On Wed, 20 Jan 1999, Kenneth Jacker wrote:
> But since "modules" run as part of the kernel, can't a (malicious)
> user essentially execute what they wish within their module code
> (e.g., change ownership of files, access restricted info, etc.)?
> Hopefully my fears are unwarranted.
>
> I figure that I have two options:
>
> o Use the root-limiting capability of 'sudo' and "trust the Force"
>
> o Disconnect the real-time machines from our campus net
>
> I am most interested in your comments. How do you allow your users
> access to 'insmod', etc.? Do you just "trust" them? Have you had any
> problems similar to those I have aired above?
You can trust your students to load standard modules, compiled by you. E.g
allow by sudo "/sbin/insmod /lib/modules/misc/rt_xxx.o". But if you allow
inserting modules written and compilled by students, then this is kernel
space and if they have enough knowledge (or find relevant site on the
Internet) they can do everything.
You may try to assemble some SUID script taking the source file, sending it
to you, compiling and inserting as a module. Then at least you know what code
was executed. But this is all lots of trouble.
I would recommend making a master copy of installed RT-Linux system HD
partition, and giving student root access. Disconnect from your campus net,
or use another Linux as a firewall passing only FTP and HTTP, so students can
browse LLP site :-)
You may even thing about fitting RT-Linux on a single floppy and giving it to
students (see http://www.linuxrouter.org/)
Regards,
--
Tomasz Motylewski
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
