From: Andrii Nakryiko <andrii@xxxxxxxxxx> [ Upstream commit 88918dc12dc357a06d8d722a684617b1c87a4654 ] If BTF is corrupted DATASEC's variable type ID might be incorrect. Prevent this easy to detect situation with extra NULL check. Reported by oss-fuzz project. Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Acked-by: Yonghong Song <yhs@xxxxxx> Link: https://lore.kernel.org/bpf/20211103173213.1376990-3-andrii@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/lib/bpf/libbpf.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b5bf1c074832e..18651e11b9ba3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2752,13 +2752,12 @@ static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { t_var = btf__type_by_id(btf, vsi->type); - var = btf_var(t_var); - - if (!btf_is_var(t_var)) { + if (!t_var || !btf_is_var(t_var)) { pr_debug("Non-VAR type seen in section %s\n", name); return -EINVAL; } + var = btf_var(t_var); if (var->linkage == BTF_VAR_STATIC) continue; -- 2.34.1
