#include <linux/bitops.h>
#include <linux/key.h>
#include <linux/interrupt.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/user_namespace.h>
+/*
+ * userns count is 1 for root user, 1 for init_uts_ns,
+ * and 1 for... ?
+ */
+struct user_namespace init_user_ns = {
+ .kref = {
+ .refcount = ATOMIC_INIT(3),
+ },
+ .creator = &root_user,
+};
+EXPORT_SYMBOL_GPL(init_user_ns);
+
/*
* UID task count cache, to get fast user lookup in "alloc_uid"
* when changing user ID's (ie setuid() and friends).
*/
static DEFINE_SPINLOCK(uidhash_lock);
+/* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->user_ns */
struct user_struct root_user = {
- .__count = ATOMIC_INIT(1),
+ .__count = ATOMIC_INIT(2),
.processes = ATOMIC_INIT(1),
.files = ATOMIC_INIT(0),
.sigpending = ATOMIC_INIT(0),
- .mq_bytes = 0,
.locked_shm = 0,
-#ifdef CONFIG_KEYS
- .uid_keyring = &root_user_keyring,
- .session_keyring = &root_session_keyring,
-#endif
-#ifdef CONFIG_FAIR_USER_SCHED
- .tg = &init_task_group,
-#endif
+ .user_ns = &init_user_ns,
};
/*
* These routines must be called with the uidhash spinlock held!
*/
-static inline void uid_hash_insert(struct user_struct *up,
- struct hlist_head *hashent)
+static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
{
hlist_add_head(&up->uidhash_node, hashent);
}
-static inline void uid_hash_remove(struct user_struct *up)
+static void uid_hash_remove(struct user_struct *up)
{
hlist_del_init(&up->uidhash_node);
+ put_user_ns(up->user_ns);
}
-static inline struct user_struct *uid_hash_find(uid_t uid,
- struct hlist_head *hashent)
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
{
struct user_struct *user;
struct hlist_node *h;
return NULL;
}
-#ifdef CONFIG_FAIR_USER_SCHED
-
-static void sched_destroy_user(struct user_struct *up)
-{
- sched_destroy_group(up->tg);
-}
-
-static int sched_create_user(struct user_struct *up)
-{
- int rc = 0;
-
- up->tg = sched_create_group();
- if (IS_ERR(up->tg))
- rc = -ENOMEM;
-
- return rc;
-}
-
-static void sched_switch_user(struct task_struct *p)
-{
- sched_move_task(p);
-}
-
-#else /* CONFIG_FAIR_USER_SCHED */
-
-static void sched_destroy_user(struct user_struct *up) { }
-static int sched_create_user(struct user_struct *up) { return 0; }
-static void sched_switch_user(struct task_struct *p) { }
-
-#endif /* CONFIG_FAIR_USER_SCHED */
-
-#if defined(CONFIG_FAIR_USER_SCHED) && defined(CONFIG_SYSFS)
-
-static struct kobject uids_kobject; /* represents /sys/kernel/uids directory */
-static DEFINE_MUTEX(uids_mutex);
-
-static inline void uids_mutex_lock(void)
-{
- mutex_lock(&uids_mutex);
-}
-
-static inline void uids_mutex_unlock(void)
-{
- mutex_unlock(&uids_mutex);
-}
-
-/* return cpu shares held by the user */
-ssize_t cpu_shares_show(struct kset *kset, char *buffer)
-{
- struct user_struct *up = container_of(kset, struct user_struct, kset);
-
- return sprintf(buffer, "%lu\n", sched_group_shares(up->tg));
-}
-
-/* modify cpu shares held by the user */
-ssize_t cpu_shares_store(struct kset *kset, const char *buffer, size_t size)
-{
- struct user_struct *up = container_of(kset, struct user_struct, kset);
- unsigned long shares;
- int rc;
-
- sscanf(buffer, "%lu", &shares);
-
- rc = sched_group_set_shares(up->tg, shares);
-
- return (rc ? rc : size);
-}
-
-static void user_attr_init(struct subsys_attribute *sa, char *name, int mode)
-{
- sa->attr.name = name;
- sa->attr.mode = mode;
- sa->show = cpu_shares_show;
- sa->store = cpu_shares_store;
-}
-
-/* Create "/sys/kernel/uids/<uid>" directory and
- * "/sys/kernel/uids/<uid>/cpu_share" file for this user.
