Date: Wed, 22 Dec 2010 14:03:49 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-security-module@vger.kernel.org, jmorris@namei.org,
        eric.dumazet@gmail.com, tgraf@infradead.org, eugeneteo@kernel.org,
        kees.cook@canonical.com, davem@davemloft.net, a.p.zijlstra@chello.nl,
        akpm@linux-foundation.org, eparis@parisplace.org,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v4] kptr_restrict for hiding kernel pointers
Message-ID: <20101222130349.GB13412@elte.hu>
References: <1292708499.10804.89.camel@dan>
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* Dan Rosenberg <drosenberg@vsecurity.com> wrote:

> +kptr_restrict:
> +
> +This toggle indicates whether restrictions are placed on
> +exposing kernel addresses via /proc and other interfaces.  When
> +kptr_restrict is set to (0), the default, there are no
> +restrictions.  When kptr_restrict is set to (1), kernel pointers
> +printed using the %pK format specifier will be replaced with 0's
> +unless the user has CAP_SYSLOG.  When kptr_restrict is set to
> +(2), kernel pointers printed using %pK will be replaced with 0's
> +regardless of privileges.

Hm, why is it off by default? Is there some user-space regression that is caused by 
this?

We really want good security measures to be active by default (and to work by 
default) - they are not worth much if they are not.

Thanks,

	Ingo
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