From 9327f7053e3993c125944fdb137a0618319ef2a0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 4 Dec 2009 03:46:54 +0000 Subject: [PATCH] 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 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet6_hashtables.h | 2 +- include/net/inet_hashtables.h | 8 +++++--- net/dccp/ipv4.c | 2 +- net/dccp/ipv6.c | 4 ++-- net/ipv4/inet_hashtables.c | 22 ++++++++++++++++------ net/ipv4/tcp_ipv4.c | 2 +- net/ipv6/inet6_hashtables.c | 8 +++++++- net/ipv6/tcp_ipv6.c | 4 ++-- 8 files changed, 35 insertions(+), 17 deletions(-) diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index 92838d3a1ab7..e46674d5daea 100644 --- a/include/net/inet6_hashtables.h +++ b/include/net/inet6_hashtables.h @@ -53,7 +53,7 @@ static inline int inet6_sk_ehashfn(const struct sock *sk) return inet6_ehashfn(net, laddr, lport, faddr, fport); } -extern void __inet6_hash(struct sock *sk); +extern int __inet6_hash(struct sock *sk, struct inet_timewait_sock *twp); /* * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 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 */ diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index efbcfdc12796..dad7bc4878e0 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -408,7 +408,7 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb, dccp_sync_mss(newsk, dst_mtu(dst)); - __inet_hash_nolisten(newsk); + __inet_hash_nolisten(newsk, NULL); __inet_inherit_port(sk, newsk); return newsk; diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 6574215a1f51..baf05cf43c28 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -46,7 +46,7 @@ static void dccp_v6_hash(struct sock *sk) return; } local_bh_disable(); - __inet6_hash(sk); + __inet6_hash(sk, NULL); local_bh_enable(); } } @@ -644,7 +644,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk, newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6; newinet->inet_rcv_saddr = LOOPBACK4_IPV6; - __inet6_hash(newsk); + __inet6_hash(newsk, NULL); __inet_inherit_port(sk, newsk); return newsk; diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 21e5e32d8c60..c4201b7ece38 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -351,12 +351,13 @@ static inline u32 inet_sk_port_offset(const struct sock *sk) inet->inet_dport); } -void __inet_hash_nolisten(struct sock *sk) +int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; struct hlist_nulls_head *list; spinlock_t *lock; struct inet_ehash_bucket *head; + int twrefcnt = 0; WARN_ON(!sk_unhashed(sk)); @@ -367,8 +368,13 @@ void __inet_hash_nolisten(struct sock *sk) spin_lock(lock); __sk_nulls_add_node_rcu(sk, list); + if (tw) { + WARN_ON(sk->sk_hash != tw->tw_hash); + twrefcnt = inet_twsk_unhash(tw); + } spin_unlock(lock); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + return twrefcnt; } EXPORT_SYMBOL_GPL(__inet_hash_nolisten); @@ -378,7 +384,7 @@ static void __inet_hash(struct sock *sk) struct inet_listen_hashbucket *ilb; if (sk->sk_state != TCP_LISTEN) { - __inet_hash_nolisten(sk); + __inet_hash_nolisten(sk, NULL); return; } @@ -427,7 +433,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, 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)) { struct inet_hashinfo *hinfo = death_row->hashinfo; const unsigned short snum = inet_sk(sk)->inet_num; @@ -435,6 +441,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, struct inet_bind_bucket *tb; int ret; struct net *net = sock_net(sk); + int twrefcnt = 1; if (!snum) { int i, remaining, low, high, port; @@ -493,13 +500,16 @@ ok: inet_bind_hash(sk, tb, port); if (sk_unhashed(sk)) { inet_sk(sk)->inet_sport = htons(port); - hash(sk); + twrefcnt += hash(sk, tw); } spin_unlock(&head->lock); if (tw) { inet_twsk_deschedule(tw, death_row); - inet_twsk_put(tw); + while (twrefcnt) { + twrefcnt--; + inet_twsk_put(tw); + } } ret = 0; @@ -510,7 +520,7 @@ ok: tb = inet_csk(sk)->icsk_bind_hash; spin_lock_bh(&head->lock); if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { - hash(sk); + hash(sk, NULL); spin_unlock_bh(&head->lock); return 0; } else { diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 29002ab26e0d..15e96030ce47 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1464,7 +1464,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, } #endif - __inet_hash_nolisten(newsk); + __inet_hash_nolisten(newsk, NULL); __inet_inherit_port(sk, newsk); return newsk; diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index c813e294ec0c..633a6c266136 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -22,9 +22,10 @@ #include #include -void __inet6_hash(struct sock *sk) +int __inet6_hash(struct sock *sk, struct inet_timewait_sock *tw) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + int twrefcnt = 0; WARN_ON(!sk_unhashed(sk)); @@ -45,10 +46,15 @@ void __inet6_hash(struct sock *sk) lock = inet_ehash_lockp(hashinfo, hash); spin_lock(lock); __sk_nulls_add_node_rcu(sk, list); + if (tw) { + WARN_ON(sk->sk_hash != tw->tw_hash); + twrefcnt = inet_twsk_unhash(tw); + } spin_unlock(lock); } sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + return twrefcnt; } EXPORT_SYMBOL(__inet6_hash); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index aadd7cef73b3..ee9cf62458d4 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -96,7 +96,7 @@ static void tcp_v6_hash(struct sock *sk) return; } local_bh_disable(); - __inet6_hash(sk); + __inet6_hash(sk, NULL); local_bh_enable(); } } @@ -1496,7 +1496,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb, } #endif - __inet6_hash(newsk); + __inet6_hash(newsk, NULL); __inet_inherit_port(sk, newsk); return newsk; -- 2.30.2