security/tomoyo/memory.c

Source file repositories/reference/linux-study-clean/security/tomoyo/memory.c

File Facts

System
Linux kernel
Corpus path
security/tomoyo/memory.c
Extension
.c
Size
5561 bytes
Lines
208
Domain
Core OS
Bucket
Security And Isolation
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (entry) {
			INIT_LIST_HEAD(&entry->member_list);
			atomic_set(&entry->head.users, 1);
			list_add_tail_rcu(&entry->head.list, list);
			group = entry;
			found = true;
		}
	}
	mutex_unlock(&tomoyo_policy_lock);
out:
	tomoyo_put_name(e.group_name);
	return found ? group : NULL;
}

/*
 * tomoyo_name_list is used for holding string data used by TOMOYO.
 * Since same string data is likely used for multiple times (e.g.
 * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of
 * "const struct tomoyo_path_info *".
 */
struct list_head tomoyo_name_list[TOMOYO_MAX_HASH];

/**
 * 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_get_name(const char *name)
{
	struct tomoyo_name *ptr;
	unsigned int hash;
	int len;
	struct list_head *head;

	if (!name)
		return NULL;
	len = strlen(name) + 1;
	hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
	head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
	if (mutex_lock_interruptible(&tomoyo_policy_lock))
		return NULL;
	list_for_each_entry(ptr, head, head.list) {
		if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) ||
		    atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS)
			continue;
		atomic_inc(&ptr->head.users);
		goto out;
	}
	ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS | __GFP_NOWARN);
	if (tomoyo_memory_ok(ptr)) {
		ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
		memmove((char *) ptr->entry.name, name, len);
		atomic_set(&ptr->head.users, 1);
		tomoyo_fill_path_info(&ptr->entry);
		list_add_tail(&ptr->head.list, head);
	} else {
		kfree(ptr);
		ptr = NULL;
	}
out:
	mutex_unlock(&tomoyo_policy_lock);
	return ptr ? &ptr->entry : NULL;
}

/* Initial namespace.*/
struct tomoyo_policy_namespace tomoyo_kernel_namespace;

/**
 * tomoyo_mm_init - Initialize mm related code.
 */
void __init tomoyo_mm_init(void)
{
	int idx;

	for (idx = 0; idx < TOMOYO_MAX_HASH; idx++)
		INIT_LIST_HEAD(&tomoyo_name_list[idx]);
	tomoyo_kernel_namespace.name = "<kernel>";
	tomoyo_init_policy_namespace(&tomoyo_kernel_namespace);
	tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace;
	INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
	tomoyo_kernel_domain.domainname = tomoyo_get_name("<kernel>");
	list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
}

Annotation

Implementation Notes