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Phonet: fix race for port number in concurrent bind()

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Allocating a port number to a socket and hashing that socket shall be
an atomic operation with regards to other port allocation. Otherwise,
we could allocate a port that is already being allocated to another
socket.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rémi Denis-Courmont 2009-09-23 03:17:10 +00:00 committed by David S. Miller
parent ef87979c27
commit 582b0b6113
1 changed files with 8 additions and 8 deletions
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16
net/phonet/socket.c
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@ -113,6 +113,8 @@ void pn_sock_unhash(struct sock *sk)
}
EXPORT_SYMBOL(pn_sock_unhash);
static DEFINE_MUTEX(port_mutex);
static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
{
struct sock *sk = sock->sk;
@ -140,9 +142,11 @@ static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
err = -EINVAL; /* attempt to rebind */
goto out;
}
WARN_ON(sk_hashed(sk));
mutex_lock(&port_mutex);
err = sk->sk_prot->get_port(sk, pn_port(handle));
if (err)
goto out;
goto out_port;
/* get_port() sets the port, bind() sets the address if applicable */
pn->sobject = pn_object(saddr, pn_port(pn->sobject));
@ -150,6 +154,8 @@ static int pn_socket_bind(struct socket *sock, struct sockaddr *addr, int len)
/* Enable RX on the socket */
sk->sk_prot->hash(sk);
out_port:
mutex_unlock(&port_mutex);
out:
release_sock(sk);
return err;
@ -357,8 +363,6 @@ const struct proto_ops phonet_stream_ops = {
};
EXPORT_SYMBOL(phonet_stream_ops);
static DEFINE_MUTEX(port_mutex);
/* allocate port for a socket */
int pn_sock_get_port(struct sock *sk, unsigned short sport)
{
@ -370,9 +374,7 @@ int pn_sock_get_port(struct sock *sk, unsigned short sport)
memset(&try_sa, 0, sizeof(struct sockaddr_pn));
try_sa.spn_family = AF_PHONET;
mutex_lock(&port_mutex);
WARN_ON(!mutex_is_locked(&port_mutex));
if (!sport) {
/* search free port */
int port, pmin, pmax;
@ -401,8 +403,6 @@ int pn_sock_get_port(struct sock *sk, unsigned short sport)
else
sock_put(tmpsk);
}
mutex_unlock(&port_mutex);
/* the port must be in use already */
return -EADDRINUSE;