From: Florian Westphal <fw@strlen.de>
Date: Thu, 25 Aug 2016 13:33:29 +0000 (+0200)
Subject: netfilter: restart search if moved to other chain
X-Git-Tag: v3.18.93~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=64f94c222f630b2a407a36bac38c4f543edde668;p=thirdparty%2Fkernel%2Fstable.git

netfilter: restart search if moved to other chain

commit 95a8d19f28e6b29377a880c6264391a62e07fccc upstream.

In case nf_conntrack_tuple_taken did not find a conflicting entry
check that all entries in this hash slot were tested and restart
in case an entry was moved to another chain.

Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: ea781f197d6a ("netfilter: nf_conntrack: use SLAB_DESTROY_BY_RCU and get rid of call_rcu()")
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 98cd0e78c94c5..13fbd2ab960ff 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -695,6 +695,7 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 	 * least once for the stats anyway.
 	 */
 	rcu_read_lock_bh();
+ begin:
 	hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 		ct = nf_ct_tuplehash_to_ctrack(h);
 		if (ct != ignored_conntrack &&
@@ -706,6 +707,12 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 		}
 		NF_CT_STAT_INC(net, searched);
 	}
+
+	if (get_nulls_value(n) != hash) {
+		NF_CT_STAT_INC(net, search_restart);
+		goto begin;
+	}
+
 	rcu_read_unlock_bh();
 
 	return 0;