CVE-2023-53552

In the Linux kernel, the following vulnerability has been resolved:

drm/i915: mark requests for GuC virtual engines to avoid use-after-free

References to i915_requests may be trapped by userspace inside a sync_file or dmabuf (dma-resv) and held indefinitely across different proceses. To counter-act the memory leaks, we try to not to keep references from the request past their completion. On the other side on fence release we need to know if rq->engine is valid and points to hw engine (true for non-virtual requests). To make it possible extra bit has been added to rq->execution_mask, for marking virtual engines.

(cherry picked from commit 280410677af763f3871b93e794a199cfcf6fb580)

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/5eefc5307c983b59344a4cb89009819f580c84fa
• https://git.kernel.org/stable/c/7fb464d52fa41c31a6fd1ad82888e67c65935d94
• https://git.kernel.org/stable/c/8017a27cec32eac8c8f9430b0a3055840136b856