Release 4.9 kernel/user.c
/*
* The "user cache".
*
* (C) Copyright 1991-2000 Linus Torvalds
*
* We have a per-user structure to keep track of how many
* processes, files etc the user has claimed, in order to be
* able to have per-user limits for system resources.
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/key.h>
#include <linux/interrupt.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,
.ns.inum = PROC_USER_INIT_INO,
#ifdef CONFIG_USER_NS
.ns.ops = &userns_operations,
#endif
.flags = USERNS_INIT_FLAGS,
#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(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
* occasionally also taken from softirq/tasklet context, when
* task-structs get RCU-freed. Hence all locking must be softirq-safe.
* But free_uid() is also called with local interrupts disabled, and running
* local_bh_enable() with local interrupts disabled is an error - we'll run
* softirq callbacks, and they can unconditionally enable interrupts, and
* the caller of free_uid() didn't expect that..
*/
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),
.sigpending = ATOMIC_INIT(0),
.locked_shm = 0,
.uid = GLOBAL_ROOT_UID,
};
/*
* These routines must be called with the uidhash spinlock held!
*/
static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
{
hlist_add_head(&up->uidhash_node, hashent);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
dhaval giani | dhaval giani | 22 | 84.62% | 3 | 75.00% |
kay sievers | kay sievers | 4 | 15.38% | 1 | 25.00% |
| Total | 26 | 100.00% | 4 | 100.00% |
static void uid_hash_remove(struct user_struct *up)
{
hlist_del_init(&up->uidhash_node);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
dhaval giani | dhaval giani | 18 | 94.74% | 2 | 66.67% |
srivatsa vaddagiri | srivatsa vaddagiri | 1 | 5.26% | 1 | 33.33% |
| Total | 19 | 100.00% | 3 | 100.00% |
static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
{
struct user_struct *user;
hlist_for_each_entry(user, hashent, uidhash_node) {
if (uid_eq(user->uid, uid)) {
atomic_inc(&user->__count);
return user;
}
}
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
kay sievers | kay sievers | 53 | 91.38% | 1 | 50.00% |
eric w. biederman | eric w. biederman | 5 | 8.62% | 1 | 50.00% |
| Total | 58 | 100.00% | 2 | 100.00% |
/* 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 void free_user(struct user_struct *up, unsigned long flags)
__releases(&uidhash_lockContributors
| Person | Tokens | Prop | Commits | CommitProp |
dhaval giani | dhaval giani | 7 | 43.75% | 1 | 33.33% |
pre-git | pre-git | 6 | 37.50% | 1 | 33.33% |
namhyung kim | namhyung kim | 3 | 18.75% | 1 | 33.33% |
| Total | 16 | 100.00% | 3 | 100.00% |
)
{
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
key_put(up->uid_keyring);
key_put(up->session_keyring);
kmem_cache_free(uid_cachep, up);
}
/*
* 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(kuid_t uid)
{
struct user_struct *ret;
unsigned long flags;
spin_lock_irqsave(&uidhash_lock, flags);
ret = uid_hash_find(uid, uidhashentry(uid));
spin_unlock_irqrestore(&uidhash_lock, flags);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
andrew morton | andrew morton | 30 | 60.00% | 2 | 50.00% |
ingo molnar | ingo molnar | 19 | 38.00% | 1 | 25.00% |
eric w. biederman | eric w. biederman | 1 | 2.00% | 1 | 25.00% |
| Total | 50 | 100.00% | 4 | 100.00% |
void free_uid(struct user_struct *up)
{
unsigned long flags;
if (!up)
return;
local_irq_save(flags);
if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
free_user(up, flags);
else
local_irq_restore(flags);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
pre-git | pre-git | 25 | 49.02% | 2 | 33.33% |
andrew morton | andrew morton | 23 | 45.10% | 2 | 33.33% |
ingo molnar | ingo molnar | 2 | 3.92% | 1 | 16.67% |
dhaval giani | dhaval giani | 1 | 1.96% | 1 | 16.67% |
| Total | 51 | 100.00% | 6 | 100.00% |
struct user_struct *alloc_uid(kuid_t uid)
{
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) {
new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL);
if (!new)
goto out_unlock;
new->uid = uid;
atomic_set(&new->__count, 1);
/*
* Before adding this, check whether we raced
* on adding the same user already..
*/
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
} else {
uid_hash_insert(new, hashent);
up = new;
}
spin_unlock_irq(&uidhash_lock);
}
return up;
out_unlock:
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
pre-git | pre-git | 127 | 79.38% | 2 | 22.22% |
david howells | david howells | 14 | 8.75% | 1 | 11.11% |
pavel emelianov | pavel emelianov | 12 | 7.50% | 2 | 22.22% |
andrew morton | andrew morton | 5 | 3.12% | 2 | 22.22% |
eric w. biederman | eric w. biederman | 1 | 0.62% | 1 | 11.11% |
christoph lameter | christoph lameter | 1 | 0.62% | 1 | 11.11% |
| Total | 160 | 100.00% | 9 | 100.00% |
static int __init uid_cache_init(void)
{
int n;
uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
for(n = 0; n < UIDHASH_SZ; ++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(GLOBAL_ROOT_UID));
spin_unlock_irq(&uidhash_lock);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
pre-git | pre-git | 41 | 51.25% | 2 | 22.22% |
dave jones | dave jones | 21 | 26.25% | 1 | 11.11% |
andrew morton | andrew morton | 15 | 18.75% | 3 | 33.33% |
eric w. biederman | eric w. biederman | 1 | 1.25% | 1 | 11.11% |
linus torvalds | linus torvalds | 1 | 1.25% | 1 | 11.11% |
pavel emelianov | pavel emelianov | 1 | 1.25% | 1 | 11.11% |
| Total | 80 | 100.00% | 9 | 100.00% |
subsys_initcall(uid_cache_init);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
pre-git | pre-git | 257 | 32.49% | 3 | 6.12% |
eric w. biederman | eric w. biederman | 146 | 18.46% | 8 | 16.33% |
dhaval giani | dhaval giani | 78 | 9.86% | 3 | 6.12% |
andrew morton | andrew morton | 75 | 9.48% | 6 | 12.24% |
kay sievers | kay sievers | 57 | 7.21% | 2 | 4.08% |
david howells | david howells | 33 | 4.17% | 3 | 6.12% |
pavel emelianov | pavel emelianov | 32 | 4.05% | 3 | 6.12% |
dave jones | dave jones | 28 | 3.54% | 1 | 2.04% |
ingo molnar | ingo molnar | 24 | 3.03% | 2 | 4.08% |
al viro | al viro | 16 | 2.02% | 2 | 4.08% |
chris wright | chris wright | 10 | 1.26% | 2 | 4.08% |
cedric le goater | cedric le goater | 5 | 0.63% | 1 | 2.04% |
thomas gleixner | thomas gleixner | 4 | 0.51% | 1 | 2.04% |
serge hallyn | serge hallyn | 4 | 0.51% | 2 | 4.08% |
art haas | art haas | 4 | 0.51% | 1 | 2.04% |
namhyung kim | namhyung kim | 4 | 0.51% | 1 | 2.04% |
christoph lameter | christoph lameter | 3 | 0.38% | 2 | 4.08% |
rik van riel | rik van riel | 3 | 0.38% | 1 | 2.04% |
xiao guangrong | xiao guangrong | 3 | 0.38% | 1 | 2.04% |
paul gortmaker | paul gortmaker | 2 | 0.25% | 2 | 4.08% |
linus torvalds | linus torvalds | 2 | 0.25% | 1 | 2.04% |
srivatsa vaddagiri | srivatsa vaddagiri | 1 | 0.13% | 1 | 2.04% |
| Total | 791 | 100.00% | 49 | 100.00% |