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[mirror_ubuntu-bionic-kernel.git] / kernel / nsproxy.c
CommitLineData
ab516013
SH
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.
25b21cb2
KK
10 *
11 * Jun 2006 - namespaces support
12 * OpenVZ, SWsoft Inc.
13 * Pavel Emelianov <xemul@openvz.org>
ab516013
SH
14 */
15
5a0e3ad6 16#include <linux/slab.h>
9984de1a 17#include <linux/export.h>
ab516013 18#include <linux/nsproxy.h>
0437eb59 19#include <linux/init_task.h>
6b3286ed 20#include <linux/mnt_namespace.h>
4865ecf1 21#include <linux/utsname.h>
9a575a92 22#include <linux/pid_namespace.h>
9dd776b6 23#include <net/net_namespace.h>
ae5e1b22 24#include <linux/ipc_namespace.h>
0bb80f24 25#include <linux/proc_ns.h>
0663c6f8
EB
26#include <linux/file.h>
27#include <linux/syscalls.h>
0437eb59 28
98c0d07c
CLG
29static struct kmem_cache *nsproxy_cachep;
30
8467005d 31struct nsproxy init_nsproxy = {
c2b1df2e
AL
32 .count = ATOMIC_INIT(1),
33 .uts_ns = &init_uts_ns,
8467005d 34#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
c2b1df2e 35 .ipc_ns = &init_ipc_ns,
8467005d 36#endif
c2b1df2e
AL
37 .mnt_ns = NULL,
38 .pid_ns_for_children = &init_pid_ns,
8467005d 39#ifdef CONFIG_NET
c2b1df2e 40 .net_ns = &init_net,
8467005d
AD
41#endif
42};
ab516013 43
90af90d7 44static inline struct nsproxy *create_nsproxy(void)
ab516013 45{
90af90d7 46 struct nsproxy *nsproxy;
ab516013 47
90af90d7
AD
48 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
49 if (nsproxy)
50 atomic_set(&nsproxy->count, 1);
51 return nsproxy;
ab516013
SH
52}
53
54/*
e3222c4e
BP
55 * Create new nsproxy and all of its the associated namespaces.
56 * Return the newly created nsproxy. Do not attach this to the task,
57 * leave it to the caller to do proper locking and attach it to task.
ab516013 58 */
213dd266 59static struct nsproxy *create_new_namespaces(unsigned long flags,
bcf58e72
EB
60 struct task_struct *tsk, struct user_namespace *user_ns,
61 struct fs_struct *new_fs)
ab516013 62{
e3222c4e 63 struct nsproxy *new_nsp;
467e9f4b 64 int err;
ab516013 65
90af90d7 66 new_nsp = create_nsproxy();
e3222c4e
BP
67 if (!new_nsp)
68 return ERR_PTR(-ENOMEM);
1651e14e 69
bcf58e72 70 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
467e9f4b
CLG
71 if (IS_ERR(new_nsp->mnt_ns)) {
72 err = PTR_ERR(new_nsp->mnt_ns);
e3222c4e 73 goto out_ns;
467e9f4b 74 }
e3222c4e 75
bcf58e72 76 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
467e9f4b
CLG
77 if (IS_ERR(new_nsp->uts_ns)) {
78 err = PTR_ERR(new_nsp->uts_ns);
e3222c4e 79 goto out_uts;
467e9f4b 80 }
e3222c4e 81
bcf58e72 82 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
467e9f4b
CLG
83 if (IS_ERR(new_nsp->ipc_ns)) {
84 err = PTR_ERR(new_nsp->ipc_ns);
e3222c4e 85 goto out_ipc;
467e9f4b 86 }
e3222c4e 87
c2b1df2e
AL
88 new_nsp->pid_ns_for_children =
89 copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
90 if (IS_ERR(new_nsp->pid_ns_for_children)) {
91 err = PTR_ERR(new_nsp->pid_ns_for_children);
e3222c4e 92 goto out_pid;
467e9f4b 93 }
e3222c4e 94
bcf58e72 95 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
9dd776b6
EB
96 if (IS_ERR(new_nsp->net_ns)) {
97 err = PTR_ERR(new_nsp->net_ns);
98 goto out_net;
99 }
100
e3222c4e
BP
101 return new_nsp;
102
9dd776b6 103out_net:
c2b1df2e
AL
104 if (new_nsp->pid_ns_for_children)
105 put_pid_ns(new_nsp->pid_ns_for_children);
e3222c4e
BP
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:
98c0d07c 116 kmem_cache_free(nsproxy_cachep, new_nsp);
467e9f4b 117 return ERR_PTR(err);
ab516013
SH
118}
119
120/*
121 * called from clone. This now handles copy for nsproxy and all
122 * namespaces therein.
