From: Jia-Ju Bai <baijiaju1990@gmail.com>
Date: Sat, 30 May 2020 10:41:50 +0800
Subject: net: vmxnet3: fix possible buffer overflow caused by bad DMA value in
 vmxnet3_get_rss()
Patch-mainline: v5.8-rc1
Git-commit: 3e1c6846b9e108740ef8a37be80314053f5dd52a
References: bsc#1172484

The value adapter->rss_conf is stored in DMA memory, and it is assigned
to rssConf, so rssConf->indTableSize can be modified at anytime by
malicious hardware. Because rssConf->indTableSize is assigned to n,
buffer overflow may occur when the code "rssConf->indTable[n]" is
executed.

To fix this possible bug, n is checked after being used.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/vmxnet3/vmxnet3_ethtool.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/vmxnet3/vmxnet3_ethtool.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethtool.c
@@ -954,6 +954,8 @@ vmxnet3_get_rss(struct net_device *netde
 		*hfunc = ETH_RSS_HASH_TOP;
 	if (!p)
 		return 0;
+	if (n > UPT1_RSS_MAX_IND_TABLE_SIZE)
+		return 0;
 	while (n--)
 		p[n] = rssConf->indTable[n];
 	return 0;