1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004 IBM Corporation
*
* Author: Serge Hallyn <serue@us.ibm.com>
*/
#include <linux/export.h>
#include <linux/uts.h>
#include <linux/utsname.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>
static struct kmem_cache *uts_ns_cache __ro_after_init;
static struct ucounts *inc_uts_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);
}
static void dec_uts_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES);
}
static struct uts_namespace *create_uts_ns(void)
{
struct uts_namespace *uts_ns;
uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
if (uts_ns)
kref_init(&uts_ns->kref);
return uts_ns;
}
/*
* Clone a new ns copying an original utsname, setting refcount to 1
* @old_ns: namespace to clone
* Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise
*/
static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
struct uts_namespace *old_ns)
{
struct uts_namespace *ns;
struct ucounts *ucounts;
int err;
err = -ENOSPC;
ucounts = inc_uts_namespaces(user_ns);
if (!ucounts)
goto fail;
err = -ENOMEM;
ns = create_uts_ns();
if (!ns)
goto fail_dec;
err = ns_alloc_inum(&ns->ns);
if (err)
goto fail_free;
ns->ucounts = ucounts;
ns->ns.ops = &utsns_operations;
down_read(&uts_sem);
memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
ns->user_ns = get_user_ns(user_ns);
up_read(&uts_sem);
return ns;
fail_free:
kmem_cache_free(uts_ns_cache, ns);
fail_dec:
dec_uts_namespaces(ucounts);
fail:
return ERR_PTR(err);
}
/*
* Copy task tsk's utsname namespace, or clone it if flags
* specifies CLONE_NEWUTS. In latter case, changes to the
* utsname of this process won't be seen by parent, and vice
* versa.
*/
struct uts_namespace *copy_utsname(unsigned long flags,
struct user_namespace *user_ns, struct uts_namespace *old_ns)
{
struct uts_namespace *new_ns;
BUG_ON(!old_ns);
get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS))
return old_ns;
new_ns = clone_uts_ns(user_ns, old_ns);
put_uts_ns(old_ns);
return new_ns;
}
void free_uts_ns(struct kref *kref)
{
struct uts_namespace *ns;
ns = container_of(kref, struct uts_namespace, kref);
dec_uts_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
kmem_cache_free(uts_ns_cache, ns);
}
static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
{
return container_of(ns, struct uts_namespace, ns);
}
static struct ns_common *utsns_get(struct task_struct *task)
{
struct uts_namespace *ns = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy) {
ns = nsproxy->uts_ns;
get_uts_ns(ns);
}
task_unlock(task);
return ns ? &ns->ns : NULL;
}
static void utsns_put(struct ns_common *ns)
{
put_uts_ns(to_uts_ns(ns));
}
static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new)
{
struct uts_namespace *ns = to_uts_ns(new);
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;
get_uts_ns(ns);
put_uts_ns(nsproxy->uts_ns);
nsproxy->uts_ns = ns;
return 0;
}
static struct user_namespace *utsns_owner(struct ns_common *ns)
{
return to_uts_ns(ns)->user_ns;
}
const struct proc_ns_operations utsns_operations = {
.name = "uts",
.type = CLONE_NEWUTS,
.get = utsns_get,
.put = utsns_put,
.install = utsns_install,
.owner = utsns_owner,
};
void __init uts_ns_init(void)
{
uts_ns_cache = kmem_cache_create_usercopy(
"uts_namespace", sizeof(struct uts_namespace), 0,
SLAB_PANIC|SLAB_ACCOUNT,
offsetof(struct uts_namespace, name),
sizeof_field(struct uts_namespace, name),
NULL);
}
|
