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| author | Kent Gibson <warthog618@gmail.com> | 2023-12-21 09:20:36 +0800 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-12-21 10:27:07 +0100 |
| commit | 1d656bd259edb89dc1d9938ec5c5389867088546 (patch) | |
| tree | d44fb2a19a04fdea90885e519d452edfba908b2d /drivers/gpio | |
| parent | ceb6a6f023fd3e8b07761ed900352ef574010bcb (diff) | |
| download | linux-1d656bd259edb89dc1d9938ec5c5389867088546.tar.gz linux-1d656bd259edb89dc1d9938ec5c5389867088546.tar.bz2 linux-1d656bd259edb89dc1d9938ec5c5389867088546.zip | |
gpiolib: cdev: add gpio_device locking wrapper around gpio_ioctl()
While the GPIO cdev gpio_ioctl() call is in progress, the kernel can
call gpiochip_remove() which will set gdev->chip to NULL, after which
any subsequent access will cause a crash.
gpio_ioctl() was overlooked by the previous fix to protect syscalls
(bdbbae241a04), so add protection for that.
Fixes: bdbbae241a04 ("gpiolib: protect the GPIO device against being dropped while in use by user-space")
Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 02ffda6c1e51..f713d1ef7746 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2481,10 +2481,7 @@ static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip) return 0; } -/* - * gpio_ioctl() - ioctl handler for the GPIO chardev - */ -static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +static long gpio_ioctl_unlocked(struct file *file, unsigned int cmd, unsigned long arg) { struct gpio_chardev_data *cdev = file->private_data; struct gpio_device *gdev = cdev->gdev; @@ -2521,6 +2518,17 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } } +/* + * gpio_ioctl() - ioctl handler for the GPIO chardev + */ +static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct gpio_chardev_data *cdev = file->private_data; + + return call_ioctl_locked(file, cmd, arg, cdev->gdev, + gpio_ioctl_unlocked); +} + #ifdef CONFIG_COMPAT static long gpio_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg) |