Re: [PATCH v2] tty: rfcomm: prefer struct_size over open coded arithmetic

Erick Archer
2024-05-13T17:13:11Z

Hi Kees, Jiri and Luiz,
First of all, thanks for the reviews.

On Mon, May 13, 2024 at 12:29:04PM -0400, Luiz Augusto von Dentz wrote:
> Hi Jiri, Eric,
>
> On Mon, May 13, 2024 at 1:07 AM Jiri Slaby <jirislaby@kernel.org> wrote:
> >
> > On 12. 05. 24, 13:17, Erick Archer wrote:
> > > This is an effort to get rid of all multiplications from allocation
> > > functions in order to prevent integer overflows [1][2].
> > >
> > > As the "dl" variable is a pointer to "struct rfcomm_dev_list_req" and
> > > this structure ends in a flexible array:
> > ...
> > > --- a/include/net/bluetooth/rfcomm.h
> > > +++ b/include/net/bluetooth/rfcomm.h
> > ...
> > > @@ -528,12 +527,12 @@ static int rfcomm_get_dev_list(void __user *arg)
> > > list_for_each_entry(dev, &rfcomm_dev_list, list) {
> > > if (!tty_port_get(&dev->port))
> > > continue;
> > > - (di + n)->id = dev->id;
> > > - (di + n)->flags = dev->flags;
> > > - (di + n)->state = dev->dlc->state;
> > > - (di + n)->channel = dev->channel;
> > > - bacpy(&(di + n)->src, &dev->src);
> > > - bacpy(&(di + n)->dst, &dev->dst);
> > > + di[n].id = dev->id;
> > > + di[n].flags = dev->flags;
> > > + di[n].state = dev->dlc->state;
> > > + di[n].channel = dev->channel;
> > > + bacpy(&di[n].src, &dev->src);
> > > + bacpy(&di[n].dst, &dev->dst);
> >
> > This does not relate much to "prefer struct_size over open coded
> > arithmetic". It should have been in a separate patch.
>
> +1, please split these changes into its own patch so we can apply it separately.

Ok, no problem. Also, I will simplify the "bacpy" lines with direct
assignments as Kees suggested:

di[n].src = dev->src;
di[n].dst = dev->dst;

instead of:

bacpy(&di[n].src, &dev->src);
bacpy(&di[n].dst, &dev->dst);

Regards,
Erick

> > Other than that, LGTM.
> >
> > thanks,
> > --
> > js
> > suse labs
> >
>
>
> --
> Luiz Augusto von Dentz