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/module.h>
17#include <linux/version.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 <linux/user_namespace.h>
24
25static struct kmem_cache *nsproxy_cachep;
26
27struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
28
29static inline void get_nsproxy(struct nsproxy *ns)
30{
31	atomic_inc(&ns->count);
32}
33
34void get_task_namespaces(struct task_struct *tsk)
35{
36	struct nsproxy *ns = tsk->nsproxy;
37	if (ns) {
38		get_nsproxy(ns);
39	}
40}
41
42/*
43 * creates a copy of "orig" with refcount 1.
44 */
45static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
46{
47	struct nsproxy *ns;
48
49	ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
50	if (ns) {
51		memcpy(ns, orig, sizeof(struct nsproxy));
52		atomic_set(&ns->count, 1);
53	}
54	return ns;
55}
56
57/*
58 * Create new nsproxy and all of its the associated namespaces.
59 * Return the newly created nsproxy.  Do not attach this to the task,
60 * leave it to the caller to do proper locking and attach it to task.
61 */
62static struct nsproxy *create_new_namespaces(unsigned long flags,
63			struct task_struct *tsk, struct fs_struct *new_fs)
64{
65	struct nsproxy *new_nsp;
66	int err;
67
68	new_nsp = clone_nsproxy(tsk->nsproxy);
69	if (!new_nsp)
70		return ERR_PTR(-ENOMEM);
71
72	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
73	if (IS_ERR(new_nsp->mnt_ns)) {
74		err = PTR_ERR(new_nsp->mnt_ns);
75		goto out_ns;
76	}
77
78	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
79	if (IS_ERR(new_nsp->uts_ns)) {
80		err = PTR_ERR(new_nsp->uts_ns);
81		goto out_uts;
82	}
83
84	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
85	if (IS_ERR(new_nsp->ipc_ns)) {
86		err = PTR_ERR(new_nsp->ipc_ns);
87		goto out_ipc;
88	}
89
90	new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
91	if (IS_ERR(new_nsp->pid_ns)) {
92		err = PTR_ERR(new_nsp->pid_ns);
93		goto out_pid;
94	}
95
96	new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
97	if (IS_ERR(new_nsp->user_ns)) {
98		err = PTR_ERR(new_nsp->user_ns);
99		goto out_user;
100	}
101
102	return new_nsp;
103
104out_user:
105	if (new_nsp->pid_ns)
106		put_pid_ns(new_nsp->pid_ns);
107out_pid:
108	if (new_nsp->ipc_ns)
109		put_ipc_ns(new_nsp->ipc_ns);
110out_ipc:
111	if (new_nsp->uts_ns)
112		put_uts_ns(new_nsp->uts_ns);
113out_uts:
114	if (new_nsp->mnt_ns)
115		put_mnt_ns(new_nsp->mnt_ns);
116out_ns:
117	kmem_cache_free(nsproxy_cachep, new_nsp);
118	return ERR_PTR(err);
119}
120
121/*
122 * called from clone.  This now handles copy for nsproxy and all
123 * namespaces therein.
124 */
125int copy_namespaces(unsigned long flags, struct task_struct *tsk)
126{
127	struct nsproxy *old_ns = tsk->nsproxy;
128	struct nsproxy *new_ns;
129	int err = 0;
130
131	if (!old_ns)
132		return 0;
133
134	get_nsproxy(old_ns);
135
136	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER)))
137		return 0;
138
139	if (!capable(CAP_SYS_ADMIN)) {
140		err = -EPERM;
141		goto out;
142	}
143
144	new_ns = create_new_namespaces(flags, tsk, tsk->fs);
145	if (IS_ERR(new_ns)) {
146		err = PTR_ERR(new_ns);
147		goto out;
148	}
149
150	tsk->nsproxy = new_ns;
151out:
152	put_nsproxy(old_ns);
153	return err;
154}
155
156void free_nsproxy(struct nsproxy *ns)
157{
158	if (ns->mnt_ns)
159		put_mnt_ns(ns->mnt_ns);
160	if (ns->uts_ns)
161		put_uts_ns(ns->uts_ns);
162	if (ns->ipc_ns)
163		put_ipc_ns(ns->ipc_ns);
164	if (ns->pid_ns)
165		put_pid_ns(ns->pid_ns);
166	if (ns->user_ns)
167		put_user_ns(ns->user_ns);
168	kmem_cache_free(nsproxy_cachep, ns);
169}
170
171/*
172 * Called from unshare. Unshare all the namespaces part of nsproxy.
173 * On success, returns the new nsproxy.
174 */
175int unshare_nsproxy_namespaces(unsigned long unshare_flags,
176		struct nsproxy **new_nsp, struct fs_struct *new_fs)
177{
178	int err = 0;
179
180	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
181			       CLONE_NEWUSER)))
182		return 0;
183
184	if (!capable(CAP_SYS_ADMIN))
185		return -EPERM;
186
187	*new_nsp = create_new_namespaces(unshare_flags, current,
188				new_fs ? new_fs : current->fs);
189	if (IS_ERR(*new_nsp))
190		err = PTR_ERR(*new_nsp);
191	return err;
192}
193
194static int __init nsproxy_cache_init(void)
195{
196	nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
197					   0, SLAB_PANIC, NULL, NULL);
198	return 0;
199}
200
201module_init(nsproxy_cache_init);
202