linux/net/core/net_namespace.c
Linus Torvalds dcdaa2f948 Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit
Pull audit updates from Paul Moore:
 "After the small number of patches for v4.9, we've got a much bigger
  pile for v4.10.

  The bulk of these patches involve a rework of the audit backlog queue
  to enable us to move the netlink multicasting out of the task/thread
  that generates the audit record and into the kernel thread that emits
  the record (just like we do for the audit unicast to auditd).

  While we were playing with the backlog queue(s) we fixed a number of
  other little problems with the code, and from all the testing so far
  things look to be in much better shape now. Doing this also allowed us
  to re-enable disabling IRQs for some netns operations ("netns: avoid
  disabling irq for netns id").

  The remaining patches fix some small problems that are well documented
  in the commit descriptions, as well as adding session ID filtering
  support"

* 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit:
  audit: use proper refcount locking on audit_sock
  netns: avoid disabling irq for netns id
  audit: don't ever sleep on a command record/message
  audit: handle a clean auditd shutdown with grace
  audit: wake up kauditd_thread after auditd registers
  audit: rework audit_log_start()
  audit: rework the audit queue handling
  audit: rename the queues and kauditd related functions
  audit: queue netlink multicast sends just like we do for unicast sends
  audit: fixup audit_init()
  audit: move kaudit thread start from auditd registration to kaudit init (#2)
  audit: add support for session ID user filter
  audit: fix formatting of AUDIT_CONFIG_CHANGE events
  audit: skip sessionid sentinel value when auto-incrementing
  audit: tame initialization warning len_abuf in audit_log_execve_info
  audit: less stack usage for /proc/*/loginuid
2016-12-14 14:06:40 -08:00

1053 lines
24 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 MIN_PERNET_OPS_ID \
((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
#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;
unsigned int generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
ng = kzalloc(generic_size, GFP_KERNEL);
if (ng)
ng->s.len = max_gen_ptrs;
return ng;
}
static int net_assign_generic(struct net *net, unsigned int id, void *data)
{
struct net_generic *ng, *old_ng;
BUG_ON(!mutex_is_locked(&net_mutex));
BUG_ON(id < MIN_PERNET_OPS_ID);
old_ng = rcu_dereference_protected(net->gen,
lockdep_is_held(&net_mutex));
if (old_ng->s.len > id) {
old_ng->ptr[id] = data;
return 0;
}
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[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID],
(old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *));
ng->ptr[id] = data;
rcu_assign_pointer(net->gen, ng);
kfree_rcu(old_ng, s.rcu);
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) {
kfree(net_generic(net, *ops->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;
if (atomic_read(&net->count) == 0)
return NETNSA_NSID_NOT_ASSIGNED;
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);
rv = mutex_lock_killable(&net_mutex);
if (rv < 0) {
net_free(net);
dec_net_namespaces(ucounts);
put_user_ns(user_ns);
return ERR_PTR(rv);
}
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, MIN_PERNET_OPS_ID, ops->id);
if (error < 0) {
if (error == -EAGAIN) {
ida_pre_get(&net_generic_ids, GFP_KERNEL);
goto again;
}
return error;
}
max_gen_ptrs = max(max_gen_ptrs, *ops->id + 1);
}
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