Re: [PATCH] ff-memless: fix signed to unsigned bit overflow in?ml_combile_effects()

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thursday 07 May 2009 16:53:50 Anssi Hannula wrote:
> Jussi Kivilinna wrote:
> > When userspace sets effect->u.rumble.strong_magnitude to 0x8001 or
> > larger, ml_combine_effects() would always return strong_magnitude 0xffff.
> >
> > Problem is that 'gain' is passed in as signed integer. Multiplying
> > magnitude (__u16) with gain (int) causes magnitude read as signed and
> > results negative value (with magnitude > 0x8000). This signed integer is
> > then divided and value, still negative, converted to 32bit unsigned
> > integer. Finally checking combine overflow min(new+old, 0xffff) gives out
> > 0xffff.
> >
> > Fix is to simply change 'gain' to unsigned int.
> >
> > Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
>
> Acked-by: Anssi Hannula <anssi.hannula@gmail.com>
>

Applied, thank you.

-- 
Dmitry