Re: possible NULL dereference?

[Joris Huizer]

--- On Thu, 4/9/09, Paul Vriens  wrote:
> From: Paul Vriens 
> Subject: Re: possible NULL dereference?
> To: "Joris Huizer" 
> Cc: [e-mail]
> Date: Thursday, April 9, 2009, 7:53 AM
> Joris Huizer wrote:
> > Looking at git commit
>
> dcb3e52e2dfd0d6e494164932fb2b684d463a005, it seems, passing
> a NULL size pointer to GetUserNameEx[AW] is likely to
> crash.
> > You may want to test whether Windows versions crash on
>
> it, and check for it if needed.
> > HTH, Joris
>
> There is also another one (mentioned by Coverity) where
> passing a NULL lpNameBuffer and a big enough nSize will
> crash. I tested that one on W2K3 and this also crashes on
> W2K3.
>
> I didn't test the NULL nSize however.
>
> If time permits I'll add some tests and comments in the
> case of crashes.  If somebody wants to be beat me to
> it, be my guest.
>
> Out of curiosity, did you find this by visual inspection?
>
> -- Cheers,
>
> Paul.

Yea I just noticed this while skimming through, now and then I look at the latest changes on git.

I assume Coverity doesn't complain as it noticed you don't test the nSize pointer in any code path, so it assumes you know what you're doing.

That seems like a general problem - if it could pick up the WINAPI flag (explicitly different calling convention) and realize every argument is suspect, it would find all such problems as well; Such behavior would be desirable for library functions in general, except that different projects are likely to have very different requirements about when a function is a library function to be treated like that. 
Specifying "what is a library function" might already be supported or perhaps it could be requested as a generally useful feature?

regards,
Joris