From: Yuhao Huang Date: Mon, 26 Jan 2026 04:03:48 +0000 (+0800) Subject: gpio: virtuser: fix UAF in configfs release path X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=53ad4a948a4586359b841d607c08fb16c5503230;p=thirdparty%2Fkernel%2Flinux.git gpio: virtuser: fix UAF in configfs release path The gpio-virtuser configfs release path uses guard(mutex) to protect the device structure. However, the device is freed before the guard cleanup runs, causing mutex_unlock() to operate on freed memory. Specifically, gpio_virtuser_device_config_group_release() destroys the mutex and frees the device while still inside the guard(mutex) scope. When the function returns, the guard cleanup invokes mutex_unlock(&dev->lock), resulting in a slab use-after-free. Limit the mutex lifetime by using a scoped_guard() only around the activation check, so that the lock is released before mutex_destroy() and kfree() are called. Fixes: 91581c4b3f29 ("gpio: virtuser: new virtual testing driver for the GPIO API") Signed-off-by: Yuhao Huang Link: https://lore.kernel.org/r/20260126040348.11167-1-yuhaohuang@YuhaodeMacBook-Pro.local Signed-off-by: Bartosz Golaszewski --- diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c index 37f2ce20f1ae..098e67d70ffa 100644 --- a/drivers/gpio/gpio-virtuser.c +++ b/drivers/gpio/gpio-virtuser.c @@ -1682,10 +1682,10 @@ static void gpio_virtuser_device_config_group_release(struct config_item *item) { struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item); - guard(mutex)(&dev->lock); - - if (gpio_virtuser_device_is_live(dev)) - gpio_virtuser_device_deactivate(dev); + scoped_guard(mutex, &dev->lock) { + if (gpio_virtuser_device_is_live(dev)) + gpio_virtuser_device_deactivate(dev); + } mutex_destroy(&dev->lock); ida_free(&gpio_virtuser_ida, dev->id);