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=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 F229FC433E0 for ; Thu, 9 Jul 2020 02:08:27 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 B2CBE206F6 for ; Thu, 9 Jul 2020 02:08:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=intel.onmicrosoft.com header.i=@intel.onmicrosoft.com header.b="mZpwmLco" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2CBE206F6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 7E19E895BA; Thu, 9 Jul 2020 02:08:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xBzMsFELg9ad; Thu, 9 Jul 2020 02:08:26 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 99557895B7; Thu, 9 Jul 2020 02:08:26 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 74854C077B; Thu, 9 Jul 2020 02:08:26 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 50793C016F for ; Thu, 9 Jul 2020 02:08:25 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 3FEE487B68 for ; Thu, 9 Jul 2020 02:08:25 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id X1-gfSIjnXyV for ; Thu, 9 Jul 2020 02:08:24 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 6F6EC878DF for ; Thu, 9 Jul 2020 02:08:24 +0000 (UTC) IronPort-SDR: 9ap34TdTKIoOKK+CWIhH3omxe7Z3nhx1jLpr8luJmlzVOq7J1/y9xCR4pKNMlNDOVpFaHegvUZ juNfIkSLnlGg== X-IronPort-AV: E=McAfee;i="6000,8403,9676"; a="147000987" X-IronPort-AV: E=Sophos;i="5.75,330,1589266800"; d="scan'208";a="147000987" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2020 19:08:23 -0700 IronPort-SDR: cOJdczbpWduFj0S+DuPb8p3NayuUmw4/Ff/ys0tORgBvs24nJKdYVpB5kgmswsIWjxy7hTEUgu 3aCYnEW/sVrA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,330,1589266800"; d="scan'208";a="484093331" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by fmsmga005.fm.intel.com with ESMTP; 08 Jul 2020 19:08:23 -0700 Received: from fmsmsx611.amr.corp.intel.com (10.18.126.91) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jul 2020 19:08:23 -0700 Received: from fmsmsx611.amr.corp.intel.com (10.18.126.91) by fmsmsx611.amr.corp.intel.com (10.18.126.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 8 Jul 2020 19:08:22 -0700 Received: from FMSEDG002.ED.cps.intel.com (10.1.192.134) by fmsmsx611.amr.corp.intel.com (10.18.126.91) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1713.5 via Frontend Transport; Wed, 8 Jul 2020 19:08:22 -0700 Received: from NAM12-BN8-obe.outbound.protection.outlook.com (104.47.55.176) by edgegateway.intel.com (192.55.55.69) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 8 Jul 2020 19:08:22 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=RLzdc+Dtq9+V9EM7wAdE/7Qa1TKFPZ4/03sxWQvaMdG3mRvBXAymljx3HX4+6HuB5D+D6uLxLjmFP//G+J1wYs4Z7x++9cHAoVYjuu0zRm8UhvDObP2qH/BZ40s5Kbgb74gAnuYBDo8/0obIo2nHgvLi/e1l31wPNwhXmvYF4PzFVz2B804eEvwLGLeDG+t4zE/CEwv1d1AuMqnWGFuuIftAVrexhlh0KN6VP2mTW2dr+KtT52EoshCidi2VFX3IhHrY37hevozZr6GP7ce1iQdIxGudTvmU9agXTuXCSjPwbKb0qJtuDN0LHvB6+U9D/27euTIrSw2ZE31spTB2Lg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9vFStrjVMYLHRM5mIpJ64o+QaRQlx8weva2fvgbvLkU=; b=CbfwmTDx27HQQ+VJqxRG66msf4avTo5KMuSJalMu85sgipf94BWrcV5NZ2IvH+aB42n/Q4c6ZfPfE1jF+uSBvBrDDSn2EnHcrjKfimUo1eApEGxyh7+IpqMl0amKQ9gx+2YGzRkhsMr6s0BvaoPWp/OZO7ytmm9KDSCr01ayqCw2/CCt5UXDExnEC27j6KyObNVcPEYJWaXN2F0LvQMg1qc16sU6de1rlDviRJ6oQvVk+ND6sRpp5dvw2t5M3FH7lJSNp817ArNuLqoYatEshYxT/XauOFwKFgWFImAn+gTTT+JJd8RVdHmlyqcUvfUraVisHwojuO5WCppCkSaLBg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel.onmicrosoft.com; s=selector2-intel-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=9vFStrjVMYLHRM5mIpJ64o+QaRQlx8weva2fvgbvLkU=; b=mZpwmLco7XHxpDgbmghTK7HL9XjFO04PfuMF6wTcxp/nQzHgEJOLuKjtgHGY3sYqs/hJpe6dNq/y7mHKEcFBfGM2UdUa8G4lSXt/yb8nyKVkMMD8quK0SjxNDSOQdlyGW0RIJ3TlwVxhGHkbxkbooqbgcjnWCIBSY/RUFl5yZDc= Received: from DM5PR11MB1435.namprd11.prod.outlook.com (2603:10b6:4:7::18) by