From eb996edb03a665d038de7bc318182412e44c52f9 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Sat, 25 Mar 2017 14:26:39 +0000 Subject: [PATCH] netvsc: fix dereference before null check errors ndev is being checked to see if it is a null pointer however before the null check ndev is being dereferenced; hence there is a potential null pointer dereference bug that needs fixing. Fix this by only dereferencing ndev after the null check. Detected by CoverityScan, CID#1420760, CID#140761 ("Dereference before null check") Signed-off-by: Colin Ian King Reviewed-by: Haiyang Zhang Signed-off-by: David S. Miller --- drivers/net/hyperv/netvsc_drv.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index f830bbb..f24c289 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1135,7 +1135,7 @@ static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, { struct net_device_context *ndc = netdev_priv(dev); struct netvsc_device *ndev = rcu_dereference(ndc->nvdev); - struct rndis_device *rndis_dev = ndev->extension; + struct rndis_device *rndis_dev; int i; if (!ndev) @@ -1144,6 +1144,7 @@ static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, if (hfunc) *hfunc = ETH_RSS_HASH_TOP; /* Toeplitz */ + rndis_dev = ndev->extension; if (indir) { for (i = 0; i < ITAB_NUM; i++) indir[i] = rndis_dev->ind_table[i]; @@ -1160,7 +1161,7 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir, { struct net_device_context *ndc = netdev_priv(dev); struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev); - struct rndis_device *rndis_dev = ndev->extension; + struct rndis_device *rndis_dev; int i; if (!ndev) @@ -1169,6 +1170,7 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir, if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP; + rndis_dev = ndev->extension; if (indir) { for (i = 0; i < ITAB_NUM; i++) if (indir[i] >= dev->num_rx_queues) -- 2.7.4