linux-kernel - Re: [PATCH] power: disable hibernation if module loading is disabled

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Message-ID: <20110304211035.GA28842@albatros>
Date:	Sat, 5 Mar 2011 00:10:35 +0300
From:	Vasiliy Kulikov <segoon@...nwall.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	linux-kernel@...r.kernel.org, security@...nel.org,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	linux-pm@...ts.linux-foundation.org
Subject: Re: [PATCH] power: disable hibernation if module loading is
 disabled

On Fri, Mar 04, 2011 at 21:42 +0100, Rafael J. Wysocki wrote:
> That "everyone" is actually the "full root" (in the case of /sys/power/state)
> or someone having CAP_SYS_ADMIN in the /dev/snapshot case, right?

Yes, sorry for my bad english.  "Everyone" is indeed misleading :-D

> Second, there's _zero_ relationship between /proc/sys/kernel/modules_disabled
> and the hibernation interface, so please find a different way to solve the
> problem (if there is any).

If modules_disabled is set to 1, then nobody, even full root may not write
to the kernel, right?  So, if something permits to indirectly pass
modules_disabled restriction, this is a bug.  Otherwise,
modules_disabled is confusing as it gives false sense of security.

-OR-

modules_disabled's documentation should be changed to note that it
doesn't prevent rootkit uploading, but only forbids modprob'ing modules
via the "official" init_module(2) gate, disallowing e.g. module autoloading.

Thanks,

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