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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-03-18 21:16:45 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-03-18 21:16:45 -0700 |
| commit | 0641e4fbf2f824faee00ea74c459a088d94905fd (patch) | |
| tree | 54fdd8bc2e3a928ff0f7621c06e1e604eaf0529c | |
| parent | 54d259d474e1fee6f6bb8f0f1360d85195199ac5 (diff) | |
| download | blackbird-op-linux-0641e4fbf2f824faee00ea74c459a088d94905fd.tar.gz blackbird-op-linux-0641e4fbf2f824faee00ea74c459a088d94905fd.zip | |
net: Potential null skb->dev dereference
When doing "ifenslave -d bond0 eth0", there is chance to get NULL
dereference in netif_receive_skb(), because dev->master suddenly becomes
NULL after we tested it.
We should use ACCESS_ONCE() to avoid this (or rcu_dereference())
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/netdevice.h | 8 | ||||
| -rw-r--r-- | net/8021q/vlan_core.c | 4 | ||||
| -rw-r--r-- | net/core/dev.c | 8 |
3 files changed, 11 insertions, 9 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index c79a88be7c33..fa8b47637997 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2059,12 +2059,12 @@ static inline void skb_bond_set_mac_by_master(struct sk_buff *skb, * duplicates except for 802.3ad ETH_P_SLOW, alb non-mcast/bcast, and * ARP on active-backup slaves with arp_validate enabled. */ -static inline int skb_bond_should_drop(struct sk_buff *skb) +static inline int skb_bond_should_drop(struct sk_buff *skb, + struct net_device *master) { - struct net_device *dev = skb->dev; - struct net_device *master = dev->master; - if (master) { + struct net_device *dev = skb->dev; + if (master->priv_flags & IFF_MASTER_ARPMON) dev->last_rx = jiffies; diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c index c0316e0ca6e8..c584a0af77d3 100644 --- a/net/8021q/vlan_core.c +++ b/net/8021q/vlan_core.c @@ -11,7 +11,7 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp, if (netpoll_rx(skb)) return NET_RX_DROP; - if (skb_bond_should_drop(skb)) + if (skb_bond_should_drop(skb, ACCESS_ONCE(skb->dev->master))) goto drop; skb->skb_iif = skb->dev->ifindex; @@ -83,7 +83,7 @@ vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp, { struct sk_buff *p; - if (skb_bond_should_drop(skb)) + if (skb_bond_should_drop(skb, ACCESS_ONCE(skb->dev->master))) goto drop; skb->skb_iif = skb->dev->ifindex; diff --git a/net/core/dev.c b/net/core/dev.c index bcc490cc9452..59d4394d2ce8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2483,6 +2483,7 @@ int netif_receive_skb(struct sk_buff *skb) { struct packet_type *ptype, *pt_prev; struct net_device *orig_dev; + struct net_device *master; struct net_device *null_or_orig; struct net_device *null_or_bond; int ret = NET_RX_DROP; @@ -2503,11 +2504,12 @@ int netif_receive_skb(struct sk_buff *skb) null_or_orig = NULL; orig_dev = skb->dev; - if (orig_dev->master) { - if (skb_bond_should_drop(skb)) + master = ACCESS_ONCE(orig_dev->master); + if (master) { + if (skb_bond_should_drop(skb, master)) null_or_orig = orig_dev; /* deliver only exact match */ else - skb->dev = orig_dev->master; + skb->dev = master; } __get_cpu_var(netdev_rx_stat).total++; |
