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TOMOYO: Add refcounter on string data.

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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>
This commit is contained in:
Tetsuo Handa
2010-02-11 09:41:58 +09:00
committed by James Morris
parent ca0b7df337
commit bf24fb016c
5 changed files with 77 additions and 40 deletions
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30
security/tomoyo/realpath.c
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@@ -253,21 +253,6 @@ static unsigned int tomoyo_quota_for_savename;
#define TOMOYO_HASH_BITS 8
#define TOMOYO_MAX_HASH (1u<<TOMOYO_HASH_BITS)
/*
* tomoyo_name_entry is a structure which is used for linking
* "struct tomoyo_path_info" into tomoyo_name_list .
*
* Since tomoyo_name_list manages a list of strings which are shared by
* multiple processes (whereas "struct tomoyo_path_info" inside
* "struct tomoyo_path_info_with_data" is not shared), a reference counter will
* be added to "struct tomoyo_name_entry" rather than "struct tomoyo_path_info"
* when TOMOYO starts supporting garbage collector.
*/
struct tomoyo_name_entry {
struct list_head list;
struct tomoyo_path_info entry;
};
/*
* tomoyo_name_list is used for holding string data used by TOMOYO.
* Since same string data is likely used for multiple times (e.g.
@@ -277,13 +262,13 @@ struct tomoyo_name_entry {
static struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];
/**
* tomoyo_save_name - Allocate permanent memory for string data.
* tomoyo_get_name - Allocate permanent memory for string data.
*
* @name: The string to store into the permernent memory.
*
* Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
*/
const struct tomoyo_path_info *tomoyo_save_name(const char *name)
const struct tomoyo_path_info *tomoyo_get_name(const char *name)
{
static DEFINE_MUTEX(lock);
struct tomoyo_name_entry *ptr;
@@ -299,8 +284,10 @@ const struct tomoyo_path_info *tomoyo_save_name(const char *name)
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;
if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
continue;
atomic_inc(&ptr->users);
goto out;
}
ptr = kzalloc(sizeof(*ptr) + len, GFP_KERNEL);
allocated_len = ptr ? ksize(ptr) : 0;
@@ -309,7 +296,7 @@ const struct tomoyo_path_info *tomoyo_save_name(const char *name)
> tomoyo_quota_for_savename)) {
kfree(ptr);
printk(KERN_WARNING "ERROR: Out of memory "
"for tomoyo_save_name().\n");
"for tomoyo_get_name().\n");
if (!tomoyo_policy_loaded)
panic("MAC Initialization failed.\n");
ptr = NULL;
@@ -318,6 +305,7 @@ const struct tomoyo_path_info *tomoyo_save_name(const char *name)
tomoyo_allocated_memory_for_savename += allocated_len;
ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
memmove((char *) ptr->entry.name, name, len);
atomic_set(&ptr->users, 1);
tomoyo_fill_path_info(&ptr->entry);
list_add_tail(&ptr->list, head);
out:
@@ -336,7 +324,7 @@ void __init tomoyo_realpath_init(void)
for (i = 0; i < TOMOYO_MAX_HASH; i++)
INIT_LIST_HEAD(&tomoyo_name_list[i]);
INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
tomoyo_kernel_domain.domainname = tomoyo_save_name(TOMOYO_ROOT_NAME);
tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME);
/*
* tomoyo_read_lock() is not needed because this function is
* called before the first "delete" request.