linux/security/tomoyo/gc.c

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/*
* security/tomoyo/gc.c
*
* Copyright (C) 2005-2011 NTT DATA CORPORATION
*/
#include "common.h"
#include <linux/kthread.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
/**
* tomoyo_memory_free - Free memory for elements.
*
* @ptr: Pointer to allocated memory.
*
* Returns nothing.
*
* Caller holds tomoyo_policy_lock mutex.
*/
static inline void tomoyo_memory_free(void *ptr)
{
tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= ksize(ptr);
kfree(ptr);
}
/* The list for "struct tomoyo_io_buffer". */
static LIST_HEAD(tomoyo_io_buffer_list);
/* Lock for protecting tomoyo_io_buffer_list. */
static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock);
/**
* tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not.
*
* @element: Pointer to "struct list_head".
*
* Returns true if @element is used by /sys/kernel/security/tomoyo/ users,
* false otherwise.
*/
static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element)
{
struct tomoyo_io_buffer *head;
bool in_use = false;
spin_lock(&tomoyo_io_buffer_list_lock);
list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
head->users++;
spin_unlock(&tomoyo_io_buffer_list_lock);
mutex_lock(&head->io_sem);
if (head->r.domain == element || head->r.group == element ||
head->r.acl == element || &head->w.domain->list == element)
in_use = true;
mutex_unlock(&head->io_sem);
spin_lock(&tomoyo_io_buffer_list_lock);
head->users--;
if (in_use)
break;
}
spin_unlock(&tomoyo_io_buffer_list_lock);
return in_use;
}
/**
* tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not.
*
* @string: String to check.
*
* Returns true if @string is used by /sys/kernel/security/tomoyo/ users,
* false otherwise.
*/
static bool tomoyo_name_used_by_io_buffer(const char *string)
{
struct tomoyo_io_buffer *head;
const size_t size = strlen(string) + 1;
bool in_use = false;
spin_lock(&tomoyo_io_buffer_list_lock);
list_for_each_entry(head, &tomoyo_io_buffer_list, list) {
int i;
head->users++;
spin_unlock(&tomoyo_io_buffer_list_lock);
mutex_lock(&head->io_sem);
for (i = 0; i < TOMOYO_MAX_IO_READ_QUEUE; i++) {
const char *w = head->r.w[i];
if (w < string || w > string + size)
continue;
in_use = true;
break;
}
mutex_unlock(&head->io_sem);
spin_lock(&tomoyo_io_buffer_list_lock);
head->users--;
if (in_use)
break;
}
spin_unlock(&tomoyo_io_buffer_list_lock);
return in_use;
}
/**
* tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_transition_control(struct list_head *element)
{
struct tomoyo_transition_control *ptr =
container_of(element, typeof(*ptr), head.list);
tomoyo_put_name(ptr->domainname);
tomoyo_put_name(ptr->program);
}
/**
* tomoyo_del_aggregator - Delete members in "struct tomoyo_aggregator".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_aggregator(struct list_head *element)
{
struct tomoyo_aggregator *ptr =
container_of(element, typeof(*ptr), head.list);
tomoyo_put_name(ptr->original_name);
tomoyo_put_name(ptr->aggregated_name);
}
/**
* tomoyo_del_manager - Delete members in "struct tomoyo_manager".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_manager(struct list_head *element)
{
struct tomoyo_manager *ptr =
container_of(element, typeof(*ptr), head.list);
tomoyo_put_name(ptr->manager);
}
/**
* tomoyo_del_acl - Delete members in "struct tomoyo_acl_info".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static void tomoyo_del_acl(struct list_head *element)
{
struct tomoyo_acl_info *acl =
container_of(element, typeof(*acl), list);
tomoyo_put_condition(acl->cond);
switch (acl->type) {
case TOMOYO_TYPE_PATH_ACL:
{
struct tomoyo_path_acl *entry
= container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->name);
}
break;
case TOMOYO_TYPE_PATH2_ACL:
{
struct tomoyo_path2_acl *entry
= container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->name1);
tomoyo_put_name_union(&entry->name2);
}
break;
case TOMOYO_TYPE_PATH_NUMBER_ACL:
{
struct tomoyo_path_number_acl *entry
= container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->name);
tomoyo_put_number_union(&entry->number);
}
break;
case TOMOYO_TYPE_MKDEV_ACL:
{
struct tomoyo_mkdev_acl *entry
= container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->name);
tomoyo_put_number_union(&entry->mode);
