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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#include <linux/module.h>
#include <linux/version.h>
#include <linux/nsproxy.h>
#include <linux/user_namespace.h>
struct user_namespace init_user_ns = {
.kref = {
.refcount = ATOMIC_INIT(2),
},
.root_user = &root_user,
};
EXPORT_SYMBOL_GPL(init_user_ns);
#ifdef CONFIG_USER_NS
/*
* Clone a new ns copying an original user ns, setting refcount to 1
* @old_ns: namespace to clone
* Return NULL on error (failure to kmalloc), new ns otherwise
*/
static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
{
struct user_namespace *ns;
struct user_struct *new_user;
int n;
ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
if (!ns)
return ERR_PTR(-ENOMEM);
kref_init(&ns->kref);
for (n = 0; n < UIDHASH_SZ; ++n)
INIT_HLIST_HEAD(ns->uidhash_table + n);
/* Insert new root user. */
ns->root_user = alloc_uid(ns, 0);
if (!ns->root_user) {
kfree(ns);
return ERR_PTR(-ENOMEM);
}
/* Reset current->user with a new one */
new_user = alloc_uid(ns, current->uid);
if (!new_user) {
free_uid(ns->root_user);
kfree(ns);
return ERR_PTR(-ENOMEM);
}
switch_uid(new_user);
return ns;
}
struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
{
struct user_namespace *new_ns;
BUG_ON(!old_ns);
get_user_ns(old_ns);
if (!(flags & CLONE_NEWUSER))
return old_ns;
new_ns = clone_user_ns(old_ns);
put_user_ns(old_ns);
return new_ns;
}
void free_user_ns(struct kref *kref)
{
struct user_namespace *ns;
ns = container_of(kref, struct user_namespace, kref);
free_uid(ns->root_user);
kfree(ns);
}
#endif /* CONFIG_USER_NS */
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