Re: [kernel-hardening] Re: [PATCH] proc: restrict access to /proc/interrupts

[Vasiliy Kulikov <segoon@openwall.com>]

On Mon, Nov 07, 2011 at 11:18 -0800, H. Peter Anvin wrote:
> On 11/07/2011 11:01 AM, Vasiliy Kulikov wrote:
> > 
> > What's wrong with old good DAC?  You can create a group "sysinfo", do
> > "chown sysinfo /proc/interrupts", and add the permitted users to the
> > group.  If you need to give different access levels to different interrupts,
> > you need another /proc/interrupts design, it does nothing with DAC vs. LSM.
> > 
> 
> I would like to propose that we add a mount option to procfs, and
> possibly sysfs, called, say, admingrp.

Similar proposals:

(procfs for /proc/$PID/* permissions, sorry about different threads)
https://lkml.org/lkml/2011/6/15/172
https://lkml.org/lkml/2011/6/15/174
https://lkml.org/lkml/2011/6/15/173
https://lkml.org/lkml/2011/6/15/177
https://lkml.org/lkml/2011/6/15/175
https://lkml.org/lkml/2011/6/15/176

(change uid/gid for newly created sysfs objects)
https://lkml.org/lkml/2011/5/18/272


As to procfs, I see no real need of adding mode/group mount option for
global procfs files (/proc/interrupts, /proc/stat, etc.) - it can be
done by distro specific init scripts (chown+chmod).  I don't mind
against such an option for the convenience, though.


> The current Linux trend seems to be do instead force those users to
> become root constantly, which is *not* helping the situation.

Agreed.


Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments