From: Andrii Nakryiko <andrii@kernel.org>
Date: Wed, 3 Nov 2021 10:32:10 -0700
Subject: libbpf: Improve sanity checking during BTF fix up
Patch-mainline: v5.17-rc1
Git-commit: 88918dc12dc357a06d8d722a684617b1c87a4654
References: jsc#PED-1368
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@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211103173213.1376990-3-andrii@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/lib/bpf/libbpf.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2752,13 +2752,12 @@ static int btf_fixup_datasec(struct bpf_
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;