kernel: added new prctl CMD_GET_MANAGER_UID to get the uid of the crowned manager (tiann#2673)

Author: rifsxd

kernel/core_hook.c

@@ -413,6 +413,17 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 		return 0;
 	}
 
+	if (arg2 == CMD_GET_MANAGER_UID) {
+		uid_t manager_uid = ksu_get_manager_uid();
+		if (copy_to_user(arg3, &manager_uid, sizeof(manager_uid))) {
+			pr_err("get manager uid failed\n");
+		}
+		if (copy_to_user(result, &reply_ok, sizeof(reply_ok))) {
+			pr_err("prctl reply error, cmd: %lu\n", arg2);
+		}
+		return 0;
+	}
+
 	// all other cmds are for 'root manager'
 	if (!from_manager) {
 		return 0;

kernel/ksu.h

@@ -23,6 +23,7 @@
 #define CMD_UID_SHOULD_UMOUNT 13
 #define CMD_IS_SU_ENABLED 14
 #define CMD_ENABLE_SU 15
+#define CMD_GET_MANAGER_UID 16
 
 #define EVENT_POST_FS_DATA 1
 #define EVENT_BOOT_COMPLETED 2