diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c
index 89b09c51ab7c..38a5bb764c7b 100644
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -1376,6 +1376,7 @@ isdn_ioctl(struct file *file, uint cmd, ulong arg)
 			if (arg) {
 				if (copy_from_user(bname, argp, sizeof(bname) - 1))
 					return -EFAULT;
+				bname[sizeof(bname)-1] = 0;
 			} else
 				return -EINVAL;
 			ret = mutex_lock_interruptible(&dev->mtx);
diff --git a/drivers/isdn/i4l/isdn_net.c b/drivers/isdn/i4l/isdn_net.c
index c151c6daa67e..f63a110b7bcb 100644
--- a/drivers/isdn/i4l/isdn_net.c
+++ b/drivers/isdn/i4l/isdn_net.c
@@ -2611,10 +2611,9 @@ isdn_net_newslave(char *parm)
 	char newname[10];
 
 	if (p) {
-		/* Slave-Name MUST not be empty */
-		if (!strlen(p + 1))
+		/* Slave-Name MUST not be empty or overflow 'newname' */
+		if (strscpy(newname, p + 1, sizeof(newname)) <= 0)
 			return NULL;
-		strcpy(newname, p + 1);
 		*p = 0;
 		/* Master must already exist */
 		if (!(n = isdn_net_findif(parm)))