--- usb_modeswitch_dispatcher.c.orig	2014-02-20 15:08:44.665397121 +0700
+++ usb_modeswitch_dispatcher.c	2014-02-21 01:11:20.351366429 +0700
@@ -183,6 +183,10 @@
 void prepare_run_dir();
 int check_success(char *dir, char *ifdir);
 
+static int min(int a, int b){
+	return a>b?b:a;
+}
+
 int main(int argc, char* argv[])
 {
 	regex_t reg;
@@ -190,6 +194,7 @@
 	char *val, *tmpval, *tmp;
 	char bus_id[PATH_MAX], *kernel_name = NULL;
 	char dev_top[PATH_MAX];
+	int  length;
 	char *udev_args = NULL;
 	char *msg, *sys_dir, *fname, *selected_config, *ifdir;
 	char line[PATH_MAX];
@@ -279,8 +284,9 @@
 	else
 		kernel_name = "";
 
-	strncpy (bus_id, udev_args, strlen(udev_args) - strlen(kernel_name) - 1);
-	bus_id[strlen(bus_id)] = '\0';
+	length = min(kernel_name - udev_args - 1, sizeof(bus_id) - 1);
+	strncpy (bus_id, udev_args, length);
+	bus_id[length] = '\0';
 
 	if (strlen(kernel_name) > 0 && strlen(bus_id) == 0) {
 		char *colon = strchr (kernel_name, ':');
@@ -289,8 +295,12 @@
 		modeswitch_log(" Trying to determine it from kernel name (%s) ...\n", kernel_name);
 
 		if (colon) {
-			strncpy (dev_top, kernel_name, strlen(kernel_name) - strlen(colon));
-			dev_top[strlen(dev_top)] = '\0';
+			length = min(colon - kernel_name, sizeof(dev_top) - 1);
+			strncpy (dev_top, kernel_name, length);
+			dev_top[length] = '\0';
+		}else{ //sometimes udev_args is "/1-1"
+			strncpy (dev_top, kernel_name, sizeof(dev_top)-1);
+			dev_top[sizeof(dev_top)-1] = '\0';
 		}
 	}
 	else if (strlen(bus_id) > 0) {