From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Kent Gibson <warthog618@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Linus Walleij <linus.walleij@linaro.org>,
kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v8 02/20] gpiolib: cdev: replace strncpy with strscpy
Date: Tue, 15 Sep 2020 13:11:40 +0300 [thread overview]
Message-ID: <CAHp75Vf_JVJwc7t7mMACRB9xhBgNODz-474tiK77bQ-t_X_BiQ@mail.gmail.com> (raw)
In-Reply-To: <20200909102640.1657622-3-warthog618@gmail.com>
On Wed, Sep 9, 2020 at 1:34 PM Kent Gibson <warthog618@gmail.com> wrote:
>
> Replace usage of strncpy with strscpy to remove -Wstringop-truncation
strnspy() with strscpy()
> warnings.
>
> The structs being populated are zeroed, to prevent stack leakage as
structures
> they are returned to userspace, so strscpy performs the equivalent
strscpy()
> function without the warnings.
Isn't this what I commented on like half a year ago and back then
reply was something that there is no warnings or so?
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Kent Gibson <warthog618@gmail.com>
> ---
>
> The memset in gpio_desc_to_lineinfo(), in conjunction with the strscpy,
> is necessary as strncpy zero pads the remainder of the destination.
> It also guarantees that the info cannot leak kernel stack to userspace.
> This is useful here, but is even more important for the v2 info, that
> this function is changed to generate in a subsequent patch, as that
> struct contains padding and attribute arrays that also need to be
> initialised.
>
> drivers/gpio/gpiolib-cdev.c | 23 +++++++----------------
> 1 file changed, 7 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index e95e3eab9867..8b012879fe3f 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -752,6 +752,7 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> bool ok_for_pinctrl;
> unsigned long flags;
>
> + memset(info, 0, sizeof(*info));
> info->line_offset = gpio_chip_hwgpio(desc);
> /*
> * This function takes a mutex so we must check this before taking
> @@ -765,19 +766,11 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
>
> spin_lock_irqsave(&gpio_lock, flags);
>
> - if (desc->name) {
> - strncpy(info->name, desc->name, sizeof(info->name));
> - info->name[sizeof(info->name) - 1] = '\0';
> - } else {
> - info->name[0] = '\0';
> - }
> + if (desc->name)
> + strscpy(info->name, desc->name, sizeof(info->name));
>
> - if (desc->label) {
> - strncpy(info->consumer, desc->label, sizeof(info->consumer));
> - info->consumer[sizeof(info->consumer) - 1] = '\0';
> - } else {
> - info->consumer[0] = '\0';
> - }
> + if (desc->label)
> + strscpy(info->consumer, desc->label, sizeof(info->consumer));
>
> /*
> * Userspace only need to know that the kernel is using this GPIO so
> @@ -841,12 +834,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>
> memset(&chipinfo, 0, sizeof(chipinfo));
>
> - strncpy(chipinfo.name, dev_name(&gdev->dev),
> + strscpy(chipinfo.name, dev_name(&gdev->dev),
> sizeof(chipinfo.name));
> - chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
> - strncpy(chipinfo.label, gdev->label,
> + strscpy(chipinfo.label, gdev->label,
> sizeof(chipinfo.label));
> - chipinfo.label[sizeof(chipinfo.label)-1] = '\0';
> chipinfo.lines = gdev->ngpio;
> if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
> return -EFAULT;
> --
> 2.28.0
>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-09-15 10:12 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-09 10:26 [PATCH v8 00/20] gpio: cdev: add uAPI v2 Kent Gibson
2020-09-09 10:26 ` [PATCH v8 01/20] gpiolib: cdev: desc_to_lineinfo should set info offset Kent Gibson
2020-09-15 10:08 ` Andy Shevchenko
2020-09-09 10:26 ` [PATCH v8 02/20] gpiolib: cdev: replace strncpy with strscpy Kent Gibson
2020-09-15 10:11 ` Andy Shevchenko [this message]
2020-09-09 10:26 ` [PATCH v8 03/20] gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes Kent Gibson
2020-09-15 10:12 ` Andy Shevchenko
2020-09-09 10:26 ` [PATCH v8 04/20] gpio: uapi: define uAPI v2 Kent Gibson
2020-09-15 10:06 ` Andy Shevchenko
2020-09-20 10:48 ` Kent Gibson
2020-09-09 10:26 ` [PATCH v8 05/20] gpiolib: make cdev a build option Kent Gibson
2020-09-15 10:12 ` Andy Shevchenko
2020-09-09 10:26 ` [PATCH v8 06/20] gpiolib: add build option for CDEV v1 ABI Kent Gibson
2020-09-15 10:15 ` Andy Shevchenko
2020-09-09 10:26 ` [PATCH v8 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Kent Gibson
2020-09-15 15:29 ` Andy Shevchenko
2020-09-09 10:26 ` [PATCH v8 08/20] gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Kent Gibson
2020-09-09 10:26 ` [PATCH v8 09/20] gpiolib: cdev: support edge detection for uAPI v2 Kent Gibson
2020-09-15 10:39 ` Andy Shevchenko
2020-09-18 12:44 ` Kent Gibson
2020-09-18 14:00 ` Andy Shevchenko
2020-09-20 11:23 ` Kent Gibson
2020-09-09 10:26 ` [PATCH v8 10/20] gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Kent Gibson
2020-09-09 10:26 ` [PATCH v8 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Kent Gibson
2020-09-09 10:26 ` [PATCH v8 12/20] gpiolib: cdev: support setting debounce Kent Gibson
2020-09-09 10:26 ` [PATCH v8 13/20] gpio: uapi: document uAPI v1 as deprecated Kent Gibson
2020-09-09 10:26 ` [PATCH v8 14/20] tools: gpio: port lsgpio to v2 uAPI Kent Gibson
2020-09-09 10:26 ` [PATCH v8 15/20] tools: gpio: port gpio-watch " Kent Gibson
2020-09-09 10:26 ` [PATCH v8 16/20] tools: gpio: rename nlines to num_lines Kent Gibson
2020-09-09 10:26 ` [PATCH v8 17/20] tools: gpio: port gpio-hammer to v2 uAPI Kent Gibson
2020-09-09 10:26 ` [PATCH v8 18/20] tools: gpio: port gpio-event-mon " Kent Gibson
2020-09-09 10:26 ` [PATCH v8 19/20] tools: gpio: add multi-line monitoring to gpio-event-mon Kent Gibson
2020-09-09 10:26 ` [PATCH v8 20/20] tools: gpio: add debounce support " Kent Gibson
2020-09-14 12:45 ` [PATCH v8 00/20] gpio: cdev: add uAPI v2 Bartosz Golaszewski
2020-09-14 12:47 ` Bartosz Golaszewski
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