1 files changed, 419 insertions, 93 deletions

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 7b660834a4c..85b62691f4f 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -1,3 +1,5 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/workqueue.h>
 #include <linux/rtnetlink.h>
 #include <linux/cache.h>
@@ -5,7 +7,16 @@
 #include <linux/list.h>
 #include <linux/delay.h>
 #include <linux/sched.h>
+#include <linux/idr.h>
+#include <linux/rculist.h>
+#include <linux/nsproxy.h>
+#include <linux/fs.h>
+#include <linux/proc_ns.h>
+#include <linux/file.h>
+#include <linux/export.h>
+#include <linux/user_namespace.h>
 #include <net/net_namespace.h>
+#include <net/netns/generic.h>
 
 /*
  *	Our network namespace constructor/destructor lists
@@ -13,32 +24,149 @@
 
 static LIST_HEAD(pernet_list);
 static struct list_head *first_device = &pernet_list;
-static DEFINE_MUTEX(net_mutex);
+DEFINE_MUTEX(net_mutex);
 
 LIST_HEAD(net_namespace_list);
+EXPORT_SYMBOL_GPL(net_namespace_list);
 
-struct net init_net;
+struct net init_net = {
+	.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
+};
 EXPORT_SYMBOL(init_net);
 
+#define INITIAL_NET_GEN_PTRS	13 /* +1 for len +2 for rcu_head */
+
+static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
+
+static struct net_generic *net_alloc_generic(void)
+{
+	struct net_generic *ng;
+	size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
+
+	ng = kzalloc(generic_size, GFP_KERNEL);
+	if (ng)
+		ng->len = max_gen_ptrs;
+
+	return ng;
+}
+
+static int net_assign_generic(struct net *net, int id, void *data)
+{
+	struct net_generic *ng, *old_ng;
+
+	BUG_ON(!mutex_is_locked(&net_mutex));
+	BUG_ON(id == 0);
+
+	old_ng = rcu_dereference_protected(net->gen,
+					   lockdep_is_held(&net_mutex));
+	ng = old_ng;
+	if (old_ng->len >= id)
+		goto assign;
+
+	ng = net_alloc_generic();
+	if (ng == NULL)
+		return -ENOMEM;
+
+	/*
+	 * Some synchronisation notes:
+	 *
+	 * The net_generic explores the net->gen array inside rcu
+	 * read section. Besides once set the net->gen->ptr[x]
+	 * pointer never changes (see rules in netns/generic.h).
+	 *
+	 * That said, we simply duplicate this array and schedule
+	 * the old copy for kfree after a grace period.
+	 */
+
+	memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
+
+	rcu_assign_pointer(net->gen, ng);
+	kfree_rcu(old_ng, rcu);
+assign:
+	ng->ptr[id - 1] = data;
+	return 0;
+}
+
+static int ops_init(const struct pernet_operations *ops, struct net *net)
+{
+	int err = -ENOMEM;
+	void *data = NULL;
+
+	if (ops->id && ops->size) {
+		data = kzalloc(ops->size, GFP_KERNEL);
+		if (!data)
+			goto out;
+
+		err = net_assign_generic(net, *ops->id, data);
+		if (err)
+			goto cleanup;
+	}
+	err = 0;
+	if (ops->init)
+		err = ops->init(net);
+	if (!err)
+		return 0;
+
+cleanup:
+	kfree(data);
+
+out:
+	return err;
+}
+
+static void ops_free(const struct pernet_operations *ops, struct net *net)
+{
+	if (ops->id && ops->size) {
+		int id = *ops->id;
+		kfree(net_generic(net, id));
+	}
+}
+
+static void ops_exit_list(const struct pernet_operations *ops,
+			  struct list_head *net_exit_list)
+{
+	struct net *net;
+	if (ops->exit) {
+		list_for_each_entry(net, net_exit_list, exit_list)
+			ops->exit(net);
+	}
+	if (ops->exit_batch)
+		ops->exit_batch(net_exit_list);
+}
+
+static void ops_free_list(const struct pernet_operations *ops,
+			  struct list_head *net_exit_list)
+{
+	struct net *net;
+	if (ops->size && ops->id) {
+		list_for_each_entry(net, net_exit_list, exit_list)
+			ops_free(ops, net);
+	}
+}
+
 /*
  * setup_net runs the initializers for the network namespace object.
  */
-static __net_init int setup_net(struct net *net)
+static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
 {
 	/* Must be called with net_mutex held */
-	struct pernet_operations *ops;
-	int error;
+	const struct pernet_operations *ops, *saved_ops;
+	int error = 0;
+	LIST_HEAD(net_exit_list);
 
