In this post we describe a bug we found in the udmabuf driver a while back, and how we exploited it to achieve root access in affected systems. This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within a fault handler. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an array. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel.
🔖PoC exploit here
⚠️The exploit was tested on a vulnerable Ubuntu 22.04, and it requires access to the
/dev/udmabuf device. This is only accessible to users in the kvm group, so you may need to add your test user to this group when testing the exploit.