2005-04-17 06:20:36 +08:00
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/*
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* The "user cache".
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*
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* (C) Copyright 1991-2000 Linus Torvalds
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*
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* We have a per-user structure to keep track of how many
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* processes, files etc the user has claimed, in order to be
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* able to have per-user limits for system resources.
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*/
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/bitops.h>
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#include <linux/key.h>
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2006-01-25 22:23:07 +08:00
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#include <linux/interrupt.h>
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2007-07-16 14:40:59 +08:00
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#include <linux/module.h>
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#include <linux/user_namespace.h>
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CRED: Inaugurate COW credentials
Inaugurate copy-on-write credentials management. This uses RCU to manage the
credentials pointer in the task_struct with respect to accesses by other tasks.
A process may only modify its own credentials, and so does not need locking to
access or modify its own credentials.
A mutex (cred_replace_mutex) is added to the task_struct to control the effect
of PTRACE_ATTACHED on credential calculations, particularly with respect to
execve().
With this patch, the contents of an active credentials struct may not be
changed directly; rather a new set of credentials must be prepared, modified
and committed using something like the following sequence of events:
struct cred *new = prepare_creds();
int ret = blah(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
There are some exceptions to this rule: the keyrings pointed to by the active
credentials may be instantiated - keyrings violate the COW rule as managing
COW keyrings is tricky, given that it is possible for a task to directly alter
the keys in a keyring in use by another task.
To help enforce this, various pointers to sets of credentials, such as those in
the task_struct, are declared const. The purpose of this is compile-time
discouragement of altering credentials through those pointers. Once a set of
credentials has been made public through one of these pointers, it may not be
modified, except under special circumstances:
(1) Its reference count may incremented and decremented.
(2) The keyrings to which it points may be modified, but not replaced.
The only safe way to modify anything else is to create a replacement and commit
using the functions described in Documentation/credentials.txt (which will be
added by a later patch).
This patch and the preceding patches have been tested with the LTP SELinux
testsuite.
This patch makes several logical sets of alteration:
(1) execve().
This now prepares and commits credentials in various places in the
security code rather than altering the current creds directly.
(2) Temporary credential overrides.
do_coredump() and sys_faccessat() now prepare their own credentials and
temporarily override the ones currently on the acting thread, whilst
preventing interference from other threads by holding cred_replace_mutex
on the thread being dumped.
This will be replaced in a future patch by something that hands down the
credentials directly to the functions being called, rather than altering
the task's objective credentials.
(3) LSM interface.
A number of functions have been changed, added or removed:
(*) security_capset_check(), ->capset_check()
(*) security_capset_set(), ->capset_set()
Removed in favour of security_capset().
(*) security_capset(), ->capset()
New. This is passed a pointer to the new creds, a pointer to the old
creds and the proposed capability sets. It should fill in the new
creds or return an error. All pointers, barring the pointer to the
new creds, are now const.
(*) security_bprm_apply_creds(), ->bprm_apply_creds()
Changed; now returns a value, which will cause the process to be
killed if it's an error.
(*) security_task_alloc(), ->task_alloc_security()
Removed in favour of security_prepare_creds().
(*) security_cred_free(), ->cred_free()
New. Free security data attached to cred->security.
(*) security_prepare_creds(), ->cred_prepare()
New. Duplicate any security data attached to cred->security.
(*) security_commit_creds(), ->cred_commit()
New. Apply any security effects for the upcoming installation of new
security by commit_creds().
(*) security_task_post_setuid(), ->task_post_setuid()
Removed in favour of security_task_fix_setuid().
(*) security_task_fix_setuid(), ->task_fix_setuid()
Fix up the proposed new credentials for setuid(). This is used by
cap_set_fix_setuid() to implicitly adjust capabilities in line with
setuid() changes. Changes are made to the new credentials, rather
than the task itself as in security_task_post_setuid().
(*) security_task_reparent_to_init(), ->task_reparent_to_init()
Removed. Instead the task being reparented to init is referred
directly to init's credentials.
NOTE! This results in the loss of some state: SELinux's osid no
longer records the sid of the thread that forked it.
(*) security_key_alloc(), ->key_alloc()
(*) security_key_permission(), ->key_permission()
Changed. These now take cred pointers rather than task pointers to
refer to the security context.
