staging: vt6655: buffer overflow in ioctl

->u.generic_elem.len is a user controlled number between 0-255.  We
should limit it to avoid memory corruption.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/hostap.c

@@ -350,6 +350,9 @@ static int hostap_set_generic_element(PSDevice pDevice,
 {
 	PSMgmtObject    pMgmt = pDevice->pMgmt;
 
+	if (param->u.generic_elem.len > sizeof(pMgmt->abyWPAIE))
+		return -EINVAL;
+
 	memcpy(pMgmt->abyWPAIE,
 	       param->u.generic_elem.data,
 	       param->u.generic_elem.len