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Date: Fri, 04 Dec 2009 14:46:54 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: kapil dakhane <kdakhane@...il.com>,
"David S. Miller" <davem@...emloft.net>
CC: netdev@...r.kernel.org, netfilter@...r.kernel.org,
Evgeniy Polyakov <zbr@...emap.net>
Subject: [PATCH 1/2] 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@...il.com>
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
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 92838d3..e46674d 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 41cbddd..74358d1 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 efbcfdc..dad7bc4 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 6574215..baf05cf 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 21e5e32..c4201b7 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 29002ab..15e9603 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 c813e29..633a6c2 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -22,9 +22,10 @@
#include <net/inet6_hashtables.h>
#include <net/ip.h>
-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 aadd7ce..ee9cf62 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;
--
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