diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9c6ad157a..b71c5274b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4708,8 +4708,15 @@ static int check_map_kptr_access(struct bpf_verifier_env *env, return ret; } else if (class == BPF_STX) { val_reg = reg_state(env, value_regno); - if (!bpf_register_is_null(val_reg) && - map_kptr_match_type(env, kptr_field, val_reg, value_regno)) + if (bpf_register_is_null(val_reg)) { + /* + * This store is valid only because the scalar is known to be + * zero. Mark it precise so another scalar cannot be pruned + * against this state. + */ + return mark_chain_precision(env, value_regno); + } + if (map_kptr_match_type(env, kptr_field, val_reg, value_regno)) return -EACCES; } else if (class == BPF_ST) { if (insn->imm) { |