lkml.org 
[lkml]   [2023]   [Sep]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] gpiolib: cdev: Annotate struct linereq with __counted_by
From


On 9/22/23 11:52, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct linereq.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Bartosz Golaszewski <brgl@bgdev.pl>
> Cc: Andy Shevchenko <andy@kernel.org>
> Cc: linux-gpio@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
> drivers/gpio/gpiolib-cdev.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index e39d344feb28..31fc71a612c2 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -572,7 +572,7 @@ struct linereq {
> DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
> atomic_t seqno;
> struct mutex config_mutex;
> - struct line lines[];
> + struct line lines[] __counted_by(num_lines);
> };
>
> #define GPIO_V2_LINE_BIAS_FLAGS \
> @@ -1656,6 +1656,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
> lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
> if (!lr)
> return -ENOMEM;
> + lr->num_lines = ulr.num_lines;
>
> lr->gdev = gpio_device_get(gdev);
>
> @@ -1684,7 +1685,6 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
> lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
>
> atomic_set(&lr->seqno, 0);
> - lr->num_lines = ulr.num_lines;
>
> /* Request each GPIO */
> for (i = 0; i < ulr.num_lines; i++) {

\
 
 \ /
  Last update: 2023-09-23 22:23    [W:0.056 / U:0.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site