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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 C9097C5CFFE for ; Mon, 10 Dec 2018 16:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9473320870 for ; Mon, 10 Dec 2018 16:31:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9473320870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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 S1728722AbeLJQbt (ORCPT ); Mon, 10 Dec 2018 11:31:49 -0500 Received: from foss.arm.com ([217.140.101.70]:58168 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726946AbeLJQbs (ORCPT ); Mon, 10 Dec 2018 11:31:48 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 33C071596; Mon, 10 Dec 2018 08:31:48 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D001C3F6A8; Mon, 10 Dec 2018 08:31:46 -0800 (PST) Subject: Re: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range To: Souptick Joarder Cc: Andrew Morton , Matthew Wilcox , Michal Hocko , joro@8bytes.org, Linux-MM , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20181206184343.GA30569@jordon-HP-15-Notebook-PC> From: Robin Murphy Message-ID: <67137be3-c56f-fb01-5ebe-86e9ebf5714b@arm.com> Date: Mon, 10 Dec 2018 16:31:45 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/12/2018 20:41, Souptick Joarder wrote: > On Fri, Dec 7, 2018 at 7:17 PM Robin Murphy wrote: >> >> On 06/12/2018 18:43, Souptick Joarder wrote: >>> Convert to use vm_insert_range() to map range of kernel >>> memory to user vma. >>> >>> Signed-off-by: Souptick Joarder >>> Reviewed-by: Matthew Wilcox >>> --- >>> drivers/iommu/dma-iommu.c | 13 +++---------- >>> 1 file changed, 3 insertions(+), 10 deletions(-) >>> >>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c >>> index d1b0475..a2c65e2 100644 >>> --- a/drivers/iommu/dma-iommu.c >>> +++ b/drivers/iommu/dma-iommu.c >>> @@ -622,17 +622,10 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, >>> >>> int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma) >>> { >>> - unsigned long uaddr = vma->vm_start; >>> - unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT; >>> - int ret = -ENXIO; >>> + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; >>> >>> - for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) { >>> - ret = vm_insert_page(vma, uaddr, pages[i]); >>> - if (ret) >>> - break; >>> - uaddr += PAGE_SIZE; >>> - } >>> - return ret; >>> + return vm_insert_range(vma, vma->vm_start, >>> + pages + vma->vm_pgoff, count); >> >> You also need to adjust count to compensate for the pages skipped by >> vm_pgoff, otherwise you've got an out-of-bounds dereference triggered >> from userspace, which is pretty high up the "not good" scale (not to >> mention the entire call would then propagate -EFAULT back from >> vm_insert_page() and thus always appear to fail for nonzero offsets). > > So this should something similar to -> > > return vm_insert_range(vma, vma->vm_start, > pages + vma->vm_pgoff, count - vma->vm_pgoff); > Yup, I think that looks appropriate. Robin.