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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> |
5b825c3a | 17 | #include <linux/cred.h> |
59607db3 | 18 | #include <linux/user_namespace.h> |
0bb80f24 | 19 | #include <linux/proc_ns.h> |
4865ecf1 | 20 | |
f7af3d1c EB |
21 | static struct ucounts *inc_uts_namespaces(struct user_namespace *ns) |
22 | { | |
23 | return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES); | |
24 | } | |
25 | ||
26 | static void dec_uts_namespaces(struct ucounts *ucounts) | |
27 | { | |
28 | dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES); | |
29 | } | |
30 | ||
4c2a7e72 AD |
31 | static struct uts_namespace *create_uts_ns(void) |
32 | { | |
33 | struct uts_namespace *uts_ns; | |
34 | ||
35 | uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); | |
36 | if (uts_ns) | |
37 | kref_init(&uts_ns->kref); | |
38 | return uts_ns; | |
39 | } | |
40 | ||
071df104 SH |
41 | /* |
42 | * Clone a new ns copying an original utsname, setting refcount to 1 | |
43 | * @old_ns: namespace to clone | |
bf531536 | 44 | * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise |
071df104 | 45 | */ |
bcf58e72 | 46 | static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, |
bb96a6f5 | 47 | struct uts_namespace *old_ns) |
071df104 SH |
48 | { |
49 | struct uts_namespace *ns; | |
f7af3d1c | 50 | struct ucounts *ucounts; |
98f842e6 | 51 | int err; |
071df104 | 52 | |
df75e774 | 53 | err = -ENOSPC; |
f7af3d1c EB |
54 | ucounts = inc_uts_namespaces(user_ns); |
55 | if (!ucounts) | |
56 | goto fail; | |
57 | ||
58 | err = -ENOMEM; | |
4c2a7e72 | 59 | ns = create_uts_ns(); |
467e9f4b | 60 | if (!ns) |
f7af3d1c | 61 | goto fail_dec; |
467e9f4b | 62 | |
6344c433 | 63 | err = ns_alloc_inum(&ns->ns); |
f7af3d1c EB |
64 | if (err) |
65 | goto fail_free; | |
98f842e6 | 66 | |
f7af3d1c | 67 | ns->ucounts = ucounts; |
33c42940 AV |
68 | ns->ns.ops = &utsns_operations; |
69 | ||
efc63c4f | 70 | down_read(&uts_sem); |
467e9f4b | 71 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
bcf58e72 | 72 | ns->user_ns = get_user_ns(user_ns); |
efc63c4f | 73 | up_read(&uts_sem); |
071df104 | 74 | return ns; |
f7af3d1c EB |
75 | |
76 | fail_free: | |
77 | kfree(ns); | |
78 | fail_dec: | |
79 | dec_uts_namespaces(ucounts); | |
80 | fail: | |
81 | return ERR_PTR(err); | |
071df104 SH |
82 | } |
83 | ||
4865ecf1 SH |
84 | /* |
85 | * Copy task tsk's utsname namespace, or clone it if flags | |
86 | * specifies CLONE_NEWUTS. In latter case, changes to the | |
87 | * utsname of this process won't be seen by parent, and vice | |
88 | * versa. | |
89 | */ | |
bb96a6f5 | 90 | struct uts_namespace *copy_utsname(unsigned long flags, |
bcf58e72 | 91 | struct user_namespace *user_ns, struct uts_namespace *old_ns) |
4865ecf1 | 92 | { |
071df104 | 93 | struct uts_namespace *new_ns; |
4865ecf1 | 94 | |
e3222c4e | 95 | BUG_ON(!old_ns); |
4865ecf1 SH |
96 | get_uts_ns(old_ns); |
97 | ||
071df104 | 98 | if (!(flags & CLONE_NEWUTS)) |
e3222c4e | 99 | return old_ns; |
071df104 | 100 | |
bcf58e72 | 101 | new_ns = clone_uts_ns(user_ns, old_ns); |
071df104 | 102 | |
071df104 | 103 | put_uts_ns(old_ns); |
e3222c4e | 104 | return new_ns; |
4865ecf1 SH |
105 | } |
106 | ||
107 | void free_uts_ns(struct kref *kref) | |
108 | { | |
109 | struct uts_namespace *ns; | |
110 | ||
111 | ns = container_of(kref, struct uts_namespace, kref); | |
f7af3d1c | 112 | dec_uts_namespaces(ns->ucounts); |
59607db3 | 113 | put_user_ns(ns->user_ns); |
6344c433 | 114 | ns_free_inum(&ns->ns); |
4865ecf1 SH |
115 | kfree(ns); |
116 | } | |
34482e89 | 117 | |
3c041184 AV |
118 | static inline struct uts_namespace *to_uts_ns(struct ns_common *ns) |
119 | { | |
120 | return container_of(ns, struct uts_namespace, ns); | |
121 | } | |
122 | ||
64964528 | 123 | static struct ns_common *utsns_get(struct task_struct *task) |
34482e89 EB |
124 | { |
125 | struct uts_namespace *ns = NULL; | |
126 | struct nsproxy *nsproxy; | |
127 | ||
728dba3a EB |
128 | task_lock(task); |
129 | nsproxy = task->nsproxy; | |
34482e89 EB |
130 | if (nsproxy) { |
131 | ns = nsproxy->uts_ns; | |
132 | get_uts_ns(ns); | |
133 | } | |
728dba3a | 134 | task_unlock(task); |
34482e89 | 135 | |
3c041184 | 136 | return ns ? &ns->ns : NULL; |
34482e89 EB |
137 | } |
138 | ||
64964528 | 139 | static void utsns_put(struct ns_common *ns) |
34482e89 | 140 | { |
3c041184 | 141 | put_uts_ns(to_uts_ns(ns)); |
34482e89 EB |
142 | } |
143 | ||
64964528 | 144 | static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new) |
34482e89 | 145 | { |
3c041184 | 146 | struct uts_namespace *ns = to_uts_ns(new); |
142e1d1d | 147 | |
5e4a0847 | 148 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
c7b96acf | 149 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
142e1d1d EB |
150 | return -EPERM; |
151 | ||
34482e89 EB |
152 | get_uts_ns(ns); |
153 | put_uts_ns(nsproxy->uts_ns); | |
154 | nsproxy->uts_ns = ns; | |
155 | return 0; | |
156 | } | |
157 | ||
bcac25a5 AV |
158 | static struct user_namespace *utsns_owner(struct ns_common *ns) |
159 | { | |
160 | return to_uts_ns(ns)->user_ns; | |
161 | } | |
162 | ||
34482e89 EB |
163 | const struct proc_ns_operations utsns_operations = { |
164 | .name = "uts", | |
165 | .type = CLONE_NEWUTS, | |
166 | .get = utsns_get, | |
167 | .put = utsns_put, | |
168 | .install = utsns_install, | |
bcac25a5 | 169 | .owner = utsns_owner, |
34482e89 | 170 | }; |