bridge: use br_port_get_rtnl within rtnl lock

[ Upstream commit 1fb1754a8c70d69ab480763c423e0a74369c4a67 ]

current br_port_get_rcu is problematic in bridging path
(NULL deref). Change these calls in netlink path first.

Signed-off-by: Hong Zhiguo <zhiguohong@tencent.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index f66a034..06873e8 100644 (file)
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -203,7 +203,7 @@ int br_getlink(struct sk_buff *skb, u32 pid, u32 seq,
               struct net_device *dev, u32 filter_mask)
 {
        int err = 0;
-       struct net_bridge_port *port = br_port_get_rcu(dev);
+       struct net_bridge_port *port = br_port_get_rtnl(dev);
 
        /* not a bridge port and  */
        if (!port && !(filter_mask & RTEXT_FILTER_BRVLAN))
@@ -443,7 +443,7 @@ static size_t br_get_link_af_size(const struct net_device *dev)
        struct net_port_vlans *pv;
 
        if (br_port_exists(dev))
-               pv = nbp_get_vlan_info(br_port_get_rcu(dev));
+               pv = nbp_get_vlan_info(br_port_get_rtnl(dev));
        else if (dev->priv_flags & IFF_EBRIDGE)
                pv = br_get_vlan_info((struct net_bridge *)netdev_priv(dev));
        else

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index d11a5e1..84e0810 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -189,7 +189,7 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
        return br_port_exists(dev) ? port : NULL;
 }
 
-static inline struct net_bridge_port *br_port_get_rtnl(struct net_device *dev)
+static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
 {
        return br_port_exists(dev) ?
                rtnl_dereference(dev->rx_handler_data) : NULL;