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Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[mirror_ubuntu-bionic-kernel.git] / kernel / nsproxy.c
1 /*
2 * Copyright (C) 2006 IBM Corporation
3 *
4 * Author: Serge Hallyn <serue@us.ibm.com>
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 <xemul@openvz.org>
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
30 static struct kmem_cache *nsproxy_cachep;
31
32 struct nsproxy init_nsproxy = {
33 .count = ATOMIC_INIT(1),
34 .uts_ns = &init_uts_ns,
35 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
36 .ipc_ns = &init_ipc_ns,
37 #endif
38 .mnt_ns = NULL,
39 .pid_ns_for_children = &init_pid_ns,
40 #ifdef CONFIG_NET
41 .net_ns = &init_net,
42 #endif
43 #ifdef CONFIG_CGROUPS
44 .cgroup_ns = &init_cgroup_ns,
45 #endif
46 };
47
48 static inline struct nsproxy *create_nsproxy(void)
49 {
50 struct nsproxy *nsproxy;
51
52 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
53 if (nsproxy)
54 atomic_set(&nsproxy->count, 1);
55 return nsproxy;
56 }
57
58 /*
59 * Create new nsproxy and all of its the associated namespaces.
60 * Return the newly created nsproxy. Do not attach this to the task,
61 * leave it to the caller to do proper locking and attach it to task.
62 */
63 static struct nsproxy *create_new_namespaces(unsigned long flags,
64 struct task_struct *tsk, struct user_namespace *user_ns,
65 struct fs_struct *new_fs)
66 {
67 struct nsproxy *new_nsp;
68 int err;
69
70 new_nsp = create_nsproxy();
71 if (!new_nsp)
72 return ERR_PTR(-ENOMEM);
73
74 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
75 if (IS_ERR(new_nsp->mnt_ns)) {
76 err = PTR_ERR(new_nsp->mnt_ns);
77 goto out_ns;
78 }
79
80 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
81 if (IS_ERR(new_nsp->uts_ns)) {
82 err = PTR_ERR(new_nsp->uts_ns);
83 goto out_uts;
84 }
85
86 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
87 if (IS_ERR(new_nsp->ipc_ns)) {
88 err = PTR_ERR(new_nsp->ipc_ns);
89 goto out_ipc;
90 }
91
92 new_nsp->pid_ns_for_children =
93 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
94 if (IS_ERR(new_nsp->pid_ns_for_children)) {
95 err = PTR_ERR(new_nsp->pid_ns_for_children);
96 goto out_pid;
97 }
98
99 new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
100 tsk->nsproxy->cgroup_ns);
101 if (IS_ERR(new_nsp->cgroup_ns)) {
102 err = PTR_ERR(new_nsp->cgroup_ns);
103 goto out_cgroup;
104 }
105
106 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
107 if (IS_ERR(new_nsp->net_ns)) {
108 err = PTR_ERR(new_nsp->net_ns);
109 goto out_net;
110 }
111
112 return new_nsp;
113
114 out_net:
115 put_cgroup_ns(new_nsp->cgroup_ns);
116 out_cgroup:
117 if (new_nsp->pid_ns_for_children)
118 put_pid_ns(new_nsp->pid_ns_for_children);
119 out_pid:
120 if (new_nsp->ipc_ns)
121 put_ipc_ns(new_nsp->ipc_ns);
122 out_ipc:
123 if (new_nsp->uts_ns)
124 put_uts_ns(new_nsp->uts_ns);
125 out_uts:
126 if (new_nsp->mnt_ns)
127 put_mnt_ns(new_nsp->mnt_ns);
128 out_ns:
129 kmem_cache_free(nsproxy_cachep, new_nsp);
130 return ERR_PTR(err);
131 }
132
133 /*
134 * called from clone. This now handles copy for nsproxy and all
135 * namespaces therein.
136 */
137 int copy_namespaces(unsigned long flags, struct task_struct *tsk)
138 {
139 struct nsproxy *old_ns = tsk->nsproxy;
140 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
141 struct nsproxy *new_ns;
142
143 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
144 CLONE_NEWPID | CLONE_NEWNET |
145 CLONE_NEWCGROUP)))) {
146 get_nsproxy(old_ns);
147 return 0;
148 }
149
150 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
151 return -EPERM;
152
153 /*
154 * CLONE_NEWIPC must detach from the undolist: after switching
155 * to a new ipc namespace, the semaphore arrays from the old
156 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
157 * means share undolist with parent, so we must forbid using
158 * it along with CLONE_NEWIPC.
159 */
160 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
161 (CLONE_NEWIPC | CLONE_SYSVSEM))
162 return -EINVAL;
163
164 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
165 if (IS_ERR(new_ns))
166 return PTR_ERR(new_ns);
167
168 tsk->nsproxy = new_ns;
169 return 0;
170 }
171
172 void free_nsproxy(struct nsproxy *ns)
173 {
174 if (ns->mnt_ns)
175 put_mnt_ns(ns->mnt_ns);
176 if (ns->uts_ns)
177 put_uts_ns(ns->uts_ns);
178 if (ns->ipc_ns)
179 put_ipc_ns(ns->ipc_ns);
180 if (ns->pid_ns_for_children)
181 put_pid_ns(ns->pid_ns_for_children);
182 put_cgroup_ns(ns->cgroup_ns);
183 put_net(ns->net_ns);
184 kmem_cache_free(nsproxy_cachep, ns);
185 }
186
187 /*
188 * Called from unshare. Unshare all the namespaces part of nsproxy.
189 * On success, returns the new nsproxy.
190 */
191 int unshare_nsproxy_namespaces(unsigned long unshare_flags,
192 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
193 {
194 struct user_namespace *user_ns;
195 int err = 0;
196
197 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
198 CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
199 return 0;
200
201 user_ns = new_cred ? new_cred->user_ns : current_user_ns();
202 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
203 return -EPERM;
204
205 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
206 new_fs ? new_fs : current->fs);
207 if (IS_ERR(*new_nsp)) {
208 err = PTR_ERR(*new_nsp);
209 goto out;
210 }
211
212 out:
213 return err;
214 }
215
216 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
217 {
218 struct nsproxy *ns;
219
220 might_sleep();
221
222 task_lock(p);
223 ns = p->nsproxy;
224 p->nsproxy = new;
225 task_unlock(p);
226
227 if (ns && atomic_dec_and_test(&ns->count))
228 free_nsproxy(ns);
229 }
230
231 void exit_task_namespaces(struct task_struct *p)
232 {
233 switch_task_namespaces(p, NULL);
234 }
235
236 SYSCALL_DEFINE2(setns, int, fd, int, nstype)
237 {
238 struct task_struct *tsk = current;
239 struct nsproxy *new_nsproxy;
240 struct file *file;
241 struct ns_common *ns;
242 int err;
243
244 file = proc_ns_fget(fd);
245 if (IS_ERR(file))
246 return PTR_ERR(file);
247
248 err = -EINVAL;
249 ns = get_proc_ns(file_inode(file));
250 if (nstype && (ns->ops->type != nstype))
251 goto out;
252
253 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
254 if (IS_ERR(new_nsproxy)) {
255 err = PTR_ERR(new_nsproxy);
256 goto out;
257 }
258
259 err = ns->ops->install(new_nsproxy, ns);
260 if (err) {
261 free_nsproxy(new_nsproxy);
262 goto out;
263 }
264 switch_task_namespaces(tsk, new_nsproxy);
265 out:
266 fput(file);
267 return err;
268 }
269
270 int __init nsproxy_cache_init(void)
271 {
272 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
273 return 0;
274 }