tcp: Fix a connect() race with timewait sockets

First patch changes __inet_hash_nolisten() and __inet6_hash()
to get a timewait parameter to be able to unhash it from ehash
at same time the new socket is inserted in hash.

This makes sure timewait socket wont be found by a concurrent
writer in __inet_check_established()

Reported-by: kapil dakhane <kdakhane@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 41cbddd25b70..74358d1b3f43 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -251,7 +251,7 @@ extern void inet_put_port(struct sock *sk);
 
 void inet_hashinfo_init(struct inet_hashinfo *h);
 
-extern void __inet_hash_nolisten(struct sock *sk);
+extern int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw);
 extern void inet_hash(struct sock *sk);
 extern void inet_unhash(struct sock *sk);
 
@@ -391,10 +391,12 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
 }
 
 extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
-                struct sock *sk, u32 port_offset,
+                struct sock *sk,
+                u32 port_offset,
                 int (*check_established)(struct inet_timewait_death_row *,
                         struct sock *, __u16, struct inet_timewait_sock **),
-                               void (*hash)(struct sock *sk));
+                int (*hash)(struct sock *sk, struct inet_timewait_sock *twp));
+
 extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
                              struct sock *sk);
 #endif /* _INET_HASHTABLES_H */