DM6PR11MB4233.namprd11.prod.outlook.com (2603:10b6:5:14f::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3153.27; Thu, 9 Jul 2020 02:08:20 +0000 Received: from DM5PR11MB1435.namprd11.prod.outlook.com ([fe80::9002:97a2:d8c0:8364]) by DM5PR11MB1435.namprd11.prod.outlook.com ([fe80::9002:97a2:d8c0:8364%10]) with mapi id 15.20.3174.021; Thu, 9 Jul 2020 02:08:19 +0000 From: "Liu, Yi L" To: "Tian, Kevin" , Alex Williamson , "jacob.jun.pan@linux.intel.com" Subject: RE: [PATCH v3 06/14] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Thread-Topic: [PATCH v3 06/14] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Thread-Index: AQHWSgRRzB2G/Oy5QEmxCHQWFS0FB6j02KQAgACUCyCAB/5SUIAAxDYAgABLnwCAABmKAIAAAO4w Date: Thu, 9 Jul 2020 02:08:19 +0000 Message-ID: References: <1592988927-48009-1-git-send-email-yi.l.liu@intel.com> <1592988927-48009-7-git-send-email-yi.l.liu@intel.com> <20200702151832.048b44d1@x1.home> <20200708135444.4eac48a4@x1.home> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-reaction: no-action dlp-version: 11.2.0.6 dlp-product: dlpe-windows authentication-results: intel.com; dkim=none (message not signed) header.d=none;intel.com; dmarc=none action=none header.from=intel.com; x-originating-ip: [117.169.230.114] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: b2b53f2f-4b3b-4562-d0e1-08d823acf324 x-ms-traffictypediagnostic: DM6PR11MB4233: x-ld-processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; x-forefront-prvs: 04599F3534 x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: wH4kRd83jZu70URtmGS7ZtagtgFo5prEC+HPasr/mw54tPkS9/ZIWm+G/YTXgyjb8nh16UzGYAQHYiVOywJLIBZtErF0G0m8X6rdgpD4VaZQLaJegXHUuPlz4nzLLXKsfpgKJrXr91xJnqGixRm+Lc1rxyyH1sndx5Ikl57DGNIwvdJlLtjUstwxMts/7i+d4B65U4mi3mQ6E7dFWdFC0CbnTVCE6WnQIrA7ZBjexPBbWIUGmBzJbiPzX+8fU1l24f/WxT63/PL4GMubgjoVrsco4/6hxq8Fl/IaEW3i5Ox2SjOzMs7dr2C3+nHJTuyEuvrXmmYeSV9/tdEEj2rssA== x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DM5PR11MB1435.namprd11.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(136003)(39860400002)(346002)(376002)(366004)(396003)(5660300002)(110136005)(76116006)(8936002)(86362001)(71200400001)(478600001)(186003)(66946007)(33656002)(52536014)(66476007)(66556008)(64756008)(66446008)(26005)(2906002)(9686003)(55016002)(7416002)(8676002)(54906003)(316002)(4326008)(6506007)(7696005)(83380400001); DIR:OUT; SFP:1102; x-ms-exchange-antispam-messagedata: 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 MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM5PR11MB1435.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: b2b53f2f-4b3b-4562-d0e1-08d823acf324 X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Jul 2020 02:08:19.2329 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: RlVJE7W7ID8z4wodTGXuFNZqRYPuFlWmVESMBwXl8KqfRSyr3TbHIG4TL3MCagREItcBUChXNXrwCdtzqpbCLw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR11MB4233 X-OriginatorOrg: intel.com Cc: "jean-philippe@linaro.org" , "Raj, Ashok" , "kvm@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Sun, Yi Y" , "Wu, Hao" , "Tian, Jun J" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi Kevin, > From: Tian, Kevin > Sent: Thursday, July 9, 2020 9:57 AM > > > From: Liu, Yi L > > Sent: Thursday, July 9, 2020 8:32 AM > > > > Hi Alex, > > > > > Alex Williamson > > > Sent: Thursday, July 9, 2020 3:55 AM > > > > > > On Wed, 8 Jul 2020 08:16:16 +0000 > > > "Liu, Yi L" wrote: > > > > > > > Hi Alex, > > > > > > > > > From: Liu, Yi L < yi.l.liu@intel.com> > > > > > Sent: Friday, July 3, 2020 2:28 PM > > > > > > > > > > Hi Alex, > > > > > > > > > > > From: Alex Williamson > > > > > > Sent: Friday, July 3, 2020 5:19 AM > > > > > > > > > > > > On Wed, 24 Jun 2020 01:55:19 -0700 Liu Yi L > > > > > > wrote: > > > > > > > > > > > > > This patch allows user space to request PASID allocation/free, e.g. > > > > > > > when