Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * The "user cache". |
| 3 | * |
| 4 | * (C) Copyright 1991-2000 Linus Torvalds |
| 5 | * |
| 6 | * We have a per-user structure to keep track of how many |
| 7 | * processes, files etc the user has claimed, in order to be |
| 8 | * able to have per-user limits for system resources. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/init.h> |
| 12 | #include <linux/sched.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/bitops.h> |
| 15 | #include <linux/key.h> |
Ingo Molnar | 4021cb2 | 2006-01-25 15:23:07 +0100 | [diff] [blame] | 16 | #include <linux/interrupt.h> |
Cedric Le Goater | acce292 | 2007-07-15 23:40:59 -0700 | [diff] [blame] | 17 | #include <linux/module.h> |
| 18 | #include <linux/user_namespace.h> |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 19 | #include "cred-internals.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 21 | struct user_namespace init_user_ns = { |
| 22 | .kref = { |
Serge E. Hallyn | 1d1e975 | 2009-02-26 18:27:38 -0600 | [diff] [blame] | 23 | .refcount = ATOMIC_INIT(2), |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 24 | }, |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 25 | .creator = &root_user, |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 26 | }; |
| 27 | EXPORT_SYMBOL_GPL(init_user_ns); |
| 28 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | /* |
| 30 | * UID task count cache, to get fast user lookup in "alloc_uid" |
| 31 | * when changing user ID's (ie setuid() and friends). |
| 32 | */ |
| 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | #define UIDHASH_MASK (UIDHASH_SZ - 1) |
| 35 | #define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK) |
Cedric Le Goater | acce292 | 2007-07-15 23:40:59 -0700 | [diff] [blame] | 36 | #define uidhashentry(ns, uid) ((ns)->uidhash_table + __uidhashfn((uid))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 38 | static struct kmem_cache *uid_cachep; |
Ingo Molnar | 4021cb2 | 2006-01-25 15:23:07 +0100 | [diff] [blame] | 39 | |
| 40 | /* |
| 41 | * The uidhash_lock is mostly taken from process context, but it is |
| 42 | * occasionally also taken from softirq/tasklet context, when |
| 43 | * task-structs get RCU-freed. Hence all locking must be softirq-safe. |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 44 | * But free_uid() is also called with local interrupts disabled, and running |
| 45 | * local_bh_enable() with local interrupts disabled is an error - we'll run |
| 46 | * softirq callbacks, and they can unconditionally enable interrupts, and |
| 47 | * the caller of free_uid() didn't expect that.. |
Ingo Molnar | 4021cb2 | 2006-01-25 15:23:07 +0100 | [diff] [blame] | 48 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | static DEFINE_SPINLOCK(uidhash_lock); |
| 50 | |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 51 | /* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->creator */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | struct user_struct root_user = { |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 53 | .__count = ATOMIC_INIT(2), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | .processes = ATOMIC_INIT(1), |
| 55 | .files = ATOMIC_INIT(0), |
| 56 | .sigpending = ATOMIC_INIT(0), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | .locked_shm = 0, |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 58 | .user_ns = &init_user_ns, |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 59 | #ifdef CONFIG_USER_SCHED |
Ingo Molnar | 4cf86d7 | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 60 | .tg = &init_task_group, |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 61 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | }; |
| 63 | |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 64 | /* |
| 65 | * These routines must be called with the uidhash spinlock held! |
| 66 | */ |
Alexey Dobriyan | 40aeb40 | 2007-10-16 23:30:09 -0700 | [diff] [blame] | 67 | static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 68 | { |
| 69 | hlist_add_head(&up->uidhash_node, hashent); |
| 70 | } |
| 71 | |
Alexey Dobriyan | 40aeb40 | 2007-10-16 23:30:09 -0700 | [diff] [blame] | 72 | static void uid_hash_remove(struct user_struct *up) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 73 | { |
| 74 | hlist_del_init(&up->uidhash_node); |
Serge E. Hallyn | fb5ae64 | 2009-02-13 14:04:21 +0000 | [diff] [blame] | 75 | put_user_ns(up->user_ns); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 76 | } |
| 77 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 78 | #ifdef CONFIG_USER_SCHED |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 79 | |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 80 | static void sched_destroy_user(struct user_struct *up) |
| 81 | { |
| 82 | sched_destroy_group(up->tg); |
| 83 | } |
| 84 | |
| 85 | static int sched_create_user(struct user_struct *up) |
| 86 | { |
| 87 | int rc = 0; |
| 88 | |
Peter Zijlstra | eff766a | 2008-04-19 19:45:00 +0200 | [diff] [blame] | 89 | up->tg = sched_create_group(&root_task_group); |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 90 | if (IS_ERR(up->tg)) |
| 91 | rc = -ENOMEM; |
| 92 | |
Arun R Bharadwaj | 6c415b9 | 2008-12-01 20:49:05 +0530 | [diff] [blame] | 93 | set_tg_uid(up); |
| 94 | |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 95 | return rc; |
| 96 | } |
| 97 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 98 | #else /* CONFIG_USER_SCHED */ |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 99 | |
| 100 | static void sched_destroy_user(struct user_struct *up) { } |
| 101 | static int sched_create_user(struct user_struct *up) { return 0; } |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 102 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 103 | #endif /* CONFIG_USER_SCHED */ |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 104 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 105 | #if defined(CONFIG_USER_SCHED) && defined(CONFIG_SYSFS) |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 106 | |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 107 | static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) |
| 108 | { |
| 109 | struct user_struct *user; |
| 110 | struct hlist_node *h; |
| 111 | |
| 112 | hlist_for_each_entry(user, h, hashent, uidhash_node) { |
| 113 | if (user->uid == uid) { |
| 114 | /* possibly resurrect an "almost deleted" object */ |
| 115 | if (atomic_inc_return(&user->__count) == 1) |
| 116 | cancel_delayed_work(&user->work); |
| 117 | return user; |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | return NULL; |
| 122 | } |
| 123 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 124 | static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */ |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 125 | static DEFINE_MUTEX(uids_mutex); |
| 126 | |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 127 | static inline void uids_mutex_lock(void) |
| 128 | { |
| 129 | mutex_lock(&uids_mutex); |
| 130 | } |
| 131 | |
| 132 | static inline void uids_mutex_unlock(void) |
| 133 | { |
| 134 | mutex_unlock(&uids_mutex); |
| 135 | } |
| 136 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 137 | /* uid directory attributes */ |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 138 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 139 | static ssize_t cpu_shares_show(struct kobject *kobj, |
| 140 | struct kobj_attribute *attr, |
| 141 | char *buf) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 142 | { |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 143 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 144 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 145 | return sprintf(buf, "%lu\n", sched_group_shares(up->tg)); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 146 | } |
| 147 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 148 | static ssize_t cpu_shares_store(struct kobject *kobj, |
| 149 | struct kobj_attribute *attr, |
| 150 | const char *buf, size_t size) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 151 | { |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 152 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 153 | unsigned long shares; |
| 154 | int rc; |
| 155 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 156 | sscanf(buf, "%lu", &shares); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 157 | |
| 158 | rc = sched_group_set_shares(up->tg, shares); |
| 159 | |
| 160 | return (rc ? rc : size); |
| 161 | } |
| 162 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 163 | static struct kobj_attribute cpu_share_attr = |
| 164 | __ATTR(cpu_share, 0644, cpu_shares_show, cpu_shares_store); |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 165 | #endif |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 166 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 167 | #ifdef CONFIG_RT_GROUP_SCHED |
Peter Zijlstra | 9f0c1e5 | 2008-02-13 15:45:39 +0100 | [diff] [blame] | 168 | static ssize_t cpu_rt_runtime_show(struct kobject *kobj, |
| 169 | struct kobj_attribute *attr, |
| 170 | char *buf) |
| 171 | { |
| 172 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
| 173 | |
Peter Zijlstra | af4491e | 2008-08-19 12:33:02 +0200 | [diff] [blame] | 174 | return sprintf(buf, "%ld\n", sched_group_rt_runtime(up->tg)); |
Peter Zijlstra | 9f0c1e5 | 2008-02-13 15:45:39 +0100 | [diff] [blame] | 175 | } |
| 176 | |
| 177 | static ssize_t cpu_rt_runtime_store(struct kobject *kobj, |
| 178 | struct kobj_attribute *attr, |
| 179 | const char *buf, size_t size) |
| 180 | { |
| 181 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
| 182 | unsigned long rt_runtime; |
| 183 | int rc; |
| 184 | |
Peter Zijlstra | af4491e | 2008-08-19 12:33:02 +0200 | [diff] [blame] | 185 | sscanf(buf, "%ld", &rt_runtime); |
Peter Zijlstra | 9f0c1e5 | 2008-02-13 15:45:39 +0100 | [diff] [blame] | 186 | |
| 187 | rc = sched_group_set_rt_runtime(up->tg, rt_runtime); |
| 188 | |
| 189 | return (rc ? rc : size); |
| 190 | } |
| 191 | |
| 192 | static struct kobj_attribute cpu_rt_runtime_attr = |
| 193 | __ATTR(cpu_rt_runtime, 0644, cpu_rt_runtime_show, cpu_rt_runtime_store); |
Peter Zijlstra | d0b27fa | 2008-04-19 19:44:57 +0200 | [diff] [blame] | 194 | |
| 195 | static ssize_t cpu_rt_period_show(struct kobject *kobj, |
| 196 | struct kobj_attribute *attr, |
| 197 | char *buf) |
| 198 | { |
| 199 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
| 200 | |
| 201 | return sprintf(buf, "%lu\n", sched_group_rt_period(up->tg)); |
| 202 | } |
| 203 | |
| 204 | static ssize_t cpu_rt_period_store(struct kobject *kobj, |
| 205 | struct kobj_attribute *attr, |
| 206 | const char *buf, size_t size) |
| 207 | { |
| 208 | struct user_struct *up = container_of(kobj, struct user_struct, kobj); |
| 209 | unsigned long rt_period; |
| 210 | int rc; |
| 211 | |
| 212 | sscanf(buf, "%lu", &rt_period); |
| 213 | |
| 214 | rc = sched_group_set_rt_period(up->tg, rt_period); |
| 215 | |
| 216 | return (rc ? rc : size); |
| 217 | } |
| 218 | |
| 219 | static struct kobj_attribute cpu_rt_period_attr = |
| 220 | __ATTR(cpu_rt_period, 0644, cpu_rt_period_show, cpu_rt_period_store); |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 221 | #endif |
Peter Zijlstra | 9f0c1e5 | 2008-02-13 15:45:39 +0100 | [diff] [blame] | 222 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 223 | /* default attributes per uid directory */ |
| 224 | static struct attribute *uids_attributes[] = { |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 225 | #ifdef CONFIG_FAIR_GROUP_SCHED |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 226 | &cpu_share_attr.attr, |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 227 | #endif |
| 228 | #ifdef CONFIG_RT_GROUP_SCHED |
Peter Zijlstra | 9f0c1e5 | 2008-02-13 15:45:39 +0100 | [diff] [blame] | 229 | &cpu_rt_runtime_attr.attr, |
Peter Zijlstra | d0b27fa | 2008-04-19 19:44:57 +0200 | [diff] [blame] | 230 | &cpu_rt_period_attr.attr, |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 231 | #endif |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 232 | NULL |
| 233 | }; |
| 234 | |
| 235 | /* the lifetime of user_struct is not managed by the core (now) */ |
| 236 | static void uids_release(struct kobject *kobj) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 237 | { |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 238 | return; |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 239 | } |
| 240 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 241 | static struct kobj_type uids_ktype = { |
| 242 | .sysfs_ops = &kobj_sysfs_ops, |
| 243 | .default_attrs = uids_attributes, |
| 244 | .release = uids_release, |
| 245 | }; |
| 246 | |
Serge E. Hallyn | 94d6a5f | 2008-12-08 15:52:21 -0600 | [diff] [blame] | 247 | /* |
| 248 | * Create /sys/kernel/uids/<uid>/cpu_share file for this user |
| 249 | * We do not create this file for users in a user namespace (until |
| 250 | * sysfs tagging is implemented). |
| 251 | * |
| 252 | * See Documentation/scheduler/sched-design-CFS.txt for ramifications. |
| 253 | */ |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 254 | static int uids_user_create(struct user_struct *up) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 255 | { |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 256 | struct kobject *kobj = &up->kobj; |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 257 | int error; |
| 258 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 259 | memset(kobj, 0, sizeof(struct kobject)); |
Serge E. Hallyn | c37bbb0 | 2008-12-03 13:17:06 -0600 | [diff] [blame] | 260 | if (up->user_ns != &init_user_ns) |
| 261 | return 0; |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 262 | kobj->kset = uids_kset; |
Greg Kroah-Hartman | cf15126 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 263 | error = kobject_init_and_add(kobj, &uids_ktype, NULL, "%d", up->uid); |
| 264 | if (error) { |
| 265 | kobject_put(kobj); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 266 | goto done; |
Greg Kroah-Hartman | cf15126 | 2007-12-17 23:05:35 -0700 | [diff] [blame] | 267 | } |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 268 | |
Srivatsa Vaddagiri | fb7dde3 | 2007-10-15 17:00:18 +0200 | [diff] [blame] | 269 | kobject_uevent(kobj, KOBJ_ADD); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 270 | done: |
| 271 | return error; |
| 272 | } |
| 273 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 274 | /* create these entries in sysfs: |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 275 | * "/sys/kernel/uids" directory |
| 276 | * "/sys/kernel/uids/0" directory (for root user) |
| 277 | * "/sys/kernel/uids/0/cpu_share" file (for root user) |
| 278 | */ |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 279 | int __init uids_sysfs_init(void) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 280 | { |
Greg Kroah-Hartman | 0ff21e4 | 2007-11-06 10:36:58 -0800 | [diff] [blame] | 281 | uids_kset = kset_create_and_add("uids", NULL, kernel_kobj); |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 282 | if (!uids_kset) |
| 283 | return -ENOMEM; |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 284 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 285 | return uids_user_create(&root_user); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 286 | } |
| 287 | |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 288 | /* delayed work function to remove sysfs directory for a user and free up |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 289 | * corresponding structures. |
| 290 | */ |
Dhaval Giani | be50b834 | 2009-03-10 12:55:56 -0700 | [diff] [blame] | 291 | static void cleanup_user_struct(struct work_struct *w) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 292 | { |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 293 | struct user_struct *up = container_of(w, struct user_struct, work.work); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 294 | unsigned long flags; |
| 295 | int remove_user = 0; |
| 296 | |
| 297 | /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del() |
| 298 | * atomic. |
| 299 | */ |
| 300 | uids_mutex_lock(); |
| 301 | |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 302 | spin_lock_irqsave(&uidhash_lock, flags); |
| 303 | if (atomic_read(&up->__count) == 0) { |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 304 | uid_hash_remove(up); |
| 305 | remove_user = 1; |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 306 | } |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 307 | spin_unlock_irqrestore(&uidhash_lock, flags); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 308 | |
| 309 | if (!remove_user) |
| 310 | goto done; |
| 311 | |
Dhaval Giani | be50b834 | 2009-03-10 12:55:56 -0700 | [diff] [blame] | 312 | if (up->user_ns == &init_user_ns) { |
| 313 | kobject_uevent(&up->kobj, KOBJ_REMOVE); |
| 314 | kobject_del(&up->kobj); |
| 315 | kobject_put(&up->kobj); |
| 316 | } |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 317 | |
| 318 | sched_destroy_user(up); |
| 319 | key_put(up->uid_keyring); |
| 320 | key_put(up->session_keyring); |
| 321 | kmem_cache_free(uid_cachep, up); |
| 322 | |
| 323 | done: |
| 324 | uids_mutex_unlock(); |
| 325 | } |
| 326 | |
| 327 | /* IRQs are disabled and uidhash_lock is held upon function entry. |
| 328 | * IRQ state (as stored in flags) is restored and uidhash_lock released |
| 329 | * upon function exit. |
| 330 | */ |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 331 | static void free_user(struct user_struct *up, unsigned long flags) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 332 | { |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 333 | INIT_DELAYED_WORK(&up->work, cleanup_user_struct); |
| 334 | schedule_delayed_work(&up->work, msecs_to_jiffies(1000)); |
Thomas Gleixner | b00bc0b | 2009-11-02 13:01:56 +0100 | [diff] [blame] | 335 | spin_unlock_irqrestore(&uidhash_lock, flags); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 336 | } |
| 337 | |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 338 | #else /* CONFIG_USER_SCHED && CONFIG_SYSFS */ |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 339 | |
Kay Sievers | 3959214 | 2009-03-24 15:43:30 +0100 | [diff] [blame] | 340 | static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) |
| 341 | { |
| 342 | struct user_struct *user; |
| 343 | struct hlist_node *h; |
| 344 | |
| 345 | hlist_for_each_entry(user, h, hashent, uidhash_node) { |
| 346 | if (user->uid == uid) { |
| 347 | atomic_inc(&user->__count); |
| 348 | return user; |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | return NULL; |
| 353 | } |
| 354 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 355 | int uids_sysfs_init(void) { return 0; } |
| 356 | static inline int uids_user_create(struct user_struct *up) { return 0; } |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 357 | static inline void uids_mutex_lock(void) { } |
| 358 | static inline void uids_mutex_unlock(void) { } |
| 359 | |
| 360 | /* IRQs are disabled and uidhash_lock is held upon function entry. |
| 361 | * IRQ state (as stored in flags) is restored and uidhash_lock released |
| 362 | * upon function exit. |
| 363 | */ |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 364 | static void free_user(struct user_struct *up, unsigned long flags) |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 365 | { |
| 366 | uid_hash_remove(up); |
| 367 | spin_unlock_irqrestore(&uidhash_lock, flags); |
| 368 | sched_destroy_user(up); |
| 369 | key_put(up->uid_keyring); |
| 370 | key_put(up->session_keyring); |
| 371 | kmem_cache_free(uid_cachep, up); |
| 372 | } |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 373 | |
Dhaval Giani | b1a8c17 | 2007-10-17 16:55:11 +0200 | [diff] [blame] | 374 | #endif |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 375 | |
Dhaval Giani | 54e9912 | 2009-02-27 15:13:54 +0530 | [diff] [blame] | 376 | #if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED) |
| 377 | /* |
| 378 | * We need to check if a setuid can take place. This function should be called |
| 379 | * before successfully completing the setuid. |
| 380 | */ |
| 381 | int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) |
| 382 | { |
| 383 | |
| 384 | return sched_rt_can_attach(up->tg, tsk); |
| 385 | |
| 386 | } |
| 387 | #else |
| 388 | int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) |
| 389 | { |
| 390 | return 1; |
| 391 | } |
| 392 | #endif |
| 393 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | * Locate the user_struct for the passed UID. If found, take a ref on it. The |
| 396 | * caller must undo that ref with free_uid(). |
| 397 | * |
| 398 | * If the user_struct could not be found, return NULL. |
| 399 | */ |
| 400 | struct user_struct *find_user(uid_t uid) |
| 401 | { |
| 402 | struct user_struct *ret; |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 403 | unsigned long flags; |
Serge Hallyn | 6ded6ab | 2008-11-24 16:24:10 -0500 | [diff] [blame] | 404 | struct user_namespace *ns = current_user_ns(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 406 | spin_lock_irqsave(&uidhash_lock, flags); |
Cedric Le Goater | acce292 | 2007-07-15 23:40:59 -0700 | [diff] [blame] | 407 | ret = uid_hash_find(uid, uidhashentry(ns, uid)); |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 408 | spin_unlock_irqrestore(&uidhash_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 409 | return ret; |
| 410 | } |
| 411 | |
| 412 | void free_uid(struct user_struct *up) |
| 413 | { |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 414 | unsigned long flags; |
| 415 | |
Andrew Morton | 36f5741 | 2006-03-24 03:15:47 -0800 | [diff] [blame] | 416 | if (!up) |
| 417 | return; |
| 418 | |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 419 | local_irq_save(flags); |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 420 | if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) |
| 421 | free_user(up, flags); |
| 422 | else |
Andrew Morton | 36f5741 | 2006-03-24 03:15:47 -0800 | [diff] [blame] | 423 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | } |
| 425 | |
Andrew Morton | 354a1f4 | 2008-04-30 00:54:54 -0700 | [diff] [blame] | 426 | struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | { |
Pavel Emelyanov | 735de22 | 2007-09-18 22:46:44 -0700 | [diff] [blame] | 428 | struct hlist_head *hashent = uidhashentry(ns, uid); |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 429 | struct user_struct *up, *new; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | |
Kay Sievers | eb41d94 | 2007-11-02 13:47:53 +0100 | [diff] [blame] | 431 | /* Make uid_hash_find() + uids_user_create() + uid_hash_insert() |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 432 | * atomic. |
| 433 | */ |
| 434 | uids_mutex_lock(); |
| 435 | |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 436 | spin_lock_irq(&uidhash_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | up = uid_hash_find(uid, hashent); |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 438 | spin_unlock_irq(&uidhash_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | |
| 440 | if (!up) { |
Andrew Morton | 354a1f4 | 2008-04-30 00:54:54 -0700 | [diff] [blame] | 441 | new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL); |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 442 | if (!new) |
| 443 | goto out_unlock; |
Pavel Emelyanov | 5e8869b | 2007-11-26 21:21:49 +0100 | [diff] [blame] | 444 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | new->uid = uid; |
| 446 | atomic_set(&new->__count, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 447 | |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 448 | if (sched_create_user(new) < 0) |
David Howells | 69664cf | 2008-04-29 01:01:31 -0700 | [diff] [blame] | 449 | goto out_free_user; |
Srivatsa Vaddagiri | 24e377a | 2007-10-15 17:00:09 +0200 | [diff] [blame] | 450 | |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 451 | new->user_ns = get_user_ns(ns); |
| 452 | |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 453 | if (uids_user_create(new)) |
| 454 | goto out_destoy_sched; |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 455 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | /* |
| 457 | * Before adding this, check whether we raced |
| 458 | * on adding the same user already.. |
| 459 | */ |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 460 | spin_lock_irq(&uidhash_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | up = uid_hash_find(uid, hashent); |
| 462 | if (up) { |
Peter Zijlstra | 052f1dc | 2008-02-13 15:45:40 +0100 | [diff] [blame] | 463 | /* This case is not possible when CONFIG_USER_SCHED |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 464 | * is defined, since we serialize alloc_uid() using |
| 465 | * uids_mutex. Hence no need to call |
| 466 | * sched_destroy_user() or remove_user_sysfs_dir(). |
| 467 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | key_put(new->uid_keyring); |
| 469 | key_put(new->session_keyring); |
| 470 | kmem_cache_free(uid_cachep, new); |
| 471 | } else { |
| 472 | uid_hash_insert(new, hashent); |
| 473 | up = new; |
| 474 | } |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 475 | spin_unlock_irq(&uidhash_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | } |
Dhaval Giani | 5cb350b | 2007-10-15 17:00:14 +0200 | [diff] [blame] | 477 | |
| 478 | uids_mutex_unlock(); |
| 479 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | return up; |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 481 | |
| 482 | out_destoy_sched: |
| 483 | sched_destroy_user(new); |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 484 | put_user_ns(new->user_ns); |
Pavel Emelyanov | 8eb703e | 2008-01-25 21:08:26 +0100 | [diff] [blame] | 485 | out_free_user: |
| 486 | kmem_cache_free(uid_cachep, new); |
| 487 | out_unlock: |
| 488 | uids_mutex_unlock(); |
| 489 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | } |
| 491 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | static int __init uid_cache_init(void) |
| 493 | { |
| 494 | int n; |
| 495 | |
| 496 | uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct), |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 497 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | |
| 499 | for(n = 0; n < UIDHASH_SZ; ++n) |
Pavel Emelyanov | 735de22 | 2007-09-18 22:46:44 -0700 | [diff] [blame] | 500 | INIT_HLIST_HEAD(init_user_ns.uidhash_table + n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | |
| 502 | /* Insert the root user immediately (init already runs as root) */ |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 503 | spin_lock_irq(&uidhash_lock); |
Cedric Le Goater | acce292 | 2007-07-15 23:40:59 -0700 | [diff] [blame] | 504 | uid_hash_insert(&root_user, uidhashentry(&init_user_ns, 0)); |
Andrew Morton | 3fa97c9 | 2006-01-31 16:34:26 -0800 | [diff] [blame] | 505 | spin_unlock_irq(&uidhash_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | |
| 507 | return 0; |
| 508 | } |
| 509 | |
| 510 | module_init(uid_cache_init); |