Check VLAN interface name.

alterator-net-eth/backend3/net-eth

@@ -1080,6 +1080,18 @@ vlan_edit() {
   write_iface_option "$cachedir/$new" "VID" "$vid"
 }
 
+check_vlan()
+{
+  local name="$1"; shift
+
+  [ -n "$name" ] || return 1
+
+  if echo "$name" | grep -qs '^[[:alnum:]]$'; then
+      return 0
+  fi
+
+  return 1
+}
 
 # ADD NEW VLAN FOR SELECTED INTERFACE
 vlan_add_new() {
@@ -1095,7 +1107,8 @@ vlan_add_new() {
     return
   fi
 
-  if [ -z "$name" ]; then
+  if ! check_vlan "$name"; then
+    write_error "`_ "Invalid VLAN name: $name"`"
     return
   fi