Date: Thu, 11 Nov 2010 08:05:48 +0100
From: Ingo Molnar <mingo@elte.hu>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>, Marcus Meissner <meissner@suse.de>,
        linux-kernel@vger.kernel.org, jason.wessel@windriver.com,
        fweisbec@gmail.com, tj@kernel.org, mort@sgi.com, akpm@osdl.org,
        security@kernel.org, Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] kernel: make /proc/kallsyms mode 400 to reduce ease of
 attacking
Message-ID: <20101111070548.GA15192@elte.hu>
References: <20101104100914.GC25118@suse.de>
 <20101104114648.GA23381@elte.hu>
 <20101104122906.GH25118@suse.de>
 <20101104135802.GA31416@elte.hu>
 <20101104141104.GA31753@elte.hu>
 <20101104143322.GL25118@suse.de>
 <871v6xt3l1.fsf@basil.nowhere.org>
 <a4676065-571a-4dda-bd3a-798a9b2d7edf@email.android.com>
 <20101110085314.GB8370@elte.hu>
 <4CDB5A20.7070106@zytor.com>
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* H. Peter Anvin <hpa@zytor.com> wrote:

> Now, *relative* symbol addresses will typically not have any randomness at all, 
> which may limit the usefulness, of course.

Yeah - but it happens quite often that the scope of the vulnerability only allows 
absolute addresses. In fact it's a pretty common case: basically most derefs into 
attacker-controlled data pointers are like that.

Thanks,

	Ingo
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