Message-Id: <E1PFN7q-0000z3-Em@be1.7eggert.dyndns.org>
From: Bodo Eggert <7eggert@web.de>
Subject: Re: [PATCH RFC] Restrictions on module loading
To: Dan Rosenberg <drosenberg@vsecurity.com>, security@kernel.org,
        linux-kernel@vger.kernel.org
Reply-To: 7eggert@gmx.de
Date: Mon, 08 Nov 2010 09:30:50 +0100
References: <fMoIy-7gR-5@gated-at.bofh.it>
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Dan Rosenberg <drosenberg@vsecurity.com> wrote:

> The below patch replaces the existing "modules_disable" sysctl with a
> finer-grained "modules_restrict" sysctl.  By default, this is set at 0,
> which results in no deviation from normal module loading behavior.  When
> set to 1, unprivileged users cannot trigger the automatic loading of
> modules.  This behavior is based on grsecurity's GRKERNSEC_MODHARDEN
> setting.  The current check is against current_uid(), since several
> distributions explicitly remove CAP_SYS_MODULE from root processes, some
> of which incidentally cause (and rely on) the automatic loading of
> modules.  I expect this to be a point of discussion.

- Why don't you offer both?

- What about task switches or work queues?

- It might be more like the expected behavior if you'd used:
 0: off, 1: modules completely disabled, 2: CAP_SYS_MODULE, 3: uid==0

 Many users will forget to look into the documentation or find the current,
 stale documentation or just assume a boolean value.

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