Commit db93a363 authored Feb 08, 2018 by Cong Wang Committed by Pablo Neira Ayuso Feb 14, 2018

netfilter: ipt_CLUSTERIP: fix a refcount bug in clusterip_config_find_get()



In clusterip_config_find_get() we hold RCU read lock so it could
run concurrently with clusterip_config_entry_put(), as a result,
the refcnt could go back to 1 from 0, which leads to a double
list_del()... Just replace refcount_inc() with
refcount_inc_not_zero(), as for c->refcount.

Fixes: d73f33b1 ("netfilter: CLUSTERIP: RCU conversion")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent 57ebd808

net/ipv4/netfilter/ipt_CLUSTERIP.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -154,8 +154,12 @@ clusterip_config_find_get(struct net *net, __be32 clusterip, int entry)
		#endif
		if (unlikely(!refcount_inc_not_zero(&c->refcount)))
		c = NULL;
		else if (entry)
		refcount_inc(&c->entries);
		else if (entry) {
		if (unlikely(!refcount_inc_not_zero(&c->entries))) {
		clusterip_config_put(c);
		c = NULL;
		}
		}
		}
		rcu_read_unlock_bh();

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