diff mbox

[net] netfilter: tproxy: properly refcount tcp listeners

Message ID 1471453006.29842.15.camel@edumazet-glaptop3.roam.corp.google.com
State Accepted
Delegated to: Pablo Neira
Headers show

Commit Message

Eric Dumazet Aug. 17, 2016, 4:56 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

inet_lookup_listener() and inet6_lookup_listener() no longer
take a reference on the found listener.

This minimal patch adds back the refcounting, but we might do
this differently in net-next later.

Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Reported-and-tested-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
Note: bug added in 4.7, stable candidate.

 net/netfilter/xt_TPROXY.c |    4 ++++
 1 file changed, 4 insertions(+)



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Comments

Pablo Neira Ayuso Aug. 17, 2016, 10:51 p.m. UTC | #1 
On Wed, Aug 17, 2016 at 09:56:46AM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> inet_lookup_listener() and inet6_lookup_listener() no longer
> take a reference on the found listener.
> 
> This minimal patch adds back the refcounting, but we might do
> this differently in net-next later.

Applied, thanks Eric!
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diff mbox

Patch

diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index 7f4414d26a66..663c4c3c9072 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -127,6 +127,8 @@  nf_tproxy_get_sock_v4(struct net *net, struct sk_buff *skb, void *hp,
 						    daddr, dport,
 						    in->ifindex);
 
+			if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+				sk = NULL;
 			/* NOTE: we return listeners even if bound to
 			 * 0.0.0.0, those are filtered out in
 			 * xt_socket, since xt_TPROXY needs 0 bound
@@ -195,6 +197,8 @@  nf_tproxy_get_sock_v6(struct net *net, struct sk_buff *skb, int thoff, void *hp,
 						   daddr, ntohs(dport),
 						   in->ifindex);
 
+			if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+				sk = NULL;
 			/* NOTE: we return listeners even if bound to
 			 * 0.0.0.0, those are filtered out in
 			 * xt_socket, since xt_TPROXY needs 0 bound