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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * 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 because
      * (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");
 }

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