From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45780 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387998AbeGWNaA (ORCPT ); Mon, 23 Jul 2018 09:30:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Alex Williamson Subject: [PATCH 4.14 17/44] vfio/pci: Fix potential Spectre v1 Date: Mon, 23 Jul 2018 14:24:53 +0200 Message-Id: <20180723122438.279932573@linuxfoundation.org> In-Reply-To: <20180723122437.447870153@linuxfoundation.org> References: <20180723122437.447870153@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva commit 0e714d27786ce1fb3efa9aac58abc096e68b1c2a upstream. 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 Signed-off-by: Alex Williamson Signed-off-by: Greg Kroah-Hartman --- drivers/vfio/pci/vfio_pci.c | 4 ++++ 1 file changed, 4 insertions(+) --- 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" @@ -746,6 +747,9 @@ static long vfio_pci_ioctl(void *device_ 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;