kernel: avoding other root process being kprobed

kernel/selinux/selinux.c

@@ -18,6 +18,8 @@
 
 #define KERNEL_SU_DOMAIN "u:r:su:s0"
 
+static u32 ksu_sid;
+
 static int transive_to_domain(const char* domain) {
     struct cred* cred;
     struct task_security_struct* tsec;
@@ -35,6 +37,8 @@ static int transive_to_domain(const char* domain) {
 	error = security_secctx_to_secid(domain, strlen(domain), &sid);
 	pr_info("error: %d, sid: %d\n", error, sid);
 	if (!error) {
+        if (!ksu_sid) ksu_sid = sid;
+
 		tsec->sid = sid;
 		tsec->create_sid = 0;
 		tsec->keycreate_sid = 0;
@@ -97,4 +101,8 @@ bool getenforce() {
 #else
     return false;
 #endif
+}
+
+bool is_ksu_domain() {
+    return ksu_sid && current_sid() == ksu_sid;
 }