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1/*
2 * Copyright (C) 2004 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
12#include <linux/export.h>
13#include <linux/uts.h>
14#include <linux/utsname.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/user_namespace.h>
18#include <linux/proc_ns.h>
19
20static struct uts_namespace *create_uts_ns(void)
21{
22 struct uts_namespace *uts_ns;
23
24 uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
25 if (uts_ns)
26 kref_init(&uts_ns->kref);
27 return uts_ns;
28}
29
30/*
31 * Clone a new ns copying an original utsname, setting refcount to 1
32 * @old_ns: namespace to clone
33 * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise
34 */
35static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
36 struct uts_namespace *old_ns)
37{
38 struct uts_namespace *ns;
39 int err;
40
41 ns = create_uts_ns();
42 if (!ns)
43 return ERR_PTR(-ENOMEM);
44
45 err = proc_alloc_inum(&ns->proc_inum);
46 if (err) {
47 kfree(ns);
48 return ERR_PTR(err);
49 }
50
51 down_read(&uts_sem);
52 memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
53 ns->user_ns = get_user_ns(user_ns);
54 up_read(&uts_sem);
55 return ns;
56}
57
58/*
59 * Copy task tsk's utsname namespace, or clone it if flags
60 * specifies CLONE_NEWUTS. In latter case, changes to the
61 * utsname of this process won't be seen by parent, and vice
62 * versa.
63 */
64struct uts_namespace *copy_utsname(unsigned long flags,
65 struct user_namespace *user_ns, struct uts_namespace *old_ns)
66{
67 struct uts_namespace *new_ns;
68
69 BUG_ON(!old_ns);
70 get_uts_ns(old_ns);
71
72 if (!(flags & CLONE_NEWUTS))
73 return old_ns;
74
75 new_ns = clone_uts_ns(user_ns, old_ns);
76
77 put_uts_ns(old_ns);
78 return new_ns;
79}
80
81void free_uts_ns(struct kref *kref)
82{
83 struct uts_namespace *ns;
84
85 ns = container_of(kref, struct uts_namespace, kref);
86 put_user_ns(ns->user_ns);
87 proc_free_inum(ns->proc_inum);
88 kfree(ns);
89}
90
91static void *utsns_get(struct task_struct *task)
92{
93 struct uts_namespace *ns = NULL;
94 struct nsproxy *nsproxy;
95
96 rcu_read_lock();
97 nsproxy = task_nsproxy(task);
98 if (nsproxy) {
99 ns = nsproxy->uts_ns;
100 get_uts_ns(ns);
101 }
102 rcu_read_unlock();
103
104 return ns;
105}
106
107static void utsns_put(void *ns)
108{
109 put_uts_ns(ns);
110}
111
112static int utsns_install(struct nsproxy *nsproxy, void *new)
113{
114 struct uts_namespace *ns = new;
115
116 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
117 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
118 return -EPERM;
119
120 get_uts_ns(ns);
121 put_uts_ns(nsproxy->uts_ns);
122 nsproxy->uts_ns = ns;
123 return 0;
124}
125
126static unsigned int utsns_inum(void *vp)
127{
128 struct uts_namespace *ns = vp;
129
130 return ns->proc_inum;
131}
132
133const struct proc_ns_operations utsns_operations = {
134 .name = "uts",
135 .type = CLONE_NEWUTS,
136 .get = utsns_get,
137 .put = utsns_put,
138 .install = utsns_install,
139 .inum = utsns_inum,
140};
1/*
2 * Copyright (C) 2004 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
12#include <linux/module.h>
13#include <linux/uts.h>
14#include <linux/utsname.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/user_namespace.h>
18#include <linux/proc_fs.h>
19
20static struct uts_namespace *create_uts_ns(void)
21{
22 struct uts_namespace *uts_ns;
23
24 uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
25 if (uts_ns)
26 kref_init(&uts_ns->kref);
27 return uts_ns;
28}
29
30/*
31 * Clone a new ns copying an original utsname, setting refcount to 1
32 * @old_ns: namespace to clone
33 * Return NULL on error (failure to kmalloc), new ns otherwise
34 */
35static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
36 struct uts_namespace *old_ns)
37{
38 struct uts_namespace *ns;
39
40 ns = create_uts_ns();
41 if (!ns)
42 return ERR_PTR(-ENOMEM);
43
44 down_read(&uts_sem);
45 memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
46 ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
47 up_read(&uts_sem);
48 return ns;
49}
50
51/*
52 * Copy task tsk's utsname namespace, or clone it if flags
53 * specifies CLONE_NEWUTS. In latter case, changes to the
54 * utsname of this process won't be seen by parent, and vice
55 * versa.
56 */
57struct uts_namespace *copy_utsname(unsigned long flags,
58 struct task_struct *tsk)
59{
60 struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
61 struct uts_namespace *new_ns;
62
63 BUG_ON(!old_ns);
64 get_uts_ns(old_ns);
65
66 if (!(flags & CLONE_NEWUTS))
67 return old_ns;
68
69 new_ns = clone_uts_ns(tsk, old_ns);
70
71 put_uts_ns(old_ns);
72 return new_ns;
73}
74
75void free_uts_ns(struct kref *kref)
76{
77 struct uts_namespace *ns;
78
79 ns = container_of(kref, struct uts_namespace, kref);
80 put_user_ns(ns->user_ns);
81 kfree(ns);
82}
83
84static void *utsns_get(struct task_struct *task)
85{
86 struct uts_namespace *ns = NULL;
87 struct nsproxy *nsproxy;
88
89 rcu_read_lock();
90 nsproxy = task_nsproxy(task);
91 if (nsproxy) {
92 ns = nsproxy->uts_ns;
93 get_uts_ns(ns);
94 }
95 rcu_read_unlock();
96
97 return ns;
98}
99
100static void utsns_put(void *ns)
101{
102 put_uts_ns(ns);
103}
104
105static int utsns_install(struct nsproxy *nsproxy, void *ns)
106{
107 get_uts_ns(ns);
108 put_uts_ns(nsproxy->uts_ns);
109 nsproxy->uts_ns = ns;
110 return 0;
111}
112
113const struct proc_ns_operations utsns_operations = {
114 .name = "uts",
115 .type = CLONE_NEWUTS,
116 .get = utsns_get,
117 .put = utsns_put,
118 .install = utsns_install,
119};
120