From patchwork Fri Jun 16 09:39:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13282463 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB16FC05052 for ; Fri, 16 Jun 2023 09:41:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344579AbjFPJky (ORCPT ); Fri, 16 Jun 2023 05:40:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344428AbjFPJkL (ORCPT ); Fri, 16 Jun 2023 05:40:11 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0A65272D; Fri, 16 Jun 2023 02:40:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686908409; x=1718444409; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=w64PBZBpwikwjApBh0qcsx7B85QSOftXwQDkYqhx5Os=; b=kf1X2ty7WhMiK1t9gpk8fBROlt36XYTBjHoeZ5KUV/mre00eWBlFUNf2 OyM/ZI1K8OxIvuThw+EOSp7flNePLA2uz+ygPLRkRIaCl9QDzfwVb87El KGw8p5yfO/nUNH+VBj0oudYB3HaOhYW/ZNgQ8LULJxlxFFJQcyiRz+YpJ xdZZsFOJDZIK1xlU1Q6vGYl9fph1vMyrt0duyaD2hvMU0NHHMlj0GFBs5 zQTQR1ZwgjeyCAVZ+ABkjxNar8eSSZJp4s/ilB5XY/tW/KwHOL3id9MHn XqZKRwi4x805G8jQ4KcfUqYmdm5haVmPJ46JWXgjAS3f2KvKbY047ldhn w==; X-IronPort-AV: E=McAfee;i="6600,9927,10742"; a="361700262" X-IronPort-AV: E=Sophos;i="6.00,247,1681196400"; d="scan'208";a="361700262" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jun 2023 02:40:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10742"; a="715951114" X-IronPort-AV: E=Sophos;i="6.00,247,1681196400"; d="scan'208";a="715951114" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmsmga007.fm.intel.com with ESMTP; 16 Jun 2023 02:40:08 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Cc: joro@8bytes.org, robin.murphy@arm.com, cohuck@redhat.com, eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, chao.p.peng@linux.intel.com, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, peterx@redhat.com, jasowang@redhat.com, shameerali.kolothum.thodi@huawei.com, lulu@redhat.com, suravee.suthikulpanit@amd.com, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-s390@vger.kernel.org, xudong.hao@intel.com, yan.y.zhao@intel.com, terrence.xu@intel.com, yanting.jiang@intel.com, zhenzhong.duan@intel.com, clegoate@redhat.com Subject: [PATCH v13 09/22] vfio: Make vfio_df_open() single open for device cdev path Date: Fri, 16 Jun 2023 02:39:33 -0700 Message-Id: <20230616093946.68711-10-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230616093946.68711-1-yi.l.liu@intel.com> References: <20230616093946.68711-1-yi.l.liu@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org VFIO group has historically allowed multi-open of the device FD. This was made secure because the "open" was executed via an ioctl to the group FD which is itself only single open. However, no known use of multiple device FDs today. It is kind of a strange thing to do because new device FDs can naturally be created via dup(). When we implement the new device uAPI (only used in cdev path) there is no natural way to allow the device itself from being multi-opened in a secure manner. Without the group FD we cannot prove the security context of the opener. Thus, when moving to the new uAPI we block the ability of opening a device multiple times. Given old group path still allows it we store a vfio_group pointer in struct vfio_device_file to differentiate. Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Reviewed-by: Eric Auger Tested-by: Terrence Xu Tested-by: Nicolin Chen Tested-by: Matthew Rosato Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Signed-off-by: Yi Liu --- drivers/vfio/group.c | 2 ++ drivers/vfio/vfio.h | 1 + drivers/vfio/vfio_main.c | 7 +++++++ 3 files changed, 10 insertions(+) diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index 2751d61689c4..4e6277191eb4 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -245,6 +245,8 @@ static struct file *vfio_device_open_file(struct vfio_device *device) goto err_out; } + df->group = device->group; + ret = vfio_df_group_open(df); if (ret) goto err_free; diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index ae7dd2ca14b9..85484a971a3e 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -18,6 +18,7 @@ struct vfio_container; struct vfio_device_file { struct vfio_device *device; + struct vfio_group *group; u8 access_granted; spinlock_t kvm_ref_lock; /* protect kvm field */ diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index c37fc14599d0..be5e4ddd5901 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -492,6 +492,13 @@ int vfio_df_open(struct vfio_device_file *df) lockdep_assert_held(&device->dev_set->lock); + /* + * Only the group path allows the device to be opened multiple + * times. The device cdev path doesn't have a secure way for it. + */ + if (device->open_count != 0 && !df->group) + return -EINVAL; + device->open_count++; if (device->open_count == 1) { ret = vfio_df_device_first_open(df);