blob: a9ab0596de44afe2bf3daa75c2c4ddca064c7f97 [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>
Robert P. J. Day1aeb2722008-04-29 00:59:25 -070011#include <linux/slab.h>
Cedric Le Goateracce2922007-07-15 23:40:59 -070012#include <linux/user_namespace.h>
13
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070014/*
15 * Clone a new ns copying an original user ns, setting refcount to 1
16 * @old_ns: namespace to clone
17 * Return NULL on error (failure to kmalloc), new ns otherwise
18 */
19static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
20{
21 struct user_namespace *ns;
22 struct user_struct *new_user;
23 int n;
24
25 ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
26 if (!ns)
Cedric Le Goater467e9f42007-07-15 23:41:06 -070027 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070028
29 kref_init(&ns->kref);
30
31 for (n = 0; n < UIDHASH_SZ; ++n)
Pavel Emelyanov735de222007-09-18 22:46:44 -070032 INIT_HLIST_HEAD(ns->uidhash_table + n);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070033
34 /* Insert new root user. */
35 ns->root_user = alloc_uid(ns, 0);
36 if (!ns->root_user) {
37 kfree(ns);
Cedric Le Goater467e9f42007-07-15 23:41:06 -070038 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070039 }
40
41 /* Reset current->user with a new one */
42 new_user = alloc_uid(ns, current->uid);
43 if (!new_user) {
44 free_uid(ns->root_user);
45 kfree(ns);
Cedric Le Goater467e9f42007-07-15 23:41:06 -070046 return ERR_PTR(-ENOMEM);
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070047 }
48
49 switch_uid(new_user);
50 return ns;
51}
52
Cedric Le Goateracce2922007-07-15 23:40:59 -070053struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
54{
55 struct user_namespace *new_ns;
56
57 BUG_ON(!old_ns);
58 get_user_ns(old_ns);
59
Serge E. Hallyn77ec7392007-07-15 23:41:01 -070060 if (!(flags & CLONE_NEWUSER))
61 return old_ns;
62
63 new_ns = clone_user_ns(old_ns);
64
65 put_user_ns(old_ns);
Cedric Le Goateracce2922007-07-15 23:40:59 -070066 return new_ns;
67}
68
69void free_user_ns(struct kref *kref)
70{
71 struct user_namespace *ns;
72
73 ns = container_of(kref, struct user_namespace, kref);
Pavel Emelyanov28f300d2007-09-18 22:46:45 -070074 release_uids(ns);
Cedric Le Goateracce2922007-07-15 23:40:59 -070075 kfree(ns);
76}
Michael Halcrow6a3fd922008-04-29 00:59:52 -070077EXPORT_SYMBOL(free_user_ns);