From: James Morse james.morse@arm.com
[ Upstream commit f300769ead032513a68e4a02e806393402e626f8 ]
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 james.morse@arm.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Acked-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Pu Lehui pulehui@huawei.com --- 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 2691e53007eb..654e7ed2d1a6 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -341,6 +341,9 @@ 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;