gpiolib: avoid format string weakness in workqueue interface

[PATCH] gpiolib: avoid format string weakness in workqueue interface

Posted by Arnd Bergmann 3 weeks, 6 days ago

From: Arnd Bergmann <arnd@arndb.de>

Using a string literal as a format string is a possible bug when the
string contains '%' characters:

drivers/gpio/gpiolib-cdev.c:2813:48: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
 2813 |         gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
      |                                                       ^~~~~~~~~~~~~~~~~~~~
drivers/gpio/gpiolib-cdev.c:2813:48: note: treat the string as an argument to avoid this
 2813 |         gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
      |                                                       ^
      |                                                       "%s",

Do as clang suggests and use a trivial "%s" format string.

Fixes: 7b9b77a8bba9 ("gpiolib: add a per-gpio_device line state notification workqueue")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 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 0ec162b0ea04..088201de9627 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2810,8 +2810,8 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
 	gdev->chrdev.owner = THIS_MODULE;
 	gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
 
-	gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
-						      WQ_HIGHPRI);
+	gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI,
+						      dev_name(&gdev->dev));
 	if (!gdev->line_state_wq)
 		return -ENOMEM;
 
-- 
2.39.5

Re: [PATCH] gpiolib: avoid format string weakness in workqueue interface

Posted by Bartosz Golaszewski 3 weeks, 3 days ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Mon, 28 Oct 2024 14:21:46 +0000, Arnd Bergmann wrote:
> Using a string literal as a format string is a possible bug when the
> string contains '%' characters:
> 
> drivers/gpio/gpiolib-cdev.c:2813:48: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
>  2813 |         gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
>       |                                                       ^~~~~~~~~~~~~~~~~~~~
> drivers/gpio/gpiolib-cdev.c:2813:48: note: treat the string as an argument to avoid this
>  2813 |         gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
>       |                                                       ^
>       |                                                       "%s",
> 
> [...]

Applied, thanks!

[1/1] gpiolib: avoid format string weakness in workqueue interface
      commit: a22c9dc26d6fc522357b73858b13e29c58f49d64

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>