diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 6528a79d998d08120e9e80524164e5c759d911f3..9cfa46d8d14f16ce006460b3c870bd3fa921c1a6 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -11,6 +11,7 @@
 
 #include <linux/kernel.h>
 #include <linux/errno.h>
+#include <linux/string.h>
 #include <keys/system_keyring.h>
 #include <crypto/public_key.h>
 #include "module-internal.h"