[PATCH] [v2] gpio: virtuser: avoid non-constant format string

[PATCH] [v2] gpio: virtuser: avoid non-constant format string

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Using a string variable as an sprintf format is potentially
dangerous, and gcc can warn about this:

drivers/gpio/gpio-virtuser.c: In function 'gpio_virtuser_dbgfs_init_line_attrs':
drivers/gpio/gpio-virtuser.c:808:9: error: format not a string literal and no format arguments [-Werror=format-security]
  808 |         sprintf(data->consumer, id);
      |         ^~~~~~~

Change it to a simpler strscpy() instead to just copy it and check
the destination buffer size.

Fixes: 91581c4b3f29 ("gpio: virtuser: new virtual testing driver for the GPIO API")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpio/gpio-virtuser.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c
index 0e0d55da4f01..ccc47ea0b3e1 100644
--- a/drivers/gpio/gpio-virtuser.c
+++ b/drivers/gpio/gpio-virtuser.c
@@ -805,7 +805,7 @@ static int gpio_virtuser_dbgfs_init_line_attrs(struct device *dev,
 		return -ENOMEM;
 
 	data->ad.desc = desc;
-	sprintf(data->consumer, id);
+	strscpy(data->consumer, id);
 	atomic_set(&data->irq, 0);
 	atomic_set(&data->irq_count, 0);
 
-- 
2.39.2

Re: [PATCH] [v2] gpio: virtuser: avoid non-constant format string

[Bartosz Golaszewski]

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


On Fri, 19 Jul 2024 16:44:10 +0200, Arnd Bergmann wrote:
> Using a string variable as an sprintf format is potentially
> dangerous, and gcc can warn about this:
> 
> drivers/gpio/gpio-virtuser.c: In function 'gpio_virtuser_dbgfs_init_line_attrs':
> drivers/gpio/gpio-virtuser.c:808:9: error: format not a string literal and no format arguments [-Werror=format-security]
>   808 |         sprintf(data->consumer, id);
>       |         ^~~~~~~
> 
> [...]

Applied, thanks!

[1/1] gpio: virtuser: avoid non-constant format string
      commit: 3ae08e47742eeebf2190900d31ddac53fdd13a5b

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