From: Hugh Dickins <hugh@veritas.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>,
Franck Bui-Huu <fbuihuu@gmail.com>, Andi Kleen <ak@suse.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: unable to mmap /dev/kmem
Date: Fri, 19 Jan 2007 17:52:57 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.4.64.0701191743560.10013@blonde.wat.veritas.com> (raw)
In-Reply-To: <1169227629.3055.525.camel@laptopd505.fenrus.org>
On Fri, 19 Jan 2007, Arjan van de Ven wrote:
> On Fri, 2007-01-19 at 17:12 +0000, Hugh Dickins wrote:
> > Though so long as /dev/mem support remains, /dev/kmem might as well?
>
> they're not the same; for a long time, /dev/mem on actual memory
> returned zeros... so you couldn't use it for rootkits ;)
> (that got "fixed" a while ago)
We fixed (or "fixed") the mmap of them both, not to give zeroes on
!PageReserved pages; but read and write were never so restricted.
(Oh, I've said "never" again - expect I'll be humiliated shortly.)
Can't rootkits work as just about as easily through read & write?
Hugh
next prev parent reply other threads:[~2007-01-19 17:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-18 16:47 Nadia Derbey
2007-01-18 18:04 ` Hugh Dickins
2007-01-19 6:26 ` Nadia Derbey
2007-01-19 9:10 ` Nadia Derbey
2007-01-19 16:33 ` Hugh Dickins
2007-01-19 16:57 ` Arjan van de Ven
2007-01-19 17:12 ` Hugh Dickins
2007-01-19 17:27 ` Arjan van de Ven
2007-01-19 17:52 ` Hugh Dickins [this message]
2007-01-19 21:57 ` Andi Kleen
2007-01-19 11:31 ` Franck Bui-Huu
2007-01-19 17:02 ` Hugh Dickins
2007-01-20 17:19 ` Franck Bui-Huu
2007-01-21 9:56 ` Hugh Dickins
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