[PATCH 4/5] net: Make AF_PACKET handle multiple network namespaces

[ebiederm@xmission.com (Eric W. Biederman)]

This is done by making packet_sklist_lock and packet_sklist per
network namespace and adding an additional filter condition on
received packets to ensure they came from the proper network
namespace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 include/net/net_namespace.h |    4 +
 net/packet/af_packet.c      |  129 +++++++++++++++++++++++++++---------------
 2 files changed, 87 insertions(+), 46 deletions(-)

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index f75607a..5e9fb47 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -32,6 +32,10 @@ struct net {
 	struct hlist_head	*dev_index_head;
 
 	struct sock 		*rtnl;			/* rtnetlink socket */
+
+	/* List of all packet sockets. */
+	rwlock_t		packet_sklist_lock;
+	struct hlist_head	packet_sklist;
 };
 
 #ifdef CONFIG_NET
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index e11000a..1c3a5a8 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -135,10 +135,6 @@ dev->hard_header == NULL (ll header is added by device, we cannot control it)
    packet classifier depends on it.
  */
 
-/* List of all packet sockets. */
-static HLIST_HEAD(packet_sklist);
-static DEFINE_RWLOCK(packet_sklist_lock);
-
 static atomic_t packet_socks_nr;
 
 
@@ -252,9 +248,6 @@ static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,  struct
 	struct sock *sk;
 	struct sockaddr_pkt *spkt;
 
-	if (dev->nd_net != &init_net)
-		goto out;
-
 	/*
 	 *	When we registered the protocol we saved the socket in the data
 	 *	field for just this event.
@@ -276,6 +269,9 @@ static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,  struct
 	if (skb->pkt_type == PACKET_LOOPBACK)
 		goto out;
 
+	if (dev->nd_net != sk->sk_net)
+		goto out;
+
 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 		goto oom;
 
@@ -347,7 +343,7 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock,
 	 */
 
 	saddr->spkt_device[13] = 0;
-	dev = dev_get_by_name(&init_net, saddr->spkt_device);
+	dev = dev_get_by_name(sk->sk_net, saddr->spkt_device);
 	err = -ENODEV;
 	if (dev == NULL)
 		goto out_unlock;
@@ -455,15 +451,15 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
 	int skb_len = skb->len;
 	unsigned int snaplen, res;
 
-	if (dev->nd_net != &init_net)
-		goto drop;
-
 	if (skb->pkt_type == PACKET_LOOPBACK)
 		goto drop;
 
 	sk = pt->af_packet_priv;
 	po = pkt_sk(sk);
 
+	if (dev->nd_net != sk->sk_net)
+		goto drop;
+
 	skb->dev = dev;
 
 	if (dev->header_ops) {
@@ -572,15 +568,15 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
 	struct sk_buff *copy_skb = NULL;
 	struct timeval tv;
 
-	if (dev->nd_net != &init_net)
-		goto drop;
-
 	if (skb->pkt_type == PACKET_LOOPBACK)
 		goto drop;
 
 	sk = pt->af_packet_priv;
 	po = pkt_sk(sk);
 
+	if (dev->nd_net != sk->sk_net)
+		goto drop;
+
 	if (dev->header_ops) {
 		if (sk->sk_type != SOCK_DGRAM)
 			skb_push(skb, skb->data - skb_mac_header(skb));
@@ -738,7 +734,7 @@ static int packet_sendmsg(struct kiocb *iocb, struct socket *sock,
 	}
 
 
-	dev = dev_get_by_index(&init_net, ifindex);
+	dev = dev_get_by_index(sk->sk_net, ifindex);
 	err = -ENXIO;
 	if (dev == NULL)
 		goto out_unlock;
@@ -805,15 +801,17 @@ static int packet_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
 	struct packet_sock *po;
+	struct net *net;
 
 	if (!sk)
 		return 0;
 
+	net = sk->sk_net;
 	po = pkt_sk(sk);
 
-	write_lock_bh(&packet_sklist_lock);
+	write_lock_bh(&net->packet_sklist_lock);
 	sk_del_node_init(sk);
-	write_unlock_bh(&packet_sklist_lock);
+	write_unlock_bh(&net->packet_sklist_lock);
 