 	atomic_set(&net->count, 1);
+	atomic_set(&net->passive, 1);
+	net->dev_base_seq = 1;
+	net->user_ns = user_ns;
+
+#ifdef NETNS_REFCNT_DEBUG
 	atomic_set(&net->use_count, 0);
+#endif
 
-	error = 0;
 	list_for_each_entry(ops, &pernet_list, list) {
-		if (ops->init) {
-			error = ops->init(net);
-			if (error < 0)
-				goto out_undo;
-		}
+		error = ops_init(ops, net);
+		if (error < 0)
+			goto out_undo;
 	}
 out:
 	return error;
@@ -47,93 +175,136 @@ out_undo:
 	/* Walk through the list backwards calling the exit functions
 	 * for the pernet modules whose init functions did not fail.
 	 */
-	list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
-		if (ops->exit)
-			ops->exit(net);
-	}
+	list_add(&net->exit_list, &net_exit_list);
+	saved_ops = ops;
+	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
+		ops_exit_list(ops, &net_exit_list);
+
+	ops = saved_ops;
+	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
+		ops_free_list(ops, &net_exit_list);
 
 	rcu_barrier();
 	goto out;
 }
 
+
 #ifdef CONFIG_NET_NS
 static struct kmem_cache *net_cachep;
 static struct workqueue_struct *netns_wq;
 
 static struct net *net_alloc(void)
 {
-	return kmem_cache_zalloc(net_cachep, GFP_KERNEL);
+	struct net *net = NULL;
+	struct net_generic *ng;
+
+	ng = net_alloc_generic();
+	if (!ng)
+		goto out;
+
+	net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
+	if (!net)
+		goto out_free;
+
+	rcu_assign_pointer(net->gen, ng);
+out:
+	return net;
+
+out_free:
+	kfree(ng);
+	goto out;
 }
 
 static void net_free(struct net *net)
 {
-	if (!net)
-		return;
-
+#ifdef NETNS_REFCNT_DEBUG
 	if (unlikely(atomic_read(&net->use_count) != 0)) {
-		printk(KERN_EMERG "network namespace not free! Usage: %d\n",
-			atomic_read(&net->use_count));
+		pr_emerg("network namespace not free! Usage: %d\n",
+			 atomic_read(&net->use_count));
 		return;
 	}
-
+#endif
+	kfree(net->gen);
 	kmem_cache_free(net_cachep, net);
 }
 
-struct net *copy_net_ns(unsigned long flags, struct net *old_net)
+void net_drop_ns(void *p)
 {
-	struct net *new_net = NULL;
-	int err;
+	struct net *ns = p;
+	if (ns && atomic_dec_and_test(&ns->passive))
+		net_free(ns);
+}
 
-	get_net(old_net);
+struct net *copy_net_ns(unsigned long flags,
+			struct user_namespace *user_ns, struct net *old_net)
+{
+	struct net *net;
+	int rv;
 
 	if (!(flags & CLONE_NEWNET))
-		return old_net;
-
-	err = -ENOMEM;
-	new_net = net_alloc();
-	if (!new_net)
-		goto out;
-
-	mutex_lock(&net_mutex);
-	err = setup_net(new_net);
-	if (err)
-		goto out_unlock;
+		return get_net(old_net);
 
-	rtnl_lock();
-	list_add_tail(&new_net->list, &net_namespace_list);
-	rtnl_unlock();
+	net = net_alloc();
+	if (!net)
+		return ERR_PTR(-ENOMEM);
 
