From: Bartosz Golaszewski Date: Mon, 10 Feb 2025 10:51:57 +0000 (+0100) Subject: gpiolib: sanitize the return value of gpio_chip::set_config() X-Git-Tag: v6.15-rc1~179^2~86 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=dcf8f3bffa2de2c7f3b5771b63605194ccd2286f;p=thirdparty%2Flinux.git gpiolib: sanitize the return value of gpio_chip::set_config() The return value of the set_config() callback may be propagated to user-space. If a bad driver returns a positive number, it may confuse user programs. Tighten the API contract and check for positive numbers returned by GPIO controllers. Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-3-12ea88506cb2@linaro.org Signed-off-by: Bartosz Golaszewski --- diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index a98025b0ecf73..67a735d579427 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2593,6 +2593,9 @@ int gpio_do_set_config(struct gpio_desc *desc, unsigned long config) return -ENOTSUPP; ret = guard.gc->set_config(guard.gc, gpio_chip_hwgpio(desc), config); + if (ret > 0) + ret = -EBADE; + #ifdef CONFIG_GPIO_CDEV /* * Special case - if we're setting debounce period, we need to store diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index ce22c072337c4..f2145e938b293 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -349,7 +349,8 @@ struct gpio_irq_chip { * @set: assigns output value for signal "offset" * @set_multiple: assigns output values for multiple signals defined by "mask" * @set_config: optional hook for all kinds of settings. Uses the same - * packed config format as generic pinconf. + * packed config format as generic pinconf. Must return 0 on success and + * a negative error number on failure. * @to_irq: optional hook supporting non-static gpiod_to_irq() mappings; * implementation may not sleep * @dbg_show: optional routine to show contents in debugfs; default code