Commit | Line | Data |
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4865ecf1 SH |
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 | ||
9984de1a | 12 | #include <linux/export.h> |
4865ecf1 SH |
13 | #include <linux/uts.h> |
14 | #include <linux/utsname.h> | |
467e9f4b | 15 | #include <linux/err.h> |
1aeb272c | 16 | #include <linux/slab.h> |
59607db3 | 17 | #include <linux/user_namespace.h> |
34482e89 | 18 | #include <linux/proc_fs.h> |
4865ecf1 | 19 | |
4c2a7e72 AD |
20 | static 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 | ||
071df104 SH |
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 | */ | |
bcf58e72 | 35 | static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, |
bb96a6f5 | 36 | struct uts_namespace *old_ns) |
071df104 SH |
37 | { |
38 | struct uts_namespace *ns; | |
39 | ||
4c2a7e72 | 40 | ns = create_uts_ns(); |
467e9f4b CLG |
41 | if (!ns) |
42 | return ERR_PTR(-ENOMEM); | |
43 | ||
efc63c4f | 44 | down_read(&uts_sem); |
467e9f4b | 45 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
bcf58e72 | 46 | ns->user_ns = get_user_ns(user_ns); |
efc63c4f | 47 | up_read(&uts_sem); |
071df104 SH |
48 | return ns; |
49 | } | |
50 | ||
4865ecf1 SH |
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 | */ | |
bb96a6f5 | 57 | struct uts_namespace *copy_utsname(unsigned long flags, |
bcf58e72 | 58 | struct user_namespace *user_ns, struct uts_namespace *old_ns) |
4865ecf1 | 59 | { |
071df104 | 60 | struct uts_namespace *new_ns; |
4865ecf1 | 61 | |
e3222c4e | 62 | BUG_ON(!old_ns); |
4865ecf1 SH |
63 | get_uts_ns(old_ns); |
64 | ||
071df104 | 65 | if (!(flags & CLONE_NEWUTS)) |
e3222c4e | 66 | return old_ns; |
071df104 | 67 | |
bcf58e72 | 68 | new_ns = clone_uts_ns(user_ns, old_ns); |
071df104 | 69 | |
071df104 | 70 | put_uts_ns(old_ns); |
e3222c4e | 71 | return new_ns; |
4865ecf1 SH |
72 | } |
73 | ||
74 | void free_uts_ns(struct kref *kref) | |
75 | { | |
76 | struct uts_namespace *ns; | |
77 | ||
78 | ns = container_of(kref, struct uts_namespace, kref); | |
59607db3 | 79 | put_user_ns(ns->user_ns); |
4865ecf1 SH |
80 | kfree(ns); |
81 | } | |
34482e89 EB |
82 | |
83 | static void *utsns_get(struct task_struct *task) | |
84 | { | |
85 | struct uts_namespace *ns = NULL; | |
86 | struct nsproxy *nsproxy; | |
87 | ||
88 | rcu_read_lock(); | |
89 | nsproxy = task_nsproxy(task); | |
90 | if (nsproxy) { | |
91 | ns = nsproxy->uts_ns; | |
92 | get_uts_ns(ns); | |
93 | } | |
94 | rcu_read_unlock(); | |
95 | ||
96 | return ns; | |
97 | } | |
98 | ||
99 | static void utsns_put(void *ns) | |
100 | { | |
101 | put_uts_ns(ns); | |
102 | } | |
103 | ||
142e1d1d | 104 | static int utsns_install(struct nsproxy *nsproxy, void *new) |
34482e89 | 105 | { |
142e1d1d EB |
106 | struct uts_namespace *ns = new; |
107 | ||
108 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) | |
109 | return -EPERM; | |
110 | ||
34482e89 EB |
111 | get_uts_ns(ns); |
112 | put_uts_ns(nsproxy->uts_ns); | |
113 | nsproxy->uts_ns = ns; | |
114 | return 0; | |
115 | } | |
116 | ||
117 | const struct proc_ns_operations utsns_operations = { | |
118 | .name = "uts", | |
119 | .type = CLONE_NEWUTS, | |
120 | .get = utsns_get, | |
121 | .put = utsns_put, | |
122 | .install = utsns_install, | |
123 | }; | |
124 |