[PATCH v2 net] net: ethernet: mediatek: avoid potential invalid memory access

From: sean.wang
Date: Sat Jul 22 2017 - 08:46:27 EST


From: Sean Wang <sean.wang@xxxxxxxxxxxx>

Potential dangerous invalid memory might be accessed if invalid mac value
reflected from the forward port field in rxd4 caused by possible potential
hardware defects. So added a simple sanity checker to avoid the kind of
situation happening.

Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
Acked-by: John Crispin <john@xxxxxxxxxxx>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index c1dc08c..e69524c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -999,6 +999,10 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
RX_DMA_FPORT_MASK;
mac--;

+ if (unlikely(mac < 0 || mac >= MTK_MAC_COUNT ||
+ !eth->netdev[mac]))
+ goto release_desc;
+
netdev = eth->netdev[mac];

if (unlikely(test_bit(MTK_RESETTING, &eth->state)))
--
2.7.4