How does it deal with infinite loops in untrusted code?

It runs them infinitely. :) But, sure, we can get into that shortly.

Well, they run… forever. And block the execution =|

This would make a great tool in a bot on #ruby-lang, so you could:

irb: [1,2,3].each { |n| n + 1 }

and have it show the results on the spot. It would need to have a time limiter and an output limiter, but it would be very handy as a teaching tool.

Barfs on OS X … haven’t really had time to look into it more but here’s what we get:

dyld: NSLinkModule() error
dyld: Symbol not found: _SPECIAL_SINGLETON
  Referenced from: /usr/local/lib/ruby/gems/1.8/gems/sandbox-0.0.11/lib/sand_table.bundle
  Expected in: flat namespace

Trace/BPT trap

Ahhhh, I can see it now. A great ruby colosseum shall come to pass. With ruby scripts battling ruby scripts to the death! And one ruby interpreter to rule them all!

You The Man Now DAWG !

kevin: Oh, goody. Well, I’m not using that macro really anyway. I just put out a new gem… try?

Greatness! We’ll be seeing this slapped into balloon shortly, right?
Patrick: We already have one in camping (?eval) and TryRuby in Second Life.

require "rubygems" 
require "sandbox" 
s = Sandbox.new
s.eval("blah")

$ ruby test.rb 
(eval):1: [BUG] Bus Error
ruby 1.8.4 (2005-12-24) [powerpc-darwin8.6.0]

Abort trap

requiring files/undeclared variables all cause it to crash on my machine. Also, shouldn’t the value returned from Sandbox#eval be tainted?

IIRC , modruby exists so one doesn’t have many interpreters running on the server. If all the cgis run in sandboxes… Or is that silly?

acrylic: It’s because I haven’t finished the exception handling. And, in addition, the return value needs to be Marshalled (and tainted) for import into the master interp.

hgs: Sandboxes are pretty inexpensive. About 16K for the base. The reason mod_ruby doesn’t use multiple interpreters is because it can’t. I’m not suggesting CGIs should each have a sandbox. But each Rails app could have their own.

Mah head asplode.

FlashHater: is the code for that bot public anywhere? as an rbot plugin?

Patrick: I don’t know. It’s not entirely hard, as TryRuby has a nice kinda-API. See Rubyless Ruby for more details.

So you basically took the whole Ruby environment and turned it into a reusable variable. Very cool. Kind of what I suggested in my last ruby-talk post about selector namespaces. Of course Austin bulked and said it would be the doom of Ruby. You’re just using it as a sandbox execution space at this point. Of course that’s all good. But what’s the status on our selector namespace apocalypse? ;)

I am very much in awe. JPG stars and GIF angels for you!

I have been toying with allowing people to write postprocessing scripts for big ugly data queries on a big ugly (well kinda pretty) website I’ve been building. This is exacly what I needed to do it.

Anyone have any tips for getting these fine things to compile on the darkside of win32?

I’m really excited about the prospects of this sandbox. Well done! The examples you give are really, very cool. I’m going to see if I can hack together the little IRC IRB bot. I’ll definitely play with the idea of the reloading app, too. Fun stuff!

Thanks _why and all!

_why: works on OSX now. Sweet.

Windows users need love on this one! I can’t compile the extension :(

nothing to do with this but where can i find the markaby community to discuss the replacement of @content_for with yield?

Most excellent work.

holy freakin hell, I knew you’d come through with this eventually _why. I had faith and was rewarded!

(I’ve wanted this for a rails CMS for some time)

Wow, great timing, I was trying to think how to do something like this…

Sweet! Now textile needs an accomplice API . Meta-textile with scriptability for meta-wiki linkability. The problem is, sand boxes are way 80’s man. These are more like, like pink dumpster gardens…

This is very cool, especially for local use, but you can mimic this functionality using DRb and $SAFE, right? It’s remote and dependent on DRb, of course, but that’s just as safe, right? At least, that’s how ClassRoom works, but I haven’t done much security testing yet.. :)

what is fathom? do you have a link to it?

Actually, nix my comment. I’ve had a play and this kicks ass :)

You freakin idiot! This will bring the whole country to it’s knees!!!!!!!!!!!

Oops, sorry. Thought I was on the G dubbya Bush blog.

I propose a rename, to freakyfreakysandbox. I like the way it rolls off the toung.
Back to the snadbox, I think alot of people have been suggesting this, but _why delivers! (On time, and with minimal damage to the package too!)

Well, now that you mention it, I kind of like snadbox.

I just came back here to check if I had misspelled sandbox, as I am so apt to do. Snadbox is one of those misspellings that would make a good name…

_why deserves some kind of prize for this.

Yay! Ambiguous eating utensil!

Fathom is really just a word meaning: to understand. Of course, in this context, it has a bit of ‘hmph!’ to it and it really means “can you imagine how cool this will be?” Fathom. :)

ben: I really appreciate that. I need those holy gals right now.

Okay, some segfaults are starting to disappear and I’ve got some tests that start up hundreds of sandboxes and benchmark. Creating a Sandbox is a bit of a performance hit, so try to reuse them. I mean on my laptop a Ruby process can make about a hundred sandboxes in a second, but can run tenthousand evals in a second.

How does it know what is to be trusted or not? Can someone provide an explanation of why (pardon the pun) I can be sure that this won’t be invalidated down the line by some trivial means of injecting new untrusted code…? How are all the paths of entry being protected? Just curious, as i’ve no idea of the Ruby internals that needed to be tweaked for this hack.

Thanks :)

james: From what I understand, _why’s basicaly shifting the context of the ruby interpreter when you eval in the sandbox. This way, since currently there is no way for a sandbox to see “up”, anything running outside of it is safe. Of course, this is all speculation on my part, as I haven’t the stomach to read C. (well, yes I do, but I have no idea how ruby really works…)

I approve of my name being attached to this as many times as seems appropriate.

Isn’t YARV supposed to support multiple interpreters in a single process?

Is there a way to dump the Sandbox? marshal_dump isn’t defined in the Sanbox class at the moment.

Bovi: There will be Sandbox#dup, Sandbox#_dump and Sandbox#_load.

This should make for an interesting alternative to Liquid: ERb in a Sandbox.

Can you do

“Dir.entries(’..’).each {|f| File.delete f }”

?

Alright! Now on to writing a mud in ObjectSpace

FlashHater: Right, so the code running the Sandbox can’t be modified by the sandbox itself…

But that still leaves the remaining problem of sandbox code being able to do things it shouldn’t…or is this something you’d just rely on $SAFE fixing?

Anyway, liking the direction this is going, good stuff :)

hm, there is a eval bot in #ruby-lang. :)

Ohh, awesome sauce here why! I leave town for a week and this is what you do! Cool!

Dude, Drew, from way early in the comments, I had already thought of that a while ago, making a Ruby port of the old game droidbattles. But before sandbox, I had no idea how to keep them from just hacking other droids by modifying their classes. Yay for sandbox!