diff options
| -rw-r--r-- | security/tomoyo/common.h | 7 | ||||
| -rw-r--r-- | security/tomoyo/condition.c | 8 | ||||
| -rw-r--r-- | security/tomoyo/domain.c | 4 | ||||
| -rw-r--r-- | security/tomoyo/gc.c | 480 | ||||
| -rw-r--r-- | security/tomoyo/memory.c | 6 |
5 files changed, 186 insertions, 319 deletions
diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h index 1a19ad3e67e..a0212fbf60f 100644 --- a/security/tomoyo/common.h +++ b/security/tomoyo/common.h @@ -52,6 +52,9 @@ #define TOMOYO_EXEC_TMPSIZE 4096 +/* Garbage collector is trying to kfree() this element. */ +#define TOMOYO_GC_IN_PROGRESS -1 + /* Profile number is an integer between 0 and 255. */ #define TOMOYO_MAX_PROFILES 256 @@ -398,7 +401,7 @@ enum tomoyo_pref_index { /* Common header for holding ACL entries. */ struct tomoyo_acl_head { struct list_head list; - bool is_deleted; + s8 is_deleted; /* true or false or TOMOYO_GC_IN_PROGRESS */ } __packed; /* Common header for shared entries. */ @@ -665,7 +668,7 @@ struct tomoyo_condition { struct tomoyo_acl_info { struct list_head list; struct tomoyo_condition *cond; /* Maybe NULL. */ - bool is_deleted; + s8 is_deleted; /* true or false or TOMOYO_GC_IN_PROGRESS */ u8 type; /* One of values in "enum tomoyo_acl_entry_type_index". */ } __packed; diff --git a/security/tomoyo/condition.c b/security/tomoyo/condition.c index b854959c0fd..986330b8c73 100644 --- a/security/tomoyo/condition.c +++ b/security/tomoyo/condition.c @@ -400,8 +400,9 @@ static struct tomoyo_condition *tomoyo_commit_condition found = true; goto out; } - list_for_each_entry_rcu(ptr, &tomoyo_condition_list, head.list) { - if (!tomoyo_same_condition(ptr, entry)) + list_for_each_entry(ptr, &tomoyo_condition_list, head.list) { + if (!tomoyo_same_condition(ptr, entry) || + atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS) continue; /* Same entry found. Share this entry. */ atomic_inc(&ptr->head.users); @@ -411,8 +412,7 @@ static struct tomoyo_condition *tomoyo_commit_condition if (!found) { if (tomoyo_memory_ok(entry)) { atomic_set(&entry->head.users, 1); - list_add_rcu(&entry->head.list, - &tomoyo_condition_list); + list_add(&entry->head.list, &tomoyo_condition_list); } else { found = true; ptr = NULL; diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c index 70acf7aebbd..da16dfeed72 100644 --- a/security/tomoyo/domain.c +++ b/security/tomoyo/domain.c @@ -39,6 +39,8 @@ int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size, if (mutex_lock_interruptible(&tomoyo_policy_lock)) return -ENOMEM; list_for_each_entry_rcu(entry, list, list) { + if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS) + continue; if (!check_duplicate(entry, new_entry)) continue; entry->is_deleted = param->is_delete; @@ -115,6 +117,8 @@ int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size, if (mutex_lock_interruptible(&tomoyo_policy_lock)) goto out; list_for_each_entry_rcu(entry, list, list) { + if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS) + continue; if (!tomoyo_same_acl_head(entry, new_entry) || !check_duplicate(entry, new_entry)) continue; diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c index 7747ceb9a22..f2295c65f1e 100644 --- a/security/tomoyo/gc.c +++ b/security/tomoyo/gc.c @@ -13,35 +13,6 @@ static LIST_HEAD(tomoyo_io_buffer_list); /* Lock for protecting tomoyo_io_buffer_list. */ static DEFINE_SPINLOCK(tomoyo_io_buffer_list_lock); -/* Size of an element. */ -static const u8 tomoyo_element_size[TOMOYO_MAX_POLICY] = { - [TOMOYO_ID_GROUP] = sizeof(struct tomoyo_group), - [TOMOYO_ID_ADDRESS_GROUP] = sizeof(struct tomoyo_address_group), - [TOMOYO_ID_PATH_GROUP] = sizeof(struct tomoyo_path_group), - [TOMOYO_ID_NUMBER_GROUP] = sizeof(struct tomoyo_number_group), - [TOMOYO_ID_AGGREGATOR] = sizeof(struct tomoyo_aggregator), - [TOMOYO_ID_TRANSITION_CONTROL] = - sizeof(struct tomoyo_transition_control), - [TOMOYO_ID_MANAGER] = sizeof(struct tomoyo_manager), - /* [TOMOYO_ID_CONDITION] = "struct tomoyo_condition"->size, */ - /* [TOMOYO_ID_NAME] = "struct tomoyo_name"->size, */ - /* [TOMOYO_ID_ACL] = - tomoyo_acl_size["struct tomoyo_acl_info"->type], */ - [TOMOYO_ID_DOMAIN] = sizeof(struct tomoyo_domain_info), -}; - -/* Size of a domain ACL element. */ -static const u8 tomoyo_acl_size[] = { - [TOMOYO_TYPE_PATH_ACL] = sizeof(struct tomoyo_path_acl), - [TOMOYO_TYPE_PATH2_ACL] = sizeof(struct tomoyo_path2_acl), - [TOMOYO_TYPE_PATH_NUMBER_ACL] = sizeof(struct tomoyo_path_number_acl), - [TOMOYO_TYPE_MKDEV_ACL] = sizeof(struct tomoyo_mkdev_acl), - [TOMOYO_TYPE_MOUNT_ACL] = sizeof(struct tomoyo_mount_acl), - [TOMOYO_TYPE_INET_ACL] = sizeof(struct tomoyo_inet_acl), - [TOMOYO_TYPE_UNIX_ACL] = sizeof(struct tomoyo_unix_acl), - [TOMOYO_TYPE_ENV_ACL] = sizeof(struct tomoyo_env_acl), -}; - /** * tomoyo_struct_used_by_io_buffer - Check whether the list element is used by /sys/kernel/security/tomoyo/ users or not. * @@ -59,15 +30,11 @@ static bool tomoyo_struct_used_by_io_buffer(const struct list_head *element) list_for_each_entry(head, &tomoyo_io_buffer_list, list) { head->users++; spin_unlock(&tomoyo_io_buffer_list_lock); - if (mutex_lock_interruptible(&head->io_sem)) { - in_use = true; - goto out; - } + 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); -out: spin_lock(&tomoyo_io_buffer_list_lock); head->users--; if (in_use) @@ -81,15 +48,14 @@ out: * tomoyo_name_used_by_io_buffer - Check whether the string is used by /sys/kernel/security/tomoyo/ users or not. * * @string: String to check. - * @size: Memory allocated for @string . * * 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, - const size_t size) +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); @@ -97,10 +63,7 @@ static bool tomoyo_name_used_by_io_buffer(const char *string, int i; head->users++; spin_unlock(&tomoyo_io_buffer_list_lock); - if (mutex_lock_interruptible(&head->io_sem)) { - in_use = true; - goto out; - } + 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) @@ -109,7 +72,6 @@ static bool tomoyo_name_used_by_io_buffer(const char *string, break; } mutex_unlock(&head->io_sem); -out: spin_lock(&tomoyo_io_buffer_list_lock); head->users--; if (in_use) @@ -119,84 +81,6 @@ out: return in_use; } -/* Structure for garbage collection. */ -struct tomoyo_gc { - struct list_head list; - enum tomoyo_policy_id type; - size_t size; - struct list_head *element; -}; -/* List of entries to be deleted. */ -static LIST_HEAD(tomoyo_gc_list); -/* Length of tomoyo_gc_list. */ -static int tomoyo_gc_list_len; - -/** - * tomoyo_add_to_gc - Add an entry to to be deleted list. - * - * @type: One of values in "enum tomoyo_policy_id". - * @element: Pointer to "struct list_head". - * - * Returns true on success, false otherwise. - * - * Caller holds tomoyo_policy_lock mutex. - * - * Adding an entry needs kmalloc(). Thus, if we try to add thousands of - * entries at once, it will take too long time. Thus, do not add more than 128 - * entries per a scan. But to be able to handle worst case where all entries - * are in-use, we accept one more entry per a scan. - * - * If we use singly linked list using "struct list_head"->prev (which is - * LIST_POISON2), we can avoid kmalloc(). - */ -static bool tomoyo_add_to_gc(const int type, struct list_head *element) -{ - struct tomoyo_gc *entry = kzalloc(sizeof(*entry), GFP_ATOMIC); - if (!entry) - return false; - entry->type = type; - if (type == TOMOYO_ID_ACL) - entry->size = tomoyo_acl_size[ - container_of(element, - typeof(struct tomoyo_acl_info), - list)->type]; - else if (type == TOMOYO_ID_NAME) - entry->size = strlen(container_of(element, - typeof(struct tomoyo_name), - head.list)->entry.name) + 1; - else if (type == TOMOYO_ID_CONDITION) - entry->size = - container_of(element, typeof(struct tomoyo_condition), - head.list)->size; - else - entry->size = tomoyo_element_size[type]; - entry->element = element; - list_add(&entry->list, &tomoyo_gc_list); - list_del_rcu(element); - return tomoyo_gc_list_len++ < 128; -} - -/** - * tomoyo_element_linked_by_gc - Validate next element of an entry. - * - * @element: Pointer to an element. - * @size: Size of @element in byte. - * - * Returns true if @element is linked by other elements in the garbage - * collector's queue, false otherwise. - */ -static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size) -{ - struct tomoyo_gc *p; - list_for_each_entry(p, &tomoyo_gc_list, list) { - const u8 *ptr = (const u8 *) p->element->next; - if (ptr < element || element + size < ptr) - continue; - return true; - } - return false; -} - /** * tomoyo_del_transition_control - Delete members in "struct tomoyo_transition_control". * @@ -204,7 +88,7 @@ static bool tomoyo_element_linked_by_gc(const u8 *element, const size_t size) * * Returns nothing. */ -static void tomoyo_del_transition_control(struct list_head *element) +static inline void tomoyo_del_transition_control(struct list_head *element) { struct tomoyo_transition_control *ptr = container_of(element, typeof(*ptr), head.list); @@ -219,7 +103,7 @@ static void tomoyo_del_transition_control(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_aggregator(struct list_head *element) +static inline void tomoyo_del_aggregator(struct list_head *element) { struct tomoyo_aggregator *ptr = container_of(element, typeof(*ptr), head.list); @@ -234,7 +118,7 @@ static void tomoyo_del_aggregator(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_manager(struct list_head *element) +static inline void tomoyo_del_manager(struct list_head *element) { struct tomoyo_manager *ptr = container_of(element, typeof(*ptr), head.list); @@ -330,44 +214,24 @@ static void tomoyo_del_acl(struct list_head *element) * * @element: Pointer to "struct list_head". * - * Returns true if deleted, false otherwise. + * Returns nothing. */ -static bool tomoyo_del_domain(struct list_head *element) +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 we don't protect whole execve() operation using SRCU, - * we need to recheck domain->users at this point. - * - * (1) Reader starts SRCU section upon execve(). - * (2) Reader traverses tomoyo_domain_list and finds this domain. - * (3) Writer marks this domain as deleted. - * (4) Garbage collector removes this domain from tomoyo_domain_list - * because this domain is marked as deleted and used by nobody. - * (5) Reader saves reference to this domain into - * "struct linux_binprm"->cred->security . - * (6) Reader finishes SRCU section, although execve() operation has - * not finished yet. - * (7) Garbage collector waits for SRCU synchronization. - * (8) Garbage collector kfree() this domain because this domain is - * used by nobody. - * (9) Reader finishes execve() operation and restores this domain from - * "struct linux_binprm"->cred->security. - * - * By updating domain->users at (5), we can solve this race problem - * by rechecking domain->users at (8). + * 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. */ - if (atomic_read(&domain->users)) - return false; 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); - return true; } /** @@ -416,10 +280,9 @@ void tomoyo_del_condition(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_name(struct list_head *element) +static inline void tomoyo_del_name(struct list_head *element) { - const struct tomoyo_name *ptr = - container_of(element, typeof(*ptr), head.list); + /* Nothing to do. */ } /** @@ -429,7 +292,7 @@ static void tomoyo_del_name(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_path_group(struct list_head *element) +static inline void tomoyo_del_path_group(struct list_head *element) { struct tomoyo_path_group *member = container_of(element, typeof(*member), head.list); @@ -443,7 +306,7 @@ static void tomoyo_del_path_group(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_group(struct list_head *element) +static inline void tomoyo_del_group(struct list_head *element) { struct tomoyo_group *group = container_of(element, typeof(*group), head.list); @@ -469,10 +332,109 @@ static inline void tomoyo_del_address_group(struct list_head *element) * * Returns nothing. */ -static void tomoyo_del_number_group(struct list_head *element) +static inline void tomoyo_del_number_group(struct list_head *element) { - struct tomoyo_number_group *member = - container_of(element, typeof(*member), head.list); + /* 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; + tomoyo_del_domain(element); + break; + case TOMOYO_MAX_POLICY: + break; + } + mutex_lock(&tomoyo_policy_lock); + 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); } /** @@ -481,19 +443,19 @@ static void tomoyo_del_number_group(struct list_head *element) * @id: One of values in "enum tomoyo_policy_id". * @member_list: Pointer to "struct list_head". * - * Returns true if some elements are deleted, false otherwise. + * Returns nothing. */ -static bool tomoyo_collect_member(const enum tomoyo_policy_id id, +static void tomoyo_collect_member(const enum tomoyo_policy_id id, struct list_head *member_list) { struct tomoyo_acl_head *member; - list_for_each_entry(member, member_list, list) { + struct tomoyo_acl_head *tmp; + list_for_each_entry_safe(member, tmp, member_list, list) { if (!member->is_deleted) continue; - if (!tomoyo_add_to_gc(id, &member->list)) - return false; + member->is_deleted = TOMOYO_GC_IN_PROGRESS; + tomoyo_try_to_gc(id, &member->list); } - return true; } /** @@ -501,22 +463,22 @@ static bool tomoyo_collect_member(const enum tomoyo_policy_id id, * * @list: Pointer to "struct list_head". * - * Returns true if some elements are deleted, false otherwise. + * Returns nothing. */ -static bool tomoyo_collect_acl(struct list_head *list) +static void tomoyo_collect_acl(struct list_head *list) { struct tomoyo_acl_info *acl; - list_for_each_entry(acl, list, list) { + struct tomoyo_acl_info *tmp; + list_for_each_entry_safe(acl, tmp, list, list) { if (!acl->is_deleted) continue; - if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list)) - return false; + acl->is_deleted = TOMOYO_GC_IN_PROGRESS; + tomoyo_try_to_gc(TOMOYO_ID_ACL, &acl->list); } - return true; } /** - * tomoyo_collect_entry - Scan lists for deleted elements. + * tomoyo_collect_entry - Try to kfree() deleted elements. * * Returns nothing. */ @@ -525,36 +487,40 @@ static void tomoyo_collect_entry(void) int i; enum tomoyo_policy_id id; struct tomoyo_policy_namespace *ns; - int idx; - if (mutex_lock_interruptible(&tomoyo_policy_lock)) - return; - idx = tomoyo_read_lock(); + mutex_lock(&tomoyo_policy_lock); { struct tomoyo_domain_info *domain; - list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) { - if (!tomoyo_collect_acl(&domain->acl_info_list)) - goto unlock; + 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; - /* - * Nobody is referring this domain. But somebody may - * refer this domain after successful execve(). - * We recheck domain->users after SRCU synchronization. - */ - if (!tomoyo_add_to_gc(TOMOYO_ID_DOMAIN, &domain->list)) - goto unlock; + tomoyo_try_to_gc(TOMOYO_ID_DOMAIN, &domain->list); } } - list_for_each_entry_rcu(ns, &tomoyo_namespace_list, namespace_list) { + list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) { for (id = 0; id < TOMOYO_MAX_POLICY; id++) - if (!tomoyo_collect_member(id, &ns->policy_list[id])) - goto unlock; + tomoyo_collect_member(id, &ns->policy_list[id]); for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++) - if (!tomoyo_collect_acl(&ns->acl_group[i])) - goto unlock; + 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; @@ -566,139 +532,37 @@ static void tomoyo_collect_entry(void) id = TOMOYO_ID_ADDRESS_GROUP; break; } - list_for_each_entry(group, list, head.list) { - if (!tomoyo_collect_member - (id, &group->member_list)) - goto unlock; + 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)) + atomic_read(&group->head.users) > 0) continue; - if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP, - &group->head.list)) - goto unlock; + atomic_set(&group->head.users, + TOMOYO_GC_IN_PROGRESS); + tomoyo_try_to_gc(TOMOYO_ID_GROUP, + &group->head.list); } } } - id = TOMOYO_ID_CONDITION; - for (i = 0; i < TOMOYO_MAX_HASH + 1; i++) { - struct list_head *list = !i ? - &tomoyo_condition_list : &tomoyo_name_list[i - 1]; + for (i = 0; i < TOMOYO_MAX_HASH; i++) { + struct list_head *list = &tomoyo_name_list[i]; struct tomoyo_shared_acl_head *ptr; - list_for_each_entry(ptr, list, list) { - if (atomic_read(&ptr->users)) + struct tomoyo_shared_acl_head *tmp; + list_for_each_entry_safe(ptr, tmp, list, list) { + if (atomic_read(&ptr->users) > 0) continue; - if (!tomoyo_add_to_gc(id, &ptr->list)) - goto unlock; + atomic_set(&ptr->users, TOMOYO_GC_IN_PROGRESS); + tomoyo_try_to_gc(TOMOYO_ID_NAME, &ptr->list); } - id = TOMOYO_ID_NAME; } -unlock: - tomoyo_read_unlock(idx); mutex_unlock(&tomoyo_policy_lock); } /** - * tomoyo_kfree_entry - Delete entries in tomoyo_gc_list. - * - * Returns true if some entries were kfree()d, false otherwise. - */ -static bool tomoyo_kfree_entry(void) -{ - struct tomoyo_gc *p; - struct tomoyo_gc *tmp; - bool result = false; - - list_for_each_entry_safe(p, tmp, &tomoyo_gc_list, list) { - struct list_head *element = p->element; - - /* - * list_del_rcu() in tomoyo_add_to_gc() 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() in tomoyo_gc_thread() guarantees - * that the list element became no longer referenced by syscall - * users. - * - * However, there are three users which may still be using the - * list element. We need to defer until all of these users - * forget the list element. - * - * Firstly, defer until "struct tomoyo_io_buffer"->r.{domain, - * group,acl} and "struct tomoyo_io_buffer"->w.domain forget - * the list element. - */ - if (tomoyo_struct_used_by_io_buffer(element)) - continue; - /* - * Secondly, defer until all other elements in the - * tomoyo_gc_list list forget the list element. - */ - if (tomoyo_element_linked_by_gc((const u8 *) element, p->size)) - continue; - switch (p->type) { - case TOMOYO_ID_TRANSITION_CONTROL: - tomoyo_del_transition_control(element); - break; - case TOMOYO_ID_AGGREGATOR: - tomoyo_del_aggregator(element); - break; - case TOMOYO_ID_MANAGER: - tomoyo_del_manager(element); - break; - case TOMOYO_ID_CONDITION: - tomoyo_del_condition(element); - break; - case TOMOYO_ID_NAME: - /* - * Thirdly, defer until all "struct tomoyo_io_buffer" - * ->r.w[] forget the list element. - */ - if (tomoyo_name_used_by_io_buffer( - container_of(element, typeof(struct tomoyo_name), - head.list)->entry.name, p->size)) - continue; - tomoyo_del_name(element); - break; - case TOMOYO_ID_ACL: - tomoyo_del_acl(element); - break; - case TOMOYO_ID_DOMAIN: - if (!tomoyo_del_domain(element)) - continue; - 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_GROUP: - tomoyo_del_group(element); - break; - case TOMOYO_ID_NUMBER_GROUP: - tomoyo_del_number_group(element); - break; - case TOMOYO_MAX_POLICY: - break; - } - tomoyo_memory_free(element); - list_del(&p->list); - kfree(p); - tomoyo_gc_list_len--; - result = true; - } - return result; -} - -/** * tomoyo_gc_thread - Garbage collector thread function. * * @unused: Unused. * - * In case OOM-killer choose this thread for termination, we create this thread - * as a short live thread whenever /sys/kernel/security/tomoyo/ interface was - * close()d. - * * Returns 0. */ static int tomoyo_gc_thread(void *unused) @@ -707,13 +571,7 @@ static int tomoyo_gc_thread(void *unused) static DEFINE_MUTEX(tomoyo_gc_mutex); if (!mutex_trylock(&tomoyo_gc_mutex)) goto out; - - do { - tomoyo_collect_entry(); - if (list_empty(&tomoyo_gc_list)) - break; - synchronize_srcu(&tomoyo_ss); - } while (tomoyo_kfree_entry()); + tomoyo_collect_entry(); { struct tomoyo_io_buffer *head; struct tomoyo_io_buffer *tmp; diff --git a/security/tomoyo/memory.c b/security/tomoyo/memory.c index 7a56051146c..277b9ade440 100644 --- a/security/tomoyo/memory.c +++ b/security/tomoyo/memory.c @@ -123,7 +123,8 @@ struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param, goto out; list = ¶m->ns->group_list[idx]; list_for_each_entry(group, list, head.list) { - if (e.group_name != group->group_name) + if (e.group_name != group->group_name || + atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS) continue; atomic_inc(&group->head.users); found = true; @@ -175,7 +176,8 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name) if (mutex_lock_interruptible(&tomoyo_policy_lock)) return NULL; list_for_each_entry(ptr, head, head.list) { - if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name)) + if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) || + atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS) continue; atomic_inc(&ptr->head.users); goto out; |