// SPDX-License-Identifier: GPL-2.0
|
/*
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* security/tomoyo/gc.c
|
*
|
* Copyright (C) 2005-2011 NTT DATA CORPORATION
|
*/
|
|
#include "common.h"
|
#include <linux/kthread.h>
|
#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)
|
kthread_run(tomoyo_gc_thread, NULL, "GC for TOMOYO");
|
}
|
