| Message ID | 20231221012040.17763-2-warthog618@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | gpiolib: cdev: guard tidying | expand |
On Thu, Dec 21, 2023 at 2:21 AM Kent Gibson <warthog618@gmail.com> wrote: > > 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> > --- > drivers/gpio/gpiolib-cdev.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c > index 744734405912..9155c54acc1e 100644 > --- a/drivers/gpio/gpiolib-cdev.c > +++ b/drivers/gpio/gpiolib-cdev.c > @@ -2598,10 +2598,7 @@ 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; > @@ -2638,6 +2635,17 @@ 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) > -- > 2.39.2 > I applied this. I'll send it upstream tomorrow and once it's in master, I'll pick up the rest on Monday. Bart
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 744734405912..9155c54acc1e 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2598,10 +2598,7 @@ 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; @@ -2638,6 +2635,17 @@ 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)
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> --- drivers/gpio/gpiolib-cdev.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)