 	/*
 	 *	Unhook packet receive handler.
@@ -927,7 +925,7 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr, int add
 		return -EINVAL;
 	strlcpy(name,uaddr->sa_data,sizeof(name));
 
-	dev = dev_get_by_name(&init_net, name);
+	dev = dev_get_by_name(sk->sk_net, name);
 	if (dev) {
 		err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
 		dev_put(dev);
@@ -954,7 +952,7 @@ static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len
 
 	if (sll->sll_ifindex) {
 		err = -ENODEV;
-		dev = dev_get_by_index(&init_net, sll->sll_ifindex);
+		dev = dev_get_by_index(sk->sk_net, sll->sll_ifindex);
 		if (dev == NULL)
 			goto out;
 	}
@@ -983,9 +981,6 @@ static int packet_create(struct net *net, struct socket *sock, int protocol)
 	__be16 proto = (__force __be16)protocol; /* weird, but documented */
 	int err;
 
-	if (net != &init_net)
-		return -EAFNOSUPPORT;
-
 	if (!capable(CAP_NET_RAW))
 		return -EPERM;
 	if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
@@ -1031,9 +1026,9 @@ static int packet_create(struct net *net, struct socket *sock, int protocol)
 		po->running = 1;
 	}
 
-	write_lock_bh(&packet_sklist_lock);
-	sk_add_node(sk, &packet_sklist);
-	write_unlock_bh(&packet_sklist_lock);
+	write_lock_bh(&net->packet_sklist_lock);
+	sk_add_node(sk, &net->packet_sklist);
+	write_unlock_bh(&net->packet_sklist_lock);
 	return(0);
 out:
 	return err;
@@ -1151,7 +1146,7 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
 		return -EOPNOTSUPP;
 
 	uaddr->sa_family = AF_PACKET;
-	dev = dev_get_by_index(&init_net, pkt_sk(sk)->ifindex);
+	dev = dev_get_by_index(sk->sk_net, pkt_sk(sk)->ifindex);
 	if (dev) {
 		strlcpy(uaddr->sa_data, dev->name, 15);
 		dev_put(dev);
@@ -1176,7 +1171,7 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
 	sll->sll_family = AF_PACKET;
 	sll->sll_ifindex = po->ifindex;
 	sll->sll_protocol = po->num;
-	dev = dev_get_by_index(&init_net, po->ifindex);
+	dev = dev_get_by_index(sk->sk_net, po->ifindex);
 	if (dev) {
 		sll->sll_hatype = dev->type;
 		sll->sll_halen = dev->addr_len;
@@ -1228,7 +1223,7 @@ static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
 	rtnl_lock();
 
 	err = -ENODEV;
-	dev = __dev_get_by_index(&init_net, mreq->mr_ifindex);
+	dev = __dev_get_by_index(sk->sk_net, mreq->mr_ifindex);
 	if (!dev)
 		goto done;
 
@@ -1282,7 +1277,7 @@ static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
 			if (--ml->count == 0) {
 				struct net_device *dev;
 				*mlp = ml->next;
-				dev = dev_get_by_index(&init_net, ml->ifindex);
+				dev = dev_get_by_index(sk->sk_net, ml->ifindex);
 				if (dev) {
 					packet_dev_mc(dev, ml, -1);
 					dev_put(dev);
@@ -1310,7 +1305,7 @@ static void packet_flush_mclist(struct sock *sk)
 		struct net_device *dev;
 
 		po->mclist = ml->next;
-		if ((dev = dev_get_by_index(&init_net, ml->ifindex)) != NULL) {
+		if ((dev = dev_get_by_index(sk->sk_net, ml->ifindex)) != NULL) {
 			packet_dev_mc(dev, ml, -1);
 			dev_put(dev);
 		}
@@ -1466,12 +1461,10 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
 	struct sock *sk;
 	struct hlist_node *node;
 	struct net_device *dev = data;
+	struct net *net = dev->nd_net;
 
