Patch "usbip: Fix potential format overflow in userspace tools" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    usbip: Fix potential format overflow in userspace tools

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usbip-fix-potential-format-overflow-in-userspace-tools.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e5dfa3f902b9a642ae8c6997d57d7c41e384a90b Mon Sep 17 00:00:00 2001
From: Jonathan Dieter <jdieter@lesbg.com>
Date: Mon, 27 Feb 2017 10:31:03 +0200
Subject: usbip: Fix potential format overflow in userspace tools

From: Jonathan Dieter <jdieter@lesbg.com>

commit e5dfa3f902b9a642ae8c6997d57d7c41e384a90b upstream.

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 <peter.senna@gmail.com>
Signed-off-by: Jonathan Dieter <jdieter@lesbg.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/usb/usbip/libsrc/usbip_common.c      |    9 ++++++++-
 tools/usb/usbip/libsrc/usbip_host_common.c |   28 +++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 6 deletions(-)

--- 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_
 		       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) {
--- 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_exp
 {
 	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_exp
 	}
 
 	/* 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));


Patches currently in stable-queue which might be from jdieter@lesbg.com are

queue-4.9/usbip-fix-potential-format-overflow-in-userspace-tools.patch
queue-4.9/usbip-fix-implicit-fallthrough-warning.patch