From: Stephen Hemminger <shemminger@osdl.org>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [RFC] tcp: setsockopt congestion control autoload
Date: Thu, 26 Oct 2006 08:23:14 -0700 [thread overview]
Message-ID: <20061026082314.1dcea52c@freekitty> (raw)
In-Reply-To: <20061026145712.GA11062@2ka.mipt.ru>
On Thu, 26 Oct 2006 18:57:13 +0400
Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> On Thu, Oct 26, 2006 at 07:34:57AM -0700, Stephen Hemminger (shemminger@osdl.org) wrote:
> > Evgeniy Polyakov wrote:
> > >On Wed, Oct 25, 2006 at 11:08:43AM -0700, Stephen Hemminger
> > >(shemminger@osdl.org) wrote:
> > >
> > >>If user asks for a congestion control type with setsockopt() then it
> > >>may be available as a module not included in the kernel already.
> > >>It should be autoloaded if needed. This is done already when
> > >>the default selection is change with sysctl, but not when application
> > >>requests via sysctl.
> > >>
> > >>Only reservation is are there any bad security implications from this?
> > >>
> > >
> > >What if system is badly configured, so it is possible to load malicious
> > >module by kernel?
> > >
> > The kernel module loader has a fixed path. So one would have to be able
> > to create a module
> > in /lib/modules/<kernel release> in order to get the malicious code
> > loaded. If the intruder could
> > put a module there, it would be just as easy to patch an existing module
> > and have the
> > hack available on reboot.
>
> It just calls /sbin/modprobe, which in turn runs tons of scripts in
> /etc/hotplug, modprobe and other places...
> In the paranoid case we should not allow any user to load kernel
> modules, even known ones. Should this option be guarded by some
> capability check?
>
No capability check needed. Any additional paranoia belongs in /sbin/modprobe.
There seems to be lots of existing usage where a user can cause a module
to be loaded (see bin_fmt, xtables, etc).
--
Stephen Hemminger <shemminger@osdl.org>
next prev parent reply other threads:[~2006-10-26 15:28 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-25 18:08 [RFC] tcp: setsockopt congestion control autoload Stephen Hemminger
2006-10-25 23:21 ` Patrick McHardy
2006-10-26 5:22 ` Evgeniy Polyakov
2006-10-26 14:34 ` Stephen Hemminger
2006-10-26 14:57 ` Evgeniy Polyakov
2006-10-26 15:23 ` Stephen Hemminger [this message]
2006-10-26 17:05 ` Patrick McHardy
2006-10-26 20:55 ` David Miller
2006-10-26 17:29 ` John Heffner
2006-10-26 20:57 ` David Miller
2006-10-26 22:44 ` Hagen Paul Pfeifer
2006-10-26 22:53 ` John Heffner
2006-10-26 23:52 ` [PATCH] Check if user has CAP_NET_ADMIN to change congestion control algorithm Hagen Paul Pfeifer
2006-10-26 23:59 ` Ian McDonald
2006-10-27 0:07 ` David Miller
2006-10-27 0:20 ` Ian McDonald
2006-10-27 0:02 ` David Miller
2006-10-27 10:43 ` Hagen Paul Pfeifer
2006-10-27 14:41 ` Stephen Hemminger
2006-10-27 15:21 ` Hagen Paul Pfeifer
2006-10-27 15:48 ` Stephen Hemminger
2006-10-27 17:30 ` [PATCH] tcp: don't allow unfair congestion control to be built without warning Stephen Hemminger
2006-10-27 17:43 ` John Heffner
2006-10-27 17:59 ` [PATCH] tcp: allow restricting congestion control choices Stephen Hemminger
2006-10-27 21:17 ` [PATCH] tcp: don't allow unfair congestion control to be built without warning David Miller
2006-10-27 21:24 ` Stephen Hemminger
2006-10-27 21:37 ` David Miller
2006-10-27 21:59 ` Stephen Hemminger
2006-10-27 22:12 ` David Miller
2006-10-27 22:21 ` Stephen Hemminger
2006-10-27 22:24 ` David Miller
2006-10-28 0:48 ` Stephen Hemminger
2006-10-28 3:10 ` [RFC] tcp: available congetsion control Stephen Hemminger
2006-10-27 21:22 ` [PATCH] Check if user has CAP_NET_ADMIN to change congestion control algorithm David Miller
2006-10-27 1:03 ` Stephen Hemminger
2006-10-27 18:14 ` [PATCH] tcp: setsockopt congestion control autoload Stephen Hemminger
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