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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/net/core/net_namespace.c

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32 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
#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 <linux/sched/task.h>
#include <linux/uidgid.h>
#include <linux/cookie.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;
LIST_HEAD(net_namespace_list);
EXPORT_SYMBOL_GPL(net_namespace_list);
/* Protects net_namespace_list. Nests iside rtnl_lock() */
DECLARE_RWSEM(net_rwsem);
EXPORT_SYMBOL_GPL(net_rwsem);
#ifdef CONFIG_KEYS
static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
#endif
struct net init_net = {
.ns.count = REFCOUNT_INIT(1),
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
#ifdef CONFIG_KEYS
.key_domain = &init_net_key_domain,
#endif
};
EXPORT_SYMBOL(init_net);
static bool init_net_initialized;
/*
* pernet_ops_rwsem: protects: pernet_list, net_generic_ids,
* init_net_initialized and first_device pointer.
* This is internal net namespace object. Please, don't use it
* outside.
*/
DECLARE_RWSEM(pernet_ops_rwsem);
EXPORT_SYMBOL_GPL(pernet_ops_rwsem);
#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;
DEFINE_COOKIE(net_cookie);
u64 __net_gen_cookie(struct net *net)
{
while (1) {
u64 res = atomic64_read(&net->net_cookie);
if (res)
return res;
res = gen_cookie_next(&net_cookie);
atomic64_cmpxchg(&net->net_cookie, 0, res);
}
}
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(id < MIN_PERNET_OPS_ID);
old_ng = rcu_dereference_protected(net->gen,
lockdep_is_held(&pernet_ops_rwsem));
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_pre_exit_list(const struct pernet_operations *ops,
struct list_head *net_exit_list)
{
struct net *net;
if (ops->pre_exit) {
list_for_each_entry(net, net_exit_list, exit_list)
ops->pre_exit(net);
}
}
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;
}
/* Must be called from RCU-critical section or with nsid_lock held */
static int __peernet2id(const struct net *net, struct net *peer)
{
int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
/* Magic value for id 0. */
if (id == NET_ID_ZERO)
return 0;
if (id > 0)
return id;
return NETNSA_NSID_NOT_ASSIGNED;
}
static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
struct nlmsghdr *nlh, gfp_t gfp);
/* 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, gfp_t gfp)
{
int id;
if (refcount_read(&net->ns.count) == 0)
return NETNSA_NSID_NOT_ASSIGNED;
spin_lock_bh(&net->nsid_lock);
id = __peernet2id(net, peer);
if (id >= 0) {
spin_unlock_bh(&net->nsid_lock);
return id;
}
/* When peer is obtained from RCU lists, we may race with
* its cleanup. Check whether it's alive, and this guarantees
* we never hash a peer back to net->netns_ids, after it has
* just been idr_remove()'d from there in cleanup_net().
*/
if (!maybe_get_net(peer)) {
spin_unlock_bh(&net->nsid_lock);
return NETNSA_NSID_NOT_ASSIGNED;
}
id = alloc_netid(net, peer, -1);
spin_unlock_bh(&net->nsid_lock);
put_net(peer);
if (id < 0)
return NETNSA_NSID_NOT_ASSIGNED;
rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp);
return id;
}
EXPORT_SYMBOL_GPL(peernet2id_alloc);
/* This function returns, if assigned, the id of a peer netns. */
int peernet2id(const struct net *net, struct net *peer)
{
int id;
rcu_read_lock();
id = __peernet2id(net, peer);
rcu_read_unlock();
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(const struct net *net, struct net *peer)
{
return peernet2id(net, peer) >= 0;
}
struct net *get_net_ns_by_id(const struct net *net, int id)
{
struct net *peer;
if (id < 0)
return NULL;
rcu_read_lock();
peer = idr_find(&net->netns_ids, id);
if (peer)
peer = maybe_get_net(peer);
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 pernet_ops_rwsem held */
const struct pernet_operations *ops, *saved_ops;
int error = 0;
LIST_HEAD(net_exit_list);
refcount_set(&net->ns.count, 1);
refcount_set(&net->passive, 1);
get_random_bytes(&net->hash_mix, sizeof(u32));
net->dev_base_seq = 1;
net->user_ns = user_ns;
idr_init(&net->netns_ids);
spin_lock_init(&net->nsid_lock);
mutex_init(&net->ipv4.ra_mutex);
list_for_each_entry(ops, &pernet_list, list) {
error = ops_init(ops, net);
if (error < 0)
goto out_undo;
}
down_write(&net_rwsem);
list_add_tail_rcu(&net->list, &net_namespace_list);
up_write(&net_rwsem);
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_pre_exit_list(ops, &net_exit_list);
synchronize_rcu();
ops = saved_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;
