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However the verifier does not check against a scalar NULL, leading to real NULL pointer dereference. Reject it as well. Fixes: 94e1c70a3452 ("bpf: support 'arg:xxx' btf_decl_tag-based hints for global subprog args") Acked-by: Eduard Zingerman Signed-off-by: Amery Hung --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 99444eae917e..7aa47342dc65 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9189,7 +9189,8 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, return ret; if (check_mem_reg(env, reg, argno, arg->mem_size)) return -EINVAL; - if (!(arg->arg_type & PTR_MAYBE_NULL) && (reg->type & PTR_MAYBE_NULL)) { + if (!(arg->arg_type & PTR_MAYBE_NULL) && + (type_may_be_null(reg->type) || bpf_register_is_null(reg))) { bpf_log(log, "%s is expected to be non-NULL\n", reg_arg_name(env, argno)); return -EINVAL; -- 2.52.0