linux-kernel - Re: [PATCH 05/10] gpio: mockup: improve the debugfs input sanitization

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Date:   Mon, 29 May 2017 08:57:22 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Bamvor Jian Zhang <bamvor.zhangjian@...aro.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 05/10] gpio: mockup: improve the debugfs input sanitization

2017-05-27 18:47 GMT+02:00 Andy Shevchenko <andy.shevchenko@...il.com>:
> On Sat, May 27, 2017 at 7:45 PM, Andy Shevchenko
> <andy.shevchenko@...il.com> wrote:
>> On Thu, May 25, 2017 at 11:33 AM, Bartosz Golaszewski <brgl@...ev.pl> wrote:
>>> We're currently only checking the first character of the input to the
>>> debugfs event files, so a string like '0sdfdsf' is valid and indicates
>>> a falling edge event.
>>>
>>> Be more strict and only allow '0', '1', '0\n' & '1\n'.
>>
>> Why not to be so strict and use
>>
>> kstrtobool_from_user();
>>
>> instead?
>

Because it doesn't really make sense here - we're indicating a RISING
or FALLING edge event. This doesn't really correspond well with
boolean values IMO.

> Or if you still wish to be strict,
> ret = kstrtou8_from_user();
> if (ret)
>  return ret;
>
> if (val > 1)
>  return -ERANGE;
>
> or alike.

This one looks good, I'll include it in v2.

Thanks,
Bartosz