123 */
213dd266 124int copy_namespaces(unsigned long flags, struct task_struct *tsk)
ab516013
SH
125{
126 struct nsproxy *old_ns = tsk->nsproxy;
b33c77ef 127 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
1651e14e 128 struct nsproxy *new_ns;
ab516013 129
dbef0c1c
EB
130 if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
131 CLONE_NEWPID | CLONE_NEWNET)))) {
132 get_nsproxy(old_ns);
ab516013 133 return 0;
1651e14e
SH
134 }
135
dbef0c1c
EB
136 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
137 return -EPERM;
138
02fdb36a
SH
139 /*
140 * CLONE_NEWIPC must detach from the undolist: after switching
141 * to a new ipc namespace, the semaphore arrays from the old
142 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
143 * means share undolist with parent, so we must forbid using
144 * it along with CLONE_NEWIPC.
145 */
21e85194 146 if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
dbef0c1c
EB
147 (CLONE_NEWIPC | CLONE_SYSVSEM))
148 return -EINVAL;
02fdb36a 149
d7d48f62 150 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
dbef0c1c
EB
151 if (IS_ERR(new_ns))
152 return PTR_ERR(new_ns);
9a575a92 153
e3222c4e 154 tsk->nsproxy = new_ns;
dbef0c1c 155 return 0;
ab516013
SH
156}
157
158void free_nsproxy(struct nsproxy *ns)
159{
9a575a92
CLG
160 if (ns->mnt_ns)
161 put_mnt_ns(ns->mnt_ns);
162 if (ns->uts_ns)
163 put_uts_ns(ns->uts_ns);
164 if (ns->ipc_ns)
165 put_ipc_ns(ns->ipc_ns);
c2b1df2e
AL
166 if (ns->pid_ns_for_children)
167 put_pid_ns(ns->pid_ns_for_children);
9dd776b6 168 put_net(ns->net_ns);
98c0d07c 169 kmem_cache_free(nsproxy_cachep, ns);
ab516013 170}
e3222c4e
BP
171
172/*
173 * Called from unshare. Unshare all the namespaces part of nsproxy.
4e71e474 174 * On success, returns the new nsproxy.
e3222c4e
BP
175 */
176int unshare_nsproxy_namespaces(unsigned long unshare_flags,
b2e0d987 177 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
e3222c4e 178{
bcf58e72 179 struct user_namespace *user_ns;
e3222c4e
BP
180 int err = 0;
181
77ec739d 182 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
50804fe3 183 CLONE_NEWNET | CLONE_NEWPID)))
e3222c4e
BP
184 return 0;
185
b2e0d987
EB
186 user_ns = new_cred ? new_cred->user_ns : current_user_ns();
187 if (!ns_capable(user_ns, CAP_SYS_ADMIN))
e3222c4e
BP
188 return -EPERM;
189
bcf58e72 190 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
b2e0d987 191 new_fs ? new_fs : current->fs);
858d72ea 192 if (IS_ERR(*new_nsp)) {
e3222c4e 193 err = PTR_ERR(*new_nsp);
858d72ea
SH
194 goto out;
195 }
196
858d72ea 197out:
e3222c4e
BP
198 return err;
199}
98c0d07c 200
cf7b708c
PE
201void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
202{
203 struct nsproxy *ns;
204
205 might_sleep();
206
728dba3a 207 task_lock(p);
cf7b708c 208 ns = p->nsproxy;
728dba3a
EB
209 p->nsproxy = new;
210 task_unlock(p);
cf7b708c 211
728dba3a 212 if (ns && atomic_dec_and_test(&ns->count))
cf7b708c 213 free_nsproxy(ns);
cf7b708c
PE
214}
215
216void exit_task_namespaces(struct task_struct *p)
217{
218 switch_task_namespaces(p, NULL);
219}
220
0663c6f8
EB
221SYSCALL_DEFINE2(setns, int, fd, int, nstype)
222{
0663c6f8
EB
223 struct task_struct *tsk = current;
224 struct nsproxy *new_nsproxy;
0663c6f8 225 struct file *file;
33c42940 226 struct ns_common *ns;
0663c6f8
EB
227 int err;
228
0663c6f8
EB
229 file = proc_ns_fget(fd);
230 if (IS_ERR(file))
231 return PTR_ERR(file);
232
233 err = -EINVAL;
f77c8014 234 ns = get_proc_ns(file_inode(file));
33c42940 235 if (nstype && (ns->ops->type != nstype))
0663c6f8
EB
236 goto out;
237
bcf58e72 238 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
0663c6f8
EB
239 if (IS_ERR(new_nsproxy)) {
240 err = PTR_ERR(new_nsproxy);
241 goto out;
242 }
243
33c42940 244 err = ns->ops->install(new_nsproxy, ns);
0663c6f8
EB
245 if (err) {
246 free_nsproxy(new_nsproxy);
247 goto out;
248 }
249 switch_task_namespaces(tsk, new_nsproxy);
250out:
251 fput(file);
252 return err;
253}
254
66577193 255int __init nsproxy_cache_init(void)
98c0d07c 256{
db8906da 257 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
98c0d07c
CLG
258 return 0;
259}