- */
-static int user_kobject_create(struct user_struct *up)
-{
- struct kset *kset = &up->kset;
- struct kobject *kobj = &kset->kobj;
- int error;
-
- memset(kset, 0, sizeof(struct kset));
- kobj->parent = &uids_kobject; /* create under /sys/kernel/uids dir */
- kobject_set_name(kobj, "%d", up->uid);
- kset_init(kset);
- user_attr_init(&up->user_attr, "cpu_share", 0644);
-
- error = kobject_add(kobj);
- if (error)
- goto done;
-
- error = sysfs_create_file(kobj, &up->user_attr.attr);
- if (error)
- kobject_del(kobj);
-
- kobject_uevent(kobj, KOBJ_ADD);
-
-done:
- return error;
-}
-
-/* create these in sysfs filesystem:
- * "/sys/kernel/uids" directory
- * "/sys/kernel/uids/0" directory (for root user)
- * "/sys/kernel/uids/0/cpu_share" file (for root user)
- */
-int __init uids_kobject_init(void)
-{
- int error;
-
- /* create under /sys/kernel dir */
- uids_kobject.parent = &kernel_subsys.kobj;
- uids_kobject.kset = &kernel_subsys;
- kobject_set_name(&uids_kobject, "uids");
- kobject_init(&uids_kobject);
-
- error = kobject_add(&uids_kobject);
- if (!error)
- error = user_kobject_create(&root_user);
-
- return error;
-}
-
-/* work function to remove sysfs directory for a user and free up
- * corresponding structures.
- */
-static void remove_user_sysfs_dir(struct work_struct *w)
-{
- struct user_struct *up = container_of(w, struct user_struct, work);
- struct kobject *kobj = &up->kset.kobj;
- unsigned long flags;
- int remove_user = 0;
-
- /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
- * atomic.
- */
- uids_mutex_lock();
-
- local_irq_save(flags);
-
- if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
- uid_hash_remove(up);
- remove_user = 1;
- spin_unlock_irqrestore(&uidhash_lock, flags);
- } else {
- local_irq_restore(flags);
- }
-
- if (!remove_user)
- goto done;
-
- sysfs_remove_file(kobj, &up->user_attr.attr);
- kobject_uevent(kobj, KOBJ_REMOVE);
- kobject_del(kobj);
-
- sched_destroy_user(up);
- key_put(up->uid_keyring);
- key_put(up->session_keyring);
- kmem_cache_free(uid_cachep, up);
-
-done:
- uids_mutex_unlock();
-}
-
-/* IRQs are disabled and uidhash_lock is held upon function entry.
- * IRQ state (as stored in flags) is restored and uidhash_lock released
- * upon function exit.
- */
-static inline void free_user(struct user_struct *up, unsigned long flags)
-{
- /* restore back the count */
- atomic_inc(&up->__count);
- spin_unlock_irqrestore(&uidhash_lock, flags);
-
- INIT_WORK(&up->work, remove_user_sysfs_dir);
- schedule_work(&up->work);
-}
-
-#else /* CONFIG_FAIR_USER_SCHED && CONFIG_SYSFS */
-
-static inline int user_kobject_create(struct user_struct *up) { return 0; }
-static inline void uids_mutex_lock(void) { }
-static inline void uids_mutex_unlock(void) { }
-
/* IRQs are disabled and uidhash_lock is held upon function entry.
* IRQ state (as stored in flags) is restored and uidhash_lock released
* upon function exit.
*/
-static inline void free_user(struct user_struct *up, unsigned long flags)
+static void free_user(struct user_struct *up, unsigned long flags)
+ __releases(&uidhash_lock)
{
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
- sched_destroy_user(up);
key_put(up->uid_keyring);
key_put(up->session_keyring);
kmem_cache_free(uid_cachep, up);
}
-#endif
-
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().
