[PATCH net-next 1/2] bridge: use br_port_get_rtnl within rtnl lock

[Hong Zhiguo <honkiko@gmail.com>]

From: Hong Zhiguo <zhiguohong@tencent.com>

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>
---
 net/bridge/br_netlink.c | 4 ++--
 net/bridge/br_private.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index b9259ef..e74ddc1 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -207,7 +207,7 @@ 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))
@@ -451,7 +451,7 @@ 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 598cb0b..49fb43e 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -208,7 +208,7 @@ 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;
-- 
1.8.1.2