2 * Copyright (C) 2006 IBM Corporation
4 * Author: Serge Hallyn <serue@us.ibm.com>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2 of the
11 * Jun 2006 - namespaces support
13 * Pavel Emelianov <xemul@openvz.org>
16 #include <linux/slab.h>
17 #include <linux/export.h>
18 #include <linux/nsproxy.h>
19 #include <linux/init_task.h>
20 #include <linux/mnt_namespace.h>
21 #include <linux/utsname.h>
22 #include <linux/pid_namespace.h>
23 #include <net/net_namespace.h>
24 #include <linux/ipc_namespace.h>
25 #include <linux/proc_ns.h>
26 #include <linux/file.h>
27 #include <linux/syscalls.h>
29 static struct kmem_cache *nsproxy_cachep;
31 struct nsproxy init_nsproxy = {
32 .count = ATOMIC_INIT(1),
33 .uts_ns = &init_uts_ns,
34 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
35 .ipc_ns = &init_ipc_ns,
38 .pid_ns_for_children = &init_pid_ns,
44 static inline struct nsproxy *create_nsproxy(void)
46 struct nsproxy *nsproxy;
48 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
50 atomic_set(&nsproxy->count, 1);
55 * Create new nsproxy and all of its the associated namespaces.
56 * Return the newly created nsproxy. Do not attach this to the task,
57 * leave it to the caller to do proper locking and attach it to task.
59 static struct nsproxy *create_new_namespaces(unsigned long flags,
60 struct task_struct *tsk, struct user_namespace *user_ns,
61 struct fs_struct *new_fs)
63 struct nsproxy *new_nsp;
66 new_nsp = create_nsproxy();
68 return ERR_PTR(-ENOMEM);
70 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
71 if (IS_ERR(new_nsp->mnt_ns)) {
72 err = PTR_ERR(new_nsp->mnt_ns);
76 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
77 if (IS_ERR(new_nsp->uts_ns)) {
78 err = PTR_ERR(new_nsp->uts_ns);
82 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
83 if (IS_ERR(new_nsp->ipc_ns)) {
84 err = PTR_ERR(new_nsp->ipc_ns);
88 new_nsp->pid_ns_for_children =
89 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
90 if (IS_ERR(new_nsp->pid_ns_for_children)) {
91 err = PTR_ERR(new_nsp->pid_ns_for_children);
95 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
96 if (IS_ERR(new_nsp->net_ns)) {
97 err = PTR_ERR(new_nsp->net_ns);
104 if (new_nsp->pid_ns_for_children)
105 put_pid_ns(new_nsp->pid_ns_for_children);
108 put_ipc_ns(new_nsp->ipc_ns);
111 put_uts_ns(new_nsp->uts_ns);
114 put_mnt_ns(new_nsp->mnt_ns);
116 kmem_cache_free(nsproxy_cachep, new_nsp);
121 * called from clone. This now handles copy for nsproxy and all
122 * namespaces therein.
124 int copy_namespaces(unsigned long flags, struct task_struct *tsk)
126 struct nsproxy *old_ns = tsk->nsproxy;
127 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
128 struct nsproxy *new_ns;
130 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
131 CLONE_NEWPID | CLONE_NEWNET)))) {
136 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
140 * CLONE_NEWIPC must detach from the undolist: after switching
141 * to a new ipc namespace, the semaphore arrays from the old
142 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
143 * means share undolist with parent, so we must forbid using
144 * it along with CLONE_NEWIPC.
146 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
147 (CLONE_NEWIPC | CLONE_SYSVSEM))
150 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
152 return PTR_ERR(new_ns);
154 tsk->nsproxy = new_ns;
158 void free_nsproxy(struct nsproxy *ns)
161 put_mnt_ns(ns->mnt_ns);
163 put_uts_ns(ns->uts_ns);
165 put_ipc_ns(ns->ipc_ns);
166 if (ns->pid_ns_for_children)
167 put_pid_ns(ns->pid_ns_for_children);
169 kmem_cache_free(nsproxy_cachep, ns);
173 * Called from unshare. Unshare all the namespaces part of nsproxy.
174 * On success, returns the new nsproxy.
176 int unshare_nsproxy_namespaces(unsigned long unshare_flags,
177 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
179 struct user_namespace *user_ns;
182 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
183 CLONE_NEWNET | CLONE_NEWPID)))
186 user_ns = new_cred ? new_cred->user_ns : current_user_ns();
187 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
190 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
191 new_fs ? new_fs : current->fs);
192 if (IS_ERR(*new_nsp)) {
193 err = PTR_ERR(*new_nsp);
201 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
209 rcu_assign_pointer(p->nsproxy, new);
211 if (ns && atomic_dec_and_test(&ns->count)) {
213 * wait for others to get what they want from this nsproxy.
215 * cannot release this nsproxy via the call_rcu() since
216 * put_mnt_ns() will want to sleep
223 void exit_task_namespaces(struct task_struct *p)
225 switch_task_namespaces(p, NULL);
228 SYSCALL_DEFINE2(setns, int, fd, int, nstype)
230 const struct proc_ns_operations *ops;
231 struct task_struct *tsk = current;
232 struct nsproxy *new_nsproxy;
237 file = proc_ns_fget(fd);
239 return PTR_ERR(file);
242 ei = get_proc_ns(file_inode(file));
244 if (nstype && (ops->type != nstype))
247 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
248 if (IS_ERR(new_nsproxy)) {
249 err = PTR_ERR(new_nsproxy);
253 err = ops->install(new_nsproxy, ei->ns);
255 free_nsproxy(new_nsproxy);
258 switch_task_namespaces(tsk, new_nsproxy);
264 int __init nsproxy_cache_init(void)
266 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);