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=1.4 required=3.0 tests=DATE_IN_FUTURE_03_06, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 B2D2DC46470 for ; Thu, 9 Aug 2018 03:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A98E21C2E for ; Thu, 9 Aug 2018 03:16:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A98E21C2E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 S1727476AbeHIFjd (ORCPT ); Thu, 9 Aug 2018 01:39:33 -0400 Received: from mga09.intel.com ([134.134.136.24]:1388 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbeHIFjd (ORCPT ); Thu, 9 Aug 2018 01:39:33 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Aug 2018 20:16:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,213,1531810800"; d="scan'208";a="252547192" Received: from dazhang1-z97x.sh.intel.com (HELO [10.239.13.128]) ([10.239.13.128]) by fmsmga005.fm.intel.com with ESMTP; 08 Aug 2018 20:16:54 -0700 Subject: Re: [RFC PATCH 1/1] device-dax: check for vma range while dax_mmap. To: Dave Jiang , linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, jack@suse.cz, zwisler@kernel.org, yu.c.zhang@intel.com Cc: yi.z.zhang@intel.com References: <12a2ebd8-0f15-7d0a-697c-172ed7f77f92@intel.com> <5aaca496-af2b-71b1-26af-b2400e0bcb43@linux.intel.com> <2d9a11be-732d-23b5-80fe-fc463cef556c@intel.com> From: "Zhang,Yi" Message-ID: Date: Thu, 9 Aug 2018 19:01:00 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <2d9a11be-732d-23b5-80fe-fc463cef556c@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年08月08日 08:05, Dave Jiang wrote: > > On 08/02/2018 02:32 AM, Zhang,Yi wrote: >> >> On 2018年08月02日 03:40, Dave Jiang wrote: >>> On 07/31/2018 04:46 AM, Zhang Yi wrote: >>>> It should be prevent user map an illegal vma range which larger than >>>> dax device phiscal resourse, as we don't have swap logic while page >>>> faulting in dax device. >>> This patch prevents a user mapping an illegal vma range that is larger >>> than a dax device physical resource. >>> >>>> Applications, especailly qemu, map the /dev/dax for virtual nvdimm's >>>> backend device, we defined the v-nvdimm label area at the end of mapped >>>> rang. By using an illegal size that exceeds the physical resource of >>>> /dev/dax, then it will triger qemu a signal fault while accessing these >>>> label area. >>> When qemu maps the dax device for virtual nvdimm's backend device, the >>> v-nvdimm label area is defined at the end of mapped range. By using an >>> illegal size that exceeds the range of the device dax, it will trigger a >>> fault with qemu. >> Thanks Dava, that's could be much better. >>>> Signed-off-by: Zhang Yi >>>> --- >>>> drivers/dax/device.c | 28 ++++++++++++++++++++++++++++ >>>> 1 file changed, 28 insertions(+) >>>> >>>> diff --git a/drivers/dax/device.c b/drivers/dax/device.c >>>> index aff2c15..c9a50cd 100644 >>>> --- a/drivers/dax/device.c >>>> +++ b/drivers/dax/device.c >>>> @@ -177,6 +177,32 @@ static const struct attribute_group *dax_attribute_groups[] = { >>>> NULL, >>>> }; >>>> >>>> +static int check_vma_range(struct dev_dax *dev_dax, struct vm_area_struct *vma, >>>> + const char *func) >>>> +{ >>>> + struct device *dev = &dev_dax->dev; >>>> + struct resource *res; >>>> + unsigned long size; >>>> + int ret, i; >>>> + >>>> + if (!dax_alive(dev_dax->dax_dev)) >>>> + return -ENXIO; >>>> + >>>> + size = vma->vm_end - vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT); >>>> + ret = -EINVAL; >>>> + for (i = 0; i < dev_dax->num_resources; i++) { >>>> + res = &dev_dax->res[i]; >>>> + if (size > resource_size(res)) { >>>> + dev_info(dev, "%s: %s: fail, vma range is overflow\n", >>>> + current->comm, func); >>>> + ret = -EINVAL; >>>> + continue; >>>> + } else >>>> + return 0; >>>> + } >>>> + return ret; >>>> +} >>>> + >>>> static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, >>>> const char *func) >>>> { >>>> @@ -465,6 +491,8 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) >>>> */ >>>> id = dax_read_lock(); >>>> rc = check_vma(dev_dax, vma, __func__); >>>> + if (!rc) >>>> + rc |= check_vma_range(dev_dax, vma, __func__); > I don't see any reason to logical or the return code. It should be 0, so > you can just assign it to check_vma_range(). Ah.. Yes, Thanks for your kindly review, Dace, I will send the next version. > >>> I think you want to augment check_vma() rather than adding another >>> function? If this is added inside check_vma() then you can also skip the >>> !dax_alive() check. Do you expect this function to be called anywhere else? >> since check_vma range also will be called while dax page faulting. I >> don't wanna this check_vma_range introduce some additional workload >> while page fault. just let it checked in the mmap scenario > Good point. Ok. > >>>> dax_read_unlock(id); >>>> if (rc) >>>> return rc; >>>>