CVE-2023-53552

A use-after-free vulnerability was found in the Linux kernel Intel i915 graphics driver's GuC virtual engine request handling. A local user with access to GPU rendering can create requests on GuC virtual engines and trap references via sync_file or dmabuf, causing fence release operations to access freed engine structures when validating whether rq->engine points to a valid hardware engine, which results in memory corruption and potential privilege escalation or denial of service.

Fence release code needs to determine if rq->engine is valid for non-virtual requests, but the check was insufficient for GuC virtual engines. Userspace can hold i915_request references indefinitely across processes via sync_file or dmabuf (dma-resv). The driver attempts to free request resources after completion to prevent memory leaks, but on fence release it must validate the engine pointer. For GuC virtual engines, the validation was incorrect, allowing use-after-free when the engine structure was freed but still referenced.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the i915 module from loading. See https://access.redhat.com/solutions/41278 for instructions on blacklisting kernel modules.