bpf: Fix maximum permitted number of arguments check

Since the m->arg_size array can hold up to MAX_BPF_FUNC_ARGS argument
sizes, it's ok that nargs is equal to MAX_BPF_FUNC_ARGS.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220324164238.1274915-1-ytcoode@gmail.com

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 24788ce..0918a39 100644 (file)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5507,7 +5507,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
        }
        args = (const struct btf_param *)(func + 1);
        nargs = btf_type_vlen(func);
-       if (nargs >= MAX_BPF_FUNC_ARGS) {
+       if (nargs > MAX_BPF_FUNC_ARGS) {
                bpf_log(log,
                        "The function %s has %d arguments. Too many.\n",
                        tname, nargs);