linux/net/core/net_namespace.c
Linus Torvalds 14986a34e1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman:
 "This set of changes is a number of smaller things that have been
  overlooked in other development cycles focused on more fundamental
  change. The devpts changes are small things that were a distraction
  until we managed to kill off DEVPTS_MULTPLE_INSTANCES. There is an
  trivial regression fix to autofs for the unprivileged mount changes
  that went in last cycle. A pair of ioctls has been added by Andrey
  Vagin making it is possible to discover the relationships between
  namespaces when referring to them through file descriptors.

  The big user visible change is starting to add simple resource limits
  to catch programs that misbehave. With namespaces in general and user
  namespaces in particular allowing users to use more kinds of
  resources, it has become important to have something to limit errant
  programs. Because the purpose of these limits is to catch errant
  programs the code needs to be inexpensive to use as it always on, and
  the default limits need to be high enough that well behaved programs
  on well behaved systems don't encounter them.

  To this end, after some review I have implemented per user per user
  namespace limits, and use them to limit the number of namespaces. The
  limits being per user mean that one user can not exhause the limits of
  another user. The limits being per user namespace allow contexts where
  the limit is 0 and security conscious folks can remove from their
  threat anlysis the code used to manage namespaces (as they have
  historically done as it root only). At the same time the limits being
  per user namespace allow other parts of the system to use namespaces.

  Namespaces are increasingly being used in application sand boxing
  scenarios so an all or nothing disable for the entire system for the
  security conscious folks makes increasing use of these sandboxes
  impossible.

  There is also added a limit on the maximum number of mounts present in
  a single mount namespace. It is nontrivial to guess what a reasonable
  system wide limit on the number of mount structure in the kernel would
  be, especially as it various based on how a system is using
  containers. A limit on the number of mounts in a mount namespace
  however is much easier to understand and set. In most cases in
  practice only about 1000 mounts are used. Given that some autofs
  scenarious have the potential to be 30,000 to 50,000 mounts I have set
  the default limit for the number of mounts at 100,000 which is well
  above every known set of users but low enough that the mount hash
  tables don't degrade unreaonsably.

  These limits are a start. I expect this estabilishes a pattern that
  other limits for resources that namespaces use will follow. There has
  been interest in making inotify event limits per user per user
  namespace as well as interest expressed in making details about what
  is going on in the kernel more visible"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (28 commits)
  autofs:  Fix automounts by using current_real_cred()->uid
  mnt: Add a per mount namespace limit on the number of mounts
  netns: move {inc,dec}_net_namespaces into #ifdef
  nsfs: Simplify __ns_get_path
  tools/testing: add a test to check nsfs ioctl-s
  nsfs: add ioctl to get a parent namespace
  nsfs: add ioctl to get an owning user namespace for ns file descriptor
  kernel: add a helper to get an owning user namespace for a namespace
  devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts
  devpts: Remove sync_filesystems
  devpts: Make devpts_kill_sb safe if fsi is NULL
  devpts: Simplify devpts_mount by using mount_nodev
  devpts: Move the creation of /dev/pts/ptmx into fill_super
  devpts: Move parse_mount_options into fill_super
  userns: When the per user per user namespace limit is reached return ENOSPC
  userns; Document per user per user namespace limits.
  mntns: Add a limit on the number of mount namespaces.
  netns: Add a limit on the number of net namespaces
  cgroupns: Add a limit on the number of cgroup namespaces
  ipcns: Add a  limit on the number of ipc namespaces
  ...
