blob: 782102e59eed5b4b5379126b865fb9c795892cdd
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 | } |
275 |