blob: d055d987850cc96ed2a73cc36d064b15d552dcaf [file] [log] [blame]
Cedric Le Goateracce2922007-07-15 23:40:59 -07001/*
2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License as
4 * published by the Free Software Foundation, version 2 of the
5 * License.
6 */
7
8#include <linux/module.h>
9#include <linux/version.h>
10#include <linux/nsproxy.h>
11#include <linux/user_namespace.h>
12
13struct user_namespace init_user_ns = {
14 .kref = {
15 .refcount = ATOMIC_INIT(2),
16 },
17 .root_user = &root_user,
18};
19
20EXPORT_SYMBOL_GPL(init_user_ns);
21
22#ifdef CONFIG_USER_NS
23
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070024/*
25 * Clone a new ns copying an original user ns, setting refcount to 1
26 * @old_ns: namespace to clone
27 * Return NULL on error (failure to kmalloc), new ns otherwise
28 */
29static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
30{
31 struct user_namespace *ns;
32 struct user_struct *new_user;
33 int n;
34
35 ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
36 if (!ns)
Cedric Le Goater467e9f42007-07-15 23:41:06 -070037 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070038
39 kref_init(&ns->kref);
40
41 for (n = 0; n < UIDHASH_SZ; ++n)
42 INIT_LIST_HEAD(ns->uidhash_table + n);
43
44 /* Insert new root user. */
45 ns->root_user = alloc_uid(ns, 0);
46 if (!ns->root_user) {
47 kfree(ns);
Cedric Le Goater467e9f42007-07-15 23:41:06 -070048 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070049 }
50
51 /* Reset current->user with a new one */
52 new_user = alloc_uid(ns, current->uid);
53 if (!new_user) {
54 free_uid(ns->root_user);
55 kfree(ns);
Cedric Le Goater467e9f42007-07-15 23:41:06 -070056 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070057 }
58
59 switch_uid(new_user);
60 return ns;
61}
62
Cedric Le Goateracce2922007-07-15 23:40:59 -070063struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
64{
65 struct user_namespace *new_ns;
66
67 BUG_ON(!old_ns);
68 get_user_ns(old_ns);
69
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070070 if (!(flags & CLONE_NEWUSER))
71 return old_ns;
72
73 new_ns = clone_user_ns(old_ns);
74
75 put_user_ns(old_ns);
Cedric Le Goateracce2922007-07-15 23:40:59 -070076 return new_ns;
77}
78
79void free_user_ns(struct kref *kref)
80{
81 struct user_namespace *ns;
82
83 ns = container_of(kref, struct user_namespace, kref);
84 kfree(ns);
85}
86
87#endif /* CONFIG_USER_NS */