linux-kernel - Re: mmap to address zero with MAP_FIXED returns ENOPERM for non-root users?

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Message-ID: <20101205080855.GI8820@const.famille.thibault.fr>
Date:	Sun, 5 Dec 2010 09:08:55 +0100
From:	Samuel Thibault <samuel.thibault@...-lyon.org>
To:	Eric Smith <eric@...uhaha.com>
Cc:	Kyle Moffett <kyle@...fetthome.net>, linux-kernel@...r.kernel.org
Subject: Re: mmap to address zero with MAP_FIXED returns ENOPERM for non-root users?

Eric Smith, le Sat 04 Dec 2010 23:47:18 -0800, a écrit :
> I'm curious, though.  How likely are exploits where I can trick the 
> kernel into calling a function at 0 in my virtual address space, but not 
> trick it into calling a function at some non-zero address of my choosing?

NULL pointers are everywhere in function pointers structures & such.

About translation, maybe you could use an LDT entry to make the
processor do the translation? (additional 1-byte fs: prefix).

Samuel
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