X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fuser.c;h=766467b3bcb7f1e42da792bece602ec8404135a2;hb=c0614829c16ab9d31f1b7d40516decfbf3d32102;hp=7e8215d87b40e70a13166dcc0efa064ee19a94d2;hpb=b1a8c172c318534b96d0f0f1aecdad3898118b98;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/user.c b/kernel/user.c index 7e8215d..766467b 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -16,6 +16,15 @@ #include #include #include +#include "cred-internals.h" + +struct user_namespace init_user_ns = { + .kref = { + .refcount = ATOMIC_INIT(2), + }, + .creator = &root_user, +}; +EXPORT_SYMBOL_GPL(init_user_ns); /* * UID task count cache, to get fast user lookup in "alloc_uid" @@ -39,38 +48,31 @@ static struct kmem_cache *uid_cachep; */ static DEFINE_SPINLOCK(uidhash_lock); +/* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->creator */ 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; @@ -85,210 +87,19 @@ static inline struct user_struct *uid_hash_find(uid_t uid, 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/" directory and - * "/sys/kernel/uids//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) { 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(). @@ -299,7 +110,7 @@ struct user_struct *find_user(uid_t 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)); @@ -321,59 +132,27 @@ 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(struct user_namespace *ns, uid_t uid) { struct hlist_head *hashent = uidhashentry(ns, uid); - struct user_struct *up; + struct user_struct *up, *new; - /* Make uid_hash_find() + user_kobject_create() + uid_hash_insert() + /* Make uid_hash_find() + uids_user_create() + uid_hash_insert() * atomic. */ - uids_mutex_lock(); - 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 @@ -382,7 +161,7 @@ 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 + /* This case is not possible when CONFIG_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(). @@ -395,67 +174,14 @@ 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(¤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); + put_user_ns(new->user_ns); + kmem_cache_free(uid_cachep, new); +out_unlock: + return NULL; } static int __init uid_cache_init(void)