Running JS code on a server

Eliezer Julian Eliezer.Julian at
Mon May 1 16:20:04 UTC 2017

How, thanks for the suggestions. Like I wrote in my original post I have already limited class access. My concern now is something like an endless loop or extreme memory allocation which can tie up resources of the server

From: G W <grwongku at>
Sent: Monday, May 1, 2017 6:18:02 PM
To: Eliezer Julian
Cc: nashorn-dev at; Chen Malka; Elior Apelbaum; Moshe Robinov
Subject: Re: Running JS code on a server

Have you tried implementing jdk.nashorn.api.scripting.ClassFilter to limit Class access. Also for resource access, you need to to create wrappers.
e.g. for File access:
function File(f){
this.file = f;
this.delete = function(){
return this;
this.create = function(dr){
return this;
} = function(){
this.exists = function(){
return org.sprnkl.server.js.SprnklFile.exists(jsrequestobj,this.file);
this.length = function(){
return Math.round(org.sprnkl.server.js.SprnklFile.length(jsrequestobj,this.file));
this.list = function(){
return org.sprnkl.server.js.SprnklFile.list(jsrequestobj,this.file);
this.isDirectory = function(){
return org.sprnkl.server.js.SprnklFile.isDirectory(jsrequestobj,this.file);
this.readString = function(){
var rb =;
var rb2 = [];
for (var ct = 0;ct < rb.length;ct++){
return String.fromCharCode.apply(String, rb2);
this.write = function(b,dr){
if (dr == undefined) dr = true;

return this;
this.writeString = function(s,dr){
return this.write(s.getBytes(),dr);

I have a Framework that is  a work in process. Would be happy to share the code if interested.

On Mon, May 1, 2017 at 8:55 AM, Jim Laskey (Oracle) <james.laskey at<mailto:james.laskey at>> wrote:
From: Eliezer Julian <Eliezer.Julian at<mailto:Eliezer.Julian at> <mailto:Eliezer.Julian at<mailto:Eliezer.Julian at>>>
Subject: Running JS code on a server
Date: May 1, 2017 at 6:28:05 AM ADT
To: "nashorn-dev at<mailto:nashorn-dev at> <mailto:nashorn-dev at<mailto:nashorn-dev at>>" <nashorn-dev at<mailto:nashorn-dev at> <mailto:nashorn-dev at<mailto:nashorn-dev at>>>
Cc: Elior Apelbaum <Elior.Apelbaum at<mailto:Elior.Apelbaum at> <mailto:Elior.Apelbaum at<mailto:Elior.Apelbaum at>>>, Moshe Robinov <Moshe.Robinov at<mailto:Moshe.Robinov at> <mailto:Moshe.Robinov at<mailto:Moshe.Robinov at>>>, Chen Malka <chen.malka at<mailto:chen.malka at> <mailto:chen.malka at<mailto:chen.malka at>>>


I am developing a server side application and would like to add a feature that allows a user to submit JS code to be executed via Nashorn. My concern is that a user may submit malicious code that may compromise the server. I have already limited the script’s access to the bare minimum of Java classes, and have implemented a mechanize to kill the script if execution time runs over a certain limit. I have also manually removed many of the special methods such as print, echo, exit and quit from the Bindings object. However, this is extremely limited in scope compared to the damage a willfully malicious user may be able to effect via this feature (such as allocating too much memory, try to access the file system via the script, etc.). I was wondering if the Nashorn development team had any recommendations as far as security is concerned, and whether there are any plans to add additional security features in the future.


Eli Julian
Software Developer
Decision Division

Email: eliezer.julian at<mailto:eliezer.julian at> <mailto:eliezer.julian at<mailto:eliezer.julian at>>
Office: +972-3-7902155
Mobile: +972-50-3697238
Skype handle: eli_julian
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