From patchwork Fri Aug 3 03:40:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 10554627 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9D74B14E2 for ; Fri, 3 Aug 2018 07:14:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8223F28745 for ; Fri, 3 Aug 2018 07:14:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7471F2C36A; Fri, 3 Aug 2018 07:14:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 95A0928745 for ; Fri, 3 Aug 2018 07:14:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3720D6E69B; Fri, 3 Aug 2018 07:14:00 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from gateway32.websitewelcome.com (gateway32.websitewelcome.com [192.185.145.107]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1B9156E672 for ; Fri, 3 Aug 2018 03:40:22 +0000 (UTC) Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway32.websitewelcome.com (Postfix) with ESMTP id 1EB4390D70 for ; Thu, 2 Aug 2018 22:40:21 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id lQwuf6kO1PvAdlQwuf8xe0; Thu, 02 Aug 2018 22:40:21 -0500 X-Authority-Reason: nr=8 Received: from [189.250.50.82] (port=49190 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1flQwu-0019BB-6R; Thu, 02 Aug 2018 22:40:20 -0500 Date: Thu, 2 Aug 2018 22:40:19 -0500 From: "Gustavo A. R. Silva" To: Zhenyu Wang , Zhi Wang , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie Subject: [PATCH] drm/i915/kvmgt: Fix potential Spectre v1 Message-ID: <20180803034019.GA18366@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - lists.freedesktop.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.50.82 X-Source-L: No X-Exim-ID: 1flQwu-0019BB-6R X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.50.82]:49190 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 9 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-Mailman-Approved-At: Fri, 03 Aug 2018 07:13:57 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, "Gustavo A. R. Silva" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP info.index can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/gpu/drm/i915/gvt/kvmgt.c:1232 intel_vgpu_ioctl() warn: potential spectre issue 'vgpu->vdev.region' [r] Fix this by sanitizing info.index before indirectly using it to index vgpu->vdev.region Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva --- drivers/gpu/drm/i915/gvt/kvmgt.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 4d2f53a..b703f20 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -43,6 +43,8 @@ #include #include +#include + #include "i915_drv.h" #include "gvt.h" @@ -1139,7 +1141,8 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd, } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) { struct vfio_region_info info; struct vfio_info_cap caps = { .buf = NULL, .size = 0 }; - int i, ret; + unsigned int i; + int ret; struct vfio_region_info_cap_sparse_mmap *sparse = NULL; size_t size; int nr_areas = 1; @@ -1224,6 +1227,10 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd, if (info.index >= VFIO_PCI_NUM_REGIONS + vgpu->vdev.num_regions) return -EINVAL; + info.index = + array_index_nospec(info.index, + VFIO_PCI_NUM_REGIONS + + vgpu->vdev.num_regions); i = info.index - VFIO_PCI_NUM_REGIONS;