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dccp/tcp: Update saddr under bhash's lock.

Browse source 
When we call connect() for a socket bound to a wildcard address, we update
saddr locklessly.  However, it could result in a data race; another thread
iterating over bhash might see a corrupted address.

Let's update saddr under the bhash bucket's lock.

Fixes: 3df80d9320 ("[DCCP]: Introduce DCCPv6")
Fixes: 7c657876b6 ("[DCCP]: Initial implementation")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-11-18 17:49:13 -08:00 committed by Jakub Kicinski
parent 8acdad37cd
commit 8c5dae4c1a
7 changed files with 55 additions and 85 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
include/net/inet_hashtables.h
View file

@ -281,7 +281,7 @@ inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, in
* sk_v6_rcv_saddr (ipv6) changes after it has been binded. The socket's
* rcv_saddr field should already have been updated when this is called.
*/
int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct sock *sk);
int inet_bhash2_update_saddr(struct sock *sk, void *saddr, int family);
void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
struct inet_bind2_bucket *tb2, unsigned short port);

22
net/dccp/ipv4.c
View file

@ -45,11 +45,10 @@ static unsigned int dccp_v4_pernet_id __read_mostly;
int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
struct inet_bind_hashbucket *prev_addr_hashbucket = NULL;
__be32 daddr, nexthop, prev_sk_rcv_saddr;
struct inet_sock *inet = inet_sk(sk);
struct dccp_sock *dp = dccp_sk(sk);
__be16 orig_sport, orig_dport;
__be32 daddr, nexthop;
struct flowi4 *fl4;
struct rtable *rt;
int err;
@ -91,26 +90,13 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
daddr = fl4->daddr;
if (inet->inet_saddr == 0) {
if (inet_csk(sk)->icsk_bind2_hash) {
prev_addr_hashbucket =
inet_bhashfn_portaddr(&dccp_hashinfo, sk,
sock_net(sk),
inet->inet_num);
prev_sk_rcv_saddr = sk->sk_rcv_saddr;
}
inet->inet_saddr = fl4->saddr;
}
sk_rcv_saddr_set(sk, inet->inet_saddr);
if (prev_addr_hashbucket) {
err = inet_bhash2_update_saddr(prev_addr_hashbucket, sk);
err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
if (err) {
inet->inet_saddr = 0;
sk_rcv_saddr_set(sk, prev_sk_rcv_saddr);
ip_rt_put(rt);
return err;
}
} else {
sk_rcv_saddr_set(sk, inet->inet_saddr);
}
inet->inet_dport = usin->sin_port;

21
net/dccp/ipv6.c
View file

@ -934,26 +934,11 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
}
if (saddr == NULL) {
struct inet_bind_hashbucket *prev_addr_hashbucket = NULL;
struct in6_addr prev_v6_rcv_saddr;
if (icsk->icsk_bind2_hash) {
prev_addr_hashbucket = inet_bhashfn_portaddr(&dccp_hashinfo,
sk, sock_net(sk),
inet->inet_num);
prev_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
}
saddr = &fl6.saddr;
sk->sk_v6_rcv_saddr = *saddr;
if (prev_addr_hashbucket) {
err = inet_bhash2_update_saddr(prev_addr_hashbucket, sk);
if (err) {
sk->sk_v6_rcv_saddr = prev_v6_rcv_saddr;
goto failure;
}
}
err = inet_bhash2_update_saddr(sk, saddr, AF_INET6);
if (err)
goto failure;
}
/* set the source address */

11
net/ipv4/af_inet.c
View file

@ -1230,7 +1230,6 @@ EXPORT_SYMBOL(inet_unregister_protosw);
static int inet_sk_reselect_saddr(struct sock *sk)
{
struct inet_bind_hashbucket *prev_addr_hashbucket;
struct inet_sock *inet = inet_sk(sk);
__be32 old_saddr = inet->inet_saddr;
__be32 daddr = inet->inet_daddr;
@ -1260,16 +1259,8 @@ static int inet_sk_reselect_saddr(struct sock *sk)
return 0;
}
prev_addr_hashbucket =
inet_bhashfn_portaddr(tcp_or_dccp_get_hashinfo(sk), sk,
sock_net(sk), inet->inet_num);
inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
err = inet_bhash2_update_saddr(prev_addr_hashbucket, sk);
err = inet_bhash2_update_saddr(sk, &new_saddr, AF_INET);
if (err) {
inet->inet_saddr = old_saddr;
inet->inet_rcv_saddr = old_saddr;
ip_rt_put(rt);
return err;
}

