On 8/21/24 6:31 AM, Ma Ke wrote:
bpf_object__btf() can return NULL value. If bpf_object__btf returns null,
do not progress through codegen_subskel_datasecs(). This avoids a null ptr
dereference.
Found by code review, complie tested only.
Do you have a real case to show null ptr reference here?
Code review and compile test are not enough. You should have
a real reproducible case before you send the patch.
For this particular case, we have check
btf = bpf_object__btf(obj);
if (!btf) {
err = -1;
p_err("need btf type information for %s", obj_name);
goto out;
}
which ensures that btf is available before codegen for subskeleton,
so what you described won't happen in practice.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 00389c58ffe9 ("bpftool: Add support for subskeletons")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
---
tools/bpf/bpftool/gen.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 5a4d3240689e..7ce62f280310 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -334,6 +334,9 @@ static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name
const char *sec_name, *var_name;
__u32 var_type_id;
+ if (!btf)
+ return -EINVAL;
+
d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
if (!d)
return -errno;