{
struct user_struct *ret;
unsigned long flags;
- struct user_namespace *ns = current->nsproxy->user_ns;
+ struct user_namespace *ns = current_user_ns();
spin_lock_irqsave(&uidhash_lock, flags);
ret = uid_hash_find(uid, uidhashentry(ns, uid));
local_irq_restore(flags);
}
-struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
+struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
{
struct hlist_head *hashent = uidhashentry(ns, uid);
- struct user_struct *up;
-
- /* Make uid_hash_find() + user_kobject_create() + uid_hash_insert()
- * atomic.
- */
- uids_mutex_lock();
+ struct user_struct *up, *new;
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
spin_unlock_irq(&uidhash_lock);
if (!up) {
- struct user_struct *new;
-
- new = kmem_cache_alloc(uid_cachep, GFP_KERNEL);
+ new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL);
if (!new)
- return NULL;
+ goto out_unlock;
+
new->uid = uid;
atomic_set(&new->__count, 1);
- atomic_set(&new->processes, 0);
- atomic_set(&new->files, 0);
- atomic_set(&new->sigpending, 0);
-#ifdef CONFIG_INOTIFY_USER
- atomic_set(&new->inotify_watches, 0);
- atomic_set(&new->inotify_devs, 0);
-#endif
-
- new->mq_bytes = 0;
- new->locked_shm = 0;
-
- if (alloc_uid_keyring(new, current) < 0) {
- kmem_cache_free(uid_cachep, new);
- return NULL;
- }
-
- if (sched_create_user(new) < 0) {
- key_put(new->uid_keyring);
- key_put(new->session_keyring);
- kmem_cache_free(uid_cachep, new);
- return NULL;
- }
- if (user_kobject_create(new)) {
- sched_destroy_user(new);
- key_put(new->uid_keyring);
- key_put(new->session_keyring);
- kmem_cache_free(uid_cachep, new);
- uids_mutex_unlock();
- return NULL;
- }
+ new->user_ns = get_user_ns(ns);
/*
* Before adding this, check whether we raced
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
- /* This case is not possible when CONFIG_FAIR_USER_SCHED
- * is defined, since we serialize alloc_uid() using
- * uids_mutex. Hence no need to call
- * sched_destroy_user() or remove_user_sysfs_dir().
- */
+ put_user_ns(ns);
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
up = new;
}
spin_unlock_irq(&uidhash_lock);
-
}
- uids_mutex_unlock();
-
return up;
-}
-
-void switch_uid(struct user_struct *new_user)
-{
- struct user_struct *old_user;
-
- /* What if a process setreuid()'s and this brings the
- * new uid over his NPROC rlimit? We can check this now
- * cheaply with the new uid cache, so if it matters
- * we should be checking for it. -DaveM
- */
- old_user = current->user;
- atomic_inc(&new_user->processes);
- atomic_dec(&old_user->processes);
- switch_uid_keyring(new_user);
- current->user = new_user;
- sched_switch_user(current);
-
- /*
- * We need to synchronize with __sigqueue_alloc()
- * doing a get_uid(p->user).. If that saw the old
- * user value, we need to wait until it has exited
- * its critical region before we can free the old
- * structure.
- */
- smp_mb();
- spin_unlock_wait(¤t->sighand->siglock);
-
- free_uid(old_user);
- suid_keys(current);
-}
-
-void release_uids(struct user_namespace *ns)
-{
- int i;
- unsigned long flags;
- struct hlist_head *head;
- struct hlist_node *nd;
- spin_lock_irqsave(&uidhash_lock, flags);
- /*
- * collapse the chains so that the user_struct-s will
- * be still alive, but not in hashes. subsequent free_uid()
- * will free them.
- */
- for (i = 0; i < UIDHASH_SZ; i++) {
- head = ns->uidhash_table + i;
- while (!hlist_empty(head)) {
- nd = head->first;
- hlist_del_init(nd);
- }
- }
- spin_unlock_irqrestore(&uidhash_lock, flags);
-
- free_uid(ns->root_user);
+out_unlock:
+ return NULL;
}
static int __init uid_cache_init(void)
Code Review / linux-2.6.git / blobdiff