diff --git a/lib/tun.c b/lib/tun.c
index 0f39994..03d057c 100644
--- a/lib/tun.c
+++ b/lib/tun.c
@@ -688,7 +688,7 @@ int tun_new(struct tun_t **tun)
   } 
   
   strncpy((*tun)->devname, ifr.ifr_name, IFNAMSIZ);
-  (*tun)->devname[IFNAMSIZ] = 0;
+  (*tun)->devname[IFNAMSIZ-1] = 0;
   
   ioctl((*tun)->fd, TUNSETNOCSUM, 1); /* Disable checksums */
   return 0;
diff --git a/lib/tun.h b/lib/tun.h
index 714144a..7972c53 100644
--- a/lib/tun.h
+++ b/lib/tun.h
@@ -45,7 +45,7 @@ struct tun_t {
   struct in_addr netmask;
   int addrs;             /* Number of allocated IP addresses */
   int routes;            /* One if we allocated an automatic route */
-  char devname[IFNAMSIZ+1];/* Name of the tun device */
+  char devname[IFNAMSIZ];/* Name of the tun device */
   int (*cb_ind) (struct tun_t *tun, void *pack, unsigned len);
 };