# Safe sandbox for running untrusted code **URL:** \ **Category:** Ruby\ **Created:** [June 2, 2008, 5:13pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289 "2008-06-02T17:13:31Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 2, 2008, 5:13pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/1 "2008-06-02T17:13:31Z")
Hello @all! I’m sorry if this has been answered before, but I’m looking for an expert voice for this question. I would need if Ruby have a safe mechanism of running unsafe code on a sandbox environment. Image this situation: I lunch a contest “solve this problem in Ruby”. The users submit their code, and my system runs the code on an sandbox, with memory and time constraints, and verifies if the output meets the required result. Basicly, I need a way to run Ruby code that reads from STDIN, writes to STDOUT, and I need to be sure it doesn’t run more than “x” seconds and don’t eat all my memory. It this possible with the current VM (MRI 1.8)? Thank you for your support. ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 2, 2008, 5:20pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/2 "2008-06-02T17:20:30Z")
2008/6/2 Ruben F. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > It this possible with the current VM (MRI 1.8)? There is at least $SAFE: [http://www.ruby-doc.org/docs/ProgrammingRuby/html/taint.html#S1](http://www.ruby-doc.org/docs/ProgrammingRuby/html/taint.html#S1) But AFAIK it does not prevent your CPU or memory going through the roof or just taking ages. Depending on your platform you might be able to do it using fork and having the parent kill the child if any of your constraints (time, memory) are violated. But then you are still not safe against system(“/bin/rm”, “-rf”, “/”). That’s where $SAFE helps. Kind regards robert ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 2, 2008, 6:07pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/3 "2008-06-02T18:07:18Z")
On Tue, 3 Jun 2008 00:18:49 +0900 “Robert K.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > don’t eat all my memory. > > still not safe against system(“/bin/rm”, “-rf”, “/”). That’s where > > $SAFE helps. > > Kind regards > > robert I’d run the code within a virtualised environment. You’d be safe to rm -rf / as the “virtual server” is safely contained. vserver, xen, openvz, virtualbox, lguest… There’s also the capability of changing ram, diskspace and loads of other stuff from outside of the virtual thang. /dev/jayeola ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 2, 2008, 6:21pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/4 "2008-06-02T18:21:33Z")
ara.t.howard wrote: > On Jun 2, 2008, at 9:12 AM, Ruben F. wrote: > > > It this possible with the current VM (MRI 1.8)? > > no. > > you will need to combine using $SAFE=12 (ruby side) and ulimit/chroot > from the unix side (or similar). hi! thanks for all your input! so does anybody knows how [http://tryruby.hobix.com/](http://tryruby.hobix.com/) does it? Ruben ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 2, 2008, 6:10pm UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/5 "2008-06-02T18:10:15Z")
On Jun 2, 2008, at 9:12 AM, Ruben F. wrote: > It this possible with the current VM (MRI 1.8)? no. you will need to combine using $SAFE=12 (ruby side) and ulimit/chroot from the unix side (or similar). a @ [http://codeforpeople.com/](http://codeforpeople.com/) ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 3, 2008, 8:59am UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/6 "2008-06-03T08:59:08Z")
On Mon, Jun 2, 2008 at 6:20 PM, Ruben F. wrote: > so does anybody knows how [http://tryruby.hobix.com/](http://tryruby.hobix.com/) does it? [http://code.whytheluckystiff.net/sandbox/](http://code.whytheluckystiff.net/sandbox/) and/or search for freaky freaky sandbox. IIRC \_why got some patches in ruby regarding this – see archives for ruby-core. J. ---
**Author:** ![rubenfonseca](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bcef8e/32.png) [@rubenfonseca](https://www.ruby-forum.com/u/rubenfonseca)\ **Post date:** [June 3, 2008, 10:01am UTC](https://www.ruby-forum.com/t/safe-sandbox-for-running-untrusted-code/139289/7 "2008-06-03T10:01:26Z")
Ruben F. wrote: > ara.t.howard wrote: > > > On Jun 2, 2008, at 9:12 AM, Ruben F. wrote: > > > > > It this possible with the current VM (MRI 1.8)? > > > > no. > > > > you will need to combine using $SAFE=12 (ruby side) and ulimit/chroot > > from the unix side (or similar). > > hi! thanks for all your input! > > so does anybody knows how [http://tryruby.hobix.com/](http://tryruby.hobix.com/) does it? > > Ruben [http://www.spoj.pl/info/](http://www.spoj.pl/info/) does this with 30 programming languages, including Ruby. I don’t know how. regards, Siep