diff mbox

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

Message ID 1253711831-7947-1-git-send-email-remi@remlab.net
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Rémi Denis-Courmont Sept. 23, 2009, 1:17 p.m. UTC 
From: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>

From: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>

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>
---
 net/phonet/socket.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

Comments

David Miller Sept. 24, 2009, 10:45 p.m. UTC | #1 
From: Rémi Denis-Courmont <remi@remlab.net>
Date: Wed, 23 Sep 2009 16:17:10 +0300

> From: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
> 
> From: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
> 
> 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>

Applied.
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diff mbox

Patch

diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index 7a4ee39..07aa9f0 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -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;