From f300769ead032513a68e4a02e806393402e626f8 Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 29 Apr 2025 16:03:38 +0100 Subject: [PATCH] arm64: bpf: Only mitigate cBPF programs loaded by unprivileged users Support for eBPF programs loaded by unprivileged users is typically disabled. This means only cBPF programs need to be mitigated for BHB. In addition, only mitigate cBPF programs that were loaded by an unprivileged user. Privileged users can also load the same program via eBPF, making the mitigation pointless. Signed-off-by: James Morse Reviewed-by: Catalin Marinas Acked-by: Daniel Borkmann --- arch/arm64/net/bpf_jit_comp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 0ab8e47062d9..634d78422adb 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -952,6 +952,9 @@ static void __maybe_unused build_bhb_mitigation(struct jit_ctx *ctx) arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE) return; + if (capable(CAP_SYS_ADMIN)) + return; + if (supports_clearbhb(SCOPE_SYSTEM)) { emit(aarch64_insn_gen_hint(AARCH64_INSN_HINT_CLEARBHB), ctx); return; -- 2.50.1