#include <linux/user_namespace.h>
#include <linux/highuid.h>
#include <linux/cred.h>
+#include <linux/securebits.h>
static struct kmem_cache *user_ns_cachep __read_mostly;
*/
int create_user_ns(struct cred *new)
{
- struct user_namespace *ns;
+ struct user_namespace *ns, *parent_ns = new->user_ns;
struct user_struct *root_user;
- int n;
+ kuid_t owner = make_kuid(new->user_ns, new->euid);
+ kgid_t group = make_kgid(new->user_ns, new->egid);
+
+ /* The creator needs a mapping in the parent user namespace
+ * or else we won't be able to reasonably tell userspace who
+ * created a user_namespace.
+ */
+ if (!kuid_has_mapping(parent_ns, owner) ||
+ !kgid_has_mapping(parent_ns, group))
+ return -EPERM;
ns = kmem_cache_alloc(user_ns_cachep, GFP_KERNEL);
if (!ns)
kref_init(&ns->kref);
- for (n = 0; n < UIDHASH_SZ; ++n)
- INIT_HLIST_HEAD(ns->uidhash_table + n);
-
/* Alloc new root user. */
- root_user = alloc_uid(ns, 0);
+ root_user = alloc_uid(make_kuid(ns, 0));
if (!root_user) {
kmem_cache_free(user_ns_cachep, ns);
return -ENOMEM;
}
/* set the new root user in the credentials under preparation */
- ns->creator = new->user;
+ ns->parent = parent_ns;
+ ns->owner = owner;
+ ns->group = group;
+ free_uid(new->user);
new->user = root_user;
new->uid = new->euid = new->suid = new->fsuid = 0;
new->gid = new->egid = new->sgid = new->fsgid = 0;
put_group_info(new->group_info);
new->group_info = get_group_info(&init_groups);
+ /* Start with the same capabilities as init but useless for doing
+ * anything as the capabilities are bound to the new user namespace.
+ */
+ new->securebits = SECUREBITS_DEFAULT;
+ new->cap_inheritable = CAP_EMPTY_SET;
+ new->cap_permitted = CAP_FULL_SET;
+ new->cap_effective = CAP_FULL_SET;
+ new->cap_bset = CAP_FULL_SET;
#ifdef CONFIG_KEYS
key_put(new->request_key_auth);
new->request_key_auth = NULL;
#endif
/* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
- /* root_user holds a reference to ns, our reference can be dropped */
- put_user_ns(ns);
+ /* Leave the new->user_ns reference with the new user namespace. */
+ /* Leave the reference to our user_ns with the new cred. */
+ new->user_ns = ns;
return 0;
}
-/*
- * Deferred destructor for a user namespace. This is required because
- * free_user_ns() may be called with uidhash_lock held, but we need to call
- * back to free_uid() which will want to take the lock again.
- */
-static void free_user_ns_work(struct work_struct *work)
-{
- struct user_namespace *ns =
- container_of(work, struct user_namespace, destroyer);
- free_uid(ns->creator);
- kmem_cache_free(user_ns_cachep, ns);
-}
-
void free_user_ns(struct kref *kref)
{
- struct user_namespace *ns =
+ struct user_namespace *parent, *ns =
container_of(kref, struct user_namespace, kref);
- INIT_WORK(&ns->destroyer, free_user_ns_work);
- schedule_work(&ns->destroyer);
+ parent = ns->parent;
+ kmem_cache_free(user_ns_cachep, ns);
+ put_user_ns(parent);
}
EXPORT_SYMBOL(free_user_ns);
{
struct user_namespace *tmp;
- if (likely(to == cred->user->user_ns))
+ if (likely(to == cred->user_ns))
return uid;
-
/* Is cred->user the creator of the target user_ns
* or the creator of one of it's parents?
*/
- for ( tmp = to; tmp != &init_user_ns;
- tmp = tmp->creator->user_ns ) {
- if (cred->user == tmp->creator) {
+ for ( tmp = to; tmp != &init_user_ns; tmp = tmp->parent ) {
+ if (uid_eq(cred->user->uid, tmp->owner)) {
return (uid_t)0;
}
}
{
struct user_namespace *tmp;
- if (likely(to == cred->user->user_ns))
+ if (likely(to == cred->user_ns))
return gid;
/* Is cred->user the creator of the target user_ns
* or the creator of one of it's parents?
*/
- for ( tmp = to; tmp != &init_user_ns;
- tmp = tmp->creator->user_ns ) {
- if (cred->user == tmp->creator) {
+ for ( tmp = to; tmp != &init_user_ns; tmp = tmp->parent ) {
+ if (uid_eq(cred->user->uid, tmp->owner)) {
return (gid_t)0;
}
}