[PATCH v1] thermal: core: Fix use-after-free in thermal_cooling_device_destroy_sysfs

[PATCH v1] thermal: core: Fix use-after-free in thermal_cooling_device_destroy_sysfs

[Dmitry Osipenko]

This patch fixes use-after-free that was detected by KASAN. The bug is
triggered on a CPUFreq driver module unload by freeing 'cdev' on device
unregister and then using the freed structure during of the cdev's sysfs
data destruction. The solution is to unregister the sysfs at first, then
destroy sysfs data and finally release the cooling device.

Cc: <stable@vger.kernel.org> # v4.17+
Fixes: 8ea229511e06 ("thermal: Add cooling device's statistics in sysfs")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/thermal/thermal_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 6ab982309e6a..441778100887 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1102,8 +1102,9 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
 	mutex_unlock(&thermal_list_lock);
 
 	ida_simple_remove(&thermal_cdev_ida, cdev->id);
-	device_unregister(&cdev->device);
+	device_del(&cdev->device);
 	thermal_cooling_device_destroy_sysfs(cdev);
+	put_device(&cdev->device);
 }
 EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);
 
-- 
2.18.0

Re: [PATCH v1] thermal: core: Fix use-after-free in thermal_cooling_device_destroy_sysfs

[Viresh Kumar]

On 13-08-18, 20:14, Dmitry Osipenko wrote:
> This patch fixes use-after-free that was detected by KASAN. The bug is
> triggered on a CPUFreq driver module unload by freeing 'cdev' on device
> unregister and then using the freed structure during of the cdev's sysfs
> data destruction. The solution is to unregister the sysfs at first, then
> destroy sysfs data and finally release the cooling device.
> 
> Cc: <stable@vger.kernel.org> # v4.17+
> Fixes: 8ea229511e06 ("thermal: Add cooling device's statistics in sysfs")
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/thermal/thermal_core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 6ab982309e6a..441778100887 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1102,8 +1102,9 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
>  	mutex_unlock(&thermal_list_lock);
>  
>  	ida_simple_remove(&thermal_cdev_ida, cdev->id);
> -	device_unregister(&cdev->device);
> +	device_del(&cdev->device);
>  	thermal_cooling_device_destroy_sysfs(cdev);
> +	put_device(&cdev->device);
>  }
>  EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Re: [PATCH v1] thermal: core: Fix use-after-free in thermal_cooling_device_destroy_sysfs

[Eduardo Valentin]

On Mon, Aug 13, 2018 at 08:14:00PM +0300, Dmitry Osipenko wrote:
> This patch fixes use-after-free that was detected by KASAN. The bug is
> triggered on a CPUFreq driver module unload by freeing 'cdev' on device
> unregister and then using the freed structure during of the cdev's sysfs
> data destruction. The solution is to unregister the sysfs at first, then
> destroy sysfs data and finally release the cooling device.
> 
> Cc: <stable@vger.kernel.org> # v4.17+
> Fixes: 8ea229511e06 ("thermal: Add cooling device's statistics in sysfs")
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

Acked-by: Eduardo Valentin <edubezval@gmail.com>

Rui, can you please queue this one?

> ---
>  drivers/thermal/thermal_core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 6ab982309e6a..441778100887 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1102,8 +1102,9 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
>  	mutex_unlock(&thermal_list_lock);
>  
>  	ida_simple_remove(&thermal_cdev_ida, cdev->id);
> -	device_unregister(&cdev->device);
> +	device_del(&cdev->device);
>  	thermal_cooling_device_destroy_sysfs(cdev);
> +	put_device(&cdev->device);
>  }
>  EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);
>  
> -- 
> 2.18.0
>