utsns: Add a limit on the number of uts namespaces

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 9ee9482..f9df7dd 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -27,6 +27,7 @@
 enum ucount_type {
 	UCOUNT_USER_NAMESPACES,
 	UCOUNT_PID_NAMESPACES,
+	UCOUNT_UTS_NAMESPACES,
 	UCOUNT_COUNTS,
 };
 
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 5093f58..60f0bb8 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -24,6 +24,7 @@
 	struct kref kref;
 	struct new_utsname name;
 	struct user_namespace *user_ns;
+	struct ucounts *ucounts;
 	struct ns_common ns;
 };
 extern struct uts_namespace init_uts_ns;