From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751774AbdB0Izl (ORCPT ); Mon, 27 Feb 2017 03:55:41 -0500 Received: from smtp.lesbg.com ([178.62.242.175]:42740 "EHLO smtp.lesbg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751620AbdB0IzT (ORCPT ); Mon, 27 Feb 2017 03:55:19 -0500 From: Jonathan Dieter To: linux-kernel@vger.kernel.org Cc: Jonathan Dieter , Valentina Manea , Shuah Khan , Peter Senna Tschudin , Greg Kroah-Hartman , Krzysztof Opasiak , linux-usb@vger.kernel.org (open list:USB OVER IP DRIVER) Subject: [PATCH v4 1/2] usbip: Fix-format-overflow Date: Mon, 27 Feb 2017 10:31:03 +0200 Message-Id: <20170227083108.16391-1-jdieter@lesbg.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170222181803.16373-1-jdieter@lesbg.com> References: <20170222181803.16373-1-jdieter@lesbg.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The usbip userspace tools call sprintf()/snprintf() and don't check for the return value which can lead the paths to overflow, truncating the final file in the path. More urgently, GCC 7 now warns that these aren't checked with -Wformat-overflow, and with -Werror enabled in configure.ac, that makes these tools unbuildable. This patch fixes these problems by replacing sprintf() with snprintf() in one place and adding checks for the return value of snprintf(). Reviewed-by: Peter Senna Tschudin Signed-off-by: Jonathan Dieter --- Changes since v3 * Cast sizeof to long unsigned when printing errors to fix building for 32-bit architectures tools/usb/usbip/libsrc/usbip_common.c | 9 ++++++++- tools/usb/usbip/libsrc/usbip_host_common.c | 28 +++++++++++++++++++++++----- 2 files changed, 31 insertions(+), 6 deletions(-) diff --git a/tools/usb/usbip/libsrc/usbip_common.c b/tools/usb/usbip/libsrc/usbip_common.c index ac73710..1517a23 100644 --- a/tools/usb/usbip/libsrc/usbip_common.c +++ b/tools/usb/usbip/libsrc/usbip_common.c @@ -215,9 +215,16 @@ int read_usb_interface(struct usbip_usb_device *udev, int i, struct usbip_usb_interface *uinf) { char busid[SYSFS_BUS_ID_SIZE]; + int size; struct udev_device *sif; - sprintf(busid, "%s:%d.%d", udev->busid, udev->bConfigurationValue, i); + size = snprintf(busid, sizeof(busid), "%s:%d.%d", + udev->busid, udev->bConfigurationValue, i); + if (size < 0 || (unsigned int)size >= sizeof(busid)) { + err("busid length %i >= %lu or < 0", size, + (long unsigned)sizeof(busid)); + return -1; + } sif = udev_device_new_from_subsystem_sysname(udev_context, "usb", busid); if (!sif) { diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c index 9d41522..6ff7b60 100644 --- a/tools/usb/usbip/libsrc/usbip_host_common.c +++ b/tools/usb/usbip/libsrc/usbip_host_common.c @@ -40,13 +40,20 @@ struct udev *udev_context; static int32_t read_attr_usbip_status(struct usbip_usb_device *udev) { char status_attr_path[SYSFS_PATH_MAX]; + int size; int fd; int length; char status; int value = 0; - snprintf(status_attr_path, SYSFS_PATH_MAX, "%s/usbip_status", - udev->path); + size = snprintf(status_attr_path, sizeof(status_attr_path), + "%s/usbip_status", udev->path); + if (size < 0 || (unsigned int)size >= sizeof(status_attr_path)) { + err("usbip_status path length %i >= %lu or < 0", size, + (long unsigned)sizeof(status_attr_path)); + return -1; + } + fd = open(status_attr_path, O_RDONLY); if (fd < 0) { @@ -218,6 +225,7 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd) { char attr_name[] = "usbip_sockfd"; char sockfd_attr_path[SYSFS_PATH_MAX]; + int size; char sockfd_buff[30]; int ret; @@ -237,10 +245,20 @@ int usbip_export_device(struct usbip_exported_device *edev, int sockfd) } /* only the first interface is true */ - snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s", - edev->udev.path, attr_name); + size = snprintf(sockfd_attr_path, sizeof(sockfd_attr_path), "%s/%s", + edev->udev.path, attr_name); + if (size < 0 || (unsigned int)size >= sizeof(sockfd_attr_path)) { + err("exported device path length %i >= %lu or < 0", size, + (long unsigned)sizeof(sockfd_attr_path)); + return -1; + } - snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd); + size = snprintf(sockfd_buff, sizeof(sockfd_buff), "%d\n", sockfd); + if (size < 0 || (unsigned int)size >= sizeof(sockfd_buff)) { + err("socket length %i >= %lu or < 0", size, + (long unsigned)sizeof(sockfd_buff)); + return -1; + } ret = write_sysfs_attribute(sockfd_attr_path, sockfd_buff, strlen(sockfd_buff)); -- 2.9.3