From e5dfa3f902b9a642ae8c6997d57d7c41e384a90b Mon Sep 17 00:00:00 2001 From: Jonathan Dieter Date: Mon, 27 Feb 2017 10:31:03 +0200 Subject: [PATCH] usbip: Fix potential format overflow in userspace tools 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 Acked-by: Shuah Khan Signed-off-by: Greg Kroah-Hartman --- 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 ac73710473de..1517a232ab18 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 9d415228883d..6ff7b601f854 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)); -- 2.20.1