tomoyo_put_number_union(&entry->major);
tomoyo_put_number_union(&entry->minor);
}
break;
case TOMOYO_TYPE_MOUNT_ACL:
{
struct tomoyo_mount_acl *entry
= container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->dev_name);
tomoyo_put_name_union(&entry->dir_name);
tomoyo_put_name_union(&entry->fs_type);
tomoyo_put_number_union(&entry->flags);
}
break;
case TOMOYO_TYPE_ENV_ACL:
{
struct tomoyo_env_acl *entry =
container_of(acl, typeof(*entry), head);
tomoyo_put_name(entry->env);
}
break;
case TOMOYO_TYPE_INET_ACL:
{
struct tomoyo_inet_acl *entry =
container_of(acl, typeof(*entry), head);
tomoyo_put_group(entry->address.group);
tomoyo_put_number_union(&entry->port);
}
break;
case TOMOYO_TYPE_UNIX_ACL:
{
struct tomoyo_unix_acl *entry =
container_of(acl, typeof(*entry), head);
tomoyo_put_name_union(&entry->name);
}
break;
case TOMOYO_TYPE_MANUAL_TASK_ACL:
{
struct tomoyo_task_acl *entry =
container_of(acl, typeof(*entry), head);
tomoyo_put_name(entry->domainname);
}
break;
}
}
/**
* tomoyo_del_domain - Delete members in "struct tomoyo_domain_info".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*
* Caller holds tomoyo_policy_lock mutex.
*/
static inline void tomoyo_del_domain(struct list_head *element)
{
struct tomoyo_domain_info *domain =
container_of(element, typeof(*domain), list);
struct tomoyo_acl_info *acl;
struct tomoyo_acl_info *tmp;
/*
* Since this domain is referenced from neither
* "struct tomoyo_io_buffer" nor "struct cred"->security, we can delete
* elements without checking for is_deleted flag.
*/
list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) {
tomoyo_del_acl(&acl->list);
tomoyo_memory_free(acl);
}
tomoyo_put_name(domain->domainname);
}
/**
* tomoyo_del_condition - Delete members in "struct tomoyo_condition".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
void tomoyo_del_condition(struct list_head *element)
{
struct tomoyo_condition *cond = container_of(element, typeof(*cond),
head.list);
const u16 condc = cond->condc;
const u16 numbers_count = cond->numbers_count;
const u16 names_count = cond->names_count;
const u16 argc = cond->argc;
const u16 envc = cond->envc;
unsigned int i;
const struct tomoyo_condition_element *condp
= (const struct tomoyo_condition_element *) (cond + 1);
struct tomoyo_number_union *numbers_p
= (struct tomoyo_number_union *) (condp + condc);
struct tomoyo_name_union *names_p
= (struct tomoyo_name_union *) (numbers_p + numbers_count);
const struct tomoyo_argv *argv
= (const struct tomoyo_argv *) (names_p + names_count);
const struct tomoyo_envp *envp
= (const struct tomoyo_envp *) (argv + argc);
for (i = 0; i < numbers_count; i++)
tomoyo_put_number_union(numbers_p++);
for (i = 0; i < names_count; i++)
tomoyo_put_name_union(names_p++);
for (i = 0; i < argc; argv++, i++)
tomoyo_put_name(argv->value);
for (i = 0; i < envc; envp++, i++) {
tomoyo_put_name(envp->name);
tomoyo_put_name(envp->value);
}
}
/**
* tomoyo_del_name - Delete members in "struct tomoyo_name".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_name(struct list_head *element)
{
/* Nothing to do. */
}
/**
* tomoyo_del_path_group - Delete members in "struct tomoyo_path_group".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_path_group(struct list_head *element)
{
struct tomoyo_path_group *member =
container_of(element, typeof(*member), head.list);
tomoyo_put_name(member->member_name);
}
/**
* tomoyo_del_group - Delete "struct tomoyo_group".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_group(struct list_head *element)
{
struct tomoyo_group *group =
container_of(element, typeof(*group), head.list);
tomoyo_put_name(group->group_name);
}
/**
* tomoyo_del_address_group - Delete members in "struct tomoyo_address_group".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_address_group(struct list_head *element)
{
/* Nothing to do. */
}
/**
* tomoyo_del_number_group - Delete members in "struct tomoyo_number_group".
*
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*/
static inline void tomoyo_del_number_group(struct list_head *element)
{
/* Nothing to do. */
}
/**
* tomoyo_try_to_gc - Try to kfree() an entry.
*
* @type: One of values in "enum tomoyo_policy_id".
* @element: Pointer to "struct list_head".
*
* Returns nothing.
