TOMOYO: Add refcounter on string data.

Add refcounter to "struct tomoyo_name_entry" and replace tomoyo_save_name()
with tomoyo_get_name()/tomoyo_put_name() pair so that we can kfree() when
garbage collector is added.

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>

1 files changed, 20 insertions, 1 deletions

diff --git a/security/tomoyo/realpath.h b/security/tomoyo/realpath.h
index da4f06ff6f8d..b94cb512adb5 100644
--- a/security/tomoyo/realpath.h
+++ b/security/tomoyo/realpath.h
@@ -43,7 +43,7 @@ bool tomoyo_memory_ok(void *ptr);
  * Keep the given name on the RAM.
  * The RAM is shared, so NEVER try to modify or kfree() the returned name.
  */
-const struct tomoyo_path_info *tomoyo_save_name(const char *name);
+const struct tomoyo_path_info *tomoyo_get_name(const char *name);
 
 /* Check for memory usage. */
 int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head);
@@ -54,4 +54,23 @@ int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head);
 /* Initialize realpath related code. */
 void __init tomoyo_realpath_init(void);
 
+/*
+ * tomoyo_name_entry is a structure which is used for linking
+ * "struct tomoyo_path_info" into tomoyo_name_list .
+ */
+struct tomoyo_name_entry {
+        struct list_head list;
+        atomic_t users;
+        struct tomoyo_path_info entry;
+};
+
+static inline void tomoyo_put_name(const struct tomoyo_path_info *name)
+{
+        if (name) {
+                struct tomoyo_name_entry *ptr =
+                        container_of(name, struct tomoyo_name_entry, entry);
+                atomic_dec(&ptr->users);
+        }
+}
+
 #endif /* !defined(_SECURITY_TOMOYO_REALPATH_H) */