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| author | JianJhen Chen <kchen@synology.com> | 2019-01-06 11:28:13 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-23 08:09:47 +0100 |
| commit | b4683849b9c2b803f4dbbffe9619e56d025e8683 (patch) | |
| tree | fb88e34e812015dbbafc8593761ee30ad71e82f6 /net/bridge | |
| parent | c809028e773de4f4c5c40af3caad9e3e936ecfb9 (diff) | |
| download | linux-stable-b4683849b9c2b803f4dbbffe9619e56d025e8683.tar.gz linux-stable-b4683849b9c2b803f4dbbffe9619e56d025e8683.tar.bz2 linux-stable-b4683849b9c2b803f4dbbffe9619e56d025e8683.zip | |
net: bridge: fix a bug on using a neighbour cache entry without checking its state
[ Upstream commit 4c84edc11b76590859b1e45dd676074c59602dc4 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/bridge')
| -rw-r--r-- | net/bridge/br_netfilter_hooks.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index 7582f28ab306..3f3859b8d49f 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -275,7 +275,7 @@ 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); |