From patchwork Tue Jul 18 13:55:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13317301 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 97008EB64DD for ; Tue, 18 Jul 2023 13:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233030AbjGRN4p (ORCPT ); Tue, 18 Jul 2023 09:56:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233029AbjGRN4k (ORCPT ); Tue, 18 Jul 2023 09:56:40 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9920E1BC8; Tue, 18 Jul 2023 06:56:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689688574; x=1721224574; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=R9bRtQdJml9+TitiHGxi0ya5VN9YQ3JVW0CnvpAiveo=; b=J2qXgHwsphEEELbYRzM+hZlOcrRZGNv62r/8Mo3drahfSa7awJ04aBv4 UZ8TK8J++VuW91s6uwrJE35IsMQxyfg5sQbJwO+Gxba95ZsX3srh9keiG Q3fLF6KvbB/taTRVWlC783cSP0PGsF3soLqdo5gQcYWAmAVHlwT8kZLlI BcwJtf5SQUHIpnQR3GF4bgXnGowO7NLEjbFBSn+NGB+dfigMg4djumAey W8eFmIP+1/lLfkNkKG4xYJOZizxgRSRFpWm+HEmbKJ8uFoSWThiP263GL VZw9XC2oClGMXtUi7t9Vt0KA+cBWAbtSj9xvafo7kavs8D7ljyaxmwRfN Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10775"; a="452590642" X-IronPort-AV: E=Sophos;i="6.01,214,1684825200"; d="scan'208";a="452590642" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jul 2023 06:56:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10775"; a="970251002" X-IronPort-AV: E=Sophos;i="6.01,214,1684825200"; d="scan'208";a="970251002" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmsmga006.fm.intel.com with ESMTP; 18 Jul 2023 06:56:01 -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 v15 09/26] vfio: Make vfio_df_open() single open for device cdev path Date: Tue, 18 Jul 2023 06:55:34 -0700 Message-Id: <20230718135551.6592-10-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230718135551.6592-1-yi.l.liu@intel.com> References: <20230718135551.6592-1-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 Tested-by: Zhenzhong Duan 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);