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SubjectRe: Testers wanted: exorcised kmod.c: no more daemon!
On Mon, 13 Apr 1998, Craig Milo Rogers wrote:

[snipped]
> Ugh! But this sounds like you'd just opened a wound in
> security. I can imagine circumstances in which someone might want to
> allow an anonymous FTP user to access data through a path that
> requires an autoloaded kernel module, but loading kernel modules from
> the anonymous FTP area itself??? Even if the kernel module files have
> file protections that prevent access by the anonymous FTP server's
> processes in normal conditions, you've created an outstanding way to
> infect the kernel and take over the system if that first layer of
> protection is broken.
>
Thing is, I can't think of a reason why you would want someone playing
around as root in a chrooted environment anyway. If they're in an ftp
area, they should just be accessing files - they shouldn't have any
ability to mount drives, etc... If a person gets root in a chrooted
environment (they need root to do anything that could execute a
request_module), they can break out and get the "real" root. I don't see
how this is really a big problem

Other way to handle things is to make sure that there's no /sbin/modprobe
in the chroot'ed environment, then all request_modules executed from that
environment will fail.
As long as request_module can only be run by root, I think we're okay. Of
course, that's only my opinion, I could be (probably am) wrong :)


Greg Zornetzer - gaz+@andrew.cmu.edu
"Light shines brightest in the darkest night"
http://www.contrib.andrew.cmu.edu/~gaz



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