The patch below does not apply to the 5.11-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9601148392520e2e134936e76788fc2a6371e7be Mon Sep 17 00:00:00 2001
From: Daniel Borkmann daniel@iogearbox.net Date: Tue, 23 Mar 2021 08:32:59 +0100 Subject: [PATCH] bpf: Use correct permission flag for mixed signed bounds arithmetic
We forbid adding unknown scalars with mixed signed bounds due to the spectre v1 masking mitigation. Hence this also needs bypass_spec_v1 flag instead of allow_ptr_leaks.
Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF") Signed-off-by: Daniel Borkmann daniel@iogearbox.net Reviewed-by: John Fastabend john.fastabend@gmail.com Acked-by: Alexei Starovoitov ast@kernel.org
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3a738724a380..2ede4b850230 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6085,7 +6085,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, dst, reg_type_str[ptr_reg->type]); return -EACCES; case PTR_TO_MAP_VALUE: - if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { + if (!env->env->bypass_spec_v1 && !known && (smin_val < 0) != (smax_val < 0)) { verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", off_reg == dst_reg ? dst : src); return -EACCES;