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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 DD207C2D0A7 for ; Tue, 8 Sep 2020 19:53:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC1F9207DE for ; Tue, 8 Sep 2020 19:53:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599594823; bh=+OrY6yic2b8j2M0/KDTR0UkjhKoGy5DZysMSvf4PNF8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=GJQB91FWF1zsPYz4o9PrPgKJLx/f8kIM7rk7nu8mXeWqzg+ebXoeOeyWXu1L78sy8 oTv1ouIaQlXlUbfbmLVUgRM7SsMZqDubO7rYZb5DrAnTJUHn2NdeG5l4DlS1DPEgc8 ortXt3OJJENTvx7vLYWVqJQLoj76ri4aQETpKB2Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730165AbgIHPrH (ORCPT ); Tue, 8 Sep 2020 11:47:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:33984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730607AbgIHPn3 (ORCPT ); Tue, 8 Sep 2020 11:43:29 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 EA85B22228; Tue, 8 Sep 2020 14:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599575593; bh=+OrY6yic2b8j2M0/KDTR0UkjhKoGy5DZysMSvf4PNF8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YvT2gzuABobpfos/MY8/9MeUgl//rcFFIyJeM4wXqGoQbeswBnGzyCA6KjFlzB2DG enukFSp6c9IAHivmEzHvglfK3yhERXFTnxfz/Q8XwhgtvdpK45iqPERkw8cvRZn/00 B0OMiWVQRB7OqLEMt6H38J4xs86RzFS4Vcmm3iH8= Date: Tue, 8 Sep 2020 16:33:26 +0200 From: Greg KH To: Alex Williamson Cc: Ajay Kaher , sashal@kernel.org, cohuck@redhat.com, peterx@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, srivatsab@vmware.com, srivatsa@csail.mit.edu, vsirnapalli@vmware.com Subject: Re: [PATCH v4.14.y 0/3] vfio: Fix for CVE-2020-12888 Message-ID: <20200908143326.GA3451422@kroah.com> References: <1599509828-23596-1-git-send-email-akaher@vmware.com> <1599509828-23596-4-git-send-email-akaher@vmware.com> <20200908082904.045ff744@w520.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200908082904.045ff744@w520.home> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Sep 08, 2020 at 08:29:04AM -0600, Alex Williamson wrote: > On Tue, 8 Sep 2020 01:47:08 +0530 > Ajay Kaher wrote: > > > CVE-2020-12888 Kernel: vfio: access to disabled MMIO space of some > > devices may lead to DoS scenario > > > > The VFIO modules allow users (guest VMs) to enable or disable access to the > > devices' MMIO memory address spaces. If a user attempts to access (read/write) > > the devices' MMIO address space when it is disabled, some h/w devices issue an > > interrupt to the CPU to indicate a fatal error condition, crashing the system. > > This flaw allows a guest user or process to crash the host system resulting in > > a denial of service. > > > > Patch 1/ is to force the user fault if PFNMAP vma might be DMA mapped > > before user access. > > > > Patch 2/ setup a vm_ops handler to support dynamic faulting instead of calling > > remap_pfn_range(). Also provides a list of vmas actively mapping the area which > > can later use to invalidate those mappings. > > > > Patch 3/ block the user from accessing memory spaces which is disabled by using > > new vma list support to zap, or invalidate, those memory mappings in order to > > force them to be faulted back in on access. > > > > Upstreamed patches link: > > https://lore.kernel.org/kvm/158871401328.15589.17598154478222071285.stgit@gimli.home > > > > [PATCH v4.14.y 1/3]: > > Backporting of upsream commit 41311242221e: > > vfio/type1: Support faulting PFNMAP vmas > > > > [PATCH v4.14.y 2/3]: > > Backporting of upsream commit 11c4cd07ba11: > > vfio-pci: Fault mmaps to enable vma tracking > > > > [PATCH v4.14.y 3/3]: > > Backporting of upsream commit abafbc551fdd: > > vfio-pci: Invalidate mmaps and block MMIO access on disabled memory > > > > I'd recommend also including the following or else SR-IOV VFs will be > broken for DPDK: > > commit ebfa440ce38b7e2e04c3124aa89c8a9f4094cf21 > Author: Alex Williamson > Date: Thu Jun 25 11:04:23 2020 -0600 > > vfio/pci: Fix SR-IOV VF handling with MMIO blocking > > SR-IOV VFs do not implement the memory enable bit of the command > register, therefore this bit is not set in config space after > pci_enable_device(). This leads to an unintended difference > between PF and VF in hand-off state to the user. We can correct > this by setting the initial value of the memory enable bit in our > virtualized config space. There's really no need however to > ever fault a user on a VF though as this would only indicate an > error in the user's management of the enable bit, versus a PF > where the same access could trigger hardware faults. > > Fixes: abafbc551fdd ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory") > Signed-off-by: Alex Williamson Good catch, now queued up, thanks. greg k-h