projects/linux·blob v4.14 · refs

277 lines · 6.5 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/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>
28#include <linux/cgroup.h>
29#include <linux/perf_event.h>
30
31static struct kmem_cache *nsproxy_cachep;
32
33struct nsproxy init_nsproxy = {
34 .count = ATOMIC_INIT(1),
35 .uts_ns = &init_uts_ns,
36#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
37 .ipc_ns = &init_ipc_ns,
38#endif
39 .mnt_ns = NULL,
40 .pid_ns_for_children = &init_pid_ns,
41#ifdef CONFIG_NET
42 .net_ns = &init_net,
43#endif
44#ifdef CONFIG_CGROUPS
45 .cgroup_ns = &init_cgroup_ns,
46#endif
47};
48
49static inline struct nsproxy *create_nsproxy(void)
50{
51 struct nsproxy *nsproxy;
52
53 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
54 if (nsproxy)
55 atomic_set(&nsproxy->count, 1);
56 return nsproxy;
57}
58
59/*
60 * Create new nsproxy and all of its the associated namespaces.
61 * Return the newly created nsproxy. Do not attach this to the task,
62 * leave it to the caller to do proper locking and attach it to task.
63 */
64static struct nsproxy *create_new_namespaces(unsigned long flags,
65 struct task_struct *tsk, struct user_namespace *user_ns,
66 struct fs_struct *new_fs)
67{
68 struct nsproxy *new_nsp;
69 int err;
70
71 new_nsp = create_nsproxy();
72 if (!new_nsp)
73 return ERR_PTR(-ENOMEM);
74
75 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
76 if (IS_ERR(new_nsp->mnt_ns)) {
77 err = PTR_ERR(new_nsp->mnt_ns);
78 goto out_ns;
79 }
80
81 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
82 if (IS_ERR(new_nsp->uts_ns)) {
83 err = PTR_ERR(new_nsp->uts_ns);
84 goto out_uts;
85 }
86
87 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
88 if (IS_ERR(new_nsp->ipc_ns)) {
89 err = PTR_ERR(new_nsp->ipc_ns);
90 goto out_ipc;
91 }
92
93 new_nsp->pid_ns_for_children =
94 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
95 if (IS_ERR(new_nsp->pid_ns_for_children)) {
96 err = PTR_ERR(new_nsp->pid_ns_for_children);
97 goto out_pid;
98 }
99
100 new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
101 tsk->nsproxy->cgroup_ns);
102 if (IS_ERR(new_nsp->cgroup_ns)) {
103 err = PTR_ERR(new_nsp->cgroup_ns);
104 goto out_cgroup;
105 }
106
107 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
108 if (IS_ERR(new_nsp->net_ns)) {
109 err = PTR_ERR(new_nsp->net_ns);
110 goto out_net;
111 }
112
113 return new_nsp;
114
115out_net:
116 put_cgroup_ns(new_nsp->cgroup_ns);
117out_cgroup:
118 if (new_nsp->pid_ns_for_children)
119 put_pid_ns(new_nsp->pid_ns_for_children);
120out_pid:
121 if (new_nsp->ipc_ns)
122 put_ipc_ns(new_nsp->ipc_ns);
123out_ipc:
124 if (new_nsp->uts_ns)
125 put_uts_ns(new_nsp->uts_ns);
126out_uts:
127 if (new_nsp->mnt_ns)
128 put_mnt_ns(new_nsp->mnt_ns);
129out_ns:
130 kmem_cache_free(nsproxy_cachep, new_nsp);
131 return ERR_PTR(err);
132}
133
134/*
135 * called from clone. This now handles copy for nsproxy and all
136 * namespaces therein.
137 */
138int copy_namespaces(unsigned long flags, struct task_struct *tsk)
139{
140 struct nsproxy *old_ns = tsk->nsproxy;
141 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
142 struct nsproxy *new_ns;
143
144 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
145 CLONE_NEWPID | CLONE_NEWNET |
146 CLONE_NEWCGROUP)))) {
147 get_nsproxy(old_ns);
148 return 0;
149 }
150
151 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
152 return -EPERM;
153
154 /*
155 * CLONE_NEWIPC must detach from the undolist: after switching
156 * to a new ipc namespace, the semaphore arrays from the old
157 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
158 * means share undolist with parent, so we must forbid using
159 * it along with CLONE_NEWIPC.
160 */
161 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
162 (CLONE_NEWIPC | CLONE_SYSVSEM))
163 return -EINVAL;
164
165 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
166 if (IS_ERR(new_ns))
167 return PTR_ERR(new_ns);
168
169 tsk->nsproxy = new_ns;
170 return 0;
171}
172
173void free_nsproxy(struct nsproxy *ns)
174{
175 if (ns->mnt_ns)
176 put_mnt_ns(ns->mnt_ns);
177 if (ns->uts_ns)
178 put_uts_ns(ns->uts_ns);
179 if (ns->ipc_ns)
180 put_ipc_ns(ns->ipc_ns);
181 if (ns->pid_ns_for_children)
182 put_pid_ns(ns->pid_ns_for_children);
183 put_cgroup_ns(ns->cgroup_ns);
184 put_net(ns->net_ns);
185 kmem_cache_free(nsproxy_cachep, ns);
186}
187
188/*
189 * Called from unshare. Unshare all the namespaces part of nsproxy.
190 * On success, returns the new nsproxy.
191 */
192int unshare_nsproxy_namespaces(unsigned long unshare_flags,
193 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
194{
195 struct user_namespace *user_ns;
196 int err = 0;
197
198 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
199 CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
200 return 0;
201
202 user_ns = new_cred ? new_cred->user_ns : current_user_ns();
203 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
204 return -EPERM;
205
206 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
207 new_fs ? new_fs : current->fs);
208 if (IS_ERR(*new_nsp)) {
209 err = PTR_ERR(*new_nsp);
210 goto out;
211 }
212
213out:
214 return err;
215}
216
217void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
218{
219 struct nsproxy *ns;
220
221 might_sleep();
222
223 task_lock(p);
224 ns = p->nsproxy;
225 p->nsproxy = new;
226 task_unlock(p);
227
228 if (ns && atomic_dec_and_test(&ns->count))
229 free_nsproxy(ns);
230}
231
232void exit_task_namespaces(struct task_struct *p)
233{
234 switch_task_namespaces(p, NULL);
235}
236
237SYSCALL_DEFINE2(setns, int, fd, int, nstype)
238{
239 struct task_struct *tsk = current;
240 struct nsproxy *new_nsproxy;
241 struct file *file;
242 struct ns_common *ns;
243 int err;
244
245 file = proc_ns_fget(fd);
246 if (IS_ERR(file))
247 return PTR_ERR(file);
248
249 err = -EINVAL;
250 ns = get_proc_ns(file_inode(file));
251 if (nstype && (ns->ops->type != nstype))
252 goto out;
253
254 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
255 if (IS_ERR(new_nsproxy)) {
256 err = PTR_ERR(new_nsproxy);
257 goto out;
258 }
259
260 err = ns->ops->install(new_nsproxy, ns);
261 if (err) {
262 free_nsproxy(new_nsproxy);
263 goto out;
264 }
265 switch_task_namespaces(tsk, new_nsproxy);
266
267 perf_event_namespaces(tsk);
268out:
269 fput(file);
270 return err;
271}
272
273int __init nsproxy_cache_init(void)
274{
275 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
276 return 0;
277}