-	if (dev->nd_net != &init_net)
-		return NOTIFY_DONE;
-
-	read_lock(&packet_sklist_lock);
-	sk_for_each(sk, node, &packet_sklist) {
+	read_lock(&net->packet_sklist_lock);
+	sk_for_each(sk, node, &net->packet_sklist) {
 		struct packet_sock *po = pkt_sk(sk);
 
 		switch (msg) {
@@ -1510,7 +1503,7 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
 			break;
 		}
 	}
-	read_unlock(&packet_sklist_lock);
+	read_unlock(&net->packet_sklist_lock);
 	return NOTIFY_DONE;
 }
 
@@ -1878,12 +1871,12 @@ static struct notifier_block packet_netdev_notifier = {
 };
 
 #ifdef CONFIG_PROC_FS
-static inline struct sock *packet_seq_idx(loff_t off)
+static inline struct sock *packet_seq_idx(struct net *net, loff_t off)
 {
 	struct sock *s;
 	struct hlist_node *node;
 
-	sk_for_each(s, node, &packet_sklist) {
+	sk_for_each(s, node, &net->packet_sklist) {
 		if (!off--)
 			return s;
 	}
@@ -1892,21 +1885,24 @@ static inline struct sock *packet_seq_idx(loff_t off)
 
 static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	read_lock(&packet_sklist_lock);
-	return *pos ? packet_seq_idx(*pos - 1) : SEQ_START_TOKEN;
+	struct net *net = seq->private;
+	read_lock(&net->packet_sklist_lock);
+	return *pos ? packet_seq_idx(net, *pos - 1) : SEQ_START_TOKEN;
 }
 
 static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
+	struct net *net = seq->private;
 	++*pos;
 	return  (v == SEQ_START_TOKEN)
-		? sk_head(&packet_sklist)
+		? sk_head(&net->packet_sklist)
 		: sk_next((struct sock*)v) ;
 }
 
 static void packet_seq_stop(struct seq_file *seq, void *v)
 {
-	read_unlock(&packet_sklist_lock);
+	struct net *net = seq->private;
+	read_unlock(&net->packet_sklist_lock);
 }
 
 static int packet_seq_show(struct seq_file *seq, void *v)
@@ -1942,7 +1938,26 @@ static const struct seq_operations packet_seq_ops = {
 
 static int packet_seq_open(struct inode *inode, struct file *file)
 {
-	return seq_open(file, &packet_seq_ops);
+	struct seq_file *seq;
+	int res;
+	res = seq_open(file, &packet_seq_ops);
+	if (!res) {
+		seq = file->private_data;
+		seq->private = get_proc_net(inode);
+		if (!seq->private) {
+			seq_release(inode, file);
+			res = -ENXIO;
+		}
+	}
+	return res;
+}
+
+static int packet_seq_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq=  file->private_data;
+	struct net *net = seq->private;
+	put_net(net);
+	return seq_release(inode, file);
 }
 
 static const struct file_operations packet_seq_fops = {
@@ -1950,15 +1965,37 @@ static const struct file_operations packet_seq_fops = {
 	.open		= packet_seq_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= seq_release,
+	.release	= packet_seq_release,
 };
 
 #endif
 
+static int packet_net_init(struct net *net)
+{
+	rwlock_init(&net->packet_sklist_lock);
+	INIT_HLIST_HEAD(&net->packet_sklist);
+
+	if (!proc_net_fops_create(net, "packet", 0, &packet_seq_fops))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void packet_net_exit(struct net *net)
+{
+	proc_net_remove(net, "packet");
+}
+
+static struct pernet_operations packet_net_ops = {
+	.init = packet_net_init,
+	.exit = packet_net_exit,
+};
+
+
 static void __exit packet_exit(void)
 {
-	proc_net_remove(&init_net, "packet");
 	unregister_netdevice_notifier(&packet_netdev_notifier);
+	unregister_pernet_subsys(&packet_net_ops);
 	sock_unregister(PF_PACKET);
 	proto_unregister(&packet_proto);
 }
@@ -1971,8 +2008,8 @@ static int __init packet_init(void)
 		goto out;
 
 	sock_register(&packet_family_ops);
+	register_pernet_subsys(&packet_net_ops);
 	register_netdevice_notifier(&packet_netdev_notifier);
-	proc_net_fops_create(&init_net, "packet", 0, &packet_seq_fops);
 out:
 	return rc;
 }
-- 
1.5.3.rc6.17.g1911