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authorStephen Hemminger <shemminger@vyatta.com>2012-08-14 08:19:33 -0700
committerDavid S. Miller <davem@davemloft.net>2012-08-15 15:09:41 -0700
commitc03307eab68d583ea6db917681afa14ed1fb3b84 (patch)
treed2480b2fd892254e7a37b5b757be6f2c40c2ca6b
parent7bab3ae7608292fd987e390dec9fc21fd6dc4d7d (diff)
bridge: fix rcu dereference outside of rcu_read_lock
Alternative solution for problem found by Linux Driver Verification project (linuxtesting.org). As it noted in the comment before the br_handle_frame_finish function, this function should be called under rcu_read_lock. The problem callgraph: br_dev_xmit -> br_nf_pre_routing_finish_bridge_slow -> -> br_handle_frame_finish -> br_port_get_rcu -> rcu_dereference And in this case there is no read-lock section. Reported-by: Denis Efremov <yefremov.denis@gmail.com> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/bridge/br_device.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 32211fa..070e8a6 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -31,9 +31,11 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
struct net_bridge_mdb_entry *mdst;
struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
+ rcu_read_lock();
#ifdef CONFIG_BRIDGE_NETFILTER
if (skb->nf_bridge && (skb->nf_bridge->mask & BRNF_BRIDGED_DNAT)) {
br_nf_pre_routing_finish_bridge_slow(skb);
+ rcu_read_unlock();
return NETDEV_TX_OK;
}
#endif
@@ -48,7 +50,6 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
skb_reset_mac_header(skb);
skb_pull(skb, ETH_HLEN);
- rcu_read_lock();
if (is_broadcast_ether_addr(dest))
br_flood_deliver(br, skb);
else if (is_multicast_ether_addr(dest)) {