+++ b/sysdeps/unix/sysv/linux/if_index.c
@@ -38,12 +38,19 @@ __if_nametoindex (const char *ifname)
   return 0;
 #else
   struct ifreq ifr;
+  if (strlen (ifname) >= IFNAMSIZ)
+    {
+      __set_errno (ENODEV);
+      return 0;
+    }
+
+  strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
+
   int fd = __opensock ();
 
   if (fd < 0)
     return 0;
 

  StatusPtr first_bad_status(nullptr);

  for (const auto& dt : device_threads_) {
    StatusPtr async_wait_status(TF_NewStatus());
    dt->AsyncWait(async_wait_status.get());
    // Prefer non cancelled errors to uncover real failures.
    if (TF_GetCode(async_wait_status.get()) != TF_OK &&
        (first_bad_status == nullptr ||
         TF_GetCode(first_bad_status.get()) == TF_CANCELLED)) {
      first_bad_status.reset(TF_NewStatus());