/*
* security/tomoyo/memory.c
*
* Memory management functions for TOMOYO.
*
* Copyright (C) 2005-2010 NTT DATA CORPORATION
*/
#include <linux/hash.h>
#include <linux/slab.h>
#include "common.h"
/**
* tomoyo_warn_oom - Print out of memory warning message.
*
* @function: Function's name.
*/
void tomoyo_warn_oom(const char *function)
{
/* Reduce error messages. */
static pid_t tomoyo_last_pid;
const pid_t pid = current->pid;
if (tomoyo_last_pid != pid) {
printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
function);
tomoyo_last_pid = pid;
}
if (!tomoyo_policy_loaded)
panic("MAC Initialization failed.\n");
}
/* Memory allocated for policy. */
static atomic_t tomoyo_policy_memory_size;
/* Quota for holding policy. */
static unsigned int tomoyo_quota_for_policy;
/**
* tomoyo_memory_ok - Check memory quota.
*
* @ptr: Pointer to allocated memory.
*
* Returns true on success, false otherwise.
*
* Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
*/
bool tomoyo_memory_ok(void *ptr)
{
size_t s = ptr ? ksize(ptr) : 0;
atomic_add(s, &tomoyo_policy_memory_size);
if (ptr && (!tomoyo_quota_for_policy ||
atomic_read(&tomoyo_policy_memory_size)
<= tomoyo_quota_for_policy)) {
memset(ptr, 0, s);
return true;
}
atomic_sub(s, &tomoyo_policy_memory_size);
tomoyo_warn_oom(__func__);
return false;
}
/**
* tomoyo_commit_ok - Check memory quota.
*
* @data: Data to copy from.
* @size: Size in byte.
*
* Returns pointer to allocated memory on success, NULL otherwise.
* @data is zero-cleared on success.
*/
void *tomoyo_commit_ok(void *data, const unsigned int size)
{
void *ptr = kzalloc(size, GFP_NOFS);
if (tomoyo_memory_ok(ptr)) {
memmove(ptr, data, size);
memset(data, 0, size);
return ptr;
}
return NULL;
}
/**
* tomoyo_memory_free - Free memory for elements.
*
* @ptr: Pointer to allocated memory.
*/
void tomoyo_memory_free(void *ptr)
{
atomic_sub(ksize(ptr), &tomoyo_policy_memory_size);
kfree(ptr);
}
/*
* 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_entry *ptr;
unsigned int hash;
int len;
int allocated_len;
struct list_head *head;
if (!name)
return NULL;
len = strlen(name) + 1;
hash = full_name_hash((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, list) {
if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name))
continue;
atomic_inc(&ptr->users);
goto out;
}
ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS);
allocated_len = ptr ? ksize(ptr) : 0;
if (!ptr || (tomoyo_quota_for_policy &&
atomic_read(&tomoyo_policy_memory_size) + allocated_len
> tomoyo_quota_for_policy)) {
kfree(ptr);
ptr = NULL;
tomoyo_warn_oom(__func__);
goto out;
}
atomic_add(allocated_len, &tomoyo_policy_memory_size);
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:
mutex_unlock(&tomoyo_policy_lock);
return ptr ? &ptr->entry : NULL;
}
/**
* 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]);
INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list);
tomoyo_kernel_domain.domainname = tomoyo_get_name(TOMOYO_ROOT_NAME);
list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list);
idx = tomoyo_read_lock();
if (tomoyo_find_domain(TOMOYO_ROOT_NAME) != &tomoyo_kernel_domain)
panic("Can't register tomoyo_kernel_domain");
{
/* Load built-in policy. */
tomoyo_write_domain_initializer_policy("/sbin/hotplug",
false, false);
tomoyo_write_domain_initializer_policy("/sbin/modprobe",
false, false);
}
tomoyo_read_unlock(idx);
}
/* Memory allocated for query lists. */
unsigned int tomoyo_query_memory_size;
/* Quota for holding query lists. */
unsigned int tomoyo_quota_for_query;
/**
* tomoyo_read_memory_counter - Check for memory usage in bytes.
*
* @head: Pointer to "struct tomoyo_io_buffer".
*
* Returns memory usage.
*/
int tomoyo_read_memory_counter(struct tomoyo_io_buffer *head)
{
if (!head->read_eof) {
const unsigned int policy
= atomic_read(&tomoyo_policy_memory_size);
const unsigned int query = tomoyo_query_memory_size;
char buffer[64];
memset(buffer, 0, sizeof(buffer));
if (tomoyo_quota_for_policy)
snprintf(buffer, sizeof(buffer) - 1,
" (Quota: %10u)",
tomoyo_quota_for_policy);
else
buffer[0] = '\0';
tomoyo_io_printf(head, "Policy: %10u%s\n", policy,
buffer);
if (tomoyo_quota_for_query)
snprintf(buffer, sizeof(buffer) - 1,
" (Quota: %10u)",
tomoyo_quota_for_query);
else
buffer[0] = '\0';
tomoyo_io_printf(head, "Query lists: %10u%s\n", query,
buffer);
tomoyo_io_printf(head, "Total: %10u\n", policy + query);
head->read_eof = true;
}
return 0;
}
/**
* tomoyo_write_memory_quota - Set memory quota.
*
* @head: Pointer to "struct tomoyo_io_buffer".
*
* Returns 0.
*/
int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head)
{
char *data = head->write_buf;
unsigned int size;
if (sscanf(data, "Policy: %u", &size) == 1)
tomoyo_quota_for_policy = size;
else if (sscanf(data, "Query lists: %u", &size) == 1)
tomoyo_quota_for_query = size;
return 0;
}
