projects/linux·blob v2.6.25-rc1 · refs

241 lines · 5.1 KiB

1/*
2 * Copyright (C) 2006 IBM Corporation
3 *
4 * Author: Serge Hallyn <[email protected]>
5 *
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
9 * License.
10 *
11 * Jun 2006 - namespaces support
12 * OpenVZ, SWsoft Inc.
13 * Pavel Emelianov <[email protected]>
14 */
15
16#include <linux/module.h>
17#include <linux/version.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
26static struct kmem_cache *nsproxy_cachep;
27
28struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
29
30/*
31 * creates a copy of "orig" with refcount 1.
32 */
33static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
34{
35 struct nsproxy *ns;
36
37 ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
38 if (ns) {
39 memcpy(ns, orig, sizeof(struct nsproxy));
40 atomic_set(&ns->count, 1);
41 }
42 return ns;
43}
44
45/*
46 * Create new nsproxy and all of its the associated namespaces.
47 * Return the newly created nsproxy. Do not attach this to the task,
48 * leave it to the caller to do proper locking and attach it to task.
49 */
50static struct nsproxy *create_new_namespaces(unsigned long flags,
51 struct task_struct *tsk, struct fs_struct *new_fs)
52{
53 struct nsproxy *new_nsp;
54 int err;
55
56 new_nsp = clone_nsproxy(tsk->nsproxy);
57 if (!new_nsp)
58 return ERR_PTR(-ENOMEM);
59
60 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
61 if (IS_ERR(new_nsp->mnt_ns)) {
62 err = PTR_ERR(new_nsp->mnt_ns);
63 goto out_ns;
64 }
65
66 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
67 if (IS_ERR(new_nsp->uts_ns)) {
68 err = PTR_ERR(new_nsp->uts_ns);
69 goto out_uts;
70 }
71
72 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
73 if (IS_ERR(new_nsp->ipc_ns)) {
74 err = PTR_ERR(new_nsp->ipc_ns);
75 goto out_ipc;
76 }
77
78 new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
79 if (IS_ERR(new_nsp->pid_ns)) {
80 err = PTR_ERR(new_nsp->pid_ns);
81 goto out_pid;
82 }
83
84 new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
85 if (IS_ERR(new_nsp->user_ns)) {
86 err = PTR_ERR(new_nsp->user_ns);
87 goto out_user;
88 }
89
90 new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
91 if (IS_ERR(new_nsp->net_ns)) {
92 err = PTR_ERR(new_nsp->net_ns);
93 goto out_net;
94 }
95
96 return new_nsp;
97
98out_net:
99 if (new_nsp->user_ns)
100 put_user_ns(new_nsp->user_ns);
101out_user:
102 if (new_nsp->pid_ns)
103 put_pid_ns(new_nsp->pid_ns);
104out_pid:
105 if (new_nsp->ipc_ns)
106 put_ipc_ns(new_nsp->ipc_ns);
107out_ipc:
108 if (new_nsp->uts_ns)
109 put_uts_ns(new_nsp->uts_ns);
110out_uts:
111 if (new_nsp->mnt_ns)
112 put_mnt_ns(new_nsp->mnt_ns);
113out_ns:
114 kmem_cache_free(nsproxy_cachep, new_nsp);
115 return ERR_PTR(err);
116}
117
118/*
119 * called from clone. This now handles copy for nsproxy and all
120 * namespaces therein.
121 */
122int copy_namespaces(unsigned long flags, struct task_struct *tsk)
123{
124 struct nsproxy *old_ns = tsk->nsproxy;
125 struct nsproxy *new_ns;
126 int err = 0;
127
128 if (!old_ns)
129 return 0;
130
131 get_nsproxy(old_ns);
132
133 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
134 CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNET)))
135 return 0;
136
137 if (!capable(CAP_SYS_ADMIN)) {
138 err = -EPERM;
139 goto out;
140 }
141
142 new_ns = create_new_namespaces(flags, tsk, tsk->fs);
143 if (IS_ERR(new_ns)) {
144 err = PTR_ERR(new_ns);
145 goto out;
146 }
147
148 err = ns_cgroup_clone(tsk);
149 if (err) {
150 put_nsproxy(new_ns);
151 goto out;
152 }
153
154 tsk->nsproxy = new_ns;
155
156out:
157 put_nsproxy(old_ns);
158 return err;
159}
160
161void free_nsproxy(struct nsproxy *ns)
162{
163 if (ns->mnt_ns)
164 put_mnt_ns(ns->mnt_ns);
165 if (ns->uts_ns)
166 put_uts_ns(ns->uts_ns);
167 if (ns->ipc_ns)
168 put_ipc_ns(ns->ipc_ns);
169 if (ns->pid_ns)
170 put_pid_ns(ns->pid_ns);
171 if (ns->user_ns)
172 put_user_ns(ns->user_ns);
173 put_net(ns->net_ns);
174 kmem_cache_free(nsproxy_cachep, ns);
175}
176
177/*
178 * Called from unshare. Unshare all the namespaces part of nsproxy.
179 * On success, returns the new nsproxy.
180 */
181int unshare_nsproxy_namespaces(unsigned long unshare_flags,
182 struct nsproxy **new_nsp, struct fs_struct *new_fs)
183{
184 int err = 0;
185
186 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
187 CLONE_NEWUSER | CLONE_NEWNET)))
188 return 0;
189
190 if (!capable(CAP_SYS_ADMIN))
191 return -EPERM;
192
193 *new_nsp = create_new_namespaces(unshare_flags, current,
194 new_fs ? new_fs : current->fs);
195 if (IS_ERR(*new_nsp)) {
196 err = PTR_ERR(*new_nsp);
197 goto out;
198 }
199
200 err = ns_cgroup_clone(current);
201 if (err)
202 put_nsproxy(*new_nsp);
203
204out:
205 return err;
206}
207
208void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
209{
210 struct nsproxy *ns;
211
212 might_sleep();
213
214 ns = p->nsproxy;
215
216 rcu_assign_pointer(p->nsproxy, new);
217
218 if (ns && atomic_dec_and_test(&ns->count)) {
219 /*
220 * wait for others to get what they want from this nsproxy.
221 *
222 * cannot release this nsproxy via the call_rcu() since
223 * put_mnt_ns() will want to sleep
224 */
225 synchronize_rcu();
226 free_nsproxy(ns);
227 }
228}
229
230void exit_task_namespaces(struct task_struct *p)
231{
232 switch_task_namespaces(p, NULL);
233}
234
235static int __init nsproxy_cache_init(void)
236{
237 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
238 return 0;
239}
240
241module_init(nsproxy_cache_init);