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=-2.3 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 382D4ECDFB1 for ; Tue, 17 Jul 2018 17:39:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8268206B8 for ; Tue, 17 Jul 2018 17:39:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8268206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729952AbeGQSNT (ORCPT ); Tue, 17 Jul 2018 14:13:19 -0400 Received: from gateway21.websitewelcome.com ([192.185.45.163]:13509 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729721AbeGQSNT (ORCPT ); Tue, 17 Jul 2018 14:13:19 -0400 Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway21.websitewelcome.com (Postfix) with ESMTP id F3CDF400D4943 for ; Tue, 17 Jul 2018 12:39:36 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id fTwDf5UrpPvAdfTwYfAiHo; Tue, 17 Jul 2018 12:39:36 -0500 X-Authority-Reason: nr=8 Received: from [189.250.65.56] (port=49734 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1ffTwD-003btg-DR; Tue, 17 Jul 2018 12:39:01 -0500 Date: Tue, 17 Jul 2018 12:39:00 -0500 From: "Gustavo A. R. Silva" To: Alex Williamson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] vfio/pci: Fix potential Spectre v1 Message-ID: <20180717173900.GA24627@embeddedor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.65.56 X-Source-L: No X-Exim-ID: 1ffTwD-003btg-DR X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.65.56]:49734 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/vfio/pci/vfio_pci.c:734 vfio_pci_ioctl() warn: potential spectre issue 'vdev->region' Fix this by sanitizing info.index before indirectly using it to index 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/vfio/pci/vfio_pci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index b423a30..125b58e 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "vfio_pci_private.h" @@ -727,6 +728,9 @@ static long vfio_pci_ioctl(void *device_data, if (info.index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions) return -EINVAL; + info.index = array_index_nospec(info.index, + VFIO_PCI_NUM_REGIONS + + vdev->num_regions); i = info.index - VFIO_PCI_NUM_REGIONS; -- 2.7.4