blob: 831ea71082320e1859daa1f434008816c3052333 [file] [log] [blame]
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -07001/*
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
Paul Gortmaker9984de12011-05-23 14:51:41 -040012#include <linux/export.h>
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070013#include <linux/uts.h>
14#include <linux/utsname.h>
Cedric Le Goater467e9f42007-07-15 23:41:06 -070015#include <linux/err.h>
Robert P. J. Day1aeb2722008-04-29 00:59:25 -070016#include <linux/slab.h>
Serge E. Hallyn59607db2011-03-23 16:43:16 -070017#include <linux/user_namespace.h>
David Howells0bb80f22013-04-12 01:50:06 +010018#include <linux/proc_ns.h>
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070019
Alexey Dobriyan4c2a7e72009-06-17 16:27:54 -070020static 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
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070030/*
Serge E. Hallyn071df102006-10-02 02:18:17 -070031 * Clone a new ns copying an original utsname, setting refcount to 1
32 * @old_ns: namespace to clone
Yuanhan Liubf531532013-02-27 17:05:30 -080033 * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise
Serge E. Hallyn071df102006-10-02 02:18:17 -070034 */
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070035static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
Serge E. Hallynbb96a6f2011-03-23 16:43:18 -070036 struct uts_namespace *old_ns)
Serge E. Hallyn071df102006-10-02 02:18:17 -070037{
38 struct uts_namespace *ns;
Eric W. Biederman98f842e2011-06-15 10:21:48 -070039 int err;
Serge E. Hallyn071df102006-10-02 02:18:17 -070040
Alexey Dobriyan4c2a7e72009-06-17 16:27:54 -070041 ns = create_uts_ns();
Cedric Le Goater467e9f42007-07-15 23:41:06 -070042 if (!ns)
43 return ERR_PTR(-ENOMEM);
44
Al Viro6344c432014-11-01 00:45:45 -040045 err = ns_alloc_inum(&ns->ns);
Eric W. Biederman98f842e2011-06-15 10:21:48 -070046 if (err) {
47 kfree(ns);
48 return ERR_PTR(err);
49 }
50
Al Viro33c42942014-11-01 02:32:53 -040051 ns->ns.ops = &utsns_operations;
52
Alexey Dobriyanefc63c42007-09-18 22:46:27 -070053 down_read(&uts_sem);
Cedric Le Goater467e9f42007-07-15 23:41:06 -070054 memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070055 ns->user_ns = get_user_ns(user_ns);
Alexey Dobriyanefc63c42007-09-18 22:46:27 -070056 up_read(&uts_sem);
Serge E. Hallyn071df102006-10-02 02:18:17 -070057 return ns;
58}
59
60/*
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070061 * Copy task tsk's utsname namespace, or clone it if flags
62 * specifies CLONE_NEWUTS. In latter case, changes to the
63 * utsname of this process won't be seen by parent, and vice
64 * versa.
65 */
Serge E. Hallynbb96a6f2011-03-23 16:43:18 -070066struct uts_namespace *copy_utsname(unsigned long flags,
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070067 struct user_namespace *user_ns, struct uts_namespace *old_ns)
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070068{
Serge E. Hallyn071df102006-10-02 02:18:17 -070069 struct uts_namespace *new_ns;
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070070
Badari Pulavartye3222c42007-05-08 00:25:21 -070071 BUG_ON(!old_ns);
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070072 get_uts_ns(old_ns);
73
Serge E. Hallyn071df102006-10-02 02:18:17 -070074 if (!(flags & CLONE_NEWUTS))
Badari Pulavartye3222c42007-05-08 00:25:21 -070075 return old_ns;
Serge E. Hallyn071df102006-10-02 02:18:17 -070076
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070077 new_ns = clone_uts_ns(user_ns, old_ns);
Serge E. Hallyn071df102006-10-02 02:18:17 -070078
Serge E. Hallyn071df102006-10-02 02:18:17 -070079 put_uts_ns(old_ns);
Badari Pulavartye3222c42007-05-08 00:25:21 -070080 return new_ns;
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070081}
82
83void free_uts_ns(struct kref *kref)
84{
85 struct uts_namespace *ns;
86
87 ns = container_of(kref, struct uts_namespace, kref);
Serge E. Hallyn59607db2011-03-23 16:43:16 -070088 put_user_ns(ns->user_ns);
Al Viro6344c432014-11-01 00:45:45 -040089 ns_free_inum(&ns->ns);
Serge E. Hallyn4865ecf2006-10-02 02:18:14 -070090 kfree(ns);
91}
Eric W. Biederman34482e82010-03-07 18:43:27 -080092
Al Viro3c041182014-11-01 00:25:30 -040093static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
94{
95 return container_of(ns, struct uts_namespace, ns);
96}
97
Al Viro64964522014-11-01 00:37:32 -040098static struct ns_common *utsns_get(struct task_struct *task)
Eric W. Biederman34482e82010-03-07 18:43:27 -080099{
100 struct uts_namespace *ns = NULL;
101 struct nsproxy *nsproxy;
102
Eric W. Biederman728dba32014-02-03 19:13:49 -0800103 task_lock(task);
104 nsproxy = task->nsproxy;
Eric W. Biederman34482e82010-03-07 18:43:27 -0800105 if (nsproxy) {
106 ns = nsproxy->uts_ns;
107 get_uts_ns(ns);
108 }
Eric W. Biederman728dba32014-02-03 19:13:49 -0800109 task_unlock(task);
Eric W. Biederman34482e82010-03-07 18:43:27 -0800110
Al Viro3c041182014-11-01 00:25:30 -0400111 return ns ? &ns->ns : NULL;
Eric W. Biederman34482e82010-03-07 18:43:27 -0800112}
113
Al Viro64964522014-11-01 00:37:32 -0400114static void utsns_put(struct ns_common *ns)
Eric W. Biederman34482e82010-03-07 18:43:27 -0800115{
Al Viro3c041182014-11-01 00:25:30 -0400116 put_uts_ns(to_uts_ns(ns));
Eric W. Biederman34482e82010-03-07 18:43:27 -0800117}
118
Al Viro64964522014-11-01 00:37:32 -0400119static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new)
Eric W. Biederman34482e82010-03-07 18:43:27 -0800120{
Al Viro3c041182014-11-01 00:25:30 -0400121 struct uts_namespace *ns = to_uts_ns(new);
Eric W. Biederman142e1d12012-07-26 01:13:20 -0700122
Eric W. Biederman5e4a0842012-12-14 07:55:36 -0800123 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
Eric W. Biedermanc7b96ac2013-03-20 12:49:49 -0700124 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
Eric W. Biederman142e1d12012-07-26 01:13:20 -0700125 return -EPERM;
126
Eric W. Biederman34482e82010-03-07 18:43:27 -0800127 get_uts_ns(ns);
128 put_uts_ns(nsproxy->uts_ns);
129 nsproxy->uts_ns = ns;
130 return 0;
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};