TOMOYO: Remove memory pool for string data.

Currently, TOMOYO allocates memory for string data from memory pool allocated
by kmalloc(PAGE_SIZE). But that makes it difficult to kfree() when garbage
collector is added. Thus, remove memory pool and use kmalloc(strlen()).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

security/tomoyo/realpath.c

@@ -293,13 +293,6 @@ struct tomoyo_name_entry {
 	struct tomoyo_path_info entry;
 };
 
-/* Structure for available memory region. */
-struct tomoyo_free_memory_block_list {
-	struct list_head list;
-	char *ptr;             /* Pointer to a free area. */
-	int len;               /* Length of the area.     */
-};
-
 /*
  * tomoyo_name_list is used for holding string data used by TOMOYO.
  * Since same string data is likely used for multiple times (e.g.
@@ -314,77 +307,44 @@ static struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
  * @name: The string to store into the permernent memory.
  *
  * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
- *
- * 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)
 {
-	static LIST_HEAD(fmb_list);
 	static DEFINE_MUTEX(lock);
 	struct tomoyo_name_entry *ptr;
 	unsigned int hash;
-	/* fmb contains available size in bytes.
-	   fmb is removed from the fmb_list when fmb->len becomes 0. */
-	struct tomoyo_free_memory_block_list *fmb;
 	int len;
-	char *cp;
+	int allocated_len;
 	struct list_head *head;
 
 	if (!name)
 		return NULL;
 	len = strlen(name) + 1;
-	if (len > TOMOYO_MAX_PATHNAME_LEN) {
-		printk(KERN_WARNING "ERROR: Name too long "
-		       "for tomoyo_save_name().\n");
-		return NULL;
-	}
 	hash = full_name_hash((const unsigned char *) name, len - 1);
 	head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
-
 	mutex_lock(&lock);
 	list_for_each_entry(ptr, head, list) {
 		if (hash == ptr->entry.hash && !strcmp(name, ptr->entry.name))
 			goto out;
 	}
-	list_for_each_entry(fmb, &fmb_list, list) {
-		if (len <= fmb->len)
-			goto ready;
-	}
-	if (!tomoyo_quota_for_savename ||
-	    tomoyo_allocated_memory_for_savename + PATH_MAX
-	    <= tomoyo_quota_for_savename)
-		cp = kzalloc(PATH_MAX, GFP_KERNEL);
-	else
-		cp = NULL;
-	fmb = kzalloc(sizeof(*fmb), GFP_KERNEL);
-	if (!cp || !fmb) {
-		kfree(cp);
-		kfree(fmb);
+	ptr = kzalloc(sizeof(*ptr) + len, GFP_KERNEL);
+	allocated_len = ptr ? ksize(ptr) : 0;
+	if (!ptr || (tomoyo_quota_for_savename &&
+		     tomoyo_allocated_memory_for_savename + allocated_len
+		     > tomoyo_quota_for_savename)) {
+		kfree(ptr);
 		printk(KERN_WARNING "ERROR: Out of memory "
 		       "for tomoyo_save_name().\n");
 		if (!tomoyo_policy_loaded)
 			panic("MAC Initialization failed.\n");
 		ptr = NULL;
 		goto out;
 	}
-	tomoyo_allocated_memory_for_savename += PATH_MAX;
-	list_add(&fmb->list, &fmb_list);
-	fmb->ptr = cp;
-	fmb->len = PATH_MAX;
- ready:
-	ptr = tomoyo_alloc_element(sizeof(*ptr));
-	if (!ptr)
-		goto out;
-	ptr->entry.name = fmb->ptr;
-	memmove(fmb->ptr, name, len);
+	tomoyo_allocated_memory_for_savename += allocated_len;
+	ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
+	memmove((char *) ptr->entry.name, name, len);
 	tomoyo_fill_path_info(&ptr->entry);
-	fmb->ptr += len;
-	fmb->len -= len;
 	list_add_tail(&ptr->list, head);
-	if (fmb->len == 0) {
-		list_del(&fmb->list);
-		kfree(fmb);
-	}
  out:
 	mutex_unlock(&lock);
 	return ptr ? &ptr->entry : NULL;