From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
James Chapman <jchapman@katalix.com>
Subject: [PATCH net] l2tp: use rcu_dereference_sk_user_data() in l2tp_udp_encap_recv()
Date: Tue, 23 Apr 2019 09:43:26 -0700 [thread overview]
Message-ID: <20190423164326.108651-1-edumazet@google.com> (raw)
Canonical way to fetch sk_user_data from an encap_rcv() handler called
from UDP stack in rcu protected section is to use rcu_dereference_sk_user_data(),
otherwise compiler might read it multiple times.
Fixes: d00fa9adc528 ("il2tp: fix races with tunnel socket close")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
---
net/l2tp/l2tp_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index fed6becc5daf86afa2ad9188bb28e151244bb5a6..aee33d1320184e411dbedff72b5bf5199481e53f 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -909,7 +909,7 @@ int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
{
struct l2tp_tunnel *tunnel;
- tunnel = l2tp_tunnel(sk);
+ tunnel = rcu_dereference_sk_user_data(sk);
if (tunnel == NULL)
goto pass_up;
--
2.21.0.593.g511ec345e18-goog
next reply other threads:[~2019-04-23 16:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-23 16:43 Eric Dumazet [this message]
2019-04-24 9:58 ` [PATCH net] l2tp: use rcu_dereference_sk_user_data() in l2tp_udp_encap_recv() Guillaume Nault
2019-04-24 11:33 ` Eric Dumazet
2019-04-24 18:21 ` Guillaume Nault
2019-04-24 18:29 ` Eric Dumazet
2019-04-24 19:04 ` Guillaume Nault
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