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authorJianJhen Chen <kchen@synology.com>2019-01-06 06:28:13 +0300
committerDavid S. Miller <davem@davemloft.net>2019-01-07 20:09:02 +0300
commit4c84edc11b76590859b1e45dd676074c59602dc4 (patch)
treee0f06b0072608a1a55800a50e5dab17526fdc9d5 /net/bridge
parentf87d8ad9233f115db92c6c087d58403b0009ed36 (diff)
downloadlinux-4c84edc11b76590859b1e45dd676074c59602dc4.tar.xz
net: bridge: fix a bug on using a neighbour cache entry without checking its state
When handling DNAT'ed packets on a bridge device, the neighbour cache entry from lookup was used without checking its state. It means that a cache entry in the NUD_STALE state will be used directly instead of entering the NUD_DELAY state to confirm the reachability of the neighbor. This problem becomes worse after commit 2724680bceee ("neigh: Keep neighbour cache entries if number of them is small enough."), since all neighbour cache entries in the NUD_STALE state will be kept in the neighbour table as long as the number of cache entries does not exceed the value specified in gc_thresh1. This commit validates the state of a neighbour cache entry before using the entry. Signed-off-by: JianJhen Chen <kchen@synology.com> Reviewed-by: JinLin Chen <jlchen@synology.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/br_netfilter_hooks.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index d21a23698410..c93c35bb73dd 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -265,7 +265,7 @@ int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_
struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
int ret;
- if (neigh->hh.hh_len) {
+ if ((neigh->nud_state & NUD_CONNECTED) && neigh->hh.hh_len) {
neigh_hh_bridge(&neigh->hh, skb);
skb->dev = nf_bridge->physindev;
ret = br_handle_frame_finish(net, sk, skb);