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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 06E25C433DB for ; Wed, 3 Feb 2021 17:16:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B0BC664F9E for ; Wed, 3 Feb 2021 17:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232100AbhBCRQz (ORCPT ); Wed, 3 Feb 2021 12:16:55 -0500 Received: from mga18.intel.com ([134.134.136.126]:19332 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231794AbhBCRQx (ORCPT ); Wed, 3 Feb 2021 12:16:53 -0500 IronPort-SDR: pnXZrjrBTEkyD7ChDcnOdpHCiy1/Zal0oGummYcTfYB4DgojkKHtl4ousjbhsgt2pgM8PA/Y3G W2HLRiEazzug== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="168761297" X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="168761297" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 09:16:12 -0800 IronPort-SDR: kRBAlNWa/d0or8aMCNCiw4lcmGHwaVitVviGAbiEXOCLh21PNebMsCUDBPD4l5Wt+xpTd8MMkB kSdrJB4e6+WQ== X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="433497230" Received: from lrenaud-mobl1.amr.corp.intel.com (HELO intel.com) ([10.252.131.246]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 09:16:11 -0800 Date: Wed, 3 Feb 2021 09:16:10 -0800 From: Ben Widawsky To: Dan Williams Cc: Konrad Rzeszutek Wilk , linux-cxl@vger.kernel.org, Linux ACPI , Linux Kernel Mailing List , linux-nvdimm , Linux PCI , Bjorn Helgaas , Chris Browy , Christoph Hellwig , Ira Weiny , Jon Masters , Jonathan Cameron , Rafael Wysocki , Randy Dunlap , Vishal Verma , daniel.lll@alibaba-inc.com, "John Groves (jgroves)" , "Kelley, Sean V" Subject: Re: [PATCH 13/14] cxl/mem: Add limited Get Log command (0401h) Message-ID: <20210203171610.2y2x4krijol5dvkk@intel.com> References: <20210130002438.1872527-1-ben.widawsky@intel.com> <20210130002438.1872527-14-ben.widawsky@intel.com> <20210201182848.GL197521@fedora> <20210202235103.v36v3znh5tsi4g5x@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 21-02-02 15:57:03, Dan Williams wrote: > On Tue, Feb 2, 2021 at 3:51 PM Ben Widawsky wrote: > > > > On 21-02-01 13:28:48, Konrad Rzeszutek Wilk wrote: > > > On Fri, Jan 29, 2021 at 04:24:37PM -0800, Ben Widawsky wrote: > > > > The Get Log command returns the actual log entries that are advertised > > > > via the Get Supported Logs command (0400h). CXL device logs are selected > > > > by UUID which is part of the CXL spec. Because the driver tries to > > > > sanitize what is sent to hardware, there becomes a need to restrict the > > > > types of logs which can be accessed by userspace. For example, the > > > > vendor specific log might only be consumable by proprietary, or offline > > > > applications, and therefore a good candidate for userspace. > > > > > > > > The current driver infrastructure does allow basic validation for all > > > > commands, but doesn't inspect any of the payload data. Along with Get > > > > Log support comes new infrastructure to add a hook for payload > > > > validation. This infrastructure is used to filter out the CEL UUID, > > > > which the userspace driver doesn't have business knowing, and taints on > > > > invalid UUIDs being sent to hardware. > > > > > > Perhaps a better option is to reject invalid UUIDs? > > > > > > And if you really really want to use invalid UUIDs then: > > > > > > 1) Make that code wrapped in CONFIG_CXL_DEBUG_THIS_IS_GOING_TO..? > > > > > > 2) Wrap it with lockdown code so that you can't do this at all > > > when in LOCKDOWN_INTEGRITY or such? > > > > > > > The commit message needs update btw as CEL is allowed in the latest rev of the > > patches. > > > > We could potentially combine this with the now added (in a branch) CONFIG_RAW > > config option. Indeed I think that makes sense. Dan, thoughts? > > Yeah, unknown UUIDs blocking is the same risk as raw commands as a > vendor can trigger any behavior they want. A "CONFIG_RAW depends on > !CONFIG_INTEGRITY" policy sounds reasonable as well. What about LOCKDOWN_NONE though? I think we need something runtime for this. Can we summarize the CONFIG options here? CXL_MEM_INSECURE_DEBUG // no change CXL_MEM_RAW_COMMANDS // if !security_locked_down(LOCKDOWN_NONE) bool cxl_unsafe() { #ifndef CXL_MEM_RAW_COMMANDS return false; #else return !security_locked_down(LOCKDOWN_NONE); #endif } --- Did I get that right?