Red Hat: CVE-2021-33200: CVE-2021-33200 kernel: out-of-bounds reads and writes due to enforcing incorrect limits for pointer arithmetic operations by BPF verifier (Multiple Advisories)

kernel/bpf/verifier.c in the Linux kernel through 5.12.7 enforces incorrect limits for pointer arithmetic operations, aka CID-bb01a1bba579. This can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation to root. In particular, there is a corner case where the off reg causes a masking direction change, which then results in an incorrect final aux->alu_limit.