0010-xen-netfront-add-range-check-for-Tx-response-id.patch

From b5bc80763b7bf0f9e32a9a4d4f930ff50d02385d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Wed, 16 Dec 2015 05:22:24 +0100
Subject: [PATCH] xen-netfront: add range check for Tx response id
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Tx response ID is fetched from shared page, so make sure it is sane
before using it as an array index.

This is part of XSA155.

CC: stable@vger.kernel.org
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
 drivers/net/xen-netfront.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 56c8a4a32672..e11df925c0dc 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -392,6 +392,7 @@ static void xennet_tx_buf_gc(struct netfront_queue *queue)
 				continue;
 
 			id  = txrsp.id;
+			BUG_ON(id >= NET_TX_RING_SIZE);
 			skb = queue->tx_skbs[id].skb;
 			if (unlikely(gnttab_query_foreign_access(
 				queue->grant_tx_ref[id]) != 0)) {
-- 
2.21.0