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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_fs.h> |
26 | #include <linux/file.h> |
27 | #include <linux/syscalls.h> |
28 | |
29 | static struct kmem_cache *nsproxy_cachep; |
30 | |
31 | struct nsproxy init_nsproxy = { |
32 | .count = ATOMIC_INIT(1), |
33 | .uts_ns = &init_uts_ns, |
34 | #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC) |
35 | .ipc_ns = &init_ipc_ns, |
36 | #endif |
37 | .mnt_ns = NULL, |
38 | .pid_ns = &init_pid_ns, |
39 | #ifdef CONFIG_NET |
40 | .net_ns = &init_net, |
41 | #endif |
42 | }; |
43 | |
44 | static inline struct nsproxy *create_nsproxy(void) |
45 | { |
46 | struct nsproxy *nsproxy; |
47 | |
48 | nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); |
49 | if (nsproxy) |
50 | atomic_set(&nsproxy->count, 1); |
51 | return nsproxy; |
52 | } |
53 | |
54 | /* |
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. |
58 | */ |
59 | static struct nsproxy *create_new_namespaces(unsigned long flags, |
60 | struct task_struct *tsk, struct user_namespace *user_ns, |
61 | struct fs_struct *new_fs) |
62 | { |
63 | struct nsproxy *new_nsp; |
64 | int err; |
65 | |
66 | new_nsp = create_nsproxy(); |
67 | if (!new_nsp) |
68 | return ERR_PTR(-ENOMEM); |
69 | |
70 | new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs); |
71 | if (IS_ERR(new_nsp->mnt_ns)) { |
72 | err = PTR_ERR(new_nsp->mnt_ns); |
73 | goto out_ns; |
74 | } |
75 | |
76 | new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns); |
77 | if (IS_ERR(new_nsp->uts_ns)) { |
78 | err = PTR_ERR(new_nsp->uts_ns); |
79 | goto out_uts; |
80 | } |
81 | |
82 | new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns); |
83 | if (IS_ERR(new_nsp->ipc_ns)) { |
84 | err = PTR_ERR(new_nsp->ipc_ns); |
85 | goto out_ipc; |
86 | } |
87 | |
88 | new_nsp->pid_ns = copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns); |
89 | if (IS_ERR(new_nsp->pid_ns)) { |
90 | err = PTR_ERR(new_nsp->pid_ns); |
91 | goto out_pid; |
92 | } |
93 | |
94 | new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns); |
95 | if (IS_ERR(new_nsp->net_ns)) { |
96 | err = PTR_ERR(new_nsp->net_ns); |
97 | goto out_net; |
98 | } |
99 | |
100 | return new_nsp; |
101 | |
102 | out_net: |
103 | if (new_nsp->pid_ns) |
104 | put_pid_ns(new_nsp->pid_ns); |
105 | out_pid: |
106 | if (new_nsp->ipc_ns) |
107 | put_ipc_ns(new_nsp->ipc_ns); |
108 | out_ipc: |
109 | if (new_nsp->uts_ns) |
110 | put_uts_ns(new_nsp->uts_ns); |
111 | out_uts: |
112 | if (new_nsp->mnt_ns) |
113 | put_mnt_ns(new_nsp->mnt_ns); |
114 | out_ns: |
115 | kmem_cache_free(nsproxy_cachep, new_nsp); |
116 | return ERR_PTR(err); |
117 | } |
118 | |
119 | /* |
120 | * called from clone. This now handles copy for nsproxy and all |
121 | * namespaces therein. |
122 | */ |
123 | int copy_namespaces(unsigned long flags, struct task_struct *tsk) |
124 | { |
125 | struct nsproxy *old_ns = tsk->nsproxy; |
126 | struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); |
127 | struct nsproxy *new_ns; |
128 | int err = 0; |
129 | |
130 | if (!old_ns) |
131 | return 0; |
132 | |
133 | get_nsproxy(old_ns); |
134 | |
135 | if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | |
136 | CLONE_NEWPID | CLONE_NEWNET))) |
137 | return 0; |
138 | |
139 | if (!ns_capable(user_ns, CAP_SYS_ADMIN)) { |
140 | err = -EPERM; |
141 | goto out; |
142 | } |
143 | |
144 | /* |
145 | * CLONE_NEWIPC must detach from the undolist: after switching |
146 | * to a new ipc namespace, the semaphore arrays from the old |
147 | * namespace are unreachable. In clone parlance, CLONE_SYSVSEM |
