===================================================================
RCS file: /cvsroot/mozilla/content/events/src/nsEventStateManager.cpp,v
retrieving revision 1.312
diff -u -r1.312 nsEventStateManager.cpp
--- content/events/src/nsEventStateManager.cpp  6 Dec 2001 15:29:01 -00001.312
+++ content/events/src/nsEventStateManager.cpp  14 Dec 2001 07:15:21 -0000
@@ -684,6 +684,7 @@
             nsEvent event;
             event.eventStructType = NS_EVENT;
             event.message = NS_BLUR_CONTENT;
+            event.flags = 0;
             nsCOMPtr<nsIEventStateManager> esm;
             oldPresContext->GetEventStateManager(getter_AddRefs(esm));
             esm->SetFocusedContent(gLastFocusedContent);

Peter, would you review this please?

Comment 2

[Peter Van der Beken [:peterv]]

r=peterv

Comment 3

[Johnny Stenback (:jst)]

Pushing to mozilla1.0

Comment 4

[Mike Shaver (:shaver emeritus)]

Boy, I'd love to see those grow a constructor.   But I have no real belief that
we'll actually solve this right, so sure: what's another snippet of wallpaper
between friends?

sr=shaver.

Comment 5

[Johnny Stenback (:jst)]

FIXED.

Comment 6

[[e-mail] (gone - use [e-mail] instead)]

verified fixed with the latest win32 tip