+	get_user_ns(user_ns);
 
-out_unlock:
+	mutex_lock(&net_mutex);
+	rv = setup_net(net, user_ns);
+	if (rv == 0) {
+		rtnl_lock();
+		list_add_tail_rcu(&net->list, &net_namespace_list);
+		rtnl_unlock();
+	}
 	mutex_unlock(&net_mutex);
-out:
-	put_net(old_net);
-	if (err) {
-		net_free(new_net);
-		new_net = ERR_PTR(err);
+	if (rv < 0) {
+		put_user_ns(user_ns);
+		net_drop_ns(net);
+		return ERR_PTR(rv);
 	}
-	return new_net;
+	return net;
 }
 
+static DEFINE_SPINLOCK(cleanup_list_lock);
+static LIST_HEAD(cleanup_list);  /* Must hold cleanup_list_lock to touch */
+
 static void cleanup_net(struct work_struct *work)
 {
-	struct pernet_operations *ops;
-	struct net *net;
+	const struct pernet_operations *ops;
+	struct net *net, *tmp;
+	struct list_head net_kill_list;
+	LIST_HEAD(net_exit_list);
 
-	net = container_of(work, struct net, work);
+	/* Atomically snapshot the list of namespaces to cleanup */
+	spin_lock_irq(&cleanup_list_lock);
+	list_replace_init(&cleanup_list, &net_kill_list);
+	spin_unlock_irq(&cleanup_list_lock);
 
 	mutex_lock(&net_mutex);
 
 	/* Don't let anyone else find us. */
 	rtnl_lock();
-	list_del(&net->list);
+	list_for_each_entry(net, &net_kill_list, cleanup_list) {
+		list_del_rcu(&net->list);
+		list_add_tail(&net->exit_list, &net_exit_list);
+	}
 	rtnl_unlock();
 
+	/*
+	 * Another CPU might be rcu-iterating the list, wait for it.
+	 * This needs to be before calling the exit() notifiers, so
+	 * the rcu_barrier() below isn't sufficient alone.
+	 */
+	synchronize_rcu();
+
 	/* Run all of the network namespace exit methods */
-	list_for_each_entry_reverse(ops, &pernet_list, list) {
-		if (ops->exit)
-			ops->exit(net);
-	}
+	list_for_each_entry_reverse(ops, &pernet_list, list)
+		ops_exit_list(ops, &net_exit_list);
+
+	/* Free the net generic variables */
+	list_for_each_entry_reverse(ops, &pernet_list, list)
+		ops_free_list(ops, &net_exit_list);
 
 	mutex_unlock(&net_mutex);
 
@@ -143,31 +314,93 @@ static void cleanup_net(struct work_struct *work)
 	rcu_barrier();
 
 	/* Finally it is safe to free my network namespace structure */
-	net_free(net);
+	list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
+		list_del_init(&net->exit_list);
+		put_user_ns(net->user_ns);
+		net_drop_ns(net);
+	}
 }
+static DECLARE_WORK(net_cleanup_work, cleanup_net);
 
 void __put_net(struct net *net)
 {
 	/* Cleanup the network namespace in process context */
-	INIT_WORK(&net->work, cleanup_net);
-	queue_work(netns_wq, &net->work);
+	unsigned long flags;
+
+	spin_lock_irqsave(&cleanup_list_lock, flags);
+	list_add(&net->cleanup_list, &cleanup_list);
+	spin_unlock_irqrestore(&cleanup_list_lock, flags);
+
+	queue_work(netns_wq, &net_cleanup_work);
 }
 EXPORT_SYMBOL_GPL(__put_net);
 
+struct net *get_net_ns_by_fd(int fd)
+{
+	struct proc_ns *ei;
+	struct file *file;
+	struct net *net;
+
+	file = proc_ns_fget(fd);
+	if (IS_ERR(file))
+		return ERR_CAST(file);
+
+	ei = get_proc_ns(file_inode(file));
+	if (ei->ns_ops == &netns_operations)
+		net = get_net(ei->ns);
+	else
+		net = ERR_PTR(-EINVAL);
+
+	fput(file);
+	return net;
+}
+
 #else
-struct net *copy_net_ns(unsigned long flags, struct net *old_net)
+struct net *get_net_ns_by_fd(int fd)
 {
-	if (flags & CLONE_NEWNET)
-		return ERR_PTR(-EINVAL);
-	return old_net;
+	return ERR_PTR(-EINVAL);
 }
 #endif
 
