CVE-2022-30283 — Time-of-check Time-of-use (TOCTOU) Race Condition in Kernel

In UsbCoreDxe, tampering with the contents of the USB working buffer using DMA while certain USB transactions are in process leads to a TOCTOU problem that could be used by an attacker to cause SMRAM corruption and escalation of privileges The UsbCoreDxe module creates a working buffer for USB transactions outside of SMRAM. The code which uses can be inside of SMM, making the working buffer untrusted input. The buffer can be corrupted by DMA transfers. The SMM code code attempts to sanitize poin…