Linux Kernel eBPF OR NULL Pointer Local Privilege Escalation Exploit

The bpf verifier(kernel/bpf/verifier.c) did not properly restrict several *_OR_NULL pointer types which allows these types to do pointer arithmetic. An unprivileged user could use this flaw to escalate their privileges on a system. Setting parameter "kernel.unprivileged_bpf_disabled=1" prevents such privilege escalation by restricting access to bpf(2) call.