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authorCong Wang <xiyou.wangcong@gmail.com>2018-02-08 13:53:52 -0800
committerPablo Neira Ayuso <pablo@netfilter.org>2018-02-14 21:05:32 +0100
commitdb93a3632b0f8773a3899e04a3a3e0aa7a26eb46 (patch)
tree326e1da2fc4b76761b74712758a4fa84d7aacdce /net/ipv4
parent57ebd808a97d7c5b1e1afb937c2db22beba3c1f8 (diff)
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: d73f33b16883 ("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>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/ipt_CLUSTERIP.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 1ff72b87a066..4b02ab39ebc5 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -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();