Re: Added sanity check to WINPROC_CallWndProc
"Jukka" == Jukka Heinonen <jhei(a)iki.fi> writes:
Jukka> DeusEx causes Wine to crash (segmentation fault) because it calls Jukka> CallWindowProc and passes null in HWND parameter. While I Jukka> suspect that this is because some Wine function that should Jukka> return a valid HWND is returning a null pointer, the crashing can Jukka> be fixed simply by adding a sanity check to WINPROC_CallWndProc. How does Windows behave on those invalid arguments? Jukka> After this patch, both DeusEx installer and DeusEx dialog for Jukka> choosing rendering engine work. However, DeusEx still crashes Jukka> later because DeusEx for some reason generates a division by zero Jukka> FP exception. DeusEx handler for this exception calls Jukka> __CxxFrameHandler which is not implemented by Wine and thus Jukka> exception handling ends into infinite recursion. Luckily stack Jukka> overflow makes Wine to crash :) Native msvcrt has __CxxFrameHandler, but I aggree that wine-msvcrt needs exception facilities too. Bye -- Uwe Bonnes bon(a)elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
On Sun, Jul 15, 2001, Uwe Bonnes wrote:
"Jukka" == Jukka Heinonen <jhei(a)iki.fi> writes: Jukka> DeusEx causes Wine to crash (segmentation fault) because it calls Jukka> CallWindowProc and passes null in HWND parameter. While I Jukka> suspect that this is because some Wine function that should Jukka> return a valid HWND is returning a null pointer, the crashing can Jukka> be fixed simply by adding a sanity check to WINPROC_CallWndProc.
How does Windows behave on those invalid arguments?
On a Windows NT machine, CallWindowProc does not check any of its arguments. However, DefWindowProc and all WNDPROC handlers do check HWND argument. Many (if not all) Wine WNDPROC handlers do not have this check and null HWND handles therefore make Wine crash even though Windows doesn't. So, my patch was incorrect after all. Correct fix to Wine is simple: just go through all WNDPROC handlers and check after first WIN_FindWndPtr call that the returned pointer is non-null. Wine DefWindowProc is a good example of this. I might look at this next weekend unless someone else volunteers. It is likely that in every case where applications pass HWND handles to Wine, there should be a similar check. Confirming this would be pretty boring, though.
Jukka> After this patch, both DeusEx installer and DeusEx dialog for Jukka> choosing rendering engine work. However, DeusEx still crashes Jukka> later because DeusEx for some reason generates a division by zero Jukka> FP exception. DeusEx handler for this exception calls Jukka> __CxxFrameHandler which is not implemented by Wine and thus Jukka> exception handling ends into infinite recursion. Luckily stack Jukka> overflow makes Wine to crash :)
Native msvcrt has __CxxFrameHandler, but I aggree that wine-msvcrt needs exception facilities too.
Actually, I looked at Windows development documents and tried some tests myself and found out that 1.0/0.0 (division by zero) should only raise an exception if a function call to _control87 or _controlfp is made to enable floating point exceptions. DeusEx does no such call. Therefore, Wine should not have raised this exception or at least it should have passed control right back to the application instead of invoking exception handlers. Likely Wine startup fails to properly initialize the floating point unit. Fixing this should not be too hard, but I have to see when I have enough time to look at it. I am not going to do anything regarding __CxxFrameHandler (is this C++ exception handling stuff?) since I have not found any documentation about it and I'm hoping that DeusEx doesn't really need it. -- Jukka Heinonen <http://www.iki.fi/jhei/>
participants (2)
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Jukka Heinonen -
Uwe Bonnes