*
* Caller holds tomoyo_policy_lock mutex.
*/
static void tomoyo_try_to_gc(const enum tomoyo_policy_id type,
struct list_head *element)
{
/*
* __list_del_entry() guarantees that the list element became no longer
* reachable from the list which the element was originally on (e.g.
* tomoyo_domain_list). Also, synchronize_srcu() guarantees that the
* list element became no longer referenced by syscall users.
*/
__list_del_entry(element);
mutex_unlock(&tomoyo_policy_lock);
synchronize_srcu(&tomoyo_ss);
/*
* However, there are two users which may still be using the list
* element. We need to defer until both users forget this element.
*
* Don't kfree() until "struct tomoyo_io_buffer"->r.{domain,group,acl}
* and "struct tomoyo_io_buffer"->w.domain forget this element.
*/
if (tomoyo_struct_used_by_io_buffer(element))
goto reinject;
switch (type) {
case TOMOYO_ID_TRANSITION_CONTROL:
tomoyo_del_transition_control(element);
break;
case TOMOYO_ID_MANAGER:
tomoyo_del_manager(element);
break;
case TOMOYO_ID_AGGREGATOR:
tomoyo_del_aggregator(element);
break;
case TOMOYO_ID_GROUP:
tomoyo_del_group(element);
break;
case TOMOYO_ID_PATH_GROUP:
tomoyo_del_path_group(element);
break;
case TOMOYO_ID_ADDRESS_GROUP:
tomoyo_del_address_group(element);
break;
case TOMOYO_ID_NUMBER_GROUP:
tomoyo_del_number_group(element);
break;
case TOMOYO_ID_CONDITION:
tomoyo_del_condition(element);
break;
case TOMOYO_ID_NAME:
/*
* Don't kfree() until all "struct tomoyo_io_buffer"->r.w[]
* forget this element.
*/
if (tomoyo_name_used_by_io_buffer
(container_of(element, typeof(struct tomoyo_name),
head.list)->entry.name))
goto reinject;
tomoyo_del_name(element);
break;
case TOMOYO_ID_ACL:
tomoyo_del_acl(element);
break;
case TOMOYO_ID_DOMAIN:
/*
* Don't kfree() until all "struct cred"->security forget this
* element.
*/
if (atomic_read(&container_of
(element, typeof(struct tomoyo_domain_info),
list)->users))
goto reinject;
break;
case TOMOYO_MAX_POLICY:
break;
}
mutex_lock(&tomoyo_policy_lock);
if (type == TOMOYO_ID_DOMAIN)
tomoyo_del_domain(element);
tomoyo_memory_free(element);
return;
reinject:
/*
* We can safely reinject this element here bacause
* (1) Appending list elements and removing list elements are protected
* by tomoyo_policy_lock mutex.
* (2) Only this function removes list elements and this function is
* exclusively executed by tomoyo_gc_mutex mutex.
* are true.
*/
mutex_lock(&tomoyo_policy_lock);
list_add_rcu(element, element->prev);
}
/**
* tomoyo_collect_member - Delete elements with "struct tomoyo_acl_head".
*
* @id: One of values in "enum tomoyo_policy_id".
* @member_list: Pointer to "struct list_head".
*
* Returns nothing.
*/
static void tomoyo_collect_member(const enum tomoyo_policy_id id,
struct list_head *member_list)
{
struct tomoyo_acl_head *member;
struct tomoyo_acl_head *tmp;
list_for_each_entry_safe(member, tmp, member_list, list) {
if (!member->is_deleted)
continue;
member->is_deleted = TOMOYO_GC_IN_PROGRESS;
tomoyo_try_to_gc(id, &member->list);
}
}
/**
* tomoyo_collect_acl - Delete elements in "struct tomoyo_domain_info".
*
* @list: Pointer to "struct list_head".
*
* Returns nothing.
*/
static void tomoyo_collect_acl(struct list_head *list)
{
struct tomoyo_acl_info *acl;
struct tomoyo_acl_info *tmp;
list_for_each_entry_safe(acl, tmp, list, list) {
if (!acl->is_deleted)
continue;
acl->is_deleted = TOMOYO_GC_IN_PROGRESS;
tomoyo_try_to_gc(TOMOYO_ID_ACL, &acl->list);
}
}
/**
* tomoyo_collect_entry - Try to kfree() deleted elements.
*
* Returns nothing.