(4) sys_capset().
This has been simplified and uses less locking. The LSM functions it
calls have been merged.
(5) reparent_to_kthreadd().
This gives the current thread the same credentials as init by simply using
commit_thread() to point that way.
(6) __sigqueue_alloc() and switch_uid()
__sigqueue_alloc() can't stop the target task from changing its creds
beneath it, so this function gets a reference to the currently applicable
user_struct which it then passes into the sigqueue struct it returns if
successful.
switch_uid() is now called from commit_creds(), and possibly should be
folded into that. commit_creds() should take care of protecting
__sigqueue_alloc().
(7) [sg]et[ug]id() and co and [sg]et_current_groups.
The set functions now all use prepare_creds(), commit_creds() and
abort_creds() to build and check a new set of credentials before applying
it.
security_task_set[ug]id() is called inside the prepared section. This
guarantees that nothing else will affect the creds until we've finished.
The calling of set_dumpable() has been moved into commit_creds().
Much of the functionality of set_user() has been moved into
commit_creds().
The get functions all simply access the data directly.
(8) security_task_prctl() and cap_task_prctl().
security_task_prctl() has been modified to return -ENOSYS if it doesn't
want to handle a function, or otherwise return the return value directly
rather than through an argument.
Additionally, cap_task_prctl() now prepares a new set of credentials, even
if it doesn't end up using it.
(9) Keyrings.
A number of changes have been made to the keyrings code:
(a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
all been dropped and built in to the credentials functions directly.
They may want separating out again later.
(b) key_alloc() and search_process_keyrings() now take a cred pointer
rather than a task pointer to specify the security context.
(c) copy_creds() gives a new thread within the same thread group a new
thread keyring if its parent had one, otherwise it discards the thread
keyring.
(d) The authorisation key now points directly to the credentials to extend
the search into rather pointing to the task that carries them.
(e) Installing thread, process or session keyrings causes a new set of
credentials to be created, even though it's not strictly necessary for
process or session keyrings (they're shared).
(10) Usermode helper.
The usermode helper code now carries a cred struct pointer in its
subprocess_info struct instead of a new session keyring pointer. This set
of credentials is derived from init_cred and installed on the new process
after it has been cloned.
call_usermodehelper_setup() allocates the new credentials and
call_usermodehelper_freeinfo() discards them if they haven't been used. A
special cred function (prepare_usermodeinfo_creds()) is provided
specifically for call_usermodehelper_setup() to call.
call_usermodehelper_setkeys() adjusts the credentials to sport the
supplied keyring as the new session keyring.
(11) SELinux.
SELinux has a number of changes, in addition to those to support the LSM
interface changes mentioned above:
(a) selinux_setprocattr() no longer does its check for whether the
current ptracer can access processes with the new SID inside the lock
that covers getting the ptracer's SID. Whilst this lock ensures that
the check is done with the ptracer pinned, the result is only valid
until the lock is released, so there's no point doing it inside the
lock.
(12) is_single_threaded().
This function has been extracted from selinux_setprocattr() and put into
a file of its own in the lib/ directory as join_session_keyring() now
wants to use it too.
The code in SELinux just checked to see whether a task shared mm_structs
with other tasks (CLONE_VM), but that isn't good enough. We really want
to know if they're part of the same thread group (CLONE_THREAD).
(13) nfsd.
The NFS server daemon now has to use the COW credentials to set the
credentials it is going to use. It really needs to pass the credentials
down to the functions it calls, but it can't do that until other patches
in this series have been applied.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 07:39:23 +08:00
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#include "cred-internals.h"
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2005-04-17 06:20:36 +08:00
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2008-02-08 20:18:23 +08:00
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struct user_namespace init_user_ns = {
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.kref = {
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2008-10-16 05:38:45 +08:00
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.refcount = ATOMIC_INIT(1),
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2008-02-08 20:18:23 +08:00
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},
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2008-10-16 05:38:45 +08:00
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.creator = &root_user,
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2008-02-08 20:18:23 +08:00
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};
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EXPORT_SYMBOL_GPL(init_user_ns);
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2005-04-17 06:20:36 +08:00
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/*
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* UID task count cache, to get fast user lookup in "alloc_uid"
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* when changing user ID's (ie setuid() and friends).
