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>
diff --git a/drivers/staging/vt6655/hostap.c b/drivers/staging/vt6655/hostap.c
index f105c2a..164136b 100644
--- a/drivers/staging/vt6655/hostap.c
+++ b/drivers/staging/vt6655/hostap.c
@@ -350,6 +350,9 @@
 {
 	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