target/linux/mediatek/patches-4.9/0055-net-ethernet-mediatek-avoid-potential-invalid-memory.patch

   1 From a3360b3543b9fb833ba691019e396e72293a313f Mon Sep 17 00:00:00 2001
   2 From: John Crispin <john@phrozen.org>
   3 Date: Thu, 10 Aug 2017 16:31:45 +0200
   4 Subject: [PATCH 55/57] net: ethernet: mediatek: avoid potential invalid memory
   5  access
   6
   7 Potential dangerous invalid memory might be accessed if invalid mac value
   8 reflected from the forward port field in rxd4 caused by possible potential
   9 hardware defects. So added a simple sanity checker to avoid the kind of
  10 situation happening.
  11
  12 Signed-off-by: Sean Wang <sean.wang@mediatek.com>
  13 Acked-by: John Crispin <john@phrozen.org>
  14 Signed-off-by: David S. Miller <davem@davemloft.net>
  15 ---
  16  drivers/net/ethernet/mediatek/mtk_eth_soc.c | 4 ++++
  17  1 file changed, 4 insertions(+)
  18
  19 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  20 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  21 @@ -964,6 +964,10 @@ static int mtk_poll_rx(struct napi_struc
  22                         mac--;
  23                 }
  24
  25 +               if (unlikely(mac < 0 || mac >= MTK_MAC_COUNT ||
  26 +                            !eth->netdev[mac]))
  27 +                       goto release_desc;
  28 +
  29                 netdev = eth->netdev[mac];
  30
  31                 if (unlikely(test_bit(MTK_RESETTING, &eth->state)))