projects/linux·blob v2.6.23 · refs

200 lines · 4.4 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
24static struct kmem_cache *nsproxy_cachep;
25
26struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
27
28static inline void get_nsproxy(struct nsproxy *ns)
29{
30 atomic_inc(&ns->count);
31}
32
33void get_task_namespaces(struct task_struct *tsk)
34{
35 struct nsproxy *ns = tsk->nsproxy;
36 if (ns) {
37 get_nsproxy(ns);
38 }
39}
40
41/*
42 * creates a copy of "orig" with refcount 1.
43 */
44static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
45{
46 struct nsproxy *ns;
47
48 ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
49 if (ns) {
50 memcpy(ns, orig, sizeof(struct nsproxy));
51 atomic_set(&ns->count, 1);
52 }
53 return ns;
54}
55
56/*
57 * Create new nsproxy and all of its the associated namespaces.
58 * Return the newly created nsproxy. Do not attach this to the task,
59 * leave it to the caller to do proper locking and attach it to task.
60 */
61static struct nsproxy *create_new_namespaces(unsigned long flags,
62 struct task_struct *tsk, struct fs_struct *new_fs)
63{
64 struct nsproxy *new_nsp;
65 int err;
66
67 new_nsp = clone_nsproxy(tsk->nsproxy);
68 if (!new_nsp)
69 return ERR_PTR(-ENOMEM);
70
71 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
72 if (IS_ERR(new_nsp->mnt_ns)) {
73 err = PTR_ERR(new_nsp->mnt_ns);
74 goto out_ns;
75 }
76
77 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
78 if (IS_ERR(new_nsp->uts_ns)) {
79 err = PTR_ERR(new_nsp->uts_ns);
80 goto out_uts;
81 }
82
83 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
84 if (IS_ERR(new_nsp->ipc_ns)) {
85 err = PTR_ERR(new_nsp->ipc_ns);
86 goto out_ipc;
87 }
88
89 new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
90 if (IS_ERR(new_nsp->pid_ns)) {
91 err = PTR_ERR(new_nsp->pid_ns);
92 goto out_pid;
93 }
94
95 new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
96 if (IS_ERR(new_nsp->user_ns)) {
97 err = PTR_ERR(new_nsp->user_ns);
98 goto out_user;
99 }
100
101 return new_nsp;
102
103out_user:
104 if (new_nsp->pid_ns)
105 put_pid_ns(new_nsp->pid_ns);
106out_pid:
107 if (new_nsp->ipc_ns)
108 put_ipc_ns(new_nsp->ipc_ns);
109out_ipc:
110 if (new_nsp->uts_ns)
111 put_uts_ns(new_nsp->uts_ns);
112out_uts:
113 if (new_nsp->mnt_ns)
114 put_mnt_ns(new_nsp->mnt_ns);
115out_ns:
116 kmem_cache_free(nsproxy_cachep, new_nsp);
117 return ERR_PTR(err);
118}
119
120/*
121 * called from clone. This now handles copy for nsproxy and all
122 * namespaces therein.
123 */
124int copy_namespaces(unsigned long flags, struct task_struct *tsk)
125{
126 struct nsproxy *old_ns = tsk->nsproxy;
127 struct nsproxy *new_ns;
128 int err = 0;
129
130 if (!old_ns)
131 return 0;
132
133 get_nsproxy(old_ns);
134
135 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER)))
136 return 0;
137
138 if (!capable(CAP_SYS_ADMIN)) {
139 err = -EPERM;
140 goto out;
141 }
142
143 new_ns = create_new_namespaces(flags, tsk, tsk->fs);
144 if (IS_ERR(new_ns)) {
145 err = PTR_ERR(new_ns);
146 goto out;
147 }
148
149 tsk->nsproxy = new_ns;
150out:
151 put_nsproxy(old_ns);
152 return err;
153}
154
155void free_nsproxy(struct nsproxy *ns)
156{
157 if (ns->mnt_ns)
158 put_mnt_ns(ns->mnt_ns);
159 if (ns->uts_ns)
160 put_uts_ns(ns->uts_ns);
161 if (ns->ipc_ns)
162 put_ipc_ns(ns->ipc_ns);
163 if (ns->pid_ns)
164 put_pid_ns(ns->pid_ns);
165 if (ns->user_ns)
166 put_user_ns(ns->user_ns);
167 kmem_cache_free(nsproxy_cachep, ns);
168}
169
170/*
171 * Called from unshare. Unshare all the namespaces part of nsproxy.
172 * On success, returns the new nsproxy.
173 */
174int unshare_nsproxy_namespaces(unsigned long unshare_flags,
175 struct nsproxy **new_nsp, struct fs_struct *new_fs)
176{
177 int err = 0;
178
179 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
180 CLONE_NEWUSER)))
181 return 0;
182
183 if (!capable(CAP_SYS_ADMIN))
184 return -EPERM;
185
186 *new_nsp = create_new_namespaces(unshare_flags, current,
187 new_fs ? new_fs : current->fs);
188 if (IS_ERR(*new_nsp))
189 err = PTR_ERR(*new_nsp);
190 return err;
191}
192
193static int __init nsproxy_cache_init(void)
194{
195 nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
196 0, SLAB_PANIC, NULL);
197 return 0;
198}
199
200module_init(nsproxy_cache_init);