tracing: dynevent: Add a missing lockdown check on dynevent

From: Masami Hiramatsu (Google) <[email protected]>

Since dynamic_events interface on tracefs is compatible with kprobe_events and uprobe_events, it should also check the lockdown status and reject if it is set.

Signed-off-by Masami Hiramatsu (Google) <[email protected]>

---
 kernel/trace/trace_dynevent.c |    4 ++++
 1 file changed, 4 insertions(+)

kernel/trace/trace_dynevent.c +4 -0

index 5d64a18cacac..d06854bd32b3 100644
@@ -230,6 +230,10 @@ static int dyn_event_open(struct inode *inode, struct file *file)
 {
 	int ret;
 
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
 	ret = tracing_check_open_get_tr(NULL);
 	if (ret)
 		return ret;