Re: [PATCH] find: Do not read beyond variable boundaries on small sizes

[Kees Cook]

On Fri, Dec 03, 2021 at 11:16:11AM -0800, Yury Norov wrote:
> On Fri, Dec 03, 2021 at 08:37:59AM -0800, Kees Cook wrote:
> > 
> > 
> > On December 3, 2021 4:30:35 AM PST, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > >On Fri, Dec 03, 2021 at 02:08:46AM -0800, Kees Cook wrote:
> > >> It's common practice to cast small variable arguments to the find_*_bit()
> > >
> > >It's a bad practice and should be fixed accordingly, no?
> > 
> > There's an argument to be made that the first arg should be void * but that's a pretty invasive change at this point (and orthogonal to this fix).
> 
> What for? To save at most 7 bytes of alignment overhead for bitmaps
> like char bitmap[sizeof(unsigned long) + 1]?

I just meant to simplify the calling conventions. Right now everyone has
to cast to unsigned long *, which doesn't seem right: alignment and
strides can be done in the routine. But, I have no strong opinion about
this; it's just something I noticed while looking at it.

-- 
Kees Cook