[NETNS]: Minor information leak via /proc/net/ptype file.

This file displays the registered packet types, but some of them
(packet sockets creates such) can be bound to a net device and showing
them in a wrong namespace is not correct.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2615,7 +2615,7 @@ static int ptype_seq_show(struct seq_file *seq, void *v)
 
 	if (v == SEQ_START_TOKEN)
 		seq_puts(seq, "Type Device      Function\n");
-	else {
+	else if (pt->dev == NULL || pt->dev->nd_net == seq_file_net(seq)) {
 		if (pt->type == htons(ETH_P_ALL))
 			seq_puts(seq, "ALL ");
 		else
@@ -2639,7 +2639,8 @@ static const struct seq_operations ptype_seq_ops = {
 
 static int ptype_seq_open(struct inode *inode, struct file *file)
 {
-	return seq_open(file, &ptype_seq_ops);
+	return seq_open_net(inode, file, &ptype_seq_ops,
+			sizeof(struct seq_net_private));
 }
 
 static const struct file_operations ptype_seq_fops = {
@@ -2647,7 +2648,7 @@ static const struct file_operations ptype_seq_fops = {
 	.open    = ptype_seq_open,
 	.read    = seq_read,
 	.llseek  = seq_lseek,
-	.release = seq_release,
+	.release = seq_release_net,
 };