serving the request from the guest. > > > > > > > > > > > > > > PASIDs that are not freed by userspace are automatically > > > > > > > freed > > when > > > > > > > the IOASID set is destroyed when process exits. > > > > [...] > > > > > > > +static int vfio_iommu_type1_pasid_request(struct vfio_iommu > > *iommu, > > > > > > > + unsigned long arg) > > > > > > > +{ > > > > > > > + struct vfio_iommu_type1_pasid_request req; > > > > > > > + unsigned long minsz; > > > > > > > + > > > > > > > + minsz = offsetofend(struct vfio_iommu_type1_pasid_request, > > > range); > > > > > > > + > > > > > > > + if (copy_from_user(&req, (void __user *)arg, minsz)) > > > > > > > + return -EFAULT; > > > > > > > + > > > > > > > + if (req.argsz < minsz || (req.flags & > > > ~VFIO_PASID_REQUEST_MASK)) > > > > > > > + return -EINVAL; > > > > > > > + > > > > > > > + if (req.range.min > req.range.max) > > > > > > > > > > > > Is it exploitable that a user can spin the kernel for a long > > > > > > time in the case of a free by calling this with [0, MAX_UINT] > > > > > > regardless of their > > > actual > > > > > allocations? > > > > > > > > > > IOASID can ensure that user can only free the PASIDs allocated > > > > > to the > > user. > > > but > > > > > it's true, kernel needs to loop all the PASIDs within the range > > > > > provided by user. > > > it > > > > > may take a long time. is there anything we can do? one thing may > > > > > limit > > the > > > range > > > > > provided by user? > > > > > > > > thought about it more, we have per-VM pasid quota (say 1000), so > > > > even if user passed down [0, MAX_UNIT], kernel will only loop the > > > > 1000 pasids at most. do you think we still need to do something on it? > > > > > > How do you figure that? vfio_iommu_type1_pasid_request() accepts > > > the user's min/max so long as (max > min) and passes that to > > > vfio_iommu_type1_pasid_free(), then to vfio_pasid_free_range() > > > which loops as: > > > > > > ioasid_t pasid = min; > > > for (; pasid <= max; pasid++) > > > ioasid_free(pasid); > > > > > > A user might only be able to allocate 1000 pasids, but apparently > > > they can ask to free all they want. > > > > > > It's also not obvious to me that calling ioasid_free() is only > > > allowing the user to free their own passid. Does it? It would be a > > > pretty > > Agree. I thought ioasid_free should at least carry a token since the user space is > only allowed to manage PASIDs in its own set... > > > > gaping hole if a user could free arbitrary pasids. A r-b tree of > > > passids might help both for security and to bound spinning in a loop. > > > > oh, yes. BTW. instead of r-b tree in VFIO, maybe we can add an > > ioasid_set parameter for ioasid_free(), thus to prevent the user from > > freeing PASIDs that doesn't belong to it. I remember Jacob mentioned it before. > > > > check current ioasid_free: > > spin_lock(&ioasid_allocator_lock); > ioasid_data = xa_load(&active_allocator->xa, ioasid); > if (!ioasid_data) { > pr_err("Trying to free unknown IOASID %u\n", ioasid); > goto exit_unlock; > } > > Allow an user to trigger above lock paths with MAX_UINT times might still be bad. yeah, how about the below two options: - comparing the max - min with the quota before calling ioasid_free(). If max - min > current quota of the user, then should fail it. If max - min < quota, then call ioasid_free() one by one. still trigger the above lock path with quota times. - pass the max and min to ioasid_free(), let ioasid_free() decide. should be able to avoid trigger the lock multiple times, and ioasid has have a track on how may PASIDs have been allocated, if max - min is larger than the allocated number, should fail anyway. thoughts on the above reply? Regards, Yi Liu > Thanks > Kevin _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu