diff options
Diffstat (limited to 'kernel/user.c')
| -rw-r--r-- | kernel/user.c | 121 |
1 files changed, 79 insertions, 42 deletions
diff --git a/kernel/user.c b/kernel/user.c index 69b4c3d48cde..7aef4e679a6a 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * The "user cache". * @@ -13,46 +14,68 @@ #include <linux/slab.h> #include <linux/bitops.h> #include <linux/key.h> +#include <linux/sched/user.h> #include <linux/interrupt.h> #include <linux/export.h> #include <linux/user_namespace.h> +#include <linux/binfmts.h> #include <linux/proc_ns.h> +#if IS_ENABLED(CONFIG_BINFMT_MISC) +struct binfmt_misc init_binfmt_misc = { + .entries = LIST_HEAD_INIT(init_binfmt_misc.entries), + .enabled = true, + .entries_lock = __RW_LOCK_UNLOCKED(init_binfmt_misc.entries_lock), +}; +EXPORT_SYMBOL_GPL(init_binfmt_misc); +#endif + /* * userns count is 1 for root user, 1 for init_uts_ns, * and 1 for... ? */ struct user_namespace init_user_ns = { + .ns = NS_COMMON_INIT(init_user_ns), .uid_map = { - .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, + .nr_extents = 1, }, }, .gid_map = { - .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, + .nr_extents = 1, }, }, .projid_map = { - .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, + .nr_extents = 1, }, }, - .count = ATOMIC_INIT(3), .owner = GLOBAL_ROOT_UID, .group = GLOBAL_ROOT_GID, - .proc_inum = PROC_USER_INIT_INO, - .may_mount_sysfs = true, - .may_mount_proc = true, + .flags = USERNS_INIT_FLAGS, +#ifdef CONFIG_KEYS + .keyring_name_list = LIST_HEAD_INIT(init_user_ns.keyring_name_list), + .keyring_sem = __RWSEM_INITIALIZER(init_user_ns.keyring_sem), +#endif +#if IS_ENABLED(CONFIG_BINFMT_MISC) + .binfmt_misc = &init_binfmt_misc, +#endif }; EXPORT_SYMBOL_GPL(init_user_ns); @@ -61,14 +84,14 @@ EXPORT_SYMBOL_GPL(init_user_ns); * when changing user ID's (ie setuid() and friends). */ -#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 7) +#define UIDHASH_BITS (IS_ENABLED(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(uid) (uidhash_table + __uidhashfn((__kuid_val(uid)))) static struct kmem_cache *uid_cachep; -struct hlist_head uidhash_table[UIDHASH_SZ]; +static struct hlist_head uidhash_table[UIDHASH_SZ]; /* * The uidhash_lock is mostly taken from process context, but it is @@ -83,12 +106,9 @@ 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), - .locked_shm = 0, + .__count = REFCOUNT_INIT(1), .uid = GLOBAL_ROOT_UID, + .ratelimit = RATELIMIT_STATE_INIT(root_user.ratelimit, 0, 0), }; /* @@ -110,7 +130,7 @@ static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent) hlist_for_each_entry(user, hashent, uidhash_node) { if (uid_eq(user->uid, uid)) { - atomic_inc(&user->__count); + refcount_inc(&user->__count); return user; } } @@ -118,6 +138,22 @@ static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent) return NULL; } +static int user_epoll_alloc(struct user_struct *up) +{ +#ifdef CONFIG_EPOLL + return percpu_counter_init(&up->epoll_watches, 0, GFP_KERNEL); +#else + return 0; +#endif +} + +static void user_epoll_free(struct user_struct *up) +{ +#ifdef CONFIG_EPOLL + percpu_counter_destroy(&up->epoll_watches); +#endif +} + /* 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. @@ -127,8 +163,7 @@ static void free_user(struct user_struct *up, unsigned long flags) { uid_hash_remove(up); spin_unlock_irqrestore(&uidhash_lock, flags); - key_put(up->uid_keyring); - key_put(up->session_keyring); + user_epoll_free(up); kmem_cache_free(uid_cachep, up); } @@ -156,12 +191,10 @@ void free_uid(struct user_struct *up) if (!up) return; - local_irq_save(flags); - if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) + if (refcount_dec_and_lock_irqsave(&up->__count, &uidhash_lock, &flags)) free_user(up, flags); - else - local_irq_restore(flags); } +EXPORT_SYMBOL_GPL(free_uid); struct user_struct *alloc_uid(kuid_t uid) { @@ -175,10 +208,16 @@ struct user_struct *alloc_uid(kuid_t uid) if (!up) { new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL); if (!new) - goto out_unlock; + return NULL; new->uid = uid; - atomic_set(&new->__count, 1); + refcount_set(&new->__count, 1); + if (user_epoll_alloc(new)) { + kmem_cache_free(uid_cachep, new); + return NULL; + } + ratelimit_state_init(&new->ratelimit, HZ, 100); + ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE); /* * Before adding this, check whether we raced @@ -187,8 +226,7 @@ struct user_struct *alloc_uid(kuid_t uid) spin_lock_irq(&uidhash_lock); up = uid_hash_find(uid, hashent); if (up) { - key_put(new->uid_keyring); - key_put(new->session_keyring); + user_epoll_free(new); kmem_cache_free(uid_cachep, new); } else { uid_hash_insert(new, hashent); @@ -198,9 +236,6 @@ struct user_struct *alloc_uid(kuid_t uid) } return up; - -out_unlock: - return NULL; } static int __init uid_cache_init(void) @@ -213,6 +248,9 @@ static int __init uid_cache_init(void) for(n = 0; n < UIDHASH_SZ; ++n) INIT_HLIST_HEAD(uidhash_table + n); + if (user_epoll_alloc(&root_user)) + panic("root_user epoll percpu counter alloc failed"); + /* Insert the root user immediately (init already runs as root) */ spin_lock_irq(&uidhash_lock); uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID)); @@ -220,5 +258,4 @@ static int __init uid_cache_init(void) return 0; } - -module_init(uid_cache_init); +subsys_initcall(uid_cache_init); |