projects/linux·blob v2.6.22 · refs

176 lines · 3.7 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
24struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
25
26static inline void get_nsproxy(struct nsproxy *ns)
27{
28 atomic_inc(&ns->count);
29}
30
31void get_task_namespaces(struct task_struct *tsk)
32{
33 struct nsproxy *ns = tsk->nsproxy;
34 if (ns) {
35 get_nsproxy(ns);
36 }
37}
38
39/*
40 * creates a copy of "orig" with refcount 1.
41 */
42static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
43{
44 struct nsproxy *ns;
45
46 ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL);
47 if (ns)
48 atomic_set(&ns->count, 1);
49 return ns;
50}
51
52/*
53 * Create new nsproxy and all of its the associated namespaces.
54 * Return the newly created nsproxy. Do not attach this to the task,
55 * leave it to the caller to do proper locking and attach it to task.
56 */
57static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
58 struct fs_struct *new_fs)
59{
60 struct nsproxy *new_nsp;
61
62 new_nsp = clone_nsproxy(tsk->nsproxy);
63 if (!new_nsp)
64 return ERR_PTR(-ENOMEM);
65
66 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
67 if (IS_ERR(new_nsp->mnt_ns))
68 goto out_ns;
69
70 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
71 if (IS_ERR(new_nsp->uts_ns))
72 goto out_uts;
73
74 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
75 if (IS_ERR(new_nsp->ipc_ns))
76 goto out_ipc;
77
78 new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
79 if (IS_ERR(new_nsp->pid_ns))
80 goto out_pid;
81
82 return new_nsp;
83
84out_pid:
85 if (new_nsp->ipc_ns)
86 put_ipc_ns(new_nsp->ipc_ns);
87out_ipc:
88 if (new_nsp->uts_ns)
89 put_uts_ns(new_nsp->uts_ns);
90out_uts:
91 if (new_nsp->mnt_ns)
92 put_mnt_ns(new_nsp->mnt_ns);
93out_ns:
94 kfree(new_nsp);
95 return ERR_PTR(-ENOMEM);
96}
97
98/*
99 * called from clone. This now handles copy for nsproxy and all
100 * namespaces therein.
101 */
102int copy_namespaces(int flags, struct task_struct *tsk)
103{
104 struct nsproxy *old_ns = tsk->nsproxy;
105 struct nsproxy *new_ns;
106 int err = 0;
107
108 if (!old_ns)
109 return 0;
110
111 get_nsproxy(old_ns);
112
113 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
114 return 0;
115
116 if (!capable(CAP_SYS_ADMIN)) {
117 err = -EPERM;
118 goto out;
119 }
120
121 new_ns = create_new_namespaces(flags, tsk, tsk->fs);
122 if (IS_ERR(new_ns)) {
123 err = PTR_ERR(new_ns);
124 goto out;
125 }
126
127 tsk->nsproxy = new_ns;
128out:
129 put_nsproxy(old_ns);
130 return err;
131}
132
133void free_nsproxy(struct nsproxy *ns)
134{
135 if (ns->mnt_ns)
136 put_mnt_ns(ns->mnt_ns);
137 if (ns->uts_ns)
138 put_uts_ns(ns->uts_ns);
139 if (ns->ipc_ns)
140 put_ipc_ns(ns->ipc_ns);
141 if (ns->pid_ns)
142 put_pid_ns(ns->pid_ns);
143 kfree(ns);
144}
145
146/*
147 * Called from unshare. Unshare all the namespaces part of nsproxy.
148 * On success, returns the new nsproxy.
149 */
150int unshare_nsproxy_namespaces(unsigned long unshare_flags,
151 struct nsproxy **new_nsp, struct fs_struct *new_fs)
152{
153 int err = 0;
154
155 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
156 return 0;
157
158#ifndef CONFIG_IPC_NS
159 if (unshare_flags & CLONE_NEWIPC)
160 return -EINVAL;
161#endif
162
163#ifndef CONFIG_UTS_NS
164 if (unshare_flags & CLONE_NEWUTS)
165 return -EINVAL;
166#endif
167
168 if (!capable(CAP_SYS_ADMIN))
169 return -EPERM;
170
171 *new_nsp = create_new_namespaces(unshare_flags, current,
172 new_fs ? new_fs : current->fs);
173 if (IS_ERR(*new_nsp))
174 err = PTR_ERR(*new_nsp);
175 return err;
176}