Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

[Christophe Leroy]

Le 11/05/2021 à 03:16, Michael Ellerman a écrit :
> Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx> writes:
>
> > On Sat, May 08, 2021 at 06:36:21AM +0000, Christophe Leroy wrote:
> > > UBSAN complains when a pointer is calculated with invalid
> > > 'legacy_serial_console' index, allthough the index is verified
> > > before dereferencing the pointer.
> >
> > Addressing like this is UB already.
> >
> > You could just move this:
> >
> > > -	if (legacy_serial_console < 0)
> > > -		return 0;
> >
> > to before
> >
> > > -	struct legacy_serial_info *info = &legacy_serial_infos[legacy_serial_console];
> > > -	struct plat_serial8250_port *port = &legacy_serial_ports[legacy_serial_console];
> >
> > and no other change is necessary.
>
> Yeah I sent a v2 doing that, thanks.

I wanted something looking similar to setup_legacy_serial_console(), but of course this also works.

Christophe