}
static int __net_init net_defaults_init_net(struct net *net)
{
net->core.sysctl_somaxconn = SOMAXCONN;
return 0;
}
static struct pernet_operations net_defaults_ops = {
.init = net_defaults_init_net,
};
static __init int net_defaults_init(void)
{
if (register_pernet_subsys(&net_defaults_ops))
panic("Cannot initialize net default settings");
return 0;
}
core_initcall(net_defaults_init);
#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 __ro_after_init;
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;
#ifdef CONFIG_KEYS
net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL);
if (!net->key_domain)
goto out_free_2;
refcount_set(&net->key_domain->usage, 1);
#endif
rcu_assign_pointer(net->gen, ng);
out:
return net;
#ifdef CONFIG_KEYS
out_free_2:
kmem_cache_free(net_cachep, net);
net = NULL;
#endif
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 && refcount_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) {
rv = -ENOMEM;
goto dec_ucounts;
}
refcount_set(&net->passive, 1);
net->ucounts = ucounts;
get_user_ns(user_ns);
rv = down_read_killable(&pernet_ops_rwsem);
if (rv < 0)
goto put_userns;
rv = setup_net(net, user_ns);
up_read(&pernet_ops_rwsem);
if (rv < 0) {
put_userns:
key_remove_domain(net->key_domain);
put_user_ns(user_ns);
net_drop_ns(net);
dec_ucounts:
dec_net_namespaces(ucounts);
return ERR_PTR(rv);
}
return net;
}
/**
* net_ns_get_ownership - get sysfs ownership data for @net
* @net: network namespace in question (can be NULL)
* @uid: kernel user ID for sysfs objects
* @gid: kernel group ID for sysfs objects
*
* Returns the uid/gid pair of root in the user namespace associated with the
* given network namespace.
*/
void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)
{
if (net) {
kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
if (uid_valid(ns_root_uid))
*uid = ns_root_uid;
if (gid_valid(ns_root_gid))
*gid = ns_root_gid;
} else {
*uid = GLOBAL_ROOT_UID;
*gid = GLOBAL_ROOT_GID;
}
}
EXPORT_SYMBOL_GPL(net_ns_get_ownership);
static void unhash_nsid(struct net *net, struct net *last)
{
struct net *tmp;
/* This function is only called from cleanup_net() work,
* and this work is the only process, that may delete
* a net from net_namespace_list. So, when the below
* is executing, the list may only grow. Thus, we do not
* use for_each_net_rcu() or net_rwsem.
*/
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, 0, NULL,
GFP_KERNEL);
if (tmp == last)
break;
}
spin_lock_bh(&net->nsid_lock);
idr_destroy(&net->netns_ids);
spin_unlock_bh(&net->nsid_lock);
}
static LLIST_HEAD(cleanup_list);
static void cleanup_net(struct work_struct *work)
{
const struct pernet_operations *ops;
struct net *net, *tmp, *last;
struct llist_node *net_kill_list;
LIST_HEAD(net_exit_list);
/* Atomically snapshot the list of namespaces to cleanup */
net_kill_list = llist_del_all(&cleanup_list);
down_read(&pernet_ops_rwsem);
/* Don't let anyone else find us. */
down_write(&net_rwsem);
llist_for_each_entry(net, net_kill_list, cleanup_list)
list_del_rcu(&net->list);
/* Cache last net. After we unlock rtnl, no one new net
* added to net_namespace_list can assign nsid pointer
* to a net from net_kill_list (see peernet2id_alloc()).
* So, we skip them in unhash_nsid().
*
* Note, that unhash_nsid() does not delete nsid links
* between net_kill_list's nets, as they've already
* deleted from net_namespace_list. But, this would be
* useless anyway, as netns_ids are destroyed there.
*/
last = list_last_entry(&net_namespace_list, struct net, list);
up_write(&net_rwsem);
llist_for_each_entry(net, net_kill_list, cleanup_list) {
unhash_nsid(net, last);
list_add_tail(&net->exit_list, &net_exit_list);
}
/* Run all of the network namespace pre_exit methods */
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_pre_exit_list(ops, &net_exit_list);
/*
* 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.
* Also the pre_exit() and exit() methods need this barrier.
*/
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);
up_read(&pernet_ops_rwsem);
/* 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);
key_remove_domain(net->key_domain);
put_user_ns(net->user_ns);
net_drop_ns(net);
}
}
/**
* net_ns_barrier - wait until concurrent net_cleanup_work is done
*
* cleanup_net runs from work queue and will first remove namespaces
* from the global list, then run net exit functions.
*
* Call this in module exit path to make sure that all netns
* ->exit ops have been invoked before the function is removed.
