Re: sysctl: setting key "net.core.bpf_jit_enable": Invalid argument
From: Christophe Leroy <hidden>
Date: 2021-04-11 16:23:50
Also in:
bpf, linuxppc-dev
Le 11/04/2021 à 13:09, Paul Menzel a écrit :
Dear Linux folks, Related to * [CVE-2021-29154] Linux kernel incorrect computation of branch displacements in BPF JIT compiler can be abused to execute arbitrary code in Kernel mode* [1], on the POWER8 system IBM S822LC with self-built Linux 5.12.0-rc5+, I am unable to disable `bpf_jit_enable`. $ /sbin/sysctl net.core.bpf_jit_enable net.core.bpf_jit_enable = 1 $ sudo /sbin/sysctl -w net.core.bpf_jit_enable=0 sysctl: setting key "net.core.bpf_jit_enable": Invalid argument It works on an x86 with Debian sid/unstable and Linux 5.10.26-1.
Maybe you have selected CONFIG_BPF_JIT_ALWAYS_ON in your self-built kernel ? config BPF_JIT_ALWAYS_ON bool "Permanently enable BPF JIT and remove BPF interpreter" depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT help Enables BPF JIT and removes BPF interpreter to avoid speculative execution of BPF instructions by the interpreter Christophe