Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932914Ab1ELWPz (ORCPT ); Thu, 12 May 2011 18:15:55 -0400 Received: from smtp-out.google.com ([216.239.44.51]:38646 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932786Ab1ELWPy convert rfc822-to-8bit (ORCPT ); Thu, 12 May 2011 18:15:54 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=oCrchYcdCLBZGi8OwEIdaMPZjBBcyC6MA/wOFm3Sg9D2hLoWbpY/VkdcNdKJ492RHP o4ztjV6LcFUI9G0d7Kmw== MIME-Version: 1.0 In-Reply-To: <20110512220715.GA7451@redhat.com> References: <20110512213542.GB17596@elte.hu> <20110512215023.GA20939@elte.hu> <20110512220715.GA7451@redhat.com> Date: Fri, 13 May 2011 00:15:41 +0200 Message-ID: Subject: Re: [BUG] perf: bogus correlation of kernel symbols From: Stephane Eranian To: Dave Jones , Ingo Molnar , Stephane Eranian , Linus Torvalds , Arnaldo Carvalho de Melo , LKML Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1241 Lines: 25 On Fri, May 13, 2011 at 12:07 AM, Dave Jones wrote: > On Thu, May 12, 2011 at 11:50:23PM +0200, Ingo Molnar wrote: > >  > Dunno, i would not couple them necessarily - certain users might still have >  > access to kernel symbols via some other channel - for example the System.map. > > That always made this security by obscurity feature seem pointless for the bulk > of users to me. Given the majority are going to be running distro kernels, > anyone can find those addresses easily no matter how hard we hide them on the > running system. > Unless we were somehow introduced randomness into where we unpack the kernel > each boot, and using System.map as a table of offsets instead of absolute addresses. > Good point about System.map! Even if /proc/kallsyms contains zero addresses, I can still get them from /boot/System.map which is readable by everyone, I think. It does not contain the modules addresses, but you have the core functions, unless I am somehow mistaken. -- 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/