Commit e98f787a authored by Yunjian Wang's avatar Yunjian Wang Committed by Greg Kroah-Hartman

net: bridge: Fix ethernet header pointer before check skb forwardable

[ Upstream commit 28c1382fa28f2e2d9d0d6f25ae879b5af2ecbd03 ]

The skb header should be set to ethernet header before using
is_skb_forwardable. Because the ethernet header length has been
considered in is_skb_forwardable(including dev->hard_header_len
length).

To reproduce the issue:
1, add 2 ports on linux bridge br using following commands:
$ brctl addbr br
$ brctl addif br eth0
$ brctl addif br eth1
2, the MTU of eth0 and eth1 is 1500
3, send a packet(Data 1480, UDP 8, IP 20, Ethernet 14, VLAN 4)
from eth0 to eth1

So the expect result is packet larger than 1500 cannot pass through
eth0 and eth1. But currently, the packet passes through success, it
means eth1's MTU limit doesn't take effect.

Fixes: f6367b46 ("bridge: use is_skb_forwardable in forward path")
Cc: bridge@lists.linux-foundation.org
Cc: Nkolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: default avatarYunjian Wang <wangyunjian@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 749cbfc0
...@@ -39,10 +39,10 @@ static inline int should_deliver(const struct net_bridge_port *p, ...@@ -39,10 +39,10 @@ static inline int should_deliver(const struct net_bridge_port *p,
int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb) int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
{ {
skb_push(skb, ETH_HLEN);
if (!is_skb_forwardable(skb->dev, skb)) if (!is_skb_forwardable(skb->dev, skb))
goto drop; goto drop;
skb_push(skb, ETH_HLEN);
br_drop_fake_rtable(skb); br_drop_fake_rtable(skb);
skb_sender_cpu_clear(skb); skb_sender_cpu_clear(skb);
...@@ -88,12 +88,11 @@ static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb) ...@@ -88,12 +88,11 @@ static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
skb->dev = to->dev; skb->dev = to->dev;
if (unlikely(netpoll_tx_running(to->br->dev))) { if (unlikely(netpoll_tx_running(to->br->dev))) {
skb_push(skb, ETH_HLEN);
if (!is_skb_forwardable(skb->dev, skb)) if (!is_skb_forwardable(skb->dev, skb))
kfree_skb(skb); kfree_skb(skb);
else { else
skb_push(skb, ETH_HLEN);
br_netpoll_send_skb(to, skb); br_netpoll_send_skb(to, skb);
}
return; return;
} }
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment