CVE-2023-52439

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: uio: corrige use-after-free en uio_open core-1 core-2 ------------------------------------------------------- uio_unregister_device uio_open idev = idr_find() device_unregister(&idev->dev) put_device(&idev->dev) uio_device_release get_device(&idev->dev) kfree(idev) uio_free_minor(minor) uio_release put_device(&idev->dev) kfree(idev) ------------------------------------------------------- In the core-1 uio_unregister_device(), the device_unregister se liberará idev cuando la referencia del objeto idev->dev kobject es 1. But after core-1 device_unregister, put_device and before doing kfree, the core-2 may get_device. Then: 1. After core-1 kfree idev, the core-2 will do use-after-free for idev. 2. When core-2 do uio_release and put_device, el idev se liberará dos veces. Para solucionar este problema, podemos obtener la referencia de idev atomic & inc idev con minor_lock.

A flaw was found in the Linux kernel’s uio subsystem. A use-after-free memory flaw in the uio_open functionality allows a local user to crash or escalate their privileges on the system.