security/ccsecurity/memory.c

/*
 * security/ccsecurity/gc.c
 *
 * Copyright (C) 2005-2009  NTT DATA CORPORATION
 *
 * Version: 1.7.0-pre   2009/08/24
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */

#include "internal.h"

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");
}

static atomic_t ccs_policy_memory_size;
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 otehrwise.
 */
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 - Check memory quota.
 *
 * @ptr:    Pointer to allocated memory.
 * @data:   Data to copy from.
 * @size:   Size in byte.
 *
 * Returns true if @ptr is not NULL and quota not exceeded, false otehrwise.
 */
bool ccs_commit_ok(void *ptr, void *data, const unsigned int size)
{
        if (ccs_memory_ok(ptr, size)) {
                memmove(ptr, data, size);
                memset(data, 0, size);
                return true;
        }
        return false;
}


/**
 * 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);
}

static 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;
        int error = -ENOMEM;
        if (!addr)
                return NULL;
        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
        mutex_lock(&ccs_policy_lock);
        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;
        }
        mutex_unlock(&ccs_policy_lock);
        kfree(entry);
        return ptr ? &ptr->addr : NULL;
}

/**
 * ccs_put_ipv6_address - Delete the given IPv6 address on the RAM.
 *
 * @addr: Pointer to "struct in6_addr".
 */
void ccs_put_ipv6_address(const struct in6_addr *addr)
{
        struct ccs_ipv6addr_entry *ptr;
        bool can_delete = false;
        if (!addr)
                return;
        ptr = container_of(addr, struct ccs_ipv6addr_entry, addr);
        mutex_lock(&ccs_policy_lock);
        if (atomic_dec_and_test(&ptr->users)) {
                list_del(&ptr->list);
                can_delete = true;
        }
        mutex_unlock(&ccs_policy_lock);
        if (can_delete)
                ccs_memory_free(ptr, sizeof(*ptr));
}

/**
 * ccs_put_condition - Delete memory for "struct ccs_condition".
 *
 * @cond: Pointer to "struct ccs_condition".
 */
void ccs_put_condition(struct ccs_condition *cond)
{
        const struct ccs_condition_element *condp;
        struct ccs_number_union *numbers_p;
        struct ccs_name_union *names_p;
        const struct ccs_argv_entry *argv;
        const struct ccs_envp_entry *envp;
        u16 condc;
        u16 numbers_count;
        u16 names_count;
        u16 argc;
        u16 envc;
        u16 i;
        bool can_delete = false;
        if (!cond)
                return;
        BUG_ON(atomic_read(&cond->users) <= 0);
        mutex_lock(&ccs_policy_lock);
        if (atomic_dec_and_test(&cond->users)) {
                list_del(&cond->list);
                can_delete = true;
        }
        mutex_unlock(&ccs_policy_lock);
        if (!can_delete)
                return;
        condc = cond->condc;
        numbers_count = cond->numbers_count;
        names_count = cond->names_count;
        argc = cond->argc;
        envc = cond->envc;
        condp = (const struct ccs_condition_element *) (cond + 1);
        numbers_p = (struct ccs_number_union *) (condp + condc);
        names_p = (struct ccs_name_union *) (numbers_p + numbers_count);
        argv = (const struct ccs_argv_entry *) (names_p + names_count);
        envp = (const struct ccs_envp_entry *) (argv + argc);
        for (i = 0; i < numbers_count; i++)
                ccs_put_number_union(numbers_p++);
        for (i = 0; i < names_count; i++)
                ccs_put_name_union(names_p++);
        for (i = 0; i < argc; argv++, i++)
                ccs_put_name(argv->value);
        for (i = 0; i < envc; envp++, i++) {
                ccs_put_name(envp->name);
                ccs_put_name(envp->value);
        }
        ccs_memory_free(cond, cond->size);
}

#define CCS_MAX_HASH 256

/* Structure for string data. */
struct ccs_name_entry {
        struct list_head list;
        atomic_t users;
        int size;
        struct ccs_path_info entry;
};

/* The list for "struct ccs_name_entry". */
static struct list_head ccs_name_list[CCS_MAX_HASH];
static DEFINE_MUTEX(ccs_name_list_lock);

/**
 * 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;

        if (!name)
                return NULL;
        len = strlen(name) + 1;
        hash = full_name_hash((const unsigned char *) name, len - 1);
        mutex_lock(&ccs_name_list_lock);
        list_for_each_entry(ptr, &ccs_name_list[hash % CCS_MAX_HASH], 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, GFP_KERNEL);
        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, &ccs_name_list[hash % CCS_MAX_HASH]);
 out:
        mutex_unlock(&ccs_name_list_lock);
        return ptr ? &ptr->entry : NULL;
}

/**
 * ccs_put_name - Delete shared memory for string data.
 *
 * @name: Pointer to "struct ccs_path_info".
 */
void ccs_put_name(const struct ccs_path_info *name)
{
        struct ccs_name_entry *ptr;
        bool can_delete = false;
        if (!name)
                return;
        ptr = container_of(name, struct ccs_name_entry, entry);
        mutex_lock(&ccs_name_list_lock);
        if (atomic_dec_and_test(&ptr->users)) {
                list_del(&ptr->list);
                can_delete = true;
        }
        mutex_unlock(&ccs_name_list_lock);
        if (can_delete) {
                atomic_sub(ptr->size, &ccs_policy_memory_size);
                kfree(ptr);
        }
}

/* Lock for GC. */
struct srcu_struct ccs_ss;

/**
 * ccs_realpath_init - Initialize realpath related code.
 *
 * Returns 0.
 */
static int __init ccs_realpath_init(void)
{
        int i;
        if (init_srcu_struct(&ccs_ss))
                panic("Out of memory.");
        for (i = 0; i < CCS_MAX_HASH; i++)
                INIT_LIST_HEAD(&ccs_name_list[i]);
        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);
        if (ccs_find_domain(ROOT_NAME) != &ccs_kernel_domain)
                panic("Can't register ccs_kernel_domain");
#ifdef CONFIG_CCSECURITY_BUILTIN_INITIALIZERS
        {
                /* 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;
                }
        }
#endif
        return 0;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
__initcall(ccs_realpath_init);
#else
core_initcall(ccs_realpath_init);
#endif

unsigned int ccs_audit_log_memory_size;
unsigned int ccs_quota_for_audit_log;

unsigned int ccs_query_memory_size;
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;
}