148 | * means share undolist with parent, so we must forbid using |
149 | * it along with CLONE_NEWIPC. |
150 | */ |
151 | if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) { |
152 | err = -EINVAL; |
153 | goto out; |
154 | } |
155 | |
156 | new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs); |
157 | if (IS_ERR(new_ns)) { |
158 | err = PTR_ERR(new_ns); |
159 | goto out; |
160 | } |
161 | |
162 | tsk->nsproxy = new_ns; |
163 | |
164 | out: |
165 | put_nsproxy(old_ns); |
166 | return err; |
167 | } |
168 | |
169 | void free_nsproxy(struct nsproxy *ns) |
170 | { |
171 | if (ns->mnt_ns) |
172 | put_mnt_ns(ns->mnt_ns); |
173 | if (ns->uts_ns) |
174 | put_uts_ns(ns->uts_ns); |
175 | if (ns->ipc_ns) |
176 | put_ipc_ns(ns->ipc_ns); |
177 | if (ns->pid_ns) |
178 | put_pid_ns(ns->pid_ns); |
179 | put_net(ns->net_ns); |
180 | kmem_cache_free(nsproxy_cachep, ns); |
181 | } |
182 | |
183 | /* |
184 | * Called from unshare. Unshare all the namespaces part of nsproxy. |
185 | * On success, returns the new nsproxy. |
186 | */ |
187 | int unshare_nsproxy_namespaces(unsigned long unshare_flags, |
188 | struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs) |
189 | { |
190 | struct user_namespace *user_ns; |
191 | int err = 0; |
192 | |
193 | if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | |
194 | CLONE_NEWNET | CLONE_NEWPID))) |
195 | return 0; |
196 | |
197 | user_ns = new_cred ? new_cred->user_ns : current_user_ns(); |
198 | if (!ns_capable(user_ns, CAP_SYS_ADMIN)) |
199 | return -EPERM; |
200 | |
201 | *new_nsp = create_new_namespaces(unshare_flags, current, user_ns, |
202 | new_fs ? new_fs : current->fs); |
203 | if (IS_ERR(*new_nsp)) { |
204 | err = PTR_ERR(*new_nsp); |
205 | goto out; |
206 | } |
207 | |
208 | out: |
209 | return err; |
210 | } |
211 | |
212 | void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) |
213 | { |
214 | struct nsproxy *ns; |
215 | |
216 | might_sleep(); |
217 | |
218 | ns = p->nsproxy; |
219 | |
220 | rcu_assign_pointer(p->nsproxy, new); |
221 | |
222 | if (ns && atomic_dec_and_test(&ns->count)) { |
223 | /* |
224 | * wait for others to get what they want from this nsproxy. |
225 | * |
226 | * cannot release this nsproxy via the call_rcu() since |
227 | * put_mnt_ns() will want to sleep |
228 | */ |
229 | synchronize_rcu(); |
230 | free_nsproxy(ns); |
231 | } |
232 | } |
233 | |
234 | void exit_task_namespaces(struct task_struct *p) |
235 | { |
236 | switch_task_namespaces(p, NULL); |
237 | } |
238 | |
239 | SYSCALL_DEFINE2(setns, int, fd, int, nstype) |
240 | { |
241 | const struct proc_ns_operations *ops; |
242 | struct task_struct *tsk = current; |
243 | struct nsproxy *new_nsproxy; |
244 | struct proc_inode *ei; |
245 | struct file *file; |
246 | int err; |
247 | |
248 | file = proc_ns_fget(fd); |
249 | if (IS_ERR(file)) |
250 | return PTR_ERR(file); |
251 | |
252 | err = -EINVAL; |
253 | ei = PROC_I(file_inode(file)); |
254 | ops = ei->ns_ops; |
255 | if (nstype && (ops->type != nstype)) |
256 | goto out; |
257 | |
258 | new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); |
259 | if (IS_ERR(new_nsproxy)) { |
260 | err = PTR_ERR(new_nsproxy); |
261 | goto out; |
262 | } |
263 | |
264 | err = ops->install(new_nsproxy, ei->ns); |
265 | if (err) { |
266 | free_nsproxy(new_nsproxy); |
267 | goto out; |
268 | } |
269 | switch_task_namespaces(tsk, new_nsproxy); |
270 | out: |
271 | fput(file); |
272 | return err; |
273 | } |
274 | |
275 | int __init nsproxy_cache_init(void) |
276 | { |
277 | nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); |
278 | return 0; |
279 | } |
280 |
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