[reSIProcate] Timer vulnerability

[kenho at bluebottle.com]

Alan,

I presume the scenario you described is very real and is possible to 
happen to QueryPerformanceCounter() and the likes, but GetTickCount()?
Although I have verify this myself, MSDN library clearly states that 
GetTickCount() returns the number of *milliseconds* that have elapsed 
since the system was started (note that it also says on WinCE, it 
excludes time suspended, but I failed to find similar statement 
regarding other windows families).

Ken

Alan Hawrylyshen wrote:

> One of the BIG problems with GetTickCount and families is that they no 
> longer produce monotonically increasing results.
> On devices with Intel SpeedStep technology (for example) or other 
> power management technologies, the TickCount can move in very 
> unpredictable ways. This results is wildly inaccurate timers. Care 
> must be taken to select a replacement (if done) that does not make use 
> of a fundamental that varies non-linearly.  On a plus side, we can get 
> rid of any direct calls to time() since having a contained Time 
> utility class is a Good Thing™.
>
> Alan
>
> a l a n a t j a s o m i d o t c o m
>