From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 02/21] arm64/iommu: improve mmap bounds checking Date: Sun, 7 Apr 2019 08:59:23 +0200 Message-ID: <20190407065923.GA9086@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-3-hch@lst.de> <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Robin Murphy Cc: Christoph Hellwig , Joerg Roedel , Catalin Marinas , Will Deacon , Tom Lendacky , iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: iommu@lists.linux-foundation.org On Fri, Apr 05, 2019 at 06:30:52PM +0100, Robin Murphy wrote: > On 27/03/2019 08:04, Christoph Hellwig wrote: >> The nr_pages checks should be done for all mmap requests, not just those >> using remap_pfn_range. > > Hmm, the logic in iommu_dma_mmap() inherently returns an error for the "off > >= nr_pages" case already. It's also supposed to be robust against the > "vma_pages(vma) > nr_pages - off" condition, although by making the partial > mapping and treating it as a success, rather than doing nothing and > returning an error. What's the exact motivation here? Have one error check at the front of the function that is identical to the mmap checks in the other dma_map_ops instances so that: a) we get the same error behavior for partial requests everywhere b) we can lift these checks into common code in the next round. 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 69D1AC10F0E for ; Sun, 7 Apr 2019 06:59:38 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2B59C20896 for ; Sun, 7 Apr 2019 06:59:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B59C20896 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id D5CB2ACD; Sun, 7 Apr 2019 06:59:37 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 220B9481 for ; Sun, 7 Apr 2019 06:59:37 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A914263D for ; Sun, 7 Apr 2019 06:59:36 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id B7D2A67329; Sun, 7 Apr 2019 08:59:23 +0200 (CEST) Date: Sun, 7 Apr 2019 08:59:23 +0200 From: Christoph Hellwig To: Robin Murphy Subject: Re: [PATCH 02/21] arm64/iommu: improve mmap bounds checking Message-ID: <20190407065923.GA9086@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-3-hch@lst.de> <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Tom Lendacky , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Message-ID: <20190407065923.WyTsS05gsHST-8xpTQ6M1DBMSOjOsWTPWSoOnXD8zHY@z> On Fri, Apr 05, 2019 at 06:30:52PM +0100, Robin Murphy wrote: > On 27/03/2019 08:04, Christoph Hellwig wrote: >> The nr_pages checks should be done for all mmap requests, not just those >> using remap_pfn_range. > > Hmm, the logic in iommu_dma_mmap() inherently returns an error for the "off > >= nr_pages" case already. It's also supposed to be robust against the > "vma_pages(vma) > nr_pages - off" condition, although by making the partial > mapping and treating it as a success, rather than doing nothing and > returning an error. What's the exact motivation here? Have one error check at the front of the function that is identical to the mmap checks in the other dma_map_ops instances so that: a) we get the same error behavior for partial requests everywhere b) we can lift these checks into common code in the next round. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 4A8ACC10F0E for ; Sun, 7 Apr 2019 06:59:56 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1891D20896 for ; Sun, 7 Apr 2019 06:59:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qCoEcb8A" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1891D20896 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4lri2H7VvCm3Me2bYpEGJ1no86HdZzVCRi/zY2N+QLk=; b=qCoEcb8A6AZoTm 5VhRyjZ1FD4LEyLGWoc9PCcfh7h34BQU6aAsb+vsxKVcdVfICUd+YfTKuBUshGCIFG0f3tZ2h+ZIe EOtLHzYkrjv3GqbQkZdwWr0Yd+tPFLcDg09bn5pH3R1CDcODJSAdGmPXHJYzlbgLU81L+lj0e149D V9a4HAYv2aGV8bM9rs9A2L8/YH755N46kETJzRaT4xCM6TGggm2XlDF+4TyFmdJbYJbdfHxUcuCKv gmmWZRtKDFbii+sgRKBeyaGZ2IqFRX1XiIn+1PYM3V6f78wIgXM9A2NYxUKs6peBF3/RgGKQRuqM9 h+Dv7GPQkzKZ2QfPicTA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hD1mM-0006uz-Jt; Sun, 07 Apr 2019 06:59:46 +0000 Received: from verein.lst.de ([213.95.11.211] helo=newverein.lst.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hD1mI-0006uG-Hh for linux-arm-kernel@lists.infradead.org; Sun, 07 Apr 2019 06:59:44 +0000 Received: by newverein.lst.de (Postfix, from userid 2407) id B7D2A67329; Sun, 7 Apr 2019 08:59:23 +0200 (CEST) Date: Sun, 7 Apr 2019 08:59:23 +0200 From: Christoph Hellwig To: Robin Murphy Subject: Re: [PATCH 02/21] arm64/iommu: improve mmap bounds checking Message-ID: <20190407065923.GA9086@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-3-hch@lst.de> <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3629087c-a8cb-d66e-840b-cfee125bdf4c@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190406_235942_737019_66D378F5 X-CRM114-Status: GOOD ( 12.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tom Lendacky , Catalin Marinas , Joerg Roedel , Will Deacon , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Apr 05, 2019 at 06:30:52PM +0100, Robin Murphy wrote: > On 27/03/2019 08:04, Christoph Hellwig wrote: >> The nr_pages checks should be done for all mmap requests, not just those >> using remap_pfn_range. > > Hmm, the logic in iommu_dma_mmap() inherently returns an error for the "off > >= nr_pages" case already. It's also supposed to be robust against the > "vma_pages(vma) > nr_pages - off" condition, although by making the partial > mapping and treating it as a success, rather than doing nothing and > returning an error. What's the exact motivation here? Have one error check at the front of the function that is identical to the mmap checks in the other dma_map_ops instances so that: a) we get the same error behavior for partial requests everywhere b) we can lift these checks into common code in the next round. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel