usbip: fix usbip bind writing random string after command in match_busid

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.zea@qindel.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/usb/usbip/src/utils.c b/tools/usb/usbip/src/utils.c
index 2b3d6d235015..3d7b42e77299 100644
--- 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 add)
         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 add)
                  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;