2016-10-06 09:52:23 -07:00

1041 lines
23 KiB
C

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/workqueue.h>
#include <linux/rtnetlink.h>
#include <linux/cache.h>
#include <linux/slab.h>
#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 <linux/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
/*
* Our network namespace constructor/destructor lists
*/
static LIST_HEAD(pernet_list);
static struct list_head *first_device = &pernet_list;
DEFINE_MUTEX(net_mutex);
LIST_HEAD(net_namespace_list);
EXPORT_SYMBOL_GPL(net_namespace_list);
struct net init_net = {
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
};
EXPORT_SYMBOL(init_net);
static bool init_net_initialized;
#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);
}
}
/* should be called with nsid_lock held */
static int alloc_netid(struct net *net, struct net *peer, int reqid)
{
int min = 0, max = 0;
if (reqid >= 0) {
min = reqid;
max = reqid + 1;
}
return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC);
}
/* This function is used by idr_for_each(). If net is equal to peer, the
* function returns the id so that idr_for_each() stops. Because we cannot
* returns the id 0 (idr_for_each() will not stop), we return the magic value
* NET_ID_ZERO (-1) for it.
*/
#define NET_ID_ZERO -1
static int net_eq_idr(int id, void *net, void *peer)
{
if (net_eq(net, peer))
return id ? : NET_ID_ZERO;
return 0;
}
/* Should be called with nsid_lock held. If a new id is assigned, the bool alloc
* is set to true, thus the caller knows that the new id must be notified via
* rtnl.
*/
static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
{
int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
bool alloc_it = *alloc;
*alloc = false;
/* Magic value for id 0. */
if (id == NET_ID_ZERO)
return 0;
if (id > 0)
return id;
if (alloc_it) {
id = alloc_netid(net, peer, -1);
*alloc = true;
return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
}
return NETNSA_NSID_NOT_ASSIGNED;
}
/* should be called with nsid_lock held */
static int __peernet2id(struct net *net, struct net *peer)
{
bool no = false;
return __peernet2id_alloc(net, peer, &no);
}
static void rtnl_net_notifyid(struct net *net, int cmd, int id);
/* This function returns the id of a peer netns. If no id is assigned, one will
* be allocated and returned.
*/
int peernet2id_alloc(struct net *net, struct net *peer)
{
bool alloc;
int id;
spin_lock_bh(&net->nsid_lock);
alloc = atomic_read(&peer->count) == 0 ? false : true;
id = __peernet2id_alloc(net, peer, &alloc);
spin_unlock_bh(&net->nsid_lock);
if (alloc && id >= 0)
rtnl_net_notifyid(net, RTM_NEWNSID, id);
return id;
}
/* This function returns, if assigned, the id of a peer netns. */
int peernet2id(struct net *net, struct net *peer)
{
int id;
spin_lock_bh(&net->nsid_lock);
id = __peernet2id(net, peer);
spin_unlock_bh(&net->nsid_lock);
return id;
}
EXPORT_SYMBOL(peernet2id);
/* This function returns true is the peer netns has an id assigned into the
* current netns.
*/
bool peernet_has_id(struct net *net, struct net *peer)
{
return peernet2id(net, peer) >= 0;
}
struct net *get_net_ns_by_id(struct net *net, int id)
{
struct net *peer;
if (id < 0)
return NULL;
rcu_read_lock();
spin_lock_bh(&net->nsid_lock);
peer = idr_find(&net->netns_ids, id);
if (peer)
get_net(peer);
spin_unlock_bh(&net->nsid_lock);
rcu_read_unlock();
return peer;
}
/*
* setup_net runs the initializers for the network namespace object.
*/
static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
{
/* Must be called with net_mutex held */
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;
idr_init(&net->netns_ids);
spin_lock_init(&net->nsid_lock);
list_for_each_entry(ops, &pernet_list, list) {
error = ops_init(ops, net);
if (error < 0)
goto out_undo;
}
out:
return error;
out_undo:
/* Walk through the list backwards calling the exit functions
* for the pernet modules whose init functions did not fail.
