AMD Radeon Graphics driver - IOCTL granting arbitrary I/O port and physical memory access: Improper privilege

Impact

Improper privilege management in the AMD graphics driver lets an authenticated attacker craft an IOCTL that gives I/O control over arbitrary hardware ports or physical memory. This is about as broad as a driver bug gets: arbitrary physical memory access from a user-issued IOCTL is a complete bypass of kernel memory protection, so any workload holding the GPU device node can read every other tenant's memory and take the host. AMD's PSP driver component (AMDPSP) was the affected surface.

Who can reach it

Local, authenticated, via a GPU driver IOCTL - i.e. reachable by anything that has the GPU device handed to it, which on a GPU cloud is every tenant container.

What to do

Update the AMD graphics driver package and reload the driver or reboot the node. Driver-speed fix - no BIOS, no VBIOS - so there is no excuse for leaving it. Treat as top priority on any node where untrusted workloads get a GPU device node.

References