From: Yonghong Song Date: Mon, 13 Jun 2022 05:43:14 +0000 (-0700) Subject: libbpf: Fix an unsigned < 0 bug X-Git-Tag: v6.6.17~6916^2~339^2~12 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c49a44b39b313a4191ca2f06316c547ee673264e;p=platform%2Fkernel%2Flinux-rpi.git libbpf: Fix an unsigned < 0 bug Andrii reported a bug with the following information: 2859 if (enum64_placeholder_id == 0) { 2860 enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0); >>> CID 394804: Control flow issues (NO_EFFECT) >>> This less-than-zero comparison of an unsigned value is never true. "enum64_placeholder_id < 0U". 2861 if (enum64_placeholder_id < 0) 2862 return enum64_placeholder_id; 2863 ... Here enum64_placeholder_id declared as '__u32' so enum64_placeholder_id < 0 is always false. Declare enum64_placeholder_id as 'int' in order to capture the potential error properly. Fixes: f2a625889bb8 ("libbpf: Add enum64 sanitization") Reported-by: Andrii Nakryiko Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220613054314.1251905-1-yhs@fb.com --- diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0781fae..d989b0a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2786,7 +2786,7 @@ static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); - __u32 enum64_placeholder_id = 0; + int enum64_placeholder_id = 0; struct btf_type *t; int i, j, vlen;