45
net/ipv4/inet_hashtables.c
View file

@ -858,14 +858,34 @@ inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, in
return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)];
}
int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct sock *sk)
static void inet_update_saddr(struct sock *sk, void *saddr, int family)
{
if (family == AF_INET) {
inet_sk(sk)->inet_saddr = *(__be32 *)saddr;
sk_rcv_saddr_set(sk, inet_sk(sk)->inet_saddr);
}
#if IS_ENABLED(CONFIG_IPV6)
else {
sk->sk_v6_rcv_saddr = *(struct in6_addr *)saddr;
}
#endif
}
int inet_bhash2_update_saddr(struct sock *sk, void *saddr, int family)
{
struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
struct inet_bind_hashbucket *head, *head2;
struct inet_bind2_bucket *tb2, *new_tb2;
int l3mdev = inet_sk_bound_l3mdev(sk);
struct inet_bind_hashbucket *head2;
int port = inet_sk(sk)->inet_num;
struct net *net = sock_net(sk);
int bhash;
if (!inet_csk(sk)->icsk_bind2_hash) {
/* Not bind()ed before. */
inet_update_saddr(sk, saddr, family);
return 0;
}
/* Allocate a bind2 bucket ahead of time to avoid permanently putting
* the bhash2 table in an inconsistent state if a new tb2 bucket
@ -875,14 +895,25 @@ int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct soc
if (!new_tb2)
return -ENOMEM;
bhash = inet_bhashfn(net, port, hinfo->bhash_size);
head = &hinfo->bhash[bhash];
head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
spin_lock_bh(&prev_saddr->lock);
/* If we change saddr locklessly, another thread
* iterating over bhash might see corrupted address.
*/
spin_lock_bh(&head->lock);
spin_lock(&head2->lock);
__sk_del_bind2_node(sk);
inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, inet_csk(sk)->icsk_bind2_hash);
spin_unlock_bh(&prev_saddr->lock);
spin_unlock(&head2->lock);
spin_lock_bh(&head2->lock);
inet_update_saddr(sk, saddr, family);
head2 = inet_bhashfn_portaddr(hinfo, sk, net, port);
spin_lock(&head2->lock);
tb2 = inet_bind2_bucket_find(head2, net, port, l3mdev, sk);
if (!tb2) {
tb2 = new_tb2;
@ -890,7 +921,9 @@ int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct soc
}
sk_add_bind2_node(sk, &tb2->owners);
inet_csk(sk)->icsk_bind2_hash = tb2;
spin_unlock_bh(&head2->lock);
spin_unlock(&head2->lock);
spin_unlock_bh(&head->lock);
if (tb2 != new_tb2)
kmem_cache_free(hinfo->bind2_bucket_cachep, new_tb2);

20
net/ipv4/tcp_ipv4.c
View file

@ -199,15 +199,14 @@ static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr,
/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct inet_bind_hashbucket *prev_addr_hashbucket = NULL;
struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
struct inet_timewait_death_row *tcp_death_row;
__be32 daddr, nexthop, prev_sk_rcv_saddr;
struct inet_sock *inet = inet_sk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct ip_options_rcu *inet_opt;
struct net *net = sock_net(sk);
__be16 orig_sport, orig_dport;
__be32 daddr, nexthop;
struct flowi4 *fl4;
struct rtable *rt;
int err;
@ -251,24 +250,13 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
if (!inet->inet_saddr) {
if (inet_csk(sk)->icsk_bind2_hash) {
prev_addr_hashbucket = inet_bhashfn_portaddr(tcp_death_row->hashinfo,
sk, net, inet->inet_num);
prev_sk_rcv_saddr = sk->sk_rcv_saddr;
}
inet->inet_saddr = fl4->saddr;
}
sk_rcv_saddr_set(sk, inet->inet_saddr);
if (prev_addr_hashbucket) {
err = inet_bhash2_update_saddr(prev_addr_hashbucket, sk);
err = inet_bhash2_update_saddr(sk, &fl4->saddr, AF_INET);
if (err) {
inet->inet_saddr = 0;
sk_rcv_saddr_set(sk, prev_sk_rcv_saddr);
ip_rt_put(rt);
return err;
}
} else {
sk_rcv_saddr_set(sk, inet->inet_saddr);
}
if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {

19
net/ipv6/tcp_ipv6.c
View file

@ -292,24 +292,11 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
tcp_death_row = &sock_net(sk)->ipv4.tcp_death_row;
if (!saddr) {
struct inet_bind_hashbucket *prev_addr_hashbucket = NULL;
struct in6_addr prev_v6_rcv_saddr;
if (icsk->icsk_bind2_hash) {
prev_addr_hashbucket = inet_bhashfn_portaddr(tcp_death_row->hashinfo,
sk, net, inet->inet_num);
prev_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
}
saddr = &fl6.saddr;
sk->sk_v6_rcv_saddr = *saddr;
if (prev_addr_hashbucket) {
err = inet_bhash2_update_saddr(prev_addr_hashbucket, sk);
if (err) {
sk->sk_v6_rcv_saddr = prev_v6_rcv_saddr;
goto failure;
}
}
err = inet_bhash2_update_saddr(sk, saddr, AF_INET6);
if (err)
goto failure;
}
/* set the source address */