habanalabs kernel driver (dma-buf export path): A use-after-free in the habanalabs dma-buf export path: the driver

Impact

A use-after-free in the habanalabs dma-buf export path: the driver installs a file descriptor into the process table and then keeps using the object, so a second thread that closes the fd first frees memory the driver is still writing. dma-buf is exactly the mechanism used to hand accelerator memory to another process or device, so a successful exploit is a kernel-memory write reachable from an unprivileged accelerator user.

Who can reach it

Any local user with access to the habanalabs device node - on Kubernetes that is any pod granted a Gaudi device. Requires a deliberate race, not a lucky one.

What to do

Fix ships in the Linux kernel. Update the kernel and reboot the node - in practice this is a drain plus reboot because the accelerator driver cannot be unloaded while jobs hold device file descriptors. No BIOS or firmware update needed.

References