diff --git a/timeoutd.c b/timeoutd.c
index d5d9b17..1fd1a27 100644
--- a/timeoutd.c
+++ b/timeoutd.c
@@ -138,7 +138,7 @@ struct config_ent {
 
 struct config_ent *config[MAXLINES + 1];
 char errmsg[256];
-char dev[sizeof(utmpp->ut_line)];
+char dev[sizeof(utmpp->ut_line) + 1];
 unsigned char limit_type;
 int configline = 0;
 int pending_reread = 0;