*/
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 ucounts *inc_net_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
}
static void dec_net_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
}
static struct kmem_cache *net_cachep;
static struct workqueue_struct *netns_wq;
static struct net *net_alloc(void)
{
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)
{
kfree(rcu_access_pointer(net->gen));
kmem_cache_free(net_cachep, net);
}
void net_drop_ns(void *p)
{
struct net *ns = p;
if (ns && atomic_dec_and_test(&ns->passive))
net_free(ns);
}
struct net *copy_net_ns(unsigned long flags,
struct user_namespace *user_ns, struct net *old_net)
{
struct ucounts *ucounts;
struct net *net;
int rv;
if (!(flags & CLONE_NEWNET))
return get_net(old_net);
ucounts = inc_net_namespaces(user_ns);
if (!ucounts)
return ERR_PTR(-ENOSPC);
net = net_alloc();
if (!net) {
dec_net_namespaces(ucounts);
return ERR_PTR(-ENOMEM);
}
get_user_ns(user_ns);
mutex_lock(&net_mutex);
net->ucounts = ucounts;
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);
if (rv < 0) {
dec_net_namespaces(ucounts);
put_user_ns(user_ns);
net_drop_ns(net);
return ERR_PTR(rv);
}
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)
{
const struct pernet_operations *ops;
struct net *net, *tmp;
struct list_head net_kill_list;
LIST_HEAD(net_exit_list);
/* 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_for_each_entry(net, &net_kill_list, cleanup_list) {
list_del_rcu(&net->list);
list_add_tail(&net->exit_list, &net_exit_list);
for_each_net(tmp) {
int id;
spin_lock_bh(&tmp->nsid_lock);
id = __peernet2id(tmp, net);
if (id >= 0)
idr_remove(&tmp->netns_ids, id);
spin_unlock_bh(&tmp->nsid_lock);
if (id >= 0)
rtnl_net_notifyid(tmp, RTM_DELNSID, id);
}
spin_lock_bh(&net->nsid_lock);
idr_destroy(&net->netns_ids);
spin_unlock_bh(&net->nsid_lock);
}
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)
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);
/* Ensure there are no outstanding rcu callbacks using this
* network namespace.
*/
rcu_barrier();
/* Finally it is safe to free my network namespace structure */
list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
list_del_init(&net->exit_list);
dec_net_namespaces(net->ucounts);
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 */
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 file *file;
struct ns_common *ns;
struct net *net;
file = proc_ns_fget(fd);
if (IS_ERR(file))
return ERR_CAST(file);
ns = get_proc_ns(file_inode(file));
if (ns->ops == &netns_operations)
net = get_net(container_of(ns, struct net, ns));
else
net = ERR_PTR(-EINVAL);
fput(file);
return net;
}
#else
struct net *get_net_ns_by_fd(int fd)
{
return ERR_PTR(-EINVAL);
}
#endif
EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
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;
task_lock(tsk);
nsproxy = tsk->nsproxy;
if (nsproxy)
net = get_net(nsproxy->net_ns);
task_unlock(tsk);
}
rcu_read_unlock();
return net;
}
EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
static __net_init int net_ns_net_init(struct net *net)
{
#ifdef CONFIG_NET_NS
net->ns.ops = &netns_operations;
#endif
return ns_alloc_inum(&net->ns);
}
static __net_exit void net_ns_net_exit(struct net *net)
{
ns_free_inum(&net->ns);
}
static struct pernet_operations __net_initdata net_ns_ops = {
.init = net_ns_net_init,
.exit = net_ns_net_exit,
};
static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
[NETNSA_NONE] = { .type = NLA_UNSPEC },
[NETNSA_NSID] = { .type = NLA_S32 },
[NETNSA_PID] = { .type = NLA_U32 },
[NETNSA_FD] = { .type = NLA_U32 },
};
static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[NETNSA_MAX + 1];
struct net *peer;
int nsid, err;
err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
rtnl_net_policy);
if (err < 0)
return err;
if (!tb[NETNSA_NSID])
return -EINVAL;
nsid = nla_get_s32(tb[NETNSA_NSID]);
if (tb[NETNSA_PID])
peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
else if (tb[NETNSA_FD])
peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
else
return -EINVAL;
if (IS_ERR(peer))
return PTR_ERR(peer);
spin_lock_bh(&net->nsid_lock);
if (__peernet2id(net, peer) >= 0) {
spin_unlock_bh(&net->nsid_lock);
err = -EEXIST;
goto out;
}
err = alloc_netid(net, peer, nsid);
spin_unlock_bh(&net->nsid_lock);
if (err >= 0) {
rtnl_net_notifyid(net, RTM_NEWNSID, err);
err = 0;
}
out:
put_net(peer);
return err;
}
static int rtnl_net_get_size(void)
{
return NLMSG_ALIGN(sizeof(struct rtgenmsg))
+ nla_total_size(sizeof(s32)) /* NETNSA_NSID */
;
}
