| Message ID | 1546745293-5678-1-git-send-email-kchen@synology.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [1/1] net: bridge: fix a bug on using a neighbour cache entry without checking its state | expand |
From: kchen <kchen@synology.com> Date: Sun, 6 Jan 2019 11:28:13 +0800 > From: JianJhen Chen <kchen@synology.com> > > 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> Indeed, this looks correct. Applied and queued up for -stable, thanks.
From: David Miller <davem@davemloft.net> Date: Mon, 07 Jan 2019 09:10:31 -0800 > From: David Miller <davem@davemloft.net> > > From: kchen <kchen@synology.com> > Date: Sun, 6 Jan 2019 11:28:13 +0800 > >> From: JianJhen Chen <kchen@synology.com> >> >> 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> > > Indeed, this looks correct. > > Applied and queued up for -stable, thanks. > Thank you for the confirmation.
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index b1b5e85..ed683e5 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -278,7 +278,7 @@ 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);