diff --git a/ipc/util.h b/ipc/util.h
index f2f5036..59d78aa 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -148,9 +148,9 @@
 #endif
 
 extern void free_msg(struct msg_msg *msg);
-extern struct msg_msg *load_msg(const void __user *src, int len);
+extern struct msg_msg *load_msg(const void __user *src, size_t len);
 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
-extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
+extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
 
 extern void recompute_msgmni(struct ipc_namespace *);