[PATCH net] net: avoid vlan ptype specific match to be leaked on real device

Paolo Abeni
2016-06-22T10:33:27Z

Before the commit 0dfe17823945 ("net: vlan: goto another_round
instead of calling __netif_receive_skb"), on tagged skb ingress,
ptype specific protocol matches were delivered only to the
related vlan device, if any.
After said commit, jumping back to the 'another_round' label, allows
the later ptype specific check to match both orig_dev and skb->dev,
delivering the skb to both the vlan device and the underlying
device.
This cause i.e. packet sockets bound to a specific protocol type on
one of said devices to receive also frames really targeting the
other device.
This commit resets orig_dev before performing another round due to
vlan processing, allowing the skb to be delivered once again only
to the vlan specific ptypes.

Fixes: 0dfe17823945 ("net: vlan: goto another_round instead of calling __netif_receive_skb")
Reported-by: Ryan Liu <Ryan.Liu@alcatel-lucent.com>
Reported-by: Cliff Chen <Cliff.Chen@alcatel-lucent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/core/dev.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 904ff43..9d08dd6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4144,10 +4144,15 @@ ncls:
ret = deliver_skb(skb, pt_prev, orig_dev);
pt_prev = NULL;
}
- if (vlan_do_receive(&skb))
+ if (vlan_do_receive(&skb)) {
+ /* avoid delivering to ptype registered on
+ * vlan's underlying device only
+ */
+ orig_dev = skb->dev;
goto another_round;
- else if (unlikely(!skb))
+ } else if (unlikely(!skb)) {
goto out;
+ }
}

rx_handler = rcu_dereference(skb->dev->rx_handler);
--
1.8.3.1