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-rw-r--r--security/tomoyo/gc.c354
1 files changed, 354 insertions, 0 deletions
diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c
new file mode 100644
index 00000000..a877e4c3
--- /dev/null
+++ b/security/tomoyo/gc.c
@@ -0,0 +1,354 @@
+/*
+ * security/tomoyo/gc.c
+ *
+ * Implementation of the Domain-Based Mandatory Access Control.
+ *
+ * Copyright (C) 2005-2010 NTT DATA CORPORATION
+ *
+ */
+
+#include "common.h"
+#include <linux/kthread.h>
+#include <linux/slab.h>
+
+struct tomoyo_gc {
+ struct list_head list;
+ int type;
+ struct list_head *element;
+};
+static LIST_HEAD(tomoyo_gc_queue);
+static DEFINE_MUTEX(tomoyo_gc_mutex);
+
+/* Caller holds tomoyo_policy_lock mutex. */
+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;
+ entry->element = element;
+ list_add(&entry->list, &tomoyo_gc_queue);
+ list_del_rcu(element);
+ return true;
+}
+
+static void tomoyo_del_allow_read(struct list_head *element)
+{
+ struct tomoyo_readable_file *ptr =
+ container_of(element, typeof(*ptr), head.list);
+ tomoyo_put_name(ptr->filename);
+}
+
+static void tomoyo_del_file_pattern(struct list_head *element)
+{
+ struct tomoyo_no_pattern *ptr =
+ container_of(element, typeof(*ptr), head.list);
+ tomoyo_put_name(ptr->pattern);
+}
+
+static void tomoyo_del_no_rewrite(struct list_head *element)
+{
+ struct tomoyo_no_rewrite *ptr =
+ container_of(element, typeof(*ptr), head.list);
+ tomoyo_put_name(ptr->pattern);
+}
+
+static 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);
+}
+
+static 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);
+}
+
+static void tomoyo_del_manager(struct list_head *element)
+{
+ struct tomoyo_manager *ptr =
+ container_of(element, typeof(*ptr), head.list);
+ tomoyo_put_name(ptr->manager);
+}
+
+static void tomoyo_del_acl(struct list_head *element)
+{
+ struct tomoyo_acl_info *acl =
+ container_of(element, typeof(*acl), list);
+ 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;
+ }
+}
+
+static bool 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).
+ */
+ 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;
+}
+
+
+static void tomoyo_del_name(struct list_head *element)
+{
+ const struct tomoyo_name *ptr =
+ container_of(element, typeof(*ptr), list);
+}
+
+static 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);
+}
+
+static void tomoyo_del_group(struct list_head *element)
+{
+ struct tomoyo_group *group =
+ container_of(element, typeof(*group), list);
+ tomoyo_put_name(group->group_name);
+}
+
+static void tomoyo_del_number_group(struct list_head *element)
+{
+ struct tomoyo_number_group *member =
+ container_of(element, typeof(*member), head.list);
+}
+
+static bool tomoyo_collect_member(struct list_head *member_list, int id)
+{
+ struct tomoyo_acl_head *member;
+ list_for_each_entry(member, member_list, list) {
+ if (!member->is_deleted)
+ continue;
+ if (!tomoyo_add_to_gc(id, &member->list))
+ return false;
+ }
+ return true;
+}
+
+static bool tomoyo_collect_acl(struct tomoyo_domain_info *domain)
+{
+ struct tomoyo_acl_info *acl;
+ list_for_each_entry(acl, &domain->acl_info_list, list) {
+ if (!acl->is_deleted)
+ continue;
+ if (!tomoyo_add_to_gc(TOMOYO_ID_ACL, &acl->list))
+ return false;
+ }
+ return true;
+}
+
+static void tomoyo_collect_entry(void)
+{
+ int i;
+ if (mutex_lock_interruptible(&tomoyo_policy_lock))
+ return;
+ for (i = 0; i < TOMOYO_MAX_POLICY; i++) {
+ if (!tomoyo_collect_member(&tomoyo_policy_list[i], i))
+ goto unlock;
+ }
+ {
+ struct tomoyo_domain_info *domain;
+ list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
+ if (!tomoyo_collect_acl(domain))
+ goto unlock;
+ 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;
+ }
+ }
+ for (i = 0; i < TOMOYO_MAX_HASH; i++) {
+ struct tomoyo_name *ptr;
+ list_for_each_entry_rcu(ptr, &tomoyo_name_list[i], list) {
+ if (atomic_read(&ptr->users))
+ continue;
+ if (!tomoyo_add_to_gc(TOMOYO_ID_NAME, &ptr->list))
+ goto unlock;
+ }
+ }
+ for (i = 0; i < TOMOYO_MAX_GROUP; i++) {
+ struct list_head *list = &tomoyo_group_list[i];
+ int id;
+ struct tomoyo_group *group;
+ switch (i) {
+ case 0:
+ id = TOMOYO_ID_PATH_GROUP;
+ break;
+ default:
+ id = TOMOYO_ID_NUMBER_GROUP;
+ break;
+ }
+ list_for_each_entry(group, list, list) {
+ if (!tomoyo_collect_member(&group->member_list, id))
+ goto unlock;
+ if (!list_empty(&group->member_list) ||
+ atomic_read(&group->users))
+ continue;
+ if (!tomoyo_add_to_gc(TOMOYO_ID_GROUP, &group->list))
+ goto unlock;
+ }
+ }
+ unlock:
+ mutex_unlock(&tomoyo_policy_lock);
+}
+
+static void tomoyo_kfree_entry(void)
+{
+ struct tomoyo_gc *p;
+ struct tomoyo_gc *tmp;
+
+ list_for_each_entry_safe(p, tmp, &tomoyo_gc_queue, list) {
+ struct list_head *element = p->element;
+ 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_GLOBALLY_READABLE:
+ tomoyo_del_allow_read(element);
+ break;
+ case TOMOYO_ID_PATTERN:
+ tomoyo_del_file_pattern(element);
+ break;
+ case TOMOYO_ID_NO_REWRITE:
+ tomoyo_del_no_rewrite(element);
+ break;
+ case TOMOYO_ID_MANAGER:
+ tomoyo_del_manager(element);
+ break;
+ case TOMOYO_ID_NAME:
+ 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_GROUP:
+ tomoyo_del_group(element);
+ break;
+ case TOMOYO_ID_NUMBER_GROUP:
+ tomoyo_del_number_group(element);
+ break;
+ }
+ tomoyo_memory_free(element);
+ list_del(&p->list);
+ kfree(p);
+ }
+}
+
+static int tomoyo_gc_thread(void *unused)
+{
+ daemonize("GC for TOMOYO");
+ if (mutex_trylock(&tomoyo_gc_mutex)) {
+ int i;
+ for (i = 0; i < 10; i++) {
+ tomoyo_collect_entry();
+ if (list_empty(&tomoyo_gc_queue))
+ break;
+ synchronize_srcu(&tomoyo_ss);
+ tomoyo_kfree_entry();
+ }
+ mutex_unlock(&tomoyo_gc_mutex);
+ }
+ do_exit(0);
+}
+
+void tomoyo_run_gc(void)
+{
+ struct task_struct *task = kthread_create(tomoyo_gc_thread, NULL,
+ "GC for TOMOYO");
+ if (!IS_ERR(task))
+ wake_up_process(task);
+}