diff --git a/drivers/staging/ozwpan/ozcdev.c b/drivers/staging/ozwpan/ozcdev.c
index 6ccb64fb07865821741d9c3406377bf97cfe7994..6ce0af9977d8c0ccc053e98eb818a98ec8d990f7 100644
--- a/drivers/staging/ozwpan/ozcdev.c
+++ b/drivers/staging/ozwpan/ozcdev.c
@@ -155,6 +155,9 @@ static ssize_t oz_cdev_write(struct file *filp, const char __user *buf,
 	struct oz_app_hdr *app_hdr;
 	struct oz_serial_ctx *ctx;
 
+	if (count > sizeof(ei->data) - sizeof(*elt) - sizeof(*app_hdr))
+		return -EINVAL;
+
 	spin_lock_bh(&g_cdev.lock);
 	pd = g_cdev.active_pd;
 	if (pd)