6.6-stable review patch. If anyone has any objections, please let me know.
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From: James Morse james.morse@arm.com
commit f300769ead032513a68e4a02e806393402e626f8 upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/net/bpf_jit_comp.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -666,6 +666,9 @@ static void __maybe_unused build_bhb_mit 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;