static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
int cmd, struct net *net, int nsid)
{
struct nlmsghdr *nlh;
struct rtgenmsg *rth;
nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags);
if (!nlh)
return -EMSGSIZE;
rth = nlmsg_data(nlh);
rth->rtgen_family = AF_UNSPEC;
if (nla_put_s32(skb, NETNSA_NSID, nsid))
goto nla_put_failure;
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[NETNSA_MAX + 1];
struct sk_buff *msg;
struct net *peer;
int err, id;
err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
rtnl_net_policy);
if (err < 0)
return err;
if (tb[NETNSA_PID])
peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
else if (tb[NETNSA_FD])
peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
else
return -EINVAL;
if (IS_ERR(peer))
return PTR_ERR(peer);
msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
if (!msg) {
err = -ENOMEM;
goto out;
}
id = peernet2id(net, peer);
err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0,
RTM_NEWNSID, net, id);
if (err < 0)
goto err_out;
err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
goto out;
err_out:
nlmsg_free(msg);
out:
put_net(peer);
return err;
}
struct rtnl_net_dump_cb {
struct net *net;
struct sk_buff *skb;
struct netlink_callback *cb;
int idx;
int s_idx;
};
static int rtnl_net_dumpid_one(int id, void *peer, void *data)
{
struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
int ret;
if (net_cb->idx < net_cb->s_idx)
goto cont;
ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid,
net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI,
RTM_NEWNSID, net_cb->net, id);
if (ret < 0)
return ret;
cont:
net_cb->idx++;
return 0;
}
static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
struct rtnl_net_dump_cb net_cb = {
.net = net,
.skb = skb,
.cb = cb,
.idx = 0,
.s_idx = cb->args[0],
};
spin_lock_bh(&net->nsid_lock);
idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
spin_unlock_bh(&net->nsid_lock);
cb->args[0] = net_cb.idx;
return skb->len;
}
static void rtnl_net_notifyid(struct net *net, int cmd, int id)
{
struct sk_buff *msg;
int err = -ENOMEM;
msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
if (!msg)
goto out;
err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id);
if (err < 0)
goto err_out;
rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0);
return;
err_out:
nlmsg_free(msg);
out:
rtnl_set_sk_err(net, RTNLGRP_NSID, err);
}
static int __init net_ns_init(void)
{
struct net_generic *ng;
#ifdef CONFIG_NET_NS
net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
SMP_CACHE_BYTES,
SLAB_PANIC, NULL);
/* Create workqueue for cleanup */
netns_wq = create_singlethread_workqueue("netns");
if (!netns_wq)
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);
if (setup_net(&init_net, &init_user_ns))
panic("Could not setup the initial network namespace");
init_net_initialized = true;
rtnl_lock();
list_add_tail_rcu(&init_net.list, &net_namespace_list);
rtnl_unlock();
mutex_unlock(&net_mutex);
register_pernet_subsys(&net_ns_ops);
rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL);
rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
NULL);
return 0;
}
pure_initcall(net_ns_init);
#ifdef CONFIG_NET_NS
static int __register_pernet_operations(struct list_head *list,
struct pernet_operations *ops)
{
struct net *net;
int error;
LIST_HEAD(net_exit_list);
list_add_tail(&ops->list, list);
if (ops->init || (ops->id && ops->size)) {
for_each_net(net) {
error = ops_init(ops, net);
if (error)
goto out_undo;
list_add_tail(&net->exit_list, &net_exit_list);
}
}
return 0;
out_undo:
/* If I have an error cleanup all namespaces I initialized */
list_del(&ops->list);
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)
{
struct net *net;
LIST_HEAD(net_exit_list);
list_del(&ops->list);
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)
{
if (!init_net_initialized) {
list_add_tail(&ops->list, list);
return 0;
}
return ops_init(ops, &init_net);
}
static void __unregister_pernet_operations(struct pernet_operations *ops)
{
if (!init_net_initialized) {
list_del(&ops->list);
} else {
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)
{
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)
{
__unregister_pernet_operations(ops);
rcu_barrier();
if (ops->id)
ida_remove(&net_generic_ids, *ops->id);
}
/**
* register_pernet_subsys - register a network namespace subsystem
* @ops: pernet operations structure for the subsystem
*
* Register a subsystem which has init and exit functions
* that are called when network namespaces are created and
* destroyed respectively.