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*/
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#define UIDHASH_MASK (UIDHASH_SZ - 1)
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#define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
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2007-07-16 14:40:59 +08:00
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#define uidhashentry(ns, uid) ((ns)->uidhash_table + __uidhashfn((uid)))
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2005-04-17 06:20:36 +08:00
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2006-12-07 12:33:20 +08:00
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static struct kmem_cache *uid_cachep;
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2006-01-25 22:23:07 +08:00
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/*
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* The uidhash_lock is mostly taken from process context, but it is
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* occasionally also taken from softirq/tasklet context, when
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* task-structs get RCU-freed. Hence all locking must be softirq-safe.
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2006-02-01 08:34:26 +08:00
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* But free_uid() is also called with local interrupts disabled, and running
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* local_bh_enable() with local interrupts disabled is an error - we'll run
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* softirq callbacks, and they can unconditionally enable interrupts, and
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* the caller of free_uid() didn't expect that..
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2006-01-25 22:23:07 +08:00
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*/
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2005-04-17 06:20:36 +08:00
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static DEFINE_SPINLOCK(uidhash_lock);
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2008-10-16 05:38:45 +08:00
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/* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->creator */
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2005-04-17 06:20:36 +08:00
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struct user_struct root_user = {
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2008-10-16 05:38:45 +08:00
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.__count = ATOMIC_INIT(2),
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2005-04-17 06:20:36 +08:00
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.processes = ATOMIC_INIT(1),
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.files = ATOMIC_INIT(0),
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.sigpending = ATOMIC_INIT(0),
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.locked_shm = 0,
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2008-10-16 05:38:45 +08:00
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.user_ns = &init_user_ns,
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2008-02-13 22:45:40 +08:00
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#ifdef CONFIG_USER_SCHED
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2007-10-15 23:00:14 +08:00
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.tg = &init_task_group,
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2007-10-15 23:00:09 +08:00
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#endif
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2005-04-17 06:20:36 +08:00
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};
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2007-10-15 23:00:14 +08:00
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/*
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* These routines must be called with the uidhash spinlock held!
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*/
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2007-10-17 14:30:09 +08:00
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static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
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2007-10-15 23:00:14 +08:00
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{
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hlist_add_head(&up->uidhash_node, hashent);
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}
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2007-10-17 14:30:09 +08:00
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static void uid_hash_remove(struct user_struct *up)
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2007-10-15 23:00:14 +08:00
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{
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hlist_del_init(&up->uidhash_node);
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}
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2007-10-17 14:30:09 +08:00
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static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
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2007-10-15 23:00:14 +08:00
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{
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struct user_struct *user;
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struct hlist_node *h;
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hlist_for_each_entry(user, h, hashent, uidhash_node) {
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if (user->uid == uid) {
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atomic_inc(&user->__count);
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return user;
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}
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}
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return NULL;
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}
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2008-02-13 22:45:40 +08:00
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#ifdef CONFIG_USER_SCHED
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2007-10-15 23:00:14 +08:00
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2007-10-15 23:00:09 +08:00
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static void sched_destroy_user(struct user_struct *up)
