diff options
| author | Jiri Pirko <jiri@resnulli.us> | 2013-12-05 16:27:37 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-12-06 15:41:40 -0500 |
| commit | 859828c0ea476b42f3a93d69d117aaba90994b6f (patch) | |
| tree | 202e063a5f723c95784239f525f27459fd15b313 /net/bridge/br_private.h | |
| parent | d4fb84eefe5164f6a6ea51d0a9e26280c661a0dd (diff) | |
| download | linux-859828c0ea476b42f3a93d69d117aaba90994b6f.tar.bz2 | |
br: fix use of ->rx_handler_data in code executed on non-rx_handler path
br_stp_rcv() is reached by non-rx_handler path. That means there is no
guarantee that dev is bridge port and therefore simple NULL check of
->rx_handler_data is not enough. There is need to check if dev is really
bridge port and since only rcu read lock is held here, do it by checking
->rx_handler pointer.
Note that synchronize_net() in netdev_rx_handler_unregister() ensures
this approach as valid.
Introduced originally by:
commit f350a0a87374418635689471606454abc7beaa3a
"bridge: use rx_handler_data pointer to store net_bridge_port pointer"
Fixed but not in the best way by:
commit b5ed54e94d324f17c97852296d61a143f01b227a
"bridge: fix RCU races with bridge port"
Reintroduced by:
commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2
"bridge: fix NULL pointer deref of br_port_get_rcu"
Please apply to stable trees as well. Thanks.
RH bugzilla reference: https://bugzilla.redhat.com/show_bug.cgi?id=1025770
Reported-by: Laine Stump <laine@redhat.com>
Debugged-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_private.h')
| -rw-r--r-- | net/bridge/br_private.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 229d820bdf0b..045d56eaeca2 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -426,6 +426,16 @@ netdev_features_t br_features_recompute(struct net_bridge *br, int br_handle_frame_finish(struct sk_buff *skb); rx_handler_result_t br_handle_frame(struct sk_buff **pskb); +static inline bool br_rx_handler_check_rcu(const struct net_device *dev) +{ + return rcu_dereference(dev->rx_handler) == br_handle_frame; +} + +static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev) +{ + return br_rx_handler_check_rcu(dev) ? br_port_get_rcu(dev) : NULL; +} + /* br_ioctl.c */ int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd); int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd, |