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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jia-Ju Bai <baijiaju1990@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 094/190] net: vmxnet3: fix possible buffer overflow caused by bad DMA value in vmxnet3_get_rss()
Date:   Fri, 19 Jun 2020 16:32:19 +0200
Message-Id: <20200619141638.294719692@linuxfoundation.org>
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From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit 3e1c6846b9e108740ef8a37be80314053f5dd52a ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/vmxnet3/vmxnet3_ethtool.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/vmxnet3/vmxnet3_ethtool.c b/drivers/net/vmxnet3/vmxnet3_ethtool.c
index 2ff27314e047..66c6c07c7a16 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethtool.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethtool.c
@@ -692,6 +692,8 @@ vmxnet3_get_rss(struct net_device *netdev, u32 *p, u8 *key, u8 *hfunc)
 		*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;
-- 
2.25.1