*
* When registered all network namespace init functions are
* called for every existing network namespace. Allowing kernel
* modules to have a race free view of the set of network namespaces.
*
* When a new network namespace is created all of the init
* methods are called in the order in which they were registered.
*
* When a network namespace is destroyed all of the exit methods
* are called in the reverse of the order with which they were
* registered.
*/
int register_pernet_subsys(struct pernet_operations *ops)
{
int error;
mutex_lock(&net_mutex);
error = register_pernet_operations(first_device, ops);
mutex_unlock(&net_mutex);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_subsys);
/**
* unregister_pernet_subsys - unregister a network namespace subsystem
* @ops: pernet operations structure to manipulate
*
* Remove the pernet operations structure from the list to be
* used when network namespaces are created or destroyed. In
* addition run the exit method for all existing network
* namespaces.
*/
void unregister_pernet_subsys(struct pernet_operations *ops)
{
mutex_lock(&net_mutex);
unregister_pernet_operations(ops);
mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
/**
* register_pernet_device - register a network namespace device
* @ops: pernet operations structure for the subsystem
*
* Register a device which has init and exit functions
* that are called when network namespaces are created and
* destroyed respectively.
*
* When registered all network namespace init functions are
* called for every existing network namespace. Allowing kernel
* modules to have a race free view of the set of network namespaces.
*
* When a new network namespace is created all of the init
* methods are called in the order in which they were registered.
*
* When a network namespace is destroyed all of the exit methods
* are called in the reverse of the order with which they were
* registered.
*/
int register_pernet_device(struct pernet_operations *ops)
{
int error;
mutex_lock(&net_mutex);
error = register_pernet_operations(&pernet_list, ops);
if (!error && (first_device == &pernet_list))
first_device = &ops->list;
mutex_unlock(&net_mutex);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_device);
/**
* unregister_pernet_device - unregister a network namespace netdevice
* @ops: pernet operations structure to manipulate
*
* Remove the pernet operations structure from the list to be
* used when network namespaces are created or destroyed. In
* addition run the exit method for all existing network
* namespaces.
*/
void unregister_pernet_device(struct pernet_operations *ops)
{
mutex_lock(&net_mutex);
if (&ops->list == first_device)
first_device = first_device->next;
unregister_pernet_operations(ops);
mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_device);
#ifdef CONFIG_NET_NS
static struct ns_common *netns_get(struct task_struct *task)
{
struct net *net = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy)
net = get_net(nsproxy->net_ns);
task_unlock(task);
return net ? &net->ns : NULL;
}
static inline struct net *to_net_ns(struct ns_common *ns)
{
return container_of(ns, struct net, ns);
}
static void netns_put(struct ns_common *ns)
{
put_net(to_net_ns(ns));
}
static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns)
{
struct net *net = to_net_ns(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 struct user_namespace *netns_owner(struct ns_common *ns)
{
return to_net_ns(ns)->user_ns;
}
const struct proc_ns_operations netns_operations = {
.name = "net",
.type = CLONE_NEWNET,
.get = netns_get,
.put = netns_put,
.install = netns_install,
.owner = netns_owner,
};
#endif