Commit 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program")
cached btf_id in struct bpf_iter_target_info so later on
if it can be checked cheaply compared to checking registered names.
syzbot found a bug that uninitialized value may occur to
bpf_iter_target_info->btf_id. This is because we allocated
bpf_iter_target_info structure with kmalloc and never initialized
field btf_id afterwards. This uninitialized btf_id is typically
compared to a u32 bpf program func proto btf_id, and the chance
of being equal is extremely slim.
This patch fixed the issue by using kzalloc which will also
prevent future likely instances due to adding new fields.
Reported-by: syzbot+580f4f2a272e452d55cb@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program")
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
kernel/bpf/bpf_iter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 5454161407f1..a0d9eade9c80 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -287,7 +287,7 @@ int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info)
{
struct bpf_iter_target_info *tinfo;
- tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL);
+ tinfo = kzalloc(sizeof(*tinfo), GFP_KERNEL);
if (!tinfo)
return -ENOMEM;
--
2.24.1
