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authorDavid Ahern <dsahern@gmail.com>2018-09-17 08:20:36 -0700
committerPablo Neira Ayuso <pablo@netfilter.org>2018-09-20 18:24:14 +0200
commita173f066c7cfc031acb8f541708041e009fc9812 (patch)
treeb8fdea4eee5fa7df3b4d60db301c9c5d683dffe1 /net/bridge
parent56ce3c5a50f4d8cc95361b1ec7f152006c6320d8 (diff)
netfilter: bridge: Don't sabotage nf_hook calls from an l3mdev
For starters, the bridge netfilter code registers operations that are invoked any time nh_hook is called. Specifically, ip_sabotage_in watches for nested calls for NF_INET_PRE_ROUTING when a bridge is in the stack. Packet wise, the bridge netfilter hook runs first. br_nf_pre_routing allocates nf_bridge, sets in_prerouting to 1 and calls NF_HOOK for NF_INET_PRE_ROUTING. It's finish function, br_nf_pre_routing_finish, then resets in_prerouting flag to 0 and the packet continues up the stack. The packet eventually makes it to the VRF driver and it invokes nf_hook for NF_INET_PRE_ROUTING in case any rules have been added against the vrf device. Because of the registered operations the call to nf_hook causes ip_sabotage_in to be invoked. That function sees the nf_bridge on the skb and that in_prerouting is not set. Thinking it is an invalid nested call it steals (drops) the packet. Update ip_sabotage_in to recognize that the bridge or one of its upper devices (e.g., vlan) can be enslaved to a VRF (L3 master device) and allow the packet to go through the nf_hook a second time. Fixes: 73e20b761acf ("net: vrf: Add support for PREROUTING rules on vrf device") Reported-by: D'Souza, Nelson <ndsouza@ciena.com> Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/br_netfilter_hooks.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 6e0dc6bcd32a..37278dc280eb 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -835,7 +835,8 @@ static unsigned int ip_sabotage_in(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
- if (skb->nf_bridge && !skb->nf_bridge->in_prerouting) {
+ if (skb->nf_bridge && !skb->nf_bridge->in_prerouting &&
+ !netif_is_l3_master(skb->dev)) {
state->okfn(state->net, state->sk, skb);
return NF_STOLEN;
}