From: David Ahern dsahern@gmail.com
[ Upstream commit a173f066c7cfc031acb8f541708041e009fc9812 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/br_netfilter_hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index 9b16eaf33819..58240cc185e7 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -834,7 +834,8 @@ 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; }