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{
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sched_destroy_group(up->tg);
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}
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static int sched_create_user(struct user_struct *up)
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{
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int rc = 0;
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2008-04-20 01:45:00 +08:00
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up->tg = sched_create_group(&root_task_group);
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2007-10-15 23:00:09 +08:00
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if (IS_ERR(up->tg))
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rc = -ENOMEM;
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return rc;
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}
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2008-02-13 22:45:40 +08:00
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#else /* CONFIG_USER_SCHED */
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2007-10-17 22:55:11 +08:00
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static void sched_destroy_user(struct user_struct *up) { }
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static int sched_create_user(struct user_struct *up) { return 0; }
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2008-02-13 22:45:40 +08:00
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#endif /* CONFIG_USER_SCHED */
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2007-10-17 22:55:11 +08:00
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2008-02-13 22:45:40 +08:00
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#if defined(CONFIG_USER_SCHED) && defined(CONFIG_SYSFS)
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2007-10-17 22:55:11 +08:00
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2007-11-02 20:47:53 +08:00
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static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */
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2007-10-17 22:55:11 +08:00
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static DEFINE_MUTEX(uids_mutex);
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2007-10-15 23:00:14 +08:00
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static inline void uids_mutex_lock(void)
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{
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mutex_lock(&uids_mutex);
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}
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2007-10-15 23:00:09 +08:00
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2007-10-15 23:00:14 +08:00
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static inline void uids_mutex_unlock(void)
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{
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mutex_unlock(&uids_mutex);
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}
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2007-10-15 23:00:09 +08:00
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2007-11-02 20:47:53 +08:00
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/* uid directory attributes */
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2008-02-13 22:45:40 +08:00
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#ifdef CONFIG_FAIR_GROUP_SCHED
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2007-11-02 20:47:53 +08:00
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static ssize_t cpu_shares_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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char *buf)
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2007-10-15 23:00:14 +08:00
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{
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2007-11-02 20:47:53 +08:00
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struct user_struct *up = container_of(kobj, struct user_struct, kobj);
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2007-10-15 23:00:09 +08:00
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2007-11-02 20:47:53 +08:00
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return sprintf(buf, "%lu\n", sched_group_shares(up->tg));
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2007-10-15 23:00:14 +08:00
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}
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2007-11-02 20:47:53 +08:00
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static ssize_t cpu_shares_store(struct kobject *kobj,
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struct kobj_attribute *attr,
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const char *buf, size_t size)
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2007-10-15 23:00:14 +08:00
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{
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2007-11-02 20:47:53 +08:00
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struct user_struct *up = container_of(kobj, struct user_struct, kobj);
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2007-10-15 23:00:14 +08:00
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unsigned long shares;
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int rc;
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2007-11-02 20:47:53 +08:00
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sscanf(buf, "%lu", &shares);
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2007-10-15 23:00:14 +08:00
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rc = sched_group_set_shares(up->tg, shares);
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return (rc ? rc : size);
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}
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2007-11-02 20:47:53 +08:00
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static struct kobj_attribute cpu_share_attr =
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__ATTR(cpu_share, 0644, cpu_shares_show, cpu_shares_store);
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2008-02-13 22:45:40 +08:00
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#endif
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2007-11-02 20:47:53 +08:00
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2008-02-13 22:45:40 +08:00
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#ifdef CONFIG_RT_GROUP_SCHED
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2008-02-13 22:45:39 +08:00
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static ssize_t cpu_rt_runtime_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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char *buf)
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{
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struct user_struct *up = container_of(kobj, struct user_struct, kobj);
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2008-08-19 18:33:02 +08:00
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return sprintf(buf, "%ld\n", sched_group_rt_runtime(up->tg));
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2008-02-13 22:45:39 +08:00
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}
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static ssize_t cpu_rt_runtime_store(struct kobject *kobj,
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struct kobj_attribute *attr,
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const char *buf, size_t size)
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{
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struct user_struct *up = container_of(kobj, struct user_struct, kobj);
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unsigned long rt_runtime;
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int rc;
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2008-08-19 18:33:02 +08:00
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sscanf(buf, "%ld", &rt_runtime);
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2008-02-13 22:45:39 +08:00
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rc = sched_group_set_rt_runtime(up->tg, rt_runtime);
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return (rc ? rc : size);
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}
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static struct kobj_attribute cpu_rt_runtime_attr =
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__ATTR(cpu_rt_runtime, 0644, cpu_rt_runtime_show, cpu_rt_runtime_store);
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2008-04-20 01:44:57 +08:00
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static ssize_t cpu_rt_period_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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char *buf)
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{
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|
struct user_struct *up = container_of(kobj, struct user_struct, kobj);
|
|
|
|
|
|
|
|
|
|
return sprintf(buf, "%lu\n", sched_group_rt_period(up->tg));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static ssize_t cpu_rt_period_store(struct kobject *kobj,
|
|
|
|
|
struct kobj_attribute *attr,
|
|
|
|
|
const char *buf, size_t size)
|
|
|
|
|
{
|
|
|
|
|
struct user_struct *up = container_of(kobj, struct user_struct, kobj);
|
|
|
|
|
unsigned long rt_period;
|
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
|
|
sscanf(buf, "%lu", &rt_period);
|
|
|
|
|
|
|
|
|
|
rc = sched_group_set_rt_period(up->tg, rt_period);
|
|
|
|
|
|
|
|
|
|
return (rc ? rc : size);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static struct kobj_attribute cpu_rt_period_attr =
|
|
|
|
|
__ATTR(cpu_rt_period, 0644, cpu_rt_period_show, cpu_rt_period_store);
|
2008-02-13 22:45:40 +08:00
|
|
|
#endif
|
2008-02-13 22:45:39 +08:00
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
/* default attributes per uid directory */
|
|
|
|
|
static struct attribute *uids_attributes[] = {
|
2008-02-13 22:45:40 +08:00
|
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
2007-11-02 20:47:53 +08:00
|
|
|
&cpu_share_attr.attr,
|
2008-02-13 22:45:40 +08:00
|
|
|
#endif
|
|
|
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
2008-02-13 22:45:39 +08:00
|
|
|
&cpu_rt_runtime_attr.attr,
|
2008-04-20 01:44:57 +08:00
|
|
|
&cpu_rt_period_attr.attr,
|
2008-02-13 22:45:40 +08:00
|
|
|
#endif
|
2007-11-02 20:47:53 +08:00
|
|
|
NULL
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
/* the lifetime of user_struct is not managed by the core (now) */
|
|
|
|
|
static void uids_release(struct kobject *kobj)
|
2007-10-15 23:00:14 +08:00
|
|
|
{
|
2007-11-02 20:47:53 +08:00
|
|
|
return;
|
2007-10-15 23:00:14 +08:00
|
|
|
}
|
|
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
static struct kobj_type uids_ktype = {
|
|
|
|
|
.sysfs_ops = &kobj_sysfs_ops,
|
|
|
|
|
.default_attrs = uids_attributes,
|
|
|
|
|
.release = uids_release,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
/* create /sys/kernel/uids/<uid>/cpu_share file for this user */
|
|
|
|
|
static int uids_user_create(struct user_struct *up)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2007-11-02 20:47:53 +08:00
|
|
|
struct kobject *kobj = &up->kobj;
|
2007-10-15 23:00:14 +08:00
|
|
|
int error;
|
|
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
memset(kobj, 0, sizeof(struct kobject));
|
2008-12-04 03:17:06 +08:00
|
|
|
if (up->user_ns != &init_user_ns)
|
|
|
|
|
return 0;
|
2007-11-02 20:47:53 +08:00
|
|
|
kobj->kset = uids_kset;
|
2007-12-18 14:05:35 +08:00
|
|
|
error = kobject_init_and_add(kobj, &uids_ktype, NULL, "%d", up->uid);
|
|
|
|
|
if (error) {
|
|
|
|
|
kobject_put(kobj);
|
2007-10-15 23:00:14 +08:00
|
|
|
goto done;
|
2007-12-18 14:05:35 +08:00
|
|
|
}
|
2007-10-15 23:00:14 +08:00
|
|
|
|
2007-10-15 23:00:18 +08:00
|
|
|
kobject_uevent(kobj, KOBJ_ADD);
|
2007-10-15 23:00:14 +08:00
|
|
|
done:
|
|
|
|
|
return error;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
/* create these entries in sysfs:
|
2007-10-15 23:00:14 +08:00
|
|
|
* "/sys/kernel/uids" directory
|
|
|
|
|
* "/sys/kernel/uids/0" directory (for root user)
|
|
|
|
|
* "/sys/kernel/uids/0/cpu_share" file (for root user)
|
|
|
|
|
*/
|
2007-11-02 20:47:53 +08:00
|
|
|
int __init uids_sysfs_init(void)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2007-11-07 02:36:58 +08:00
|
|
|
uids_kset = kset_create_and_add("uids", NULL, kernel_kobj);
|
2007-11-02 20:47:53 +08:00
|
|
|
if (!uids_kset)
|
|
|
|
|
return -ENOMEM;
|
2007-10-15 23:00:14 +08:00
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
return uids_user_create(&root_user);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
2007-10-15 23:00:14 +08:00
|
|
|
/* work function to remove sysfs directory for a user and free up
|
|
|
|
|
* corresponding structures.
