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
);
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