*/
static void tomoyo_collect_entry(void)
{
int i;
enum tomoyo_policy_id id;
struct tomoyo_policy_namespace *ns;
mutex_lock(&tomoyo_policy_lock);
{
struct tomoyo_domain_info *domain;
struct tomoyo_domain_info *tmp;
list_for_each_entry_safe(domain, tmp, &tomoyo_domain_list,
list) {
tomoyo_collect_acl(&domain->acl_info_list);
if (!domain->is_deleted || atomic_read(&domain->users))
continue;
tomoyo_try_to_gc(TOMOYO_ID_DOMAIN, &domain->list);
}
}
list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
for (id = 0; id < TOMOYO_MAX_POLICY; id++)
tomoyo_collect_member(id, &ns->policy_list[id]);
for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++)
tomoyo_collect_acl(&ns->acl_group[i]);
}
{
struct tomoyo_shared_acl_head *ptr;
struct tomoyo_shared_acl_head *tmp;
list_for_each_entry_safe(ptr, tmp, &tomoyo_condition_list,
list) {
if (atomic_read(&ptr->users) > 0)
continue;
atomic_set(&ptr->users, TOMOYO_GC_IN_PROGRESS);
tomoyo_try_to_gc(TOMOYO_ID_CONDITION, &ptr->list);
}
}
list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
for (i = 0; i < TOMOYO_MAX_GROUP; i++) {
struct list_head *list = &ns->group_list[i];
struct tomoyo_group *group;
struct tomoyo_group *tmp;
switch (i) {
case 0:
id = TOMOYO_ID_PATH_GROUP;
break;
case 1:
id = TOMOYO_ID_NUMBER_GROUP;
break;
default:
id = TOMOYO_ID_ADDRESS_GROUP;
break;
}
list_for_each_entry_safe(group, tmp, list, head.list) {
tomoyo_collect_member(id, &group->member_list);
if (!list_empty(&group->member_list) ||
atomic_read(&group->head.users) > 0)
continue;
atomic_set(&group->head.users,
TOMOYO_GC_IN_PROGRESS);
tomoyo_try_to_gc(TOMOYO_ID_GROUP,
&group->head.list);
}
}
}
for (i = 0; i < TOMOYO_MAX_HASH; i++) {
struct list_head *list = &tomoyo_name_list[i];
struct tomoyo_shared_acl_head *ptr;
struct tomoyo_shared_acl_head *tmp;
list_for_each_entry_safe(ptr, tmp, list, list) {
if (atomic_read(&ptr->users) > 0)
continue;
atomic_set(&ptr->users, TOMOYO_GC_IN_PROGRESS);
tomoyo_try_to_gc(TOMOYO_ID_NAME, &ptr->list);
}
}
mutex_unlock(&tomoyo_policy_lock);
}
/**
* tomoyo_gc_thread - Garbage collector thread function.
*
* @unused: Unused.
*
* Returns 0.
*/
static int tomoyo_gc_thread(void *unused)
{
/* Garbage collector thread is exclusive. */
static DEFINE_MUTEX(tomoyo_gc_mutex);
if (!mutex_trylock(&tomoyo_gc_mutex))
goto out;
tomoyo_collect_entry();
{
struct tomoyo_io_buffer *head;
struct tomoyo_io_buffer *tmp;
spin_lock(&tomoyo_io_buffer_list_lock);
list_for_each_entry_safe(head, tmp, &tomoyo_io_buffer_list,
list) {
if (head->users)
continue;
list_del(&head->list);
kfree(head->read_buf);
kfree(head->write_buf);
kfree(head);
}
spin_unlock(&tomoyo_io_buffer_list_lock);
}
mutex_unlock(&tomoyo_gc_mutex);
out:
/* This acts as do_exit(0). */
return 0;
}
/**
* tomoyo_notify_gc - Register/unregister /sys/kernel/security/tomoyo/ users.
*
* @head: Pointer to "struct tomoyo_io_buffer".
* @is_register: True if register, false if unregister.
*
* Returns nothing.
*/
void tomoyo_notify_gc(struct tomoyo_io_buffer *head, const bool is_register)
{
bool is_write = false;
spin_lock(&tomoyo_io_buffer_list_lock);
if (is_register) {
head->users = 1;
list_add(&head->list, &tomoyo_io_buffer_list);
} else {
is_write = head->write_buf != NULL;
if (!--head->users) {
list_del(&head->list);
kfree(head->read_buf);
kfree(head->write_buf);
kfree(head);
}
}
spin_unlock(&tomoyo_io_buffer_list_lock);
if (is_write) {
struct task_struct *task = kthread_create(tomoyo_gc_thread,
NULL,
"GC for TOMOYO");
if (!IS_ERR(task))
wake_up_process(task);
}
}