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authorEric Dumazet <edumazet@google.com>2019-10-10 20:17:38 -0700
committerDavid S. Miller <davem@davemloft.net>2019-10-13 10:13:08 -0700
commitd983ea6f16b835dcde2ee9a58a1e764ce68bfccc (patch)
tree2bc283f36a6769e0247c49420f0c2149f147f08c /include/linux/tcp.h
parent8caf8a91f34d55e8e3b1355ee8d658cb472146e2 (diff)
tcp: add rcu protection around tp->fastopen_rsk
Both tcp_v4_err() and tcp_v6_err() do the following operations while they do not own the socket lock : fastopen = tp->fastopen_rsk; snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; The problem is that without appropriate barrier, the compiler might reload tp->fastopen_rsk and trigger a NULL deref. request sockets are protected by RCU, we can simply add the missing annotations and barriers to solve the issue. Fixes: 168a8f58059a ("tcp: TCP Fast Open Server - main code path") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/tcp.h')
-rw-r--r--include/linux/tcp.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 99617e528ea2..668e25a76d69 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -393,7 +393,7 @@ struct tcp_sock {
/* fastopen_rsk points to request_sock that resulted in this big
* socket. Used to retransmit SYNACKs etc.
*/
- struct request_sock *fastopen_rsk;
+ struct request_sock __rcu *fastopen_rsk;
u32 *saved_syn;
};
@@ -447,8 +447,8 @@ static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
static inline bool tcp_passive_fastopen(const struct sock *sk)
{
- return (sk->sk_state == TCP_SYN_RECV &&
- tcp_sk(sk)->fastopen_rsk != NULL);
+ return sk->sk_state == TCP_SYN_RECV &&
+ rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL;
}
static inline void fastopen_queue_tune(struct sock *sk, int backlog)