|
|
|
|
|
*/
|
|
|
|
|
static void remove_user_sysfs_dir(struct work_struct *w)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2007-10-15 23:00:14 +08:00
|
|
|
struct user_struct *up = container_of(w, struct user_struct, work);
|
|
|
|
|
unsigned long flags;
|
|
|
|
|
int remove_user = 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-12-04 03:17:06 +08:00
|
|
|
if (up->user_ns != &init_user_ns)
|
|
|
|
|
return;
|
2007-10-15 23:00:14 +08:00
|
|
|
/* 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);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
2007-10-15 23:00:14 +08:00
|
|
|
if (!remove_user)
|
|
|
|
|
goto done;
|
|
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
kobject_uevent(&up->kobj, KOBJ_REMOVE);
|
|
|
|
|
kobject_del(&up->kobj);
|
|
|
|
|
kobject_put(&up->kobj);
|
2007-10-15 23:00:14 +08:00
|
|
|
|
|
|
|
|
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.
|
|
|
|
|
*/
|
2008-10-16 05:38:45 +08:00
|
|
|
static void free_user(struct user_struct *up, unsigned long flags)
|
2007-10-15 23:00:14 +08:00
|
|
|
{
|
|
|
|
|
/* restore back the count */
|
|
|
|
|
atomic_inc(&up->__count);
|
|
|
|
|
spin_unlock_irqrestore(&uidhash_lock, flags);
|
|
|
|
|
|
2008-10-16 05:38:45 +08:00
|
|
|
put_user_ns(up->user_ns);
|
2007-10-15 23:00:14 +08:00
|
|
|
INIT_WORK(&up->work, remove_user_sysfs_dir);
|
|
|
|
|
schedule_work(&up->work);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
2008-02-13 22:45:40 +08:00
|
|
|
#else /* CONFIG_USER_SCHED && CONFIG_SYSFS */
|
2007-10-15 23:00:14 +08:00
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
int uids_sysfs_init(void) { return 0; }
|
|
|
|
|
static inline int uids_user_create(struct user_struct *up) { return 0; }
|
2007-10-15 23:00:14 +08:00
|
|
|
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.
|
|
|
|
|
*/
|
2008-10-16 05:38:45 +08:00
|
|
|
static void free_user(struct user_struct *up, unsigned long flags)
|
2007-10-15 23:00:14 +08:00
|
|
|
{
|
|
|
|
|
uid_hash_remove(up);
|
|
|
|
|
spin_unlock_irqrestore(&uidhash_lock, flags);
|
|
|
|
|
sched_destroy_user(up);
|
|
|
|
|
key_put(up->uid_keyring);
|
|
|
|
|
key_put(up->session_keyring);
|
2008-10-16 05:38:45 +08:00
|
|
|
put_user_ns(up->user_ns);
|
2007-10-15 23:00:14 +08:00
|
|
|
kmem_cache_free(uid_cachep, up);
|
|
|
|
|
}
|
|
|
|
|
|
2007-10-17 22:55:11 +08:00
|
|
|
#endif
|
2007-10-15 23:00:14 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* 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 *ret;
|
2006-02-01 08:34:26 +08:00
|
|
|
unsigned long flags;
|
2008-11-25 05:24:10 +08:00
|
|
|
struct user_namespace *ns = current_user_ns();
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_lock_irqsave(&uidhash_lock, flags);
|
2007-07-16 14:40:59 +08:00
|
|
|
ret = uid_hash_find(uid, uidhashentry(ns, uid));
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_unlock_irqrestore(&uidhash_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void free_uid(struct user_struct *up)
|
|
|
|
|
{
|
2006-02-01 08:34:26 +08:00
|
|
|
unsigned long flags;
|
|
|
|
|
|
2006-03-24 19:15:47 +08:00
|
|
|
if (!up)
|
|
|
|
|
return;
|
|
|
|
|
|
2006-02-01 08:34:26 +08:00
|
|
|
local_irq_save(flags);
|
2007-10-15 23:00:14 +08:00
|
|
|
if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
|
|
|
|
|
free_user(up, flags);
|
|
|
|
|
else
|
2006-03-24 19:15:47 +08:00
|
|
|
local_irq_restore(flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
2008-04-30 15:54:54 +08:00
|
|
|
struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2007-09-19 13:46:44 +08:00
|
|
|
struct hlist_head *hashent = uidhashentry(ns, uid);
|
2008-01-26 04:08:26 +08:00
|
|
|
struct user_struct *up, *new;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-11-02 20:47:53 +08:00
|
|
|
/* Make uid_hash_find() + uids_user_create() + uid_hash_insert()
|
2007-10-15 23:00:14 +08:00
|
|
|
* atomic.
