Sandboxing in Linux

Question

I want to create a Web app which would allow the user to upload some C code, and see the results of its execution (the code would be compiled on the server). The users are u

Answer 1

I'd say this is extremely dangerous on many levels. You're essentially opening yourself up to any exploit that can be found on your system (whereas you're normally limited to the ones people can exploit remotely). I'd say don't do it if you can avoid it.

If you do want to do it, you might want to use some kind of virtual machine to run the user's code. Using something like KVM it's possible to set up a number of virtual machines using the same base image (you can even store a snapshot in an already-booted state, though I'm not sure how it will handle being cloned). You can then create the VMs on demand, run the user's code, return the results, and then kill off the VM. If you keep the VMs isolated from each other and the network, the users can wreak any havoc they want and it won't hurt your physical server. The only danger you're exposing yourself to under these conditions would be some kind of exploit that allows them to escape from the VM... those are extremely rare, and will be more rare as hardware virtualization improves.