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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 5694FC433E1 for ; Tue, 16 Jun 2020 22:20:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2353D20810 for ; Tue, 16 Jun 2020 22:20:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="zwqQ/g3X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725849AbgFPWU4 (ORCPT ); Tue, 16 Jun 2020 18:20:56 -0400 Received: from mail.zx2c4.com ([192.95.5.64]:39715 "EHLO mail.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725790AbgFPWU4 (ORCPT ); Tue, 16 Jun 2020 18:20:56 -0400 Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTP id b14129e7; Tue, 16 Jun 2020 22:02:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=mime-version :references:in-reply-to:from:date:message-id:subject:to:cc :content-type; s=mail; bh=RQicizWyLHOE2iCPPK+/7SOXm9U=; b=zwqQ/g 3Xq/tR7g2fHoBQXiJS3CWnnxoDeJkGT47tGoxmHOECjg2pvQJPYNo/Ejq0CvHM1o NCmge4rzYj7J/eHj9zJSeCG2eCkYQL9HaXTBeZrPxQo/3F7GTUifv5/bO4a4v1Ud tX/Z6mwcr0ATqWjJ5YOhLIS4J3U4wYUmcvjLJYoTjsmMdQqd2L5YBxtCdTOUFHKq mTD5KglvYfKuW154UJWyquve3RxyAMu6/S9EDsGIU4oyJc7XHMpgyuPBZdABo96n hzaxhz0tYYJKgIhXTZEKROYDp4gxesLOTbEKAPzbpWOQ+zn5bn7B9Bm251JldpEA sspq8gtWfQRzWYpw== Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 86c41781 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 16 Jun 2020 22:02:52 +0000 (UTC) Received: by mail-io1-f41.google.com with SMTP id y5so363070iob.12; Tue, 16 Jun 2020 15:20:53 -0700 (PDT) X-Gm-Message-State: AOAM531ciYCogHcehdyvkF/zUX9H3htBgXM5v4q+IUrAQuVcj3yfD3j8 iGpaLijqzXNdCQn2yewxtt+WsVcL9wzULYt4FHs= X-Google-Smtp-Source: ABdhPJzh/Fg/J98wbBnb2dT30/tZcvAhpbVxMckFzIR66mY0R34JuTMP4lkUQFiOJY295tUKmsjnNdvjO8f57XidyrQ= X-Received: by 2002:a05:6638:216f:: with SMTP id p15mr28530779jak.86.1592346052223; Tue, 16 Jun 2020 15:20:52 -0700 (PDT) MIME-Version: 1.0 References: <20200615104332.901519-1-Jason@zx2c4.com> In-Reply-To: <20200615104332.901519-1-Jason@zx2c4.com> From: "Jason A. Donenfeld" Date: Tue, 16 Jun 2020 16:20:41 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] acpi: disallow loading configfs acpi tables when locked down To: Len Brown , rjw@rjwysocki.net Cc: LKML , linux-acpi@vger.kernel.org, Kernel Hardening Content-Type: text/plain; charset="UTF-8" Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Rafael, Len, Looks like I should have CC'd you on this patch. This is probably something we should get into 5.8-rc2, so that it can then get put into stable kernels, as some people think this is security sensitive. Bigger picture is this: https://data.zx2c4.com/american-unsigned-language-2.gif https://data.zx2c4.com/american-unsigned-language-2-fedora-5.8.png Also, somebody mentioned to me that Microsoft's ACPI implementation disallows writes to system memory as a security mitigation. I haven't looked at what that actually entails, but I wonder if entirely disabling support for ACPI_ADR_SPACE_SYSTEM_MEMORY would be sensible. I haven't looked at too many DSDTs. Would that break real hardware, or does nobody do that? Alternatively, the range of acceptable addresses for SystemMemory could exclude kernel memory. Would that break anything? Have you heard about Microsoft's mitigation to know more details on what they figured out they could safely restrict without breaking hardware? Either way, food for thought I suppose. Jason