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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 | #include <linux/perf_event.h> | |
30 | ||
31 | static struct kmem_cache *nsproxy_cachep; | |
32 | ||
33 | struct 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 | ||
49 | static 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 | */ | |
64 | static 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 | ||
115 | out_net: | |
116 | put_cgroup_ns(new_nsp->cgroup_ns); | |
117 | out_cgroup: | |
118 | if (new_nsp->pid_ns_for_children) | |
119 | put_pid_ns(new_nsp->pid_ns_for_children); | |
120 | out_pid: | |
121 | if (new_nsp->ipc_ns) | |
122 | put_ipc_ns(new_nsp->ipc_ns); | |
123 | out_ipc: | |
124 | if (new_nsp->uts_ns) | |
125 | put_uts_ns(new_nsp->uts_ns); | |
126 | out_uts: | |
127 | if (new_nsp->mnt_ns) | |
128 | put_mnt_ns(new_nsp->mnt_ns); | |
129 | out_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 | */ | |
138 | int 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 | ||
173 | void 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 | */ | |
192 | int 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 | ||
213 | out: | |
214 | return err; | |
215 | } | |
216 | ||
217 | void 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 | ||
232 | void exit_task_namespaces(struct task_struct *p) | |
233 | { | |
234 | switch_task_namespaces(p, NULL); | |
235 | } | |
236 | ||
237 | SYSCALL_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); | |
268 | out: | |
269 | fput(file); | |
270 | return err; | |
271 | } | |
272 | ||
273 | int __init nsproxy_cache_init(void) | |
274 | { | |
275 | nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); | |
276 | return 0; | |
277 | } |