af-packet: Hold reference to bound network devices.
Ben Greear [Wed, 1 Jun 2011 07:18:52 +0000 (07:18 +0000)]
Old code was probably safe, but with this change we
can actually use the netdev object, not just compare
the pointer values.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

index ba248d9..636b75c 100644 (file)
@@ -1342,6 +1342,10 @@ static int packet_release(struct socket *sock)
                __dev_remove_pack(&po->prot_hook);
                __sock_put(sk);
        }
+       if (po->prot_hook.dev) {
+               dev_put(po->prot_hook.dev);
+               po->prot_hook.dev = NULL;
+       }
        spin_unlock(&po->bind_lock);
 
        packet_flush_mclist(sk);
@@ -1395,6 +1399,8 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc
 
        po->num = protocol;
        po->prot_hook.type = protocol;
+       if (po->prot_hook.dev)
+               dev_put(po->prot_hook.dev);
        po->prot_hook.dev = dev;
 
        po->ifindex = dev ? dev->ifindex : 0;
@@ -1439,10 +1445,8 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
        strlcpy(name, uaddr->sa_data, sizeof(name));
 
        dev = dev_get_by_name(sock_net(sk), name);
-       if (dev) {
+       if (dev)
                err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
-               dev_put(dev);
-       }
        return err;
 }
 
@@ -1470,8 +1474,6 @@ static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len
                        goto out;
        }
        err = packet_do_bind(sk, dev, sll->sll_protocol ? : pkt_sk(sk)->num);
-       if (dev)
-               dev_put(dev);
 
 out:
        return err;
@@ -2240,6 +2242,8 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
                                }
                                if (msg == NETDEV_UNREGISTER) {
                                        po->ifindex = -1;
+                                       if (po->prot_hook.dev)
+                                               dev_put(po->prot_hook.dev);
                                        po->prot_hook.dev = NULL;
                                }
                                spin_unlock(&po->bind_lock);