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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 9601148392520e2e134936e76788fc2a6371e7be Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Reviewed-by: John Fastabend <john.fastabend@xxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
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;