+struct net *get_net_ns_by_pid(pid_t pid)
+{
+	struct task_struct *tsk;
+	struct net *net;
+
+	/* Lookup the network namespace */
+	net = ERR_PTR(-ESRCH);
+	rcu_read_lock();
+	tsk = find_task_by_vpid(pid);
+	if (tsk) {
+		struct nsproxy *nsproxy;
+		nsproxy = task_nsproxy(tsk);
+		if (nsproxy)
+			net = get_net(nsproxy->net_ns);
+	}
+	rcu_read_unlock();
+	return net;
+}
+EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
+
+static __net_init int net_ns_net_init(struct net *net)
+{
+	return proc_alloc_inum(&net->proc_inum);
+}
+
+static __net_exit void net_ns_net_exit(struct net *net)
+{
+	proc_free_inum(net->proc_inum);
+}
+
+static struct pernet_operations __net_initdata net_ns_ops = {
+	.init = net_ns_net_init,
+	.exit = net_ns_net_exit,
+};
+
 static int __init net_ns_init(void)
 {
-	int err;
+	struct net_generic *ng;
 
-	printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net));
 #ifdef CONFIG_NET_NS
 	net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
 					SMP_CACHE_BYTES,
@@ -179,16 +412,23 @@ static int __init net_ns_init(void)
 		panic("Could not create netns workq");
 #endif
 
+	ng = net_alloc_generic();
+	if (!ng)
+		panic("Could not allocate generic netns");
+
+	rcu_assign_pointer(init_net.gen, ng);
+
 	mutex_lock(&net_mutex);
-	err = setup_net(&init_net);
+	if (setup_net(&init_net, &init_user_ns))
+		panic("Could not setup the initial network namespace");
 
 	rtnl_lock();
-	list_add_tail(&init_net.list, &net_namespace_list);
+	list_add_tail_rcu(&init_net.list, &net_namespace_list);
 	rtnl_unlock();
 
 	mutex_unlock(&net_mutex);
-	if (err)
-		panic("Could not setup the initial network namespace");
+
+	register_pernet_subsys(&net_ns_ops);
 
 	return 0;
 }
@@ -196,18 +436,20 @@ static int __init net_ns_init(void)
 pure_initcall(net_ns_init);
 
 #ifdef CONFIG_NET_NS
-static int register_pernet_operations(struct list_head *list,
-				      struct pernet_operations *ops)
+static int __register_pernet_operations(struct list_head *list,
+					struct pernet_operations *ops)
 {
-	struct net *net, *undo_net;
+	struct net *net;
 	int error;
+	LIST_HEAD(net_exit_list);
 
 	list_add_tail(&ops->list, list);
-	if (ops->init) {
+	if (ops->init || (ops->id && ops->size)) {
 		for_each_net(net) {
-			error = ops->init(net);
+			error = ops_init(ops, net);
 			if (error)
 				goto out_undo;
+			list_add_tail(&net->exit_list, &net_exit_list);
 		}
 	}
 	return 0;
@@ -215,43 +457,78 @@ static int register_pernet_operations(struct list_head *list,
 out_undo:
 	/* If I have an error cleanup all namespaces I initialized */
 	list_del(&ops->list);
-	if (ops->exit) {
-		for_each_net(undo_net) {
-			if (undo_net == net)
-				goto undone;
-			ops->exit(undo_net);
-		}
-	}
-undone:
+	ops_exit_list(ops, &net_exit_list);
+	ops_free_list(ops, &net_exit_list);
 	return error;
 }
 
