xref: /openbmc/linux/kernel/nsproxy.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 
24 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
25 
26 static inline void get_nsproxy(struct nsproxy *ns)
27 {
28 	atomic_inc(&ns->count);
29 }
30 
31 void get_task_namespaces(struct task_struct *tsk)
32 {
33 	struct nsproxy *ns = tsk->nsproxy;
34 	if (ns) {
35 		get_nsproxy(ns);
36 	}
37 }
38 
39 /*
40  * creates a copy of "orig" with refcount 1.
41  */
42 static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
43 {
44 	struct nsproxy *ns;
45 
46 	ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL);
47 	if (ns)
48 		atomic_set(&ns->count, 1);
49 	return ns;
50 }
51 
52 /*
53  * Create new nsproxy and all of its the associated namespaces.
54  * Return the newly created nsproxy.  Do not attach this to the task,
55  * leave it to the caller to do proper locking and attach it to task.
56  */
57 static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk,
58 			struct fs_struct *new_fs)
59 {
60 	struct nsproxy *new_nsp;
61 
62 	new_nsp = clone_nsproxy(tsk->nsproxy);
63 	if (!new_nsp)
64 		return ERR_PTR(-ENOMEM);
65 
66 	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
67 	if (IS_ERR(new_nsp->mnt_ns))
68 		goto out_ns;
69 
70 	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
71 	if (IS_ERR(new_nsp->uts_ns))
72 		goto out_uts;
73 
74 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
75 	if (IS_ERR(new_nsp->ipc_ns))
76 		goto out_ipc;
77 
78 	new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
79 	if (IS_ERR(new_nsp->pid_ns))
80 		goto out_pid;
81 
82 	return new_nsp;
83 
84 out_pid:
85 	if (new_nsp->ipc_ns)
86 		put_ipc_ns(new_nsp->ipc_ns);
87 out_ipc:
88 	if (new_nsp->uts_ns)
89 		put_uts_ns(new_nsp->uts_ns);
90 out_uts:
91 	if (new_nsp->mnt_ns)
92 		put_mnt_ns(new_nsp->mnt_ns);
93 out_ns:
94 	kfree(new_nsp);
95 	return ERR_PTR(-ENOMEM);
96 }
97 
98 /*
99  * called from clone.  This now handles copy for nsproxy and all
100  * namespaces therein.
101  */
102 int copy_namespaces(int flags, struct task_struct *tsk)
103 {
104 	struct nsproxy *old_ns = tsk->nsproxy;
105 	struct nsproxy *new_ns;
106 	int err = 0;
107 
108 	if (!old_ns)
109 		return 0;
110 
111 	get_nsproxy(old_ns);
112 
113 	if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
114 		return 0;
115 
116 	if (!capable(CAP_SYS_ADMIN)) {
117 		err = -EPERM;
118 		goto out;
119 	}
120 
121 	new_ns = create_new_namespaces(flags, tsk, tsk->fs);
122 	if (IS_ERR(new_ns)) {
123 		err = PTR_ERR(new_ns);
124 		goto out;
125 	}
126 
127 	tsk->nsproxy = new_ns;
128 out:
129 	put_nsproxy(old_ns);
130 	return err;
131 }
132 
133 void free_nsproxy(struct nsproxy *ns)
134 {
135 	if (ns->mnt_ns)
136 		put_mnt_ns(ns->mnt_ns);
137 	if (ns->uts_ns)
138 		put_uts_ns(ns->uts_ns);
139 	if (ns->ipc_ns)
140 		put_ipc_ns(ns->ipc_ns);
141 	if (ns->pid_ns)
142 		put_pid_ns(ns->pid_ns);
143 	kfree(ns);
144 }
145 
146 /*
147  * Called from unshare. Unshare all the namespaces part of nsproxy.
148  * On sucess, returns the new nsproxy and a reference to old nsproxy
149  * to make sure it stays around.
150  */
151 int unshare_nsproxy_namespaces(unsigned long unshare_flags,
152 		struct nsproxy **new_nsp, struct fs_struct *new_fs)
153 {
154 	struct nsproxy *old_ns = current->nsproxy;
155 	int err = 0;
156 
157 	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
158 		return 0;
159 
160 #ifndef CONFIG_IPC_NS
161 	if (unshare_flags & CLONE_NEWIPC)
162 		return -EINVAL;
163 #endif
164 
165 #ifndef CONFIG_UTS_NS
166 	if (unshare_flags & CLONE_NEWUTS)
167 		return -EINVAL;
168 #endif
169 
170 	if (!capable(CAP_SYS_ADMIN))
171 		return -EPERM;
172 
173 	get_nsproxy(old_ns);
174 
175 	*new_nsp = create_new_namespaces(unshare_flags, current,
176 				new_fs ? new_fs : current->fs);
177 	if (IS_ERR(*new_nsp)) {
178 		err = PTR_ERR(*new_nsp);
179 		put_nsproxy(old_ns);
180 	}
181 	return err;
182 }
183