From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FEBEC43441 for ; Tue, 27 Nov 2018 07:43:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25B26208E4 for ; Tue, 27 Nov 2018 07:43:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="viMfo1K1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 25B26208E4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729228AbeK0Ska (ORCPT ); Tue, 27 Nov 2018 13:40:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:59924 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729143AbeK0Sk3 (ORCPT ); Tue, 27 Nov 2018 13:40:29 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AE5EC20873; Tue, 27 Nov 2018 07:43:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543304610; bh=KMUuDeFxIIAT6StFc5ffKRNYDVzzYQhrih4Pz/zc3P0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=viMfo1K1Ji6Q196am/85M0PmwdMK6SHnqU+eHY6U5cdxIOcZvwOHifzfuO1hvqMIE xHCK4VOOAuevJWwUHme+KukzuOkF/tUgpWQqfBEm+P9zgQcsEfo758z630/INYb15u 9F8oxVgKlKfRywZR+qdEDiJ1C3I4uNmJnKrW3viM= Date: Tue, 27 Nov 2018 08:43:27 +0100 From: Greg Kroah-Hartman To: Christophe Leroy Cc: Kees Cook , Arnd Bergmann , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] lkdtm: print real addresses Message-ID: <20181127074327.GD13965@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.0 (2018-11-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 07, 2018 at 08:14:10PM +0000, Christophe Leroy wrote: > Today, when doing a lkdtm test before the readiness of the > random generator, (ptrval) is printed instead of the address > at which it perform the fault: > > [ 1597.337030] lkdtm: Performing direct entry EXEC_USERSPACE > [ 1597.337142] lkdtm: attempting ok execution at (ptrval) > [ 1597.337398] lkdtm: attempting bad execution at (ptrval) > [ 1597.337460] kernel tried to execute user page (77858000) -exploit attempt? (uid: 0) > [ 1597.344769] Unable to handle kernel paging request for instruction fetch > [ 1597.351392] Faulting instruction address: 0x77858000 > [ 1597.356312] Oops: Kernel access of bad area, sig: 11 [#1] > > If the lkdtm test is done later on, it prints an hashed address. > > In both cases this is pointless. The purpose of the test is to > ensure the kernel generates an Oops at the expected address, > so real addresses needs to be printed. This patch fixes that. I am pretty sure this is intentional. Kees?