Re: ntdll: Protect RtlAllocateHeap and RtlReAllocateHeap against integer overflows with large values of size.

[Robert Shearman]

Chris Robinson wrote:
> On Friday 18 May 2007 04:01:19 am Robert Shearman wrote:
> > - ULONGLONG llret = (ULONGLONG)a + b;
> > - if ((sizeof(SIZE_T) < sizeof(ULONGLONG)) && (llret > 0xffffffff))
> > -
> >    return FALSE;
>
> WOuldn't this be more correct (as well as function when sizeof(SIZE_T) >= 
> sizeof(ULONGLONG)):
>
> SIZE_T res = a + b;
> return (res >= a);

An example that would break using your logic:
2 + (-1)