[PATCH 1/2 nf] netfilter: nf_queue: don't re-enter same hook on packet reinjection

[Pablo Neira Ayuso <pablo@netfilter.org>]

Make sure we skip the current hook from where the packet was enqueued,
otherwise the packets gets enqueued over and over again.

Fixes: e3b37f11e6e4 ("netfilter: replace list_head with single linked list")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
I managed to reproduce this with a simple test.

 # iptables -I OUTPUT -j QUEUE
 # cd libnetfilter_queue/utils/
 # ./nfqnl_test

Without my patch, netfilter munches packets that are reinjected.

@Aaron: Please, I'd appreciate if you can have a look to confirm this bug
        and the fix. Thanks.

 net/netfilter/nf_queue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 96964a0070e1..221d7a5c2fec 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -184,6 +184,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 			verdict = NF_DROP;
 	}
 
+	hook_entry = rcu_dereference(hook_entry->next);
 	entry->state.thresh = INT_MIN;
 
 	if (verdict == NF_ACCEPT) {
-- 
2.1.4