On Sun, Oct 6, 2019 at 6:33 PM Adam Ford <aford173@xxxxxxxxx> wrote:
>
> When using mctrl_gpio_to_gpiod, it dereferences gpios into a single
> requested GPIO. This dereferencing can break if gpios is NULL,
> so this patch adds a NULL check before dereferencing it. If
> gpios is NULL, this function will also return NULL.
>
> Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
Reviewed-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
> ---
> V2: This patch is new to the V2 of this series, so patch 2/2 can
> work without risking a NULL dereference
> diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
> index d9074303c88e..fb4781292d40 100644
> --- a/drivers/tty/serial/serial_mctrl_gpio.c
> +++ b/drivers/tty/serial/serial_mctrl_gpio.c
> @@ -66,6 +66,9 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_set);
> struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> enum mctrl_gpio_idx gidx)
> {
> + if (gpios == NULL)
> + return NULL;
> +
> return gpios->gpio[gidx];
> }
> EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
> --
> 2.17.1
>
