github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-04 20:46:48 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

gpiolib: fix a NULL-pointer dereference when setting direction

Browse Source 
For optional GPIOs we may pass NULL to gpiod_direction_(input|output)().
With the call to the notifier chain added by commit 07c61d4da4
("gpiolib: notify user-space about in-kernel line state changes") we
will now dereference a NULL pointer in this case. The reason for that is
the fact that the expansion of the VALIDATE_DESC() macro (which returns
0 for NULL descriptors) was moved into the nonotify variants of the
direction setters.

Move them back to the top-level interfaces as the nonotify ones are only
ever called from inside the GPIO core and are always passed valid GPIO
descriptors. This way we'll never call the line_state notifier chain
with non-valid descs.

Fixes: 07c61d4da4 ("gpiolib: notify user-space about in-kernel line state changes")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/all/d6601a31-7685-4b21-9271-1b76116cc483@sirena.org.uk/
Tested-by: Klara Modin <klarasmodin@gmail.com>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241024133834.47395-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2024-10-24 15:38:34 +02:00
parent 4295f4ccfe
commit 1f4a640e9a
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/gpio/gpiolib.c
View File

@ -2695,6 +2695,8 @@ int gpiod_direction_input(struct gpio_desc *desc)
{
int ret;
VALIDATE_DESC(desc);
ret = gpiod_direction_input_nonotify(desc);
if (ret == 0)
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
@ -2707,8 +2709,6 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc)
{
int ret = 0;
VALIDATE_DESC(desc);
CLASS(gpio_chip_guard, guard)(desc);
if (!guard.gc)
return -ENODEV;
@ -2841,6 +2841,8 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
{
int ret;
VALIDATE_DESC(desc);
ret = gpiod_direction_output_nonotify(desc, value);
if (ret == 0)
gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
@ -2854,8 +2856,6 @@ int gpiod_direction_output_nonotify(struct gpio_desc *desc, int value)
unsigned long flags;
int ret;
VALIDATE_DESC(desc);
flags = READ_ONCE(desc->flags);
if (test_bit(FLAG_ACTIVE_LOW, &flags))