security/ccsecurity/memory.c

/*
 * security/ccsecurity/memory.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 *
 * Version: 1.7.3+   2011/04/01
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */

#include "internal.h"
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0) || defined(RHEL_MAJOR)
#include <linux/hash.h>
#endif

/**
 * ccs_warn_oom - Print out of memory warning message.
 *
 * @function: Function's name.
 */
void ccs_warn_oom(const char *function)
{
        /* Reduce error messages. */
        static pid_t ccs_last_pid;
        const pid_t pid = current->pid;
        if (ccs_last_pid != pid) {
                printk(KERN_WARNING "ERROR: Out of memory at %s.\n",
                       function);
                ccs_last_pid = pid;
        }
        if (!ccs_policy_loaded)
                panic("MAC Initialization failed.\n");
}

/* Memory allocated for policy. */
static atomic_t ccs_policy_memory_size;
/* Quota for holding policy. */
static unsigned int ccs_quota_for_policy;

/**
 * ccs_memory_ok - Check memory quota.
 *
 * @ptr:  Pointer to allocated memory.
 * @size: Size in byte.
 *
 * Returns true if @ptr is not NULL and quota not exceeded, false otherwise.
 */
bool ccs_memory_ok(const void *ptr, const unsigned int size)
{
        size_t s = ccs_round2(size);
        atomic_add(s, &ccs_policy_memory_size);
        if (ptr && (!ccs_quota_for_policy ||
                    atomic_read(&ccs_policy_memory_size)
                    <= ccs_quota_for_policy))
                return true;
        atomic_sub(s, &ccs_policy_memory_size);
        ccs_warn_oom(__func__);
        return false;
}

/**
 * ccs_commit_ok - Allocate memory and 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 *ccs_commit_ok(void *data, const unsigned int size)
{
        void *ptr = kmalloc(size, CCS_GFP_FLAGS);
        if (ccs_memory_ok(ptr, size)) {
                memmove(ptr, data, size);
                memset(data, 0, size);
                return ptr;
        }
        kfree(ptr);
        return NULL;
}

/**
 * ccs_memory_free - Free memory for elements.
 *
 * @ptr:  Pointer to allocated memory.
 * @size: Size in byte.
 */
void ccs_memory_free(const void *ptr, size_t size)
{
        atomic_sub(ccs_round2(size), &ccs_policy_memory_size);
        kfree(ptr);
}

/* List of IPv6 address. */
LIST_HEAD(ccs_address_list);

/**
 * ccs_get_ipv6_address - Keep the given IPv6 address on the RAM.
 *
 * @addr: Pointer to "struct in6_addr".
 *
 * Returns pointer to "struct in6_addr" on success, NULL otherwise.
 *
 * The RAM is shared, so NEVER try to modify or kfree() the returned address.
 */
const struct in6_addr *ccs_get_ipv6_address(const struct in6_addr *addr)
{
        struct ccs_ipv6addr_entry *entry;
        struct ccs_ipv6addr_entry *ptr = NULL;
        int error = -ENOMEM;
        if (!addr)
                return NULL;
        entry = kzalloc(sizeof(*entry), CCS_GFP_FLAGS);
        if (mutex_lock_interruptible(&ccs_policy_lock))
                goto out;
        list_for_each_entry(ptr, &ccs_address_list, list) {
                if (memcmp(&ptr->addr, addr, sizeof(*addr)))
                        continue;
                atomic_inc(&ptr->users);
                error = 0;
                break;
        }
        if (error && ccs_memory_ok(entry, sizeof(*entry))) {
                ptr = entry;
                ptr->addr = *addr;
                atomic_set(&ptr->users, 1);
                list_add_tail(&ptr->list, &ccs_address_list);
                entry = NULL;
                error = 0;
        }
        mutex_unlock(&ccs_policy_lock);
 out:
        kfree(entry);
        return !error ? &ptr->addr : NULL;
}

/* The list for "struct ccs_name_entry". */
struct list_head ccs_name_list[CCS_MAX_HASH];

