--- /dev/null
+/*
+ * 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) {
+ struct task_struct *task = kthread_create(tomoyo_gc_thread,
+ NULL,
+ "GC for TOMOYO");
+ if (!IS_ERR(task))
+ wake_up_process(task);
+ }
+}
Code Review / kvmfornfv.git / blobdiff