*/
void net_ns_barrier(void)
{
down_write(&pernet_ops_rwsem);
up_write(&pernet_ops_rwsem);
}
EXPORT_SYMBOL(net_ns_barrier);
static DECLARE_WORK(net_cleanup_work, cleanup_net);
void __put_net(struct net *net)
{
/* Cleanup the network namespace in process context */
if (llist_add(&net->cleanup_list, &cleanup_list))
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 },
[NETNSA_TARGET_NSID] = { .type = NLA_S32 },
};
static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[NETNSA_MAX + 1];
struct nlattr *nla;
struct net *peer;
int nsid, err;
err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb,
NETNSA_MAX, rtnl_net_policy, extack);
if (err < 0)
return err;
if (!tb[NETNSA_NSID]) {
NL_SET_ERR_MSG(extack, "nsid is missing");
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]));
nla = tb[NETNSA_PID];
} else if (tb[NETNSA_FD]) {
peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
nla = tb[NETNSA_FD];
} else {
NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
return -EINVAL;
}
if (IS_ERR(peer)) {
NL_SET_BAD_ATTR(extack, nla);
NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
return PTR_ERR(peer);
}
spin_lock_bh(&net->nsid_lock);
if (__peernet2id(net, peer) >= 0) {
spin_unlock_bh(&net->nsid_lock);
err = -EEXIST;
NL_SET_BAD_ATTR(extack, nla);
NL_SET_ERR_MSG(extack,
"Peer netns already has a nsid assigned");
goto out;
}
err = alloc_netid(net, peer, nsid);
spin_unlock_bh(&net->nsid_lock);
if (err >= 0) {
rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid,
nlh, GFP_KERNEL);
err = 0;
} else if (err == -ENOSPC && nsid >= 0) {
err = -EEXIST;
NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]);
NL_SET_ERR_MSG(extack, "The specified nsid is already used");
}
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 */
+ nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */
;
}
struct net_fill_args {
u32 portid;
u32 seq;
int flags;
int cmd;
int nsid;
bool add_ref;
int ref_nsid;
};
static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args)
{
struct nlmsghdr *nlh;
struct rtgenmsg *rth;
nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth),
args->flags);
if (!nlh)
return -EMSGSIZE;
rth = nlmsg_data(nlh);
rth->rtgen_family = AF_UNSPEC;
if (nla_put_s32(skb, NETNSA_NSID, args->nsid))
goto nla_put_failure;
if (args->add_ref &&
nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid))
goto nla_put_failure;
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int rtnl_net_valid_getid_req(struct sk_buff *skb,
const struct nlmsghdr *nlh,
struct nlattr **tb,
struct netlink_ext_ack *extack)
{
int i, err;
if (!netlink_strict_get_check(skb))
return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg),
tb, NETNSA_MAX, rtnl_net_policy,
extack);
err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
NETNSA_MAX, rtnl_net_policy,
extack);
if (err)
return err;
for (i = 0; i <= NETNSA_MAX; i++) {
if (!tb[i])
continue;
switch (i) {
case NETNSA_PID:
case NETNSA_FD:
case NETNSA_NSID:
case NETNSA_TARGET_NSID:
break;
default:
NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request");
return -EINVAL;
}
}
return 0;
}
static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[NETNSA_MAX + 1];
struct net_fill_args fillargs = {
.portid = NETLINK_CB(skb).portid,
.seq = nlh->nlmsg_seq,
.cmd = RTM_NEWNSID,
};
struct net *peer, *target = net;
struct nlattr *nla;
struct sk_buff *msg;
int err;
err = rtnl_net_valid_getid_req(skb, nlh, tb, extack);
if (err < 0)
return err;
if (tb[NETNSA_PID]) {
peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
nla = tb[NETNSA_PID];
} else if (tb[NETNSA_FD]) {
peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
nla = tb[NETNSA_FD];
} else if (tb[NETNSA_NSID]) {
peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID]));
if (!peer)
peer = ERR_PTR(-ENOENT);
nla = tb[NETNSA_NSID];
} else {
NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
return -EINVAL;
}
if (IS_ERR(peer)) {
NL_SET_BAD_ATTR(extack, nla);
NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
return PTR_ERR(peer);
}
if (tb[NETNSA_TARGET_NSID]) {
int id = nla_get_s32(tb[NETNSA_TARGET_NSID]);
target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id);
if (IS_ERR(target)) {
NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]);
NL_SET_ERR_MSG(extack,
"Target netns reference is invalid");
err = PTR_ERR(target);
goto out;
}
fillargs.add_ref = true;
fillargs.ref_nsid = peernet2id(net, peer);
}
msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
if (!msg) {
err = -ENOMEM;
goto out;
}
fillargs.nsid = peernet2id(target, peer);
err = rtnl_net_fill(msg, &fillargs);
if (err < 0)
goto err_out;
err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
goto out;
err_out:
nlmsg_free(msg);
out:
if (fillargs.add_ref)
put_net(target);
put_net(peer);
return err;
}
struct rtnl_net_dump_cb {
struct net *tgt_net;
struct net *ref_net;
struct sk_buff *skb;
struct net_fill_args fillargs;
int idx;
int s_idx;
};
/* Runs in RCU-critical section. */
