1 files changed, 68 insertions, 316 deletions

diff --git a/kernel/user.c b/kernel/user.c
index f0e561e6d08..4efa39350e4 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -14,19 +14,63 @@
 #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>
+#include <linux/proc_ns.h>
+
+/*
+ * userns count is 1 for root user, 1 for init_uts_ns,
+ * and 1 for... ?
+ */
+struct user_namespace init_user_ns = {
+	.uid_map = {
+		.nr_extents = 1,
+		.extent[0] = {
+			.first = 0,
+			.lower_first = 0,
+			.count = 4294967295U,
+		},
+	},
+	.gid_map = {
+		.nr_extents = 1,
+		.extent[0] = {
+			.first = 0,
+			.lower_first = 0,
+			.count = 4294967295U,
+		},
+	},
+	.projid_map = {
+		.nr_extents = 1,
+		.extent[0] = {
+			.first = 0,
+			.lower_first = 0,
+			.count = 4294967295U,
+		},
+	},
+	.count = ATOMIC_INIT(3),
+	.owner = GLOBAL_ROOT_UID,
+	.group = GLOBAL_ROOT_GID,
+	.proc_inum = PROC_USER_INIT_INO,
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+	.persistent_keyring_register_sem =
+	__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
+#endif
+};
+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).
  */
 
+#define UIDHASH_BITS	(CONFIG_BASE_SMALL ? 3 : 7)
+#define UIDHASH_SZ	(1 << UIDHASH_BITS)
 #define UIDHASH_MASK		(UIDHASH_SZ - 1)
 #define __uidhashfn(uid)	(((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
-#define uidhashentry(ns, uid)	((ns)->uidhash_table + __uidhashfn((uid)))
+#define uidhashentry(uid)	(uidhash_table + __uidhashfn((__kuid_val(uid))))
 
 static struct kmem_cache *uid_cachep;
+struct hlist_head uidhash_table[UIDHASH_SZ];
 
 /*
  * The uidhash_lock is mostly taken from process context, but it is
@@ -39,44 +83,34 @@ static struct kmem_cache *uid_cachep;
  */
 static DEFINE_SPINLOCK(uidhash_lock);
 
+/* root_user.__count is 1, for init task cred */
 struct user_struct root_user = {
 	.__count	= ATOMIC_INIT(1),
 	.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
+	.uid		= GLOBAL_ROOT_UID,
 };
 
 /*
  * 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);
 }
 
-static inline struct user_struct *uid_hash_find(uid_t uid,
-						struct hlist_head *hashent)
+static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
 {
 	struct user_struct *user;
-	struct hlist_node *h;
 
-	hlist_for_each_entry(user, h, hashent, uidhash_node) {
-		if (user->uid == uid) {
+	hlist_for_each_entry(user, hashent, uidhash_node) {
+		if (uid_eq(user->uid, uid)) {
 			atomic_inc(&user->__count);
 			return user;
 		}
@@ -85,217 +119,33 @@ static inline struct user_struct *uid_hash_find(uid_t uid,
 	return NULL;
 }
 
-#ifdef CONFIG_FAIR_USER_SCHED
-
-static struct kobject uids_kobject; /* represents /sys/kernel/uids directory */
-static DEFINE_MUTEX(uids_mutex);
-
-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);
-}
-
-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 */
-
-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) { }
-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	/* CONFIG_FAIR_USER_SCHED */
-
 /*
  * Locate the user_struct for the passed UID.  If found, take a ref on it.  The
  * caller must undo that ref with free_uid().
  *
  * If the user_struct could not be found, return NULL.
  */
-struct user_struct *find_user(uid_t uid)
+struct user_struct *find_user(kuid_t uid)
 {
 	struct user_struct *ret;
 	unsigned long flags;
-	struct user_namespace *ns = current->nsproxy->user_ns;
 
 	spin_lock_irqsave(&uidhash_lock, flags);
-	ret = uid_hash_find(uid, uidhashentry(ns, uid));
+	ret = uid_hash_find(uid, uidhashentry(uid));
 	spin_unlock_irqrestore(&uidhash_lock, flags);
 	return ret;
 }
@@ -314,59 +164,22 @@ void free_uid(struct user_struct *up)
 		local_irq_restore(flags);
 }
 
-struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
+struct user_struct *alloc_uid(kuid_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 hlist_head *hashent = uidhashentry(uid);
+	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;
-		}
 
 		/*
 		 * Before adding this, check whether we raced
@@ -375,11 +188,6 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
 		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().
-			 */
 			key_put(new->uid_keyring);
 			key_put(new->session_keyring);
 			kmem_cache_free(uid_cachep, new);
@@ -388,67 +196,12 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
 			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(&current->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)
@@ -459,14 +212,13 @@ static int __init uid_cache_init(void)
 			0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
 
 	for(n = 0; n < UIDHASH_SZ; ++n)
-		INIT_HLIST_HEAD(init_user_ns.uidhash_table + n);
+		INIT_HLIST_HEAD(uidhash_table + n);
 
 	/* Insert the root user immediately (init already runs as root) */
 	spin_lock_irq(&uidhash_lock);
-	uid_hash_insert(&root_user, uidhashentry(&init_user_ns, 0));
+	uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID));
 	spin_unlock_irq(&uidhash_lock);
 
 	return 0;
 }
-
-module_init(uid_cache_init);
+subsys_initcall(uid_cache_init);