TOMOYO: Add garbage collector.

This patch adds garbage collector support to TOMOYO.
Elements are protected by "struct srcu_struct tomoyo_ss".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/tomoyo/Makefile

@@ -1 +1 @@
-obj-y = common.o realpath.o tomoyo.o domain.o file.o
+obj-y = common.o realpath.o tomoyo.o domain.o file.o gc.o

security/tomoyo/common.c

@@ -1067,7 +1067,7 @@ static int tomoyo_read_profile(struct tomoyo_io_buffer *head)
  *
  * # cat /sys/kernel/security/tomoyo/manager
  */
-static LIST_HEAD(tomoyo_policy_manager_list);
+LIST_HEAD(tomoyo_policy_manager_list);
 
 /**
  * tomoyo_update_manager_entry - Add a manager entry.
@@ -2109,6 +2109,7 @@ static int tomoyo_write_control(struct file *file, const char __user *buffer,
 static int tomoyo_close_control(struct file *file)
 {
 	struct tomoyo_io_buffer *head = file->private_data;
+	const bool is_write = !!head->write_buf;
 
 	tomoyo_read_unlock(head->reader_idx);
 	/* Release memory used for policy I/O. */
@@ -2119,6 +2120,8 @@ static int tomoyo_close_control(struct file *file)
 	kfree(head);
 	head = NULL;
 	file->private_data = NULL;
+	if (is_write)
+		tomoyo_run_gc();
 	return 0;
 }
 

security/tomoyo/common.h

@@ -638,6 +638,11 @@ int tomoyo_check_rewrite_permission(struct tomoyo_domain_info *domain,
 				    struct file *filp);
 int tomoyo_find_next_domain(struct linux_binprm *bprm);
 
+/* Run garbage collector. */
+void tomoyo_run_gc(void);
+
+void tomoyo_memory_free(void *ptr);
+
 /********** External variable definitions. **********/
 
 /* Lock for GC. */
@@ -646,6 +651,16 @@ extern struct srcu_struct tomoyo_ss;
 /* The list for "struct tomoyo_domain_info". */
 extern struct list_head tomoyo_domain_list;
 
+extern struct list_head tomoyo_domain_initializer_list;
+extern struct list_head tomoyo_domain_keeper_list;
+extern struct list_head tomoyo_alias_list;
+extern struct list_head tomoyo_globally_readable_list;
+extern struct list_head tomoyo_pattern_list;
+extern struct list_head tomoyo_no_rewrite_list;
+extern struct list_head tomoyo_policy_manager_list;
+extern struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
+extern struct mutex tomoyo_name_list_lock;
+
 /* Lock for protecting policy. */
 extern struct mutex tomoyo_policy_lock;
 

security/tomoyo/domain.c

@@ -110,7 +110,7 @@ const char *tomoyo_get_last_name(const struct tomoyo_domain_info *domain)
  * will cause "/usr/sbin/httpd" to belong to "<kernel> /usr/sbin/httpd" domain
  * unless executed from "<kernel> /etc/rc.d/init.d/httpd" domain.
  */
-static LIST_HEAD(tomoyo_domain_initializer_list);
+LIST_HEAD(tomoyo_domain_initializer_list);
 
 /**
  * tomoyo_update_domain_initializer_entry - Update "struct tomoyo_domain_initializer_entry" list.
@@ -330,7 +330,7 @@ static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
  * "<kernel> /usr/sbin/sshd /bin/bash /usr/bin/passwd" domain, unless
  * explicitly specified by "initialize_domain".
  */
-static LIST_HEAD(tomoyo_domain_keeper_list);
+LIST_HEAD(tomoyo_domain_keeper_list);
 
 /**
  * tomoyo_update_domain_keeper_entry - Update "struct tomoyo_domain_keeper_entry" list.
@@ -533,7 +533,7 @@ static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
  * /bin/busybox and domainname which the current process will belong to after
  * execve() succeeds is calculated using /bin/cat rather than /bin/busybox .
  */
-static LIST_HEAD(tomoyo_alias_list);
+LIST_HEAD(tomoyo_alias_list);
 
 /**
  * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.

security/tomoyo/file.c

@@ -148,7 +148,7 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
  * given "allow_read /lib/libc-2.5.so" to the domain which current process
  * belongs to.
  */
-static LIST_HEAD(tomoyo_globally_readable_list);
+LIST_HEAD(tomoyo_globally_readable_list);
 
 /**
  * tomoyo_update_globally_readable_entry - Update "struct tomoyo_globally_readable_file_entry" list.
@@ -295,7 +295,7 @@ bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head)
  * which pretends as if /proc/self/ is not a symlink; so that we can forbid
  * current process from accessing other process's information.
  */
-static LIST_HEAD(tomoyo_pattern_list);
+LIST_HEAD(tomoyo_pattern_list);
 
 /**
  * tomoyo_update_file_pattern_entry - Update "struct tomoyo_pattern_entry" list.
@@ -448,7 +448,7 @@ bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head)
  * " (deleted)" suffix if the file is already unlink()ed; so that we don't
  * need to worry whether the file is already unlink()ed or not.
  */
-static LIST_HEAD(tomoyo_no_rewrite_list);
+LIST_HEAD(tomoyo_no_rewrite_list);
 
 /**
  * tomoyo_update_no_rewrite_entry - Update "struct tomoyo_no_rewrite_entry" list.