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;
net_cb->fillargs.nsid = id;
if (net_cb->fillargs.add_ref)
net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer);
ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs);
if (ret < 0)
return ret;
cont:
net_cb->idx++;
return 0;
}
static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk,
struct rtnl_net_dump_cb *net_cb,
struct netlink_callback *cb)
{
struct netlink_ext_ack *extack = cb->extack;
struct nlattr *tb[NETNSA_MAX + 1];
int err, i;
err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
NETNSA_MAX, rtnl_net_policy,
extack);
if (err < 0)
return err;
for (i = 0; i <= NETNSA_MAX; i++) {
if (!tb[i])
continue;
if (i == NETNSA_TARGET_NSID) {
struct net *net;
net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i]));
if (IS_ERR(net)) {
NL_SET_BAD_ATTR(extack, tb[i]);
NL_SET_ERR_MSG(extack,
"Invalid target network namespace id");
return PTR_ERR(net);
}
net_cb->fillargs.add_ref = true;
net_cb->ref_net = net_cb->tgt_net;
net_cb->tgt_net = net;
} else {
NL_SET_BAD_ATTR(extack, tb[i]);
NL_SET_ERR_MSG(extack,
"Unsupported attribute in dump request");
return -EINVAL;
}
}
return 0;
}
static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
{
struct rtnl_net_dump_cb net_cb = {
.tgt_net = sock_net(skb->sk),
.skb = skb,
.fillargs = {
.portid = NETLINK_CB(cb->skb).portid,
.seq = cb->nlh->nlmsg_seq,
.flags = NLM_F_MULTI,
.cmd = RTM_NEWNSID,
},
.idx = 0,
.s_idx = cb->args[0],
};
int err = 0;
if (cb->strict_check) {
err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb);
if (err < 0)
goto end;
}
rcu_read_lock();
idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
rcu_read_unlock();
cb->args[0] = net_cb.idx;
end:
if (net_cb.fillargs.add_ref)
put_net(net_cb.tgt_net);
return err < 0 ? err : skb->len;
}
static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
struct nlmsghdr *nlh, gfp_t gfp)
{
struct net_fill_args fillargs = {
.portid = portid,
.seq = nlh ? nlh->nlmsg_seq : 0,
.cmd = cmd,
.nsid = id,
};
struct sk_buff *msg;
int err = -ENOMEM;
msg = nlmsg_new(rtnl_net_get_size(), gfp);
if (!msg)
goto out;
err = rtnl_net_fill(msg, &fillargs);
if (err < 0)
goto err_out;
rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp);
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|SLAB_ACCOUNT, 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);
preempt_disable();
__net_gen_cookie(&init_net);
preempt_enable();
down_write(&pernet_ops_rwsem);
if (setup_net(&init_net, &init_user_ns))
panic("Could not setup the initial network namespace");
init_net_initialized = true;
up_write(&pernet_ops_rwsem);
if (register_pernet_subsys(&net_ns_ops))
panic("Could not register network namespace subsystems");
rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL,
RTNL_FLAG_DOIT_UNLOCKED);
rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
RTNL_FLAG_DOIT_UNLOCKED);
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)) {
/* We held write locked pernet_ops_rwsem, and parallel
* setup_net() and cleanup_net() are not possible.
*/
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_pre_exit_list(ops, &net_exit_list);
synchronize_rcu();
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);
/* See comment in __register_pernet_operations() */
for_each_net(net)
list_add_tail(&net->exit_list, &net_exit_list);
ops_pre_exit_list(ops, &net_exit_list);
synchronize_rcu();
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_pre_exit_list(ops, &net_exit_list);
synchronize_rcu();
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) {
error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID,
GFP_KERNEL);
if (error < 0)
return error;
*ops->id = 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_free(&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_free(&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;
down_write(&pernet_ops_rwsem);
error = register_pernet_operations(first_device, ops);
up_write(&pernet_ops_rwsem);
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)
{
down_write(&pernet_ops_rwsem);
unregister_pernet_operations(ops);
up_write(&pernet_ops_rwsem);
}
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;
down_write(&pernet_ops_rwsem);
error = register_pernet_operations(&pernet_list, ops);
if (!error && (first_device == &pernet_list))
first_device = &ops->list;
up_write(&pernet_ops_rwsem);
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)
{
down_write(&pernet_ops_rwsem);
if (&ops->list == first_device)
first_device = first_device->next;
unregister_pernet_operations(ops);
up_write(&pernet_ops_rwsem);
}
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 nsset *nsset, struct ns_common *ns)
{
struct nsproxy *nsproxy = nsset->nsproxy;
struct net *net = to_net_ns(ns);
if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(nsset->cred->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
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