[PATCH] net: vmxnet3: fix possible buffer overflow caused by bad DMA value in vmxnet3_get_rss()

[Jia-Ju Bai]

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 <baijiaju1...@gmail.com>
---
 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 6528940ce5f3..b53bb8bcd47f 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethtool.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethtool.c
@@ -700,6 +700,8 @@ 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;
-- 
2.17.1