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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B6719C4BA37 for ; Thu, 27 Feb 2020 02:43:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A28F24679 for ; Thu, 27 Feb 2020 02:43:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BgLqNPkv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728238AbgB0CnH (ORCPT ); Wed, 26 Feb 2020 21:43:07 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:60985 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728094AbgB0CnH (ORCPT ); Wed, 26 Feb 2020 21:43:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582771385; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=jIzd+MZl1AvxRGDWe7UFrELxx/1RAKgj7dqtWoVC2q8=; b=BgLqNPkvYkA1ftIBextYCzPG+5Gx6Rh9f1+uMANZW6+exqZaf1E+PkwDgpPStyxLvekA69 DgqJBYALfEpNcnan0JIOXrPbrHdhDEMJKzb0zGviUN3b2kWViS2MrjjSbqYwmEP5vpP/JZ Zf5KaNjIvCpT6i0RJGkULqMoRXO9/c8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-48-OiqDfqPvP-WvbDkjQd8jmA-1; Wed, 26 Feb 2020 21:43:01 -0500 X-MC-Unique: OiqDfqPvP-WvbDkjQd8jmA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3A6751005512; Thu, 27 Feb 2020 02:43:00 +0000 (UTC) Received: from localhost (ovpn-12-63.pek2.redhat.com [10.72.12.63]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 665A660BE1; Thu, 27 Feb 2020 02:42:56 +0000 (UTC) Date: Thu, 27 Feb 2020 10:42:53 +0800 From: Baoquan He To: Kees Cook , Kristen Carlson Accardi , dyoung@redhat.com Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, arjan@linux.intel.com, rick.p.edgecombe@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, kexec@lists.infradead.org Subject: Re: [RFC PATCH 09/11] kallsyms: hide layout and expose seed Message-ID: <20200227024253.GA5707@MiWiFi-R3L-srv> References: <20200205223950.1212394-1-kristen@linux.intel.com> <20200205223950.1212394-10-kristen@linux.intel.com> <202002060428.08B14F1@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/06/20 at 09:51am, Kristen Carlson Accardi wrote: > On Thu, 2020-02-06 at 04:32 -0800, Kees Cook wrote: > > In the past, making kallsyms entirely unreadable seemed to break > > weird > > stuff in userspace. How about having an alternative view that just > > contains a alphanumeric sort of the symbol names (and they will > > continue > > to have zeroed addresses for unprivileged users)? > > > > Or perhaps we wait to hear about this causing a problem, and deal > > with > > it then? :) > > > > Yeah - I don't know what people want here. Clearly, we can't leave > kallsyms the way it is. Removing it entirely is a pretty fast way to > figure out how people use it though :). Kexec-tools and makedumpfile are the users of /proc/kallsyms currently. We use kallsyms to get page_offset_base and _stext.