-static void unregister_pernet_operations(struct pernet_operations *ops)
+static void __unregister_pernet_operations(struct pernet_operations *ops)
 {
 	struct net *net;
+	LIST_HEAD(net_exit_list);
 
 	list_del(&ops->list);
-	if (ops->exit)
-		for_each_net(net)
-			ops->exit(net);
+	for_each_net(net)
+		list_add_tail(&net->exit_list, &net_exit_list);
+	ops_exit_list(ops, &net_exit_list);
+	ops_free_list(ops, &net_exit_list);
 }
 
 #else
 
+static int __register_pernet_operations(struct list_head *list,
+					struct pernet_operations *ops)
+{
+	return ops_init(ops, &init_net);
+}
+
+static void __unregister_pernet_operations(struct pernet_operations *ops)
+{
+	LIST_HEAD(net_exit_list);
+	list_add(&init_net.exit_list, &net_exit_list);
+	ops_exit_list(ops, &net_exit_list);
+	ops_free_list(ops, &net_exit_list);
+}
+
+#endif /* CONFIG_NET_NS */
+
+static DEFINE_IDA(net_generic_ids);
+
 static int register_pernet_operations(struct list_head *list,
 				      struct pernet_operations *ops)
 {
-	if (ops->init == NULL)
-		return 0;
-	return ops->init(&init_net);
+	int error;
+
+	if (ops->id) {
+again:
+		error = ida_get_new_above(&net_generic_ids, 1, ops->id);
+		if (error < 0) {
+			if (error == -EAGAIN) {
+				ida_pre_get(&net_generic_ids, GFP_KERNEL);
+				goto again;
+			}
+			return error;
+		}
+		max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id);
+	}
+	error = __register_pernet_operations(list, ops);
+	if (error) {
+		rcu_barrier();
+		if (ops->id)
+			ida_remove(&net_generic_ids, *ops->id);
+	}
+
+	return error;
 }
 
 static void unregister_pernet_operations(struct pernet_operations *ops)
 {
-	if (ops->exit)
-		ops->exit(&init_net);
+	
+	__unregister_pernet_operations(ops);
+	rcu_barrier();
+	if (ops->id)
+		ida_remove(&net_generic_ids, *ops->id);
 }
-#endif
 
 /**
  *      register_pernet_subsys - register a network namespace subsystem
@@ -291,10 +568,10 @@ EXPORT_SYMBOL_GPL(register_pernet_subsys);
  *	addition run the exit method for all existing network
  *	namespaces.
  */
-void unregister_pernet_subsys(struct pernet_operations *module)
+void unregister_pernet_subsys(struct pernet_operations *ops)
 {
 	mutex_lock(&net_mutex);
-	unregister_pernet_operations(module);
+	unregister_pernet_operations(ops);
 	mutex_unlock(&net_mutex);
 }
 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
@@ -348,3 +625,52 @@ void unregister_pernet_device(struct pernet_operations *ops)
 	mutex_unlock(&net_mutex);
 }
 EXPORT_SYMBOL_GPL(unregister_pernet_device);
+
+#ifdef CONFIG_NET_NS
+static void *netns_get(struct task_struct *task)
+{
+	struct net *net = NULL;
+	struct nsproxy *nsproxy;
+
+	rcu_read_lock();
+	nsproxy = task_nsproxy(task);
+	if (nsproxy)
+		net = get_net(nsproxy->net_ns);
+	rcu_read_unlock();
+
+	return net;
+}
+
+static void netns_put(void *ns)
+{
+	put_net(ns);
+}
+
+static int netns_install(struct nsproxy *nsproxy, void *ns)
+{
+	struct net *net = ns;
+
+	if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+		return -EPERM;
+
+	put_net(nsproxy->net_ns);
+	nsproxy->net_ns = get_net(net);
+	return 0;
+}
+
+static unsigned int netns_inum(void *ns)
+{
+	struct net *net = ns;
+	return net->proc_inum;
+}
+
+const struct proc_ns_operations netns_operations = {
+	.name		= "net",
+	.type		= CLONE_NEWNET,
+	.get		= netns_get,
+	.put		= netns_put,
+	.install	= netns_install,
+	.inum		= netns_inum,
+};
+#endif