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Does anyone know a good sandboxing technology to execute user written javascript in a safe way? (like, on other user machines or on the server)? I have som

Does anyone know a good sandboxing technology to execute user written javascript in a safe way? (like, on other user machines or on the server)? I have some ideas like "learn programming" that would benefit from this immensely.

dougk16 10y ago
https://developers.google.com/caja/ https://developers.google.com/caja/ Used it a few years ago. It was a little finnicky to get working right but I was impressed at the time. No idea where the project is at nowadays.
- novaleaf 10y ago
  i saw caja, but it looks really complex, was hoping for something better these days :(
- AgentME 10y ago
  Note that caja doesn't protect against local denial-of-service attacks: user-written javascript executed with it could allocate tons of memory or run forever (`while(true){}`). This may or may not be a problem depending on your use-case. (If you're using caja for code written by mostly-trusted 3rd parties, or for one user's code only on their own machine, then it's not much of an issue. If you're serving code written by one user to another, then it could be a problem.)
  - dougk16 10y ago
    Ha, here's an old thread where I asked the caja developers about that exact scenario: https://groups.google.com/forum/#!topic/google-caja-discuss/RAi-hHiClRA https://groups.google.com/forum/#!topic/google-caja-discuss/... Some possible mitigations but I don't know if they ever implemented them.
SomeHacker44 10y ago
What about Node.js's `vm` module?
- novaleaf 10y ago
  thanks, I didn't actually know about that. it looks like a perfect (and simple) solution for running on nodejs. wish there was something like that for browsers too! edit: i guess there is this: https://github.com/substack/vm-browserify https://github.com/substack/vm-browserify
- AgentME 10y ago
  Note that the vm module doesn't protect against local denial-of-service attacks: user-written javascript executed with it could allocate tons of memory or run forever (despite any configured timeouts: https://github.com/nodejs/node/issues/3020 https://github.com/nodejs/node/issues/3020).
wyager 10y ago
The safest way would be to embed an interpreter written in JS and remove any sort of I/O or FFI capability from the interpreter.
techplex 10y ago
Niel Fraser, the guy who created the Blockly block programming toolkit also created a JS Interpreter which allows single stepping of code. https://neil.fraser.name/software/JS-Interpreter/docs.html https://neil.fraser.name/software/JS-Interpreter/docs.html
- thomasballinger 10y ago
  I've hacked on this interpreter some, it's pretty nice to read! It implements a very limited subset of JavaScript, something like ES3. I'd be really interested to hear about other similar implementations of JavaScript in JavaScript. I stopped working on https://github.com/thomasballinger/hotswapping-js-interp#js-interpreter-with-hot-swappable-functions https://github.com/thomasballinger/hotswapping-js-interp#js-... partially because copying the state of the interpreter was relatively slow. I'd be interested in implementations that would handle this better by using a more bytecode-like VM or immutable data structures.
  - novaleaf 10y ago
    wow! this is really awesome and perfect for my needs. thanks very much :)

dougk16 10y ago

https://developers.google.com/caja/ https://developers.google.com/caja/ Used it a few years ago. It was a little finnicky to get working right but I was impressed at the time. No idea where the project is at nowadays.

novaleaf 10y ago
i saw caja, but it looks really complex, was hoping for something better these days :(
AgentME 10y ago
Note that caja doesn't protect against local denial-of-service attacks: user-written javascript executed with it could allocate tons of memory or run forever (`while(true){}`). This may or may not be a problem depending on your use-case. (If you're using caja for code written by mostly-trusted 3rd parties, or for one user's code only on their own machine, then it's not much of an issue. If you're serving code written by one user to another, then it could be a problem.)
- dougk16 10y ago
  Ha, here's an old thread where I asked the caja developers about that exact scenario: https://groups.google.com/forum/#!topic/google-caja-discuss/RAi-hHiClRA https://groups.google.com/forum/#!topic/google-caja-discuss/... Some possible mitigations but I don't know if they ever implemented them.

SomeHacker44 10y ago

What about Node.js's `vm` module?

novaleaf 10y ago
thanks, I didn't actually know about that. it looks like a perfect (and simple) solution for running on nodejs. wish there was something like that for browsers too! edit: i guess there is this: https://github.com/substack/vm-browserify https://github.com/substack/vm-browserify
AgentME 10y ago
Note that the vm module doesn't protect against local denial-of-service attacks: user-written javascript executed with it could allocate tons of memory or run forever (despite any configured timeouts: https://github.com/nodejs/node/issues/3020 https://github.com/nodejs/node/issues/3020).

wyager 10y ago

The safest way would be to embed an interpreter written in JS and remove any sort of I/O or FFI capability from the interpreter.

techplex 10y ago

Niel Fraser, the guy who created the Blockly block programming toolkit also created a JS Interpreter which allows single stepping of code. https://neil.fraser.name/software/JS-Interpreter/docs.html https://neil.fraser.name/software/JS-Interpreter/docs.html

thomasballinger 10y ago
I've hacked on this interpreter some, it's pretty nice to read! It implements a very limited subset of JavaScript, something like ES3. I'd be really interested to hear about other similar implementations of JavaScript in JavaScript. I stopped working on https://github.com/thomasballinger/hotswapping-js-interp#js-interpreter-with-hot-swappable-functions https://github.com/thomasballinger/hotswapping-js-interp#js-... partially because copying the state of the interpreter was relatively slow. I'd be interested in implementations that would handle this better by using a more bytecode-like VM or immutable data structures.
- novaleaf 10y ago
  wow! this is really awesome and perfect for my needs. thanks very much :)