linux-kernel - Re: [PATCH v1 2/2] gpiolib: of: Integrate of_gpiochip_init_valid_mask() into gpiochip_init_valid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 7 Nov 2022 23:09:19 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v1 2/2] gpiolib: of: Integrate
 of_gpiochip_init_valid_mask() into gpiochip_init_valid_mask()

On Mon, Nov 07, 2022 at 10:20:37AM -0800, Dmitry Torokhov wrote:
> On Mon, Nov 07, 2022 at 06:10:27PM +0200, Andy Shevchenko wrote:
> > +static unsigned int gpiochip_count_reserved_ranges(struct gpio_chip *gc)
> > +{
> > +	int size;
> > +
> > +	size = fwnode_property_count_u32(gc->fwnode, "gpio-reserved-ranges");
> 
> I wonder if a comment why we need even size would not be helpful.

Was it in the original code?
Anyway, if Bart thinks so as well, I may add it in v2.

> > +	if (size > 0 && size % 2 == 0)
> > +		return size;
> > +
> > +	return 0;
> > +}
> > +
> >  static int gpiochip_alloc_valid_mask(struct gpio_chip *gc)
> >  {
> > -	if (!(of_gpio_need_valid_mask(gc) || gc->init_valid_mask))
> > +	if (!(gpiochip_count_reserved_ranges(gc) || gc->init_valid_mask))
> >  		return 0;
> >  
> >  	gc->valid_mask = gpiochip_allocate_mask(gc);
> > @@ -457,8 +468,47 @@ static int gpiochip_alloc_valid_mask(struct gpio_chip *gc)
> >  	return 0;
> >  }
> >  
> > +static int gpiochip_apply_reserved_ranges(struct gpio_chip *gc, unsigned int sz)
> > +{
> > +	u32 *ranges;
> > +	int ret;
> > +
> > +	ranges = kmalloc_array(sz, sizeof(*ranges), GFP_KERNEL);
> > +	if (!ranges)
> > +		return -ENOMEM;
> > +
> > +	ret = fwnode_property_read_u32_array(gc->fwnode, "gpio-reserved-ranges", ranges, sz);
> > +	if (ret) {
> > +		kfree(ranges);
> > +		return ret;
> > +	}
> > +
> > +	while (sz) {
> > +		u32 count = ranges[--sz];
> > +		u32 start = ranges[--sz];
> 
> I know we checked sz validity, but I wonder if re-checking it in this
> function would not insulate us from errors creeping in after some other
> code refactoring.

I'm not sure I understand what you meant. The fwnode_property_read_u32_array()
will fail if the given sz is too big for the real data, so while (sz) would
never even go on the invalid data.

> In any case,
> 
> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

Thank you!

-- 
With Best Regards,
Andy Shevchenko