From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:52852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965894AbeFNOLq (ORCPT ); Thu, 14 Jun 2018 10:11:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , "Shuah Khan (Samsung OSG)" Subject: [PATCH 4.9 15/30] usbip: vhci_sysfs: fix potential Spectre v1 Date: Thu, 14 Jun 2018 16:04:56 +0200 Message-Id: <20180614132600.896201769@linuxfoundation.org> In-Reply-To: <20180614132600.255515394@linuxfoundation.org> References: <20180614132600.255515394@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva commit a0d6ec88090d7b1b008429c44532a388e29bb1bd upstream. pdev_nr and rhport can be 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/usb/usbip/vhci_sysfs.c:238 detach_store() warn: potential spectre issue 'vhcis' drivers/usb/usbip/vhci_sysfs.c:328 attach_store() warn: potential spectre issue 'vhcis' drivers/usb/usbip/vhci_sysfs.c:338 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_ss->vdev' drivers/usb/usbip/vhci_sysfs.c:340 attach_store() warn: potential spectre issue 'vhci->vhci_hcd_hs->vdev' Fix this by sanitizing pdev_nr and rhport before using them to index vhcis and vhci->vhci_hcd_ss->vdev respectively. 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 Acked-by: Shuah Khan (Samsung OSG) Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/vhci_sysfs.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) --- a/drivers/usb/usbip/vhci_sysfs.c +++ b/drivers/usb/usbip/vhci_sysfs.c @@ -24,6 +24,9 @@ #include #include +/* Hardening for Spectre-v1 */ +#include + #include "usbip_common.h" #include "vhci.h" @@ -181,16 +184,20 @@ static int vhci_port_disconnect(struct v return 0; } -static int valid_port(__u32 pdev_nr, __u32 rhport) +static int valid_port(__u32 *pdev_nr, __u32 *rhport) { - if (pdev_nr >= vhci_num_controllers) { - pr_err("pdev %u\n", pdev_nr); + if (*pdev_nr >= vhci_num_controllers) { + pr_err("pdev %u\n", *pdev_nr); return 0; } - if (rhport >= VHCI_HC_PORTS) { - pr_err("rhport %u\n", rhport); + *pdev_nr = array_index_nospec(*pdev_nr, vhci_num_controllers); + + if (*rhport >= VHCI_HC_PORTS) { + pr_err("rhport %u\n", *rhport); return 0; } + *rhport = array_index_nospec(*rhport, VHCI_HC_PORTS); + return 1; } @@ -207,7 +214,7 @@ static ssize_t store_detach(struct devic pdev_nr = port_to_pdev_nr(port); rhport = port_to_rhport(port); - if (!valid_port(pdev_nr, rhport)) + if (!valid_port(&pdev_nr, &rhport)) return -EINVAL; hcd = platform_get_drvdata(*(vhci_pdevs + pdev_nr)); @@ -226,7 +233,8 @@ static ssize_t store_detach(struct devic } static DEVICE_ATTR(detach, S_IWUSR, NULL, store_detach); -static int valid_args(__u32 pdev_nr, __u32 rhport, enum usb_device_speed speed) +static int valid_args(__u32 *pdev_nr, __u32 *rhport, + enum usb_device_speed speed) { if (!valid_port(pdev_nr, rhport)) { return 0; @@ -288,7 +296,7 @@ static ssize_t store_attach(struct devic sockfd, devid, speed); /* check received parameters */ - if (!valid_args(pdev_nr, rhport, speed)) + if (!valid_args(&pdev_nr, &rhport, speed)) return -EINVAL; hcd = platform_get_drvdata(*(vhci_pdevs + pdev_nr));