Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932827AbXASRwp (ORCPT ); Fri, 19 Jan 2007 12:52:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932831AbXASRwp (ORCPT ); Fri, 19 Jan 2007 12:52:45 -0500 Received: from extu-mxob-1.symantec.com ([216.10.194.28]:6138 "EHLO extu-mxob-1.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932827AbXASRwo (ORCPT ); Fri, 19 Jan 2007 12:52:44 -0500 X-AuditID: d80ac21c-a187abb00000330a-21-45b1056c6dad Date: Fri, 19 Jan 2007 17:52:57 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@blonde.wat.veritas.com To: Arjan van de Ven cc: Nadia Derbey , Franck Bui-Huu , Andi Kleen , LKML Subject: Re: unable to mmap /dev/kmem In-Reply-To: <1169227629.3055.525.camel@laptopd505.fenrus.org> Message-ID: References: <45AFA490.5000508@bull.net> <45B08B17.3060807@bull.net> <1169225824.3055.507.camel@laptopd505.fenrus.org> <1169227629.3055.525.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 19 Jan 2007 17:52:43.0587 (UTC) FILETIME=[9ECF7930:01C73BF2] X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 854 Lines: 19 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/