|
|
|
|
|
*/
|
|
|
|
|
uids_mutex_lock();
|
|
|
|
|
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_lock_irq(&uidhash_lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
up = uid_hash_find(uid, hashent);
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_unlock_irq(&uidhash_lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
if (!up) {
|
2008-04-30 15:54:54 +08:00
|
|
|
new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL);
|
2008-01-26 04:08:26 +08:00
|
|
|
if (!new)
|
|
|
|
|
goto out_unlock;
|
2007-11-27 04:21:49 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
new->uid = uid;
|
|
|
|
|
atomic_set(&new->__count, 1);
|
|
|
|
|
|
2008-01-26 04:08:26 +08:00
|
|
|
if (sched_create_user(new) < 0)
|
2008-04-29 16:01:31 +08:00
|
|
|
goto out_free_user;
|
2007-10-15 23:00:09 +08:00
|
|
|
|
2008-10-16 05:38:45 +08:00
|
|
|
new->user_ns = get_user_ns(ns);
|
|
|
|
|
|
2008-01-26 04:08:26 +08:00
|
|
|
if (uids_user_create(new))
|
|
|
|
|
goto out_destoy_sched;
|
2007-10-15 23:00:14 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* Before adding this, check whether we raced
|
|
|
|
|
* on adding the same user already..
|
|
|
|
|
*/
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_lock_irq(&uidhash_lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
up = uid_hash_find(uid, hashent);
|
|
|
|
|
if (up) {
|
2008-02-13 22:45:40 +08:00
|
|
|
/* This case is not possible when CONFIG_USER_SCHED
|
2007-10-15 23:00:14 +08:00
|
|
|
* is defined, since we serialize alloc_uid() using
|
|
|
|
|
* uids_mutex. Hence no need to call
|
|
|
|
|
* sched_destroy_user() or remove_user_sysfs_dir().
|
|
|
|
|
*/
|
2005-04-17 06:20:36 +08:00
|
|
|
key_put(new->uid_keyring);
|
|
|
|
|
key_put(new->session_keyring);
|
|
|
|
|
kmem_cache_free(uid_cachep, new);
|
|
|
|
|
} else {
|
|
|
|
|
uid_hash_insert(new, hashent);
|
|
|
|
|
up = new;
|
|
|
|
|
}
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_unlock_irq(&uidhash_lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2007-10-15 23:00:14 +08:00
|
|
|
|
|
|
|
|
uids_mutex_unlock();
|
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
return up;
|
2008-01-26 04:08:26 +08:00
|
|
|
|
|
|
|
|
out_destoy_sched:
|
|
|
|
|
sched_destroy_user(new);
|
2008-10-16 05:38:45 +08:00
|
|
|
put_user_ns(new->user_ns);
|
2008-01-26 04:08:26 +08:00
|
|
|
out_free_user:
|
|
|
|
|
kmem_cache_free(uid_cachep, new);
|
|
|
|
|
out_unlock:
|
|
|
|
|
uids_mutex_unlock();
|
|
|
|
|
return NULL;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int __init uid_cache_init(void)
|
|
|
|
|
{
|
|
|
|
|
int n;
|
|
|
|
|
|
|
|
|
|
uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
|
2007-07-20 09:11:58 +08:00
|
|
|
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
for(n = 0; n < UIDHASH_SZ; ++n)
|
2007-09-19 13:46:44 +08:00
|
|
|
INIT_HLIST_HEAD(init_user_ns.uidhash_table + n);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
/* Insert the root user immediately (init already runs as root) */
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_lock_irq(&uidhash_lock);
|
2007-07-16 14:40:59 +08:00
|
|
|
uid_hash_insert(&root_user, uidhashentry(&init_user_ns, 0));
|
2006-02-01 08:34:26 +08:00
|
|
|
spin_unlock_irq(&uidhash_lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
module_init(uid_cache_init);
|