/**
 * ccs_get_name - Allocate memory for string data.
 *
 * @name: The string to store into the permernent memory.
 *
 * Returns pointer to "struct ccs_path_info" on success, NULL otherwise.
 */
const struct ccs_path_info *ccs_get_name(const char *name)
{
        struct ccs_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);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0) || defined(RHEL_MAJOR)
        head = &ccs_name_list[hash_long(hash, CCS_HASH_BITS)];
#else
        head = &ccs_name_list[hash % CCS_MAX_HASH];
#endif
        if (mutex_lock_interruptible(&ccs_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;
        }
        allocated_len = ccs_round2(sizeof(*ptr) + len);
        ptr = kzalloc(allocated_len, CCS_GFP_FLAGS);
        if (!ptr || (ccs_quota_for_policy &&
                     atomic_read(&ccs_policy_memory_size) + allocated_len
                     > ccs_quota_for_policy)) {
                kfree(ptr);
                ptr = NULL;
                ccs_warn_oom(__func__);
                goto out;
        }
        atomic_add(allocated_len, &ccs_policy_memory_size);
        ptr->entry.name = ((char *) ptr) + sizeof(*ptr);
        memmove((char *) ptr->entry.name, name, len);
        atomic_set(&ptr->users, 1);
        ccs_fill_path_info(&ptr->entry);
        ptr->size = allocated_len;
        list_add_tail(&ptr->list, head);
 out:
        mutex_unlock(&ccs_policy_lock);
        return ptr ? &ptr->entry : NULL;
}

/**
 * ccs_mm_init - Initialize mm related code.
 */
void __init ccs_mm_init(void)
{
        int idx;
        for (idx = 0; idx < CCS_MAX_HASH; idx++)
                INIT_LIST_HEAD(&ccs_name_list[idx]);
        INIT_LIST_HEAD(&ccs_kernel_domain.acl_info_list);
        ccs_kernel_domain.domainname = ccs_get_name(ROOT_NAME);
        list_add_tail_rcu(&ccs_kernel_domain.list, &ccs_domain_list);
        idx = ccs_read_lock();
        if (ccs_find_domain(ROOT_NAME) != &ccs_kernel_domain)
                panic("Can't register ccs_kernel_domain");
        {
                /* Load built-in policy. */
                static char ccs_builtin_initializers[] __initdata
                        = CONFIG_CCSECURITY_BUILTIN_INITIALIZERS;
                char *cp = ccs_builtin_initializers;
                ccs_normalize_line(cp);
                while (cp && *cp) {
                        char *cp2 = strchr(cp, ' ');
                        if (cp2)
                                *cp2++ = '\0';
                        ccs_write_domain_initializer_policy(cp, false, false);
                        cp = cp2;
                }
        }
        ccs_read_unlock(idx);
}

/* Memory allocated for audit logs. */
unsigned int ccs_audit_log_memory_size;
/* Quota for holding audit logs. */
unsigned int ccs_quota_for_audit_log;

/* Memory allocated for query lists. */
unsigned int ccs_query_memory_size;
/* Quota for holding query lists. */
unsigned int ccs_quota_for_query;

/**
 * ccs_read_memory_counter - Check for memory usage.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 */
void ccs_read_memory_counter(struct ccs_io_buffer *head)
{
        const unsigned int usage[3] = {
                atomic_read(&ccs_policy_memory_size),
                ccs_audit_log_memory_size,
                ccs_query_memory_size
        };
        const unsigned int quota[3] = {
                ccs_quota_for_policy,
                ccs_quota_for_audit_log,
                ccs_quota_for_query
        };
        static const char *header[4] = {
                "Policy:     ",
                "Audit logs: ",
                "Query lists:",
                "Total:      "
        };
        unsigned int total = 0;
        int i;
        if (head->read_eof)
                return;
        for (i = 0; i < 3; i++) {
                total += usage[i];
                ccs_io_printf(head, "%s %10u", header[i], usage[i]);
                if (quota[i])
                        ccs_io_printf(head, "   (Quota: %10u)", quota[i]);
                ccs_io_printf(head, "\n");
        }
        ccs_io_printf(head, "%s %10u\n", header[3], total);
        head->read_eof = true;
}

/**
 * ccs_write_memory_quota - Set memory quota.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
int ccs_write_memory_quota(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        unsigned int size;
        if (sscanf(data, "Policy: %u", &size) == 1)
                ccs_quota_for_policy = size;
        else if (sscanf(data, "Audit logs: %u", &size) == 1)
                ccs_quota_for_audit_log = size;
        else if (sscanf(data, "Query lists: %u", &size) == 1)
                ccs_quota_for_query = size;
        return 0;
}