[PATCH 4.14 118/146] usbip: fix usbip bind writing random string after command in match_busid

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Juan Zea <juan....@qindel.com>

commit 544c4605acc5ae4afe7dd5914147947db182f2fb upstream.

usbip bind writes commands followed by random string when writing to
match_busid attribute in sysfs, caused by using full variable size
instead of string length.

Signed-off-by: Juan Zea <juan....@qindel.com>
Acked-by: Shuah Khan <shua...@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 tools/usb/usbip/src/utils.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/tools/usb/usbip/src/utils.c
+++ b/tools/usb/usbip/src/utils.c
@@ -30,6 +30,7 @@ int modify_match_busid(char *busid, int
        char command[SYSFS_BUS_ID_SIZE + 4];
        char match_busid_attr_path[SYSFS_PATH_MAX];
        int rc;
+       int cmd_size;
 
        snprintf(match_busid_attr_path, sizeof(match_busid_attr_path),
                 "%s/%s/%s/%s/%s/%s", SYSFS_MNT_PATH, SYSFS_BUS_NAME,
@@ -37,12 +38,14 @@ int modify_match_busid(char *busid, int
                 attr_name);
 
        if (add)
-               snprintf(command, SYSFS_BUS_ID_SIZE + 4, "add %s", busid);
+               cmd_size = snprintf(command, SYSFS_BUS_ID_SIZE + 4, "add %s",
+                                   busid);
        else
-               snprintf(command, SYSFS_BUS_ID_SIZE + 4, "del %s", busid);
+               cmd_size = snprintf(command, SYSFS_BUS_ID_SIZE + 4, "del %s",
+                                   busid);
 
        rc = write_sysfs_attribute(match_busid_attr_path, command,
-                                  sizeof(command));
+                                  cmd_size);
        if (rc < 0) {
                dbg("failed to write match_busid: %s", strerror(errno));
                return -1;