Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: Pavel Machek <pavel <at> ucw.cz>
Subject: Re: RFC: disablenetwork facility. (v4)
Newsgroups: gmane.linux.kernel.lsm
Date: Sunday 27th December 2009 19:08:02 UTC (over 8 years ago)
Hi!

> > I think seccomp() is too much restricted to apply for general
applications.
> > Most applications will need some other syscalls in addition to exit(),
read()
> > and write(). Most applications cannot use seccomp().
> > 
> > What I want to do is similar to seccomp(), but allows userland process
to
> > forbid some syscalls like execve(), mount(), chroot(), link(),
unlink(),
> > socket(), bind(), listen() etc. selectively.
> 
> The nice thing about the disablenetwork module is that (AFAICS so far)
> it actually is safe for an unprivileged user to do.  I can't think of
> any setuid-root software which, if started with restricted-network by
> an unprivileged user, would become unsafe rather than simply
> failing.

"I can't see" is not strong enough test, I'd say.

For example, I can easily imagine something like pam falling back to
local authentication when network is unavailable. If you disable
network for su...

It would be also extremely easy to DoS something like sendmail -- if
it forks into background and then serves other users' requests.

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe
linux-security-module" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
 
CD: 3ms