On 2/15/24 10:23, Martin KaFai Lau wrote:
On 2/14/24 6:24 PM, thinker.li@xxxxxxxxx wrote:
From: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Recently, cfi_stubs were introduced. However, existing struct_ops types
that are not in the upstream may not be aware of this, resulting in
kernel
crashes. By rejecting struct_ops types that do not provide cfi_stubs
during
registration, these crashes can be avoided.
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
---
kernel/bpf/bpf_struct_ops.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 0d7be97a2411..e35958142dce 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct
bpf_struct_ops_desc *st_ops_desc,
}
sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
+ if (!st_ops->cfi_stubs) {
How about *(void **)(st_ops->cfi_stubs + moff) ? Does it need a NULL check?
This NULL check is necessary to prevent the crash but good to have.
Please add a test.
Got it!
+ pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
+ return -EINVAL;
+ }
+
type_id = btf_find_by_name_kind(btf, st_ops->name,
BTF_KIND_STRUCT);
if (type_id < 0) {
