From a8f12572860ad8ba659d96eee9cf09e181f6ebcc Mon Sep 17 00:00:00 2001 From: Christophe JAILLET Date: Fri, 8 Sep 2023 18:33:35 +0200 Subject: [PATCH] bpf: Fix a erroneous check after snprintf() snprintf() does not return negative error code on error, it returns the number of characters which *would* be generated for the given input. Fix the error handling check. Fixes: 57539b1c0ac2 ("bpf: Enable annotating trusted nested pointers") Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/393bdebc87b22563c08ace094defa7160eb7a6c0.1694190795.git.christophe.jaillet@wanadoo.fr Signed-off-by: Alexei Starovoitov --- kernel/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 1095bbe298593..8090d7fb11ef6 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8501,7 +8501,7 @@ bool btf_nested_type_is_trusted(struct bpf_verifier_log *log, tname = btf_name_by_offset(btf, walk_type->name_off); ret = snprintf(safe_tname, sizeof(safe_tname), "%s%s", tname, suffix); - if (ret < 0) + if (ret >= sizeof(safe_tname)) return false; safe_id = btf_find_by_name_kind(btf, safe_tname, BTF_INFO_KIND(walk_type->info));