[PATCH ebpf] bpf: Disallow unprivileged bpf by default
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Date: 2021-10-27 21:29:08
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Disabling unprivileged BPF by default would help prevent unprivileged users from creating the conditions required for potential speculative execution side-channel attacks on affected hardware as demonstrated by [1][2][3]. This will sync mainline with what most distros are currently applying. An admin can enable this at runtime if necessary. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> [1] https://access.redhat.com/security/cve/cve-2019-7308 [2] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3490 [3] https://bugzilla.redhat.com/show_bug.cgi?id=1672355#c5 --- kernel/bpf/Kconfig | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
index a82d6de86522..73d446294455 100644
--- a/kernel/bpf/Kconfig
+++ b/kernel/bpf/Kconfig@@ -64,6 +64,7 @@ config BPF_JIT_DEFAULT_ON config BPF_UNPRIV_DEFAULT_OFF bool "Disable unprivileged BPF by default" + default y depends on BPF_SYSCALL help Disables unprivileged BPF by default by setting the corresponding
@@ -72,6 +73,10 @@ config BPF_UNPRIV_DEFAULT_OFF disable it by setting it to 1 (from which no other transition to 0 is possible anymore). + Unprivileged BPF can be used to exploit potential speculative + execution side-channel vulnerabilities on affected hardware. If you + are concerned about it, answer Y. + source "kernel/bpf/preload/Kconfig" config BPF_LSM
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2.31.1