If you give someone telnet access or ssh access and allow them to do C/C++ code, is this just a risk that you take that someone would/could write some malicious code to do evil things? Or is there a way to isolate what is happening with their C/C++ code?

Thanks.

Gregg

If you mean you allow them to compile such code, or even write executable files, then they might be able to exploit a vunerability in a service or program, but your file permissions still apply and their apps will run with their user id and permissions.

There are kernel compilation options to try to stop things like buffer overflow exploits, and many complex system integrity apps out there, it just depends how closely you want to monitor and how much to restrict.

Thanks for the reply. Basically, I have a few friends who want to learn how to program. Most are on dial-up so downloading something they can use to learn with can take some time. Even the smallest cygwin download sucks on dial-up. I have a DSL connection so I thought I would give them telnet/ssh access to use my gcc and g++ to help them learn.

However, I know my friends a little too well.

But for the most part, unless they really know the ins and outs, people that are just learning how to program, I shouldn't have to worry too much, right? I mean, I know enough to teach them, and wouldn't really know how to exploit a Linux box myself.

if your on dsl then why not just download a compiler for them? make sure the permissions are correct in /dev or they can have great fun with your soundcard and other hardware. make sure everything that doesnt need to be set{u,g}id isnt. set a max processor and max memory limit for them so they cant crash your machine. you can make things as secure as you like but if you trust them that that should be plenty. dont use telnet it is completely unsecure. there is a great ssh client for windows called putty.

Not quite understanding the need for a fast internet connection to learn to program. Reading Slashdot doesnt count as work or learning

If you're letting them compile or even just save and execute code, then they could concievably nose around your box, track down some exploit code for a running service/installed app, and then gain root access. But all processes and files have permissions, so as long as your config files and executable binaries are root-write-only etc you should be fine.

unSpawn, mod in the Security forum here, knows a heck of a lot about all this.