From b02f6a9593cbe0c3a9cf6052acf58c11980d6efd Mon Sep 17 00:00:00 2001
From: Roel Kluin <roel.kluin@gmail.com>
Date: Wed, 4 Nov 2009 08:31:59 -0800
Subject: [PATCH] isdn: hfc_usb: Fix read buffer overflow

commit 286e633ef0ff5bb63c07b4516665da8004966fec upstream.

Check whether index is within bounds before testing the element.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Karsten Keil <isdn@linux-pingi.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/isdn/hisax/hfc_usb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/isdn/hisax/hfc_usb.c b/drivers/isdn/hisax/hfc_usb.c
index 9de54202c90c..a420b64472e3 100644
--- a/drivers/isdn/hisax/hfc_usb.c
+++ b/drivers/isdn/hisax/hfc_usb.c
@@ -817,8 +817,8 @@ collect_rx_frame(usb_fifo * fifo, __u8 * data, int len, int finish)
 	}
 	/* we have a complete hdlc packet */
 	if (finish) {
-		if ((!fifo->skbuff->data[fifo->skbuff->len - 1])
-		    && (fifo->skbuff->len > 3)) {
+		if (fifo->skbuff->len > 3 &&
+				!fifo->skbuff->data[fifo->skbuff->len - 1]) {
 
 			if (fifon == HFCUSB_D_RX) {
 				DBG(HFCUSB_DBG_DCHANNEL,
-- 
2.39.5