Rolf Kalbermatter wrote:
DanteAliegri dantealiegri@umbc.edu wrote:
Hey, I've come across what appears to be a simple problem in comctl32. When running icq99b, wine was dying in imagelist.c while trying to dereference a null pointer. Upon looking at the file, there was code for returning FALSE if that pointer was null, thus I felt it being null may be a valid choice. I made the attached change, and the problem was fixed. Comments?
--- imagelist.c 23 Oct 2002 22:19:11 -0000 1.65 +++ imagelist.c 2 Nov 2002 20:40:53 -0000 @@ -1082,11 +1082,14 @@ HBITMAP hImageBmp, hOldImageBmp, hOldImageListBmp, hOldMaskListBmp, hBlendMaskBmp; BOOL bIsTransparent, bBlend, bResult = FALSE; const HIMAGELIST himl = pimldp->himl;
^^^^^^^^^^^^
According to the same lines pimldp could also be NULL so this might as well cause a NULL pointer dereference and should be moved to after the check for "if (!pimldp || !(himl = pimldp->himl)) return FALSE;
Of course the question remains why would you call the function at all with a NULL pointer.
That is a good question. I didn't do any looking into this; however the function that this is in is BOOL WINAPI ImageList_DrawIndirect (IMAGELISTDRAWPARAMS *pimldp) So pimldp and himl aren't handed to that function. I was thinking that it had something do to with asking it to draw something that you hadn't given the images for yet ( so some program that just does while( 1 ) { draw() ; maybe_add_a_picture(); } ) as some way to make best response, or something silly like that.
- const INT lx = himl->cx * pimldp->i + pimldp->xBitmap;
- const INT ly = pimldp->yBitmap;
- static INT lx;
- static INT ly;
Should this be really static? Can't this function be called reentrant?
well, static is no worse than const ;) but I'll leave that to dimitrie. I was simply trying to cause as few changes as possible, and changing it to static would make it a global , rather than a stack variable, the same as const.
-Dante