Subject: [PATCH net] net: ethernet: mtk_eth_soc: out of bounds read in mtk_hwlro_get_fdir_entry()

From: Dan Carpenter <[email-masked]>
Date: Thu, 26 May 2022 11:02:42 +0300

The "fsp->location" variable comes from user via ethtool_get_rxnfc().
Check that it is valid to prevent an out of bounds read.

Fixes: 7aab747e5563 ("net: ethernet: mediatek: add ethtool functions to configure RX flows of HW LRO")
Signed-off-by: Dan Carpenter <[email-masked]>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index a9d4fd8945bb..b3b3c079a0fa 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -2212,6 +2212,9 @@ static int mtk_hwlro_get_fdir_entry(struct net_device *dev,
 	struct ethtool_rx_flow_spec *fsp =
 		(struct ethtool_rx_flow_spec *)&cmd->fs;
 
+	if (fsp->location >= ARRAY_SIZE(mac->hwlro_ip))
+		return -EINVAL;
+
 	/* only tcp dst ipv4 is meaningful, others are meaningless */
 	fsp->flow_type = TCP_V4_FLOW;
 	fsp->h_u.tcp_ip4_spec.ip4dst = ntohl(mac->hwlro_ip[fsp->location]);
-- 
2.35.1