linux-kernel - Re: [PATCH v5 08/12] gpio: aggregator: export symbols of the GPIO forwarder library

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]

Message-ID: <c10b7752-cec5-483c-90a9-ada16aa0904a@bootlin.com>
Date: Mon, 12 May 2025 16:08:35 +0200
From: Thomas Richard <thomas.richard@...tlin.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Linus Walleij <linus.walleij@...aro.org>,
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
 Bartosz Golaszewski <brgl@...ev.pl>, Kees Cook <kees@...nel.org>,
 Andy Shevchenko <andy@...nel.org>, linux-gpio@...r.kernel.org,
 linux-kernel@...r.kernel.org, thomas.petazzoni@...tlin.com,
 DanieleCleri@...on.eu, GaryWang@...on.com.tw, linux-hardening@...r.kernel.org
Subject: Re: [PATCH v5 08/12] gpio: aggregator: export symbols of the GPIO
 forwarder library

Hi Geert

Thanks a lot for the review.

On 5/9/25 11:07, Geert Uytterhoeven wrote:
> Hi Thomas,
> 
> On Tue, 6 May 2025 at 17:21, Thomas Richard <thomas.richard@...tlin.com> wrote:
>> Export all symbols and create header file for the GPIO forwarder library.
>> It will be used in the next changes.
>>
>> Signed-off-by: Thomas Richard <thomas.richard@...tlin.com>

...

>> +
>> +int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset,
>> +                       unsigned long config);
>> +
>> +int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset);
> 
> I would expect all of these to take gpiochip_fwd pointers instead of
> gpio_chip pointers.  What prevents you from passing a gpio_chip pointer
> that does not correspond to a gpiochip_fwd object, causing a crash?

Indeed nothing prevents from passing gpio_chip pointer which does not
correspond to a gpiochip_fwd object.
And it is also a bit weird to pass a gpiochip_fwd pointer in some cases
(for example gpio_fwd_gpio_add()) and a gpio_chip in other cases.

I can keep GPIO operations as is, and create exported wrappers which
take a gpiochip_fwd pointer as parameter, for example:

int gpiochip_fwd_get_multiple(struct gpiochip_fwd *fwd,
			      unsigned long *mask,
			      unsigned long *bits)
{
	struct gpio_chip *gc = gpiochip_fwd_get_gpiochip(fwd);

	return gpio_fwd_get_multiple_locked(chip, mask, bits);
}
EXPORT_SYMBOL_NS_GPL(gpiochip_fwd_get_multiple, "GPIO_FORWARDER");

So exported functions are gpiochip_fwd_*().